Fullscreen HTML5Med Res (??MB)HTML4

SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents www.siliconchip.com.au Vol.18, No.9; September 2005 FEATURES   8 Adaptive Cruise Control Smart cruise controls are on the way. This new unit uses radar to maintain a safe distance to the car in front, even if its speed changes – by Julian Edgar Build your Own Seismograph – Page 26. 22 Review: iBurst Mobile Broadband Want broadband internet on the go? iBurst works at up to 100km/h, provided you’re in the right area – by Ross Tester 66 Getting The Most From Your Digital Camera Card Hints and tips from the people who invented them 88 PICAXE In Schools, Pt.4 Making things move . . . controlling motors, solenoids and even R/C servos – by Clive Seager PROJECTS TO BUILD Bilge Sniffer – Page 36. 26 Build Your Own Seismograph A horizontal pendulum detects the earthquake waves, a PICAXE-based circuit crunches the data and a PC displays the results – by Dave Dobeson 36 Bilge Sniffer Minimise the risk of boating explosions with this easy-to-build circuit. It detects all sorts of hydrocarbon fumes and can automatically turn on bilge exhaust fans when fuel vapours are detected – by John Clarke 68 VoIP Analog Phone Adaptor A $20 project that mates with your sound card and lets you use any old phone for voice over internet to save a fortune on phone calls – by Ross Tester 76 The Mudlark A205 Valve Stereo Amplifier, Pt.2 Second article has the full construction and performance details for this innovative design – by David Whitby VoIP Phone Adaptor – Page 68. SPECIAL COLUMNS 42 Circuit Notebook (1) Antenna Input & Audio Line-Out Adaptor For Portable Radios; (2) Automatic Alternate Motor Switch; (3) Filter For “Ripple Control” Mains Tones; (4) PICAXE RGB LED Display; (5) Morse Code Practice Oscillator 48 Serviceman’s Log Oh, Goodie . . . a VCR to fix! – by the TV Serviceman 94 Salvage It! Scrounging & using shortwave radios – by Julian Edgar 100 Vintage Radio The Sprague 500 multi-band receiver – by Rodney Champness DEPARTMENTS    2   4 61 62 Publisher’s Letter Mailbag Order Form Product Showcase siliconchip.com.au 105 107 109 111 Ask Silicon Chip Notes & Errata Market Centre Ad Index Building The Mudlark A205 Valve Amplifier – Page 76. ON THE COVER: the background is the aftermath of the famous 1906 San Francisco earthquake. It would have easily been detected in Australia using our do-it-yourself seismograph. September 2005  1 SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor Peter Smith Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Lawrence Smith Benedictus Smith Pty Ltd Phone (02) 9211 8035 Fax: (02) 9211 0068 lawrence<at>benedictus-smith.com Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed, Grad.Dip.Jnl Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $83.00 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip Publisher’s Letter Do-it-yourself seismograph a great project for schools This month, we are very pleased to present Dave Dobeson’s Seismograph project, starting on page 26. It is an ideal project for schools, for a number of reasons. First, it is very simple mechanically and uses a minimum of electronics to interface it to a computer (via a PICAXE) or to a data-logger. The data-logger interface is ideal because many schools do have data-loggers, often sitting idle for want of an interesting application. Well, here is one. I can imagine this seismograph built up as a class project, set up in a glass display case and permanently linked to a PC. Every morning, the students could come in, check for any seismic activity and then check the internet for the latest earthquakes around the world. Provided the earthquakes are magnitude 6 or bigger on the Richter scale, this simple instrument has a reasonable chance of recording them. They will then be able to analyse and discuss why the seismograph has recorded them or why not. If the students are into programming, perhaps they could set up the monitoring computer to send an email when an interesting signal has been recorded or maybe they could have a school web page devoted to its latest recording. I am sure that students, and their teachers, will think of other interesting possibilities. This is a wonderful opportunity for schools to interest their students in the scientific recording of day to day events. Not only will they gain some knowledge of pendulums and simple harmonic motion, they will learn about movements in the Earth’s crust and how earthquake waves propagate around the globe, so that earthquakes occurring on the other side of the world can be recorded in a classroom in Australia. Such students may go on to build other seismographs in order to be able to sense the different types of earthquake waves and those propagating from different directions. Importantly, learning about earthquakes will also give students an awareness of tsunamis, how they can occur and what the dangers are. If they are at some time in the future caught in area when a tsunami occurs, such knowledge could save many lives. And having become accustomed to the concept of data-logging, students could also move on to the regular recording of all sorts of regular events, whether it be meteorology, electricity and water consumption or whatever. Ultimately, this could give a very good understanding of many scientific concepts and that can be no bad thing. The more people understand the extreme complexities of our environment and how modern technology interacts with it, the better off we will be. Dave Dobeson is to be congratulated for his work in fostering science with his seismograph design. There are probably many more science teachers out there doing equally interesting things with their students. We would be delighted to hear from them and to promote their projects in the same way, through the pages of SILICON CHIP. Leo Simpson siliconchip.com.au Innovative • Unique • Interesting • Hard to find products What’s New? 12v Mini PC This mini bar bones PC can operate on 12v or 240v IDE RAID Controller making it ideal for use in Attach up to four IDE drives in boats or cars. A fanless design RAID, works with HD and ensures silent operation. CD/DVD. Cat. 1150-7 $699 Cat. 2886-7 $99 A PCI card that provides 48 digital I/O lines and three 16bit counters with a maximum count rate of 10MHz. Cat. 17053-7 $249 VGA Splitter 2 WAY Low Profile Printer Cards The ideal way of providing multiple duplicate displays in training rooms, stock rooms, clubs, etc. Also available in 4 and 8 way. Cat 3070-7 $259 Replace a faulty printer port or add more ports to a PC in a low profile case. Standard size cards available. Cat. 2840-7 Single $94 Cat. 2841-7 Dual $123 Dual ADSL Router Enhance reliability and double your ADSL capacity by using two different ISP's. Cat. 10145-7 $269 High Power Bluetooth Dongle A high power Bluetooth dongle with a nominal range of 100m. Compliant with Bluetooth v1.1 Cat. 11903-7 $89 USB to Parallel Allows the user to plug an older parallel printer into a USB port. Cat. 2697-7 $39 Digital I/O Card USB to Serial Analog Telephone Adaptor Interconnect a normal PSTN phone line and the Skype network for use with a standard telephone. Cat. 10169-7 $239 Car PC Designed specifically for automotive use, this car computer has a small PC case, integrated 10.4" LCD touch screen and runs on 12 Volts. It includes a 1 GHz CPU, 256MB DDR RAM and a 20GB slim anti-vibration hard drive. Optional extras include a high precision GPS engine, a high precision GPS Active Antenna and a magnetic card reader. Cat. 1162-7 $2990 Firewire B Card Firewire B is a new Firewire standard that is twice as fast as the original Firewire A. The card has two external B ports, and two legacy A ports, one internal and one external. Compatible with 32 and 64 bit PCI BUS. Cat. 2997-7 $99 Digital & Analogue TV Tuner A unique TV tuner card that Plugs into a USB port and can can receive the older provide multiple serial ports. analogue transmissions and Cat. 2828-7 One port $54 newer DVB-T digital TV transCat. 2852-7 Two port $119 missions. Cat. 2851-7 Four port $349 Cat. 3567-7 $199 CCD Barcode Scanner A good value robust scanner, great for basic POS applications. Cat. 8698-7 $269 Internet Security Router with VPN Server Provide secure connections to your traveling salesmen or wireless users with up to 100 VPN tunnels. Cat. 10164-7 $849 • Generally delivered next day • Laser Barcode Scanner Removable HD Kit This stylish laser scanner is great for small to medium sized retail outlets. A stand is available. Cat. 1008039-7 $399 An aluminium frame and tray to convert any standard IDE HD into a removable backup/storage device. Cat. 6802-7 $79 ask<at>mgram.com.au 02 4389 8444 www.mgram.com.au Windows Based Terminal VGA to TV Video to VGA 7 Port USB 2.0 Hub Display a standard VGA output on a TV or a projector with only Video inputs. Cat. 3102-7 $399 Display any Composite or S-Video signal on a CRT monitor. Cat. 3479-7 $199 Attach up to seven USB devices to the one USB port with this powered hub. Cat. 2904-7 $77 This tiny WBT can attach to the VESA mounts on a LCD monitor. It supports RDP and emulates SCO, DEC, Wyse etc. Cat. 1239-7 $649 KVM Switches Control Multiple PCs with one console (keyboard, mouse & monitor). Cat. 11654-7 2 Way $79 Cat. 11655-7 4 Way $129 Cat. 11656-7 8 Way $449 Cat. 11657-7 16 Way $799 Wireless Hotspot Allow users to access the Internet over a secure wireless link. Great for cafes, libraries, conference rooms, motels etc. Cat. 11451-7 $949 Sharp Cash Register A basic cash register that is suitable for small retail outlets. Cat 1008129-7 $289 Mini 88 key keyboard Comes with a laptop style touchpad. A great space saving replacement for mouse & keyboard. A cordless model is available. Cat. 8751-7 $139 Phone: 02 4389 8444 Dealer FreeFax: 1800 625 777 inquiries ask<at>mgram.com.au welcome siliconchip.com.au www.mgram.com.au September 2005  3 All prices subject to change without notice. For current pricing visit our website. Pictures are indicative only. SHORE AD/MGRM0905 Not sure what product you require? Call us for friendly advice! MAILBAG Solution to interference with STBs I am writing about Robert Parnell’s letter concerning electrical interference to his digital set-top box, in the July 2005 issue. I solved my electrical interference problems as follows. The glitching on my reception was quite intolerable (every few seconds), so rather than go back to analog I sought a solution – which maybe I have. I have heard a number of stories of people in my area who are not using their STB because of electrical interference. This issue of electrical interference is rapidly becoming a major factor impeding digital uptake in Australia. I put an earth stake in the ground and connected it to the antenna system signal ground, just before the distribution amplifier. It made a huge improvement and I do not have quadshield coax! One possible explanation for the improvement is that cleaning out the LF garbage in the coax braid has removed spikes that were sufficient in amplitude to drive the tuner front-end into non-linear overload. If there is any part of the VHF spectrum that you can filter, then do this. I fitted a -50dB VHF filter (Kingray DPO-UV diplexer) and this made a difference but I am lucky because all my stations are UHF-only. The best general alternative is a triplexer (Kingray FL3BPMH) that can be used to filter out all non-TV frequencies and any unused TV bands. Electrical trade wholesalers such as Lawrence and Hanson, Middendorps, Active Electronics, etc sell 1.8m copper-plated earth stakes for about $20. I located mine in the wettest part of the garden, minding any underground gas pipes, etc. This was a shade-clothed fernery with a built-in mist-spray watering system and it also happened to be close to where the TV distribution amplifier is located. I also purchased 6m of some very heavy mains (greenyellow) wire – the copper was about 5mm diameter. I soldered the wire and clamp that 4  Silicon Chip comes with the stake and soldered the other end to the shield/braid at a splitter just before the distribution amplifier. Leave out the soldering if that is too hard but it does help reduce the earth path impedance. This arrangement almost completely eliminated audio/video drop-outs, pixellation and “no signal” indications on my digital tuner. I would not recommend using the mains earth for the antenna as this is very “dirty” and makes matters worse. Those people with STBs that run extremely hot might also benefit from my clean earth idea as the problem is eliminated if you don’t have isolated TV outlets. Before I earthed my antenna it “measured” 2000V! This is fairly common, not usually dangerous and is caused by leaky TV sets but it does cause tuner modules to run very hot. Neil (via email). Interference not the only problem with STBs I read with interest the email about the digital set top box in the July 2005 edition, from Robert Parnell. Having investigated digital reception myself, and speaking to many people on the subject, I agree that the analog system is unlikely to be shut down any time soon, if ever. I believe, however, that one of the major reasons for people not switching to digital is being overlooked, that being network programming. Many people I know (including myself) are watching a fraction of the television that they used to. In fact, most of the time now the television set is off, unless I’m watching a DVD. The vast majority of what the networks try to pass off as entertainment is absolute garbage and if you have no interest in football or cricket (a significant number of people don’t, despite what the networks think), there is not much reason to turn it on. With these points in mind, why would any one bother spending money on a digital set-up? Nobody needs to see garbage in high-definition, along with channel logos and banners. Television stations have become, like most companies, only interested in pleasing shareholders. The government will have a hard time getting enough people over to digital, until the networks are made to lift their game. I would not hold my breath though. Tony Joyce, via email. Photocopying is a cost issue in schools Leo Simpson is totally correct when he registers his concern (June 2005) about the rampant photocopying that takes in a whole variety of industries. In schools, one core reason for this practice is the fact that good quality texts for the teaching of electronics to teenagers are difficult to find and some of them are ridiculously expensive, or aimed at the juvenile level (one UK book I am considering for my classes is priced at $A149!). There are heaps of electronics training manuals and more senior texts available but they don’t “talk” to teenagers. Teachers are thus forced to compile piecemeal workbook and copy masters for classroom use, adding their own teacher-speak to explain the engineering concepts in novice terms. Everybody involved in the electronics teaching industry is absolutely flat-out just teaching and can’t find the quality time required to write and publish a good affordable text for teenagers. There are some tactics SILICON CHIP could try, apart from justifiably hammering the copyright authorities. For example, I want 25 copies of the excelsiliconchip.com.au lent current series on PICs in schools. I really can’t afford to buy 25 sets of the whole series to do this. It would cost hundreds of dollars to do so and I would just be covering PICs. Perhaps SILICON CHIP could collate them and sell them as a series package and I’d gladly buy a class set. Another tactic would be to include photocopying authorisations for individual schools so that teachers who felt professionally accountable could pay a yearly fee for photocopying rights. I’d certainly be quite happy to pay a fee of $30 or so for this service. Whatever happens, SILICON CHIP needs the support of all educators in this regard if it is to remain the world class magazine that it is. Don’t photocopy SILICON CHIP! Simple! Dave Kennedy, Collaroy, NSW. Welcome to a SILICON CHIP convert I must have been in another world to have missed SILICON CHIP until now. I dragged wartime copies (WWII) of “Radio and Hobbies” out of the cellar at the Scout Hall when I was “cub”. It was still “Radio and Hobbies” when I used to borrow it from the boy next door and when I started to buy my own, it was “Radio TV and Hobbies”. I absorbed the change to “Electronics Australia” and later on, on the Council of IREE, I worked with such luminaries as Neville Williams and Neville Thiele. I had never been a very regular subscriber to “EA” or its predecessors, almost always buying it from the newsagent on a regular basis. Then I began to miss it but try as I might, I couldn’t find a replacement. Recently I have been conserving a 1930s radio chassis and my net search for bits led me to an email address for a previous “EA” staffer. Next step: SILICON CHIP! Now I am a subscriber and I have just got my first issue. I feel like I am back home! It’s a wonderful feeling. It is interesting to note that I had picked up SILICON CHIP editions twice at the newsagent but thought “Naah!” It was the list of topics on the website that showed me that SILICON CHIP is what I have been looking for and now I am back in familiar territory. Thanks – it’s a great magazine. siliconchip.com.au Ross Tester’s July article on “WiFi”, particularly his comments on page 12 about possible illegality of sharing communications with the “NDN”, brought back some interesting memories. I couldn’t help but think how legislators, once having forbidden something, are reluctant to relinquish control. Ross probably does not remember the “Wireless License” every house had to have. My mother used to freak out if the “wireless licence” was a day overdue. It was a hurried walk to the Post Office to buy a new one. Inspectors could knock on your door at any time, and they did, to check that you were not listening to an unlicensed radio. Can you imagine it? So an extension speaker across the fence to let the “poor old dear next door” keep a check on the fate of her son away “at the war” was a breach of your licence and a loss of revenue. All that has gone, and good riddance. But I suspect that only the licence requirement was revoked, with the “sharing with a neighbour” part of the Act left untouched. Ahh! – the seduction of legislative power. Max Williams, Ringwood, Vic. Atmel’s AVR, from JED in Australia JED has designed a range of single board computers and modules as a way of using the AVR without SMT board design The AVR570 module (above) is a way of using an ATmega128 CPU on a user base board without having to lay out the intricate, surface-mounted surrounds of the CPU, and then having to manufacture your board on an SMT robot line. Instead you simply layout a square for four 0.1” spaced socket strips and plug in our pre-tested module. The module has the crystal, resetter, AVR-ISP programming header (and an optional JTAG ICE pad), as well as programming signal switching. For a little extra, we load a DS1305 RTC, crystal and Li battery underneath, which uses SPI and port G. See JED’s www site for a datasheet. AVR573 Single Board Computer Using a Train Detector with Command Control Could I suggest that R.S. of Bundaberg (Ask SILICON CHIP, July 2005) have a look at the Level Crossing Detector from the March 1994 issue of SILICON CHIP? Assuming that he only wants to know where a train is, this circuit could be used by placing the Hall Effect sensors so that the exit from one section is the start of the next. Then use suitable LEDs on the track circuit board which will light and go out as the train proceeds around the track. The only problem I have with this setup is the magnet attached to the underside of the wagons (see page 43, March 1994 issue). If you use magnetic decoupling with magnets between the rails, trains come to a sudden halt at times and wagons can derail when the two magnets come together. I use miniature glass magnetic reed switches (Jaycar SM-1002) set between tracks at just below rail level and ferrite magnets (Jaycar LM-1616) cut This board uses the AVR570 module and adds 20 An./Dig. inputs, 12 FET outputs, LCD/ Kbd, 2xRS232, 1xRS485, 1-Wire, power reg. etc. See www.jedmicro.com.au/avr.htm $330 PC-PROM Programmer This programmer plugs into a PC printer port and reads, writes and edits any 28 or 32-pin PROM. Comes with plug-pack, cable and software. Also available is a multi-PROM UV eraser with timer, and a 32/32 PLCC converter. JED Microprocessors Pty Ltd 173 Boronia Rd, Boronia, Victoria, 3155 Ph. 03 9762 3588, Fax 03 9762 5499 www.jedmicro.com.au September 2005  5 Mailbag: continued in halves and suitably fixed on edge under the wagon. I am sure the Hall Effect pickups could be easily changed to reed switches. N. J. Guy, Cohuna, Vic. Coolmaster circuit not energy-efficient I am the author of the “ultra-efficient fridge” article in Jan/March “Renew” magazine, issue 90. I got your SILICON CHIP magazine and read about your “Coolmaster” freezer thermostat kit. Perhaps you and your readers may be interested in its shortcomings. (1). The “Triac” part (that switches 240V to the freezer compressor) consumes at least 0.85W for 24 hours; ie, about 20 watt-hours per day when the fridge becomes connected to its socket. (2). The “plugpack” that you suggest using to power the 9V electronics, if carefully chosen, will consume about 1.7W for 24 hours; ie, about 40 watthours a day. Hence, the power consumption of your thermostat alone (with fridge connected but not working) is about 60Wh a day. Now, you may remember that the entire fully working fridge with my thermostat consumes only about 100Wh a day. Can you see how mediocre your thermostat really is? It seems that you have never been exposed to living with limited energy resources. You haven’t even noticed the challenge of zero-standby power consumption. The thermostat that I currently use for my fridge has zero standby 240V power consumption, essential for power-sensing inverters and people who can use every bit of saved energy that they generate. It consumes about 70mA from a NiMh battery to monitor the fridge temperature and has a built-in fast battery charger that tops up the battery when the compressor is turned on (about two minutes per hour), so that the entire system can work for many years on one battery. Please let me know if you are inter6  Silicon Chip ested to publish, test or improve my version of the thermostat. Dr Tom Chalko, Senior Scientist, Scientific Engineering Research Pty Ltd, Mt Best, Vic. Comment: it is true that the Triac does dissipate about a watt but only when it is turned on and since it is in series with the fridge, it does not add anything to the overall power drain. As far as the plugpack is concerned, it does draw power constantly as you say but our approach was intended to enable readers to easily convert a fridge without having to modify its internal wiring. As such, it can be changed back to normal operation at any time. Our circuit was designed in the knowledge that many people have unused refrigerators or freezers and these can be converted, to wine-coolers or fridges respectively, as outlined in the article. It was not intended to be ultra-efficient as your approach undoubtedly is, although our approach does substantially reduce the power consumption of any fridge. Odd Panasonic S-video behaviour We recently sold a popular infrared remote-controlled AV switcher to a customer at Glen Innes for the purpose of switching audio and S-video from his DVD player, digital STB and satellite STB, to his Panasonic TX-68P100Z which is a large flat-screen model about four or five years old. All these sources worked just fine with the Panasonic on an individual basis but with the switcher in circuit the customer reported that the set would automatically switch to 16:9 format and stubbornly refused to stay put at 4:3. I tested a sample switcher before offering them for sale and am aware of a DC offset on all the video outputs (composite, luma and chroma) of about 0.5V across a 75W load. It seemed to me that this DC offset might be the culprit but why? I made a little box with two S-video connectors and isolating capacitors (470mF non-polarised) in series with the luma and chroma and sent it off. It didn’t work as expected though. The format switching stayed at 4:3 but the picture was now unwatchable, with gross distortion and oversaturated colour. How bizarre! I contacted Panasonic at Belrose and a few emails flashed back and forth to an engineer there. Apparently, the set has an automatic format switching feature which is controlled by a DC offset on the chroma signal. I was unable to extract any specific information about this feature which Panasonic refer to as “S2 switching” and I was also unable to find out if there are any other features controlled in a similar manner (are there S1/S3/Sx?), the voltage levels, pulse widths, etc. Perhaps the Panasonic service manual has some details (who knows?) but I was not inclined to spend the money to find out. I think that Panasonic could make such information readily available. We technical types need to know about “features” like this. The engineer did reveal that they requested the feature, apparently popular in Europe, be disabled in Australian sets but the cost for modified versions was too great. Anyway, I retrieved the box from Glen Innes, connected the Y (luma) signal straight through, put a 100nF MKT capacitor in series with the C (chroma) signal and sent it back to our customer who reported a success! This was because, as you would know, the chroma is a symmetrical AC signal at 4.43MHz (or 3.58MHz for NTSC), so the average DC level is 0V but what about the luma? What about AC-coupled outputs? Why did the Panasonic set totally lose control of AC-coupled video? Surely they clamp the luma. Do they use the luma for any tricky controlling? I dunno! The problem is this: I see DC offsets on the outputs of a lot of recent equipment from Asia. I guess they are unaware of this S2 switching feature too. The engineer at Panasonic did tell me that other manufacturers have the same features in their equipment, citing Sony, Philips, NEC, and Toshiba as examples. He likened it to the fast blanking used in SCARTs but that is a different sort of feature as far as I siliconchip.com.au know, used for keying in RGB graphic overlays such as external teletext or picture-in-picture, etc. Maybe there is that sort of functionality but I can’t seem to find anything on the web or in my reference books. There are implications for manufacturers of active switchboxes and Right and wrong way to wire a 3-pin plug I was studying the photographs on page 42 of the Coolmaster article in the June 2005 issue and I noticed that the socket has been wired at the wrong end of the cable. It appears to me that the Neutral/Earth conductors are crossed, even though the socket is no doubt wired correctly. It is the lay of the cable that is my real concern. To demonstrate, I have made up two short extension leads which have correct and incorrect (“wrong” end of cable) cable lay. Both are wired in accordance with the details provided by HPM. Please note that in the “correct lay” extension cable, none of the distribution amplifiers, etc. Maybe the TV servicing fraternity may be aware of the details. There might even be scope for a project that exploits these features. I know I would be fascinated to find out about it. Joe R, via email. conductors “crosses” any of the others to reach their correct positions on the plug top or socket. Also, note the distance (2-3mm) from the opaque plastic of the plug/top socket to the other insulation of the 3-core cable. I had no difficulty in making the connections and assembling the plug top and socket. Ray Smith, Hoppers Crossing, Vic. Comment: you make an interesting point and one that we have not considered before. While it makes no difference to plug safety it possibly does make the job of wiring plugs and sockets a little easier – and it looks neater! XL-02 Quality Speaker Kits sound advice call 08 8295 4271 or visit our website www.kitaudio.com prices start from $995.00 (also available fully assembled) Ozitronics www.ozitronics.com Tel: (03) 9434 3806 Fax: (03) 9011 6220 Email: sales2005<at>ozitronics.com Stepper Motor Drivers Ideal for use with Serial Stepper Motor Controller kit featured in July SILICON CHIP UNIPOLAR motor driver 8-30VDC <at> 6A. PCB: 80x50mm K179 - $24.20 See also K109 - $30.80 This is the “wrong” way to wire a 3-pin mains plug & socket. Here, the plug and socket have been wired to the wrong ends of the cable, so that the wires have to cross each other to reach their correct terminals. BIPOLAR motor driver 8-30VDC <at> 6A max. PCB: 75x85mm K158 - $28.60 Prices include GST – shipping extra. Full documentation available from website. And this is the correct way – by reversing the direction of the mains cable, the Active, Neutral & Earth wires can be run to their correct terminals without crossing each other. siliconchip.com.au September 2005  7 Car cruise controls that use radar to maintain pace with the car in front! By Julian Edgar Adaptive Cruise Control Systems Cruise control systems have been available in cars for many years. However, a new type of cruise control is now being fitted. It’s called “Adaptive Cruise Control” and it uses radar to maintain a safe distance to the car in front, even if that car’s speed changes. O n the road, it’s a brilliant innovation that improves safety, reduces fatigue and adds convenience. But how does it work? Intelligent cars The last decade has seen the widespread introduction of systems than enhance car intelligence. Anti-Lock Braking (ABS) and Electronic Stability Control (ESP) give the car the ability to 8  Silicon Chip act in ways not specifically requested by the driver – for example, to release the brakes momentarily to prevent wheel lock-up or to reduce throttle opening if the car is sliding. Adaptive Cruise Control is another step on that road to enhanced intelligence – Fig.1 shows where it is on the path that leads to full collision avoidance. The presence of systems like ABS and ESP means that many of the input signals needed by Adaptive Cruise Control are already available. These include: • vehicle speed • vehicle lateral acceleration • driver accelerator input • driver steering input • driver brake input However, not present is the most critical of inputs – a forward-looking sensor. siliconchip.com.au Product Collision Avoidance Collision Warning Lane/Road Departure Forward Collision Warning Adaptive Cruise Control Cruise Control Future System Functionality Complete 360° vehicle coverage. Braking and active steering to avoid object. Lane keeping. Improved all-vehicle coverage (forward, side, rear) with full alert function. Partial all-vehicle coverage, with lane/road departure alerts. Vision required. Identify stopped objects. Provide warning. Provide “Braketo-Stop” and “Low Speed Cruise/Stop and Go” ACC capabilities. Vision required for advance alert features. Provide throttle control with limited braking to maintain timedheadway distance. No stopped object identification and no warning. Drive controlled system. No dynamics. Today Fig.1: Adaptive Cruise Control is seen by many as the first evolutionary step towards intelligent cars that actively avoid crashes. [Delphi] Forward-looking sensor characteristics An Adaptive Cruise Control (ACC) forward-looking sensor must meet certain strict design requirements. 1: Range – In order that an appropriate following distance can be maintained, the sensor must be capable of working over a specific range. For example, if the following distance is defined in terms of time gap between the two vehicles, a 2-second gap at 160km/h will require the distance between the vehicles to be about 90 metres. However, in order that the sensor can maintain continuous control, the actual required sensor range will be about 10% greater than this. So if the maximum speed required of the ACC is 160km/h, a sensor range of about 100 metres is the minimum requirement. This diagram shows how Adaptive Cruise Control works from a driver’s perspective. In the first image the blue car is travelling at 115km/h and the green car behind it has its cruise control set to 140km/h. As the green car draws close to the blue car, the Adaptive Cruise Control radar senses the blue car’s proximity and automatically slows the green car until it maintains a constant, safe gap. When the blue car turns off, the green car smoothly resumes its 140km/h cruise. (You can tell these diagrams are from Germany – sitting at 140km/h on cruise control in Australia? Other than in the Northern Territory, we wish!) [Bosch] siliconchip.com.au September 2005  9 Control units for engine, transmission and ESP Instrument cluster with DISTRONIC display Proximity sensor (radar aerial) Adaptive Cruise Control interfaces with existing car systems like Electronic Stability Control (ESP) and Anti-Lock Braking (ABS). An electronic throttle is also normally used on cars equipped with this type of cruise control. [DaimlerChrysler] Cruise control lever Control unit for DISTRONIC 2. Closing Rate – the sensor must be able to rapidly detect that the car ahead is being closed upon. If the sensor is slow to react, a greater range will be required otherwise the following car will draw too close before throttle reduction or braking occurs. The magnitude of permitted braking will also affect this requirement; if the car is permitted to brake hard then the sensor can be slower to react. Assuming a maximum automatic braking deceleration of 0.2G, a maximum closing rate of 50-65km/h and Brake booster a minimum following distance of 2030m, a sensor range of 80-100 metres is again a minimum requirement. 3. Field of View – the field of view (FOV) of the sensor can be defined both in terms of azimuth (left/right) and elevation (up/down) angles. The azimuth FOV is important if the system is going to be effective at working on curves. As Fig.7 shows, beam width has a major affect on the distance at which a cornering car can be tracked. At a speed of 90km/h the ACC following distance will be about 50 metres. 100 A 1 2 Control on centre console 3 B SIGNAL AMPLITUDE SIGNAL AMPLITUDE RATIO 10 1 Radar sensors 2/1 0.1 3/2 3/1 0.01 – 0 ANGLE + –8° –4° 0 ANGLE 4° 8° Fig.2: the antenna patterns of the Bosch Adaptive Cruise control radar sensor. Three lobes with overlapping patterns are used, with the angular position of the sensed object determined by comparing the signal amplitude ratios between antenna pairs. (a) shows the antenna patterns with (1) being the left lobe, (2) being the centre lobe and (3) the right lobe. In (b) the relationship between the amplitude ratios and the angular position of the object are shown. [Bosch] 10  Silicon Chip Assuming a minimum radius-ofcurvature of 300 metres, a minimum sensor FOV of 5° is required. However, additional FOV is usually needed to take into account mechanical or electrical misalignment of the antenna – a point that we will return to. In addition to these three requirements, the sensor must be able to withstand a temperature range of -40 to +80°C, be proof against water splashes and pressurised steam, be immune to vehicle vibrations, resist stone impacts and be as small as possible. Two types of forward-looking sensor have been developed – lidar (light detection and ranging) and radar (radio detection and ranging). However, the radar-based sensor is the most widely used and it is this type of sensor that will be covered here. Two types of radar sensors are used – those with stationary antennas and those that mechanically sweep back and forth. US automotive components manufacturer Delphi has developed a scanning sensor with a narrow 2° beam-width. This beam is mechanically swept over a 15° detection region and has an elevation FOV of 4°. As the siliconchip.com.au Range 2 – 120m Detectable relative speed ±50m/s Angular range ±4° Resolution 0.85m; 1.7m/s Scanning rate 10Hz Frequency range 76 – 77GHz Mean power transmission Approx. 1mw Bandwidth Approx. 200MHz Fig.3: the specifications of the radar sensor used on Bosch Adaptive Cruise Control systems. [Bosch] antenna is scanned, over 40 individual transmit/receive beams are executed with each pass. Beam object data is updated within 100ms. However, much more common is a sensor that has a fixed antenna. The Bosch system (used by DaimlerChrsyler, BMW and Audi) uses this approach. The Bosch system uses a Frequency Modulated Continuous Wave (FMCW) output. Instead of timing the period between transmission of the signal and the echo, a FMCW radar system compares the frequencies of the transmitted signal and its echo. The output frequency is changed at a rate of 200MHz per millisecond and so the time interval between the transmit and receive signals can be Fig.4: a sectional view of the Bosch Adaptive Cruise Control unit, which incorporates both the radar and the control circuitry. (1) Circuit board 1, (2) Oscillator block, (3) Beam sources, (4) Lens, (5) Lens heater contact, (6) Circuit board 3, (7) Circuit board 2, (8) Radar Transceiver. [Bosch] siliconchip.com.au Different car manufacturers give different names to Adaptive Cruise Control Systems – DaimlerChrysler calls the system ‘Distronic’. This Distronic system is mounted directly behind the Mercedes star in the grille. [DaimlerChrysler] established by determining their frequency difference. However, because the distance between the transmitter and its target may be changing, this differential frequency information contains not only the time interval component but also the frequency shift (ie, Doppler component) . This ambiguity can be resolved by the use of multiple FMCW cycles using differing rates of frequency change. Using these techniques, the distance to the target and whether the target is The location of the Adaptive Cruise Control radar sensor on a BMW. [BMW] September 2005  11 DETECTION SENSOR (RADAR, LIDAR) VEHICLE SENSOR (YAW RATE, SPEED) OBJECT DETECTION MULTI-TARGET TRACKING Fig.5: the signal processing architecture of a typical Adaptive Cruise Control. Once the objects are detected, tracking needs to occur. Both their paths and also the path of the controlled vehicle are estimated, the input commands of the driver are noted and the ACC controls the throttle and/or brakes. [Delphi] drawing closer or moving further away can be established. However, some spatial data is also needed – is the target directly ahead or to one side of the forward aim? If the target’s radar reflective characteristics are known, the amplitude of the signal echo depends on the angle at which the signal is received by the radar. However, when the reflective characteristics of the target are unknown, a different approach needs to be taken. To determine the angle at which the radar detects an object, three radar lobes are transmitted and analysed. The ratio of the signal amplitudes of the three different lobes provides this angular information. Fig.2 shows the antenna lobe patterns and how signal amplitude ratios are used to resolve the angular position of the targets. Fig.3 shows the specifications of the Bosch ACC radar sensor. The Denso system used in Toyota/ Lexus models uses a more conventional type of radar. Distance is detected by measuring the time between transmission and reception, while relative speed is detected by the frequency shift (Doppler Effect) of the reflected waves. The angular position is detected by the phase differences of the signals received by multiple antennas. The Denso unit also differs from the Bosch design in that it has separate receiving and transmitting antennas (although all the antennas are mounted in the one assembly). The physical layout of the Bosch radar sensor is shown in Fig.4. The radar and the ACC controller are integrated into one housing. The front of the unit features a Fresnel lens that is used to focus the three radar lobes. The lens is made 12  Silicon Chip HMI ALERTS (VISUAL, AUDIO) PATH ESTIMATION ACC CONTROL ACTUATOR CONTROL (THROTTLE/BRAKE) HMI DRIVER COMMANDS (TIMED HEADWAY, ETC) from a special temperature and stoneresistant plastic which is formed as part of the module casing. The lens incorporates a heating element which prevents it becoming coated in snow or ice. According to Bosch, wet snow has a great attenuating effect on the radar signal. In one iteration of the Bosch design, the sensor assembly comprises three circuit boards. The first consists of the radar transceiver unit which is mounted directly on a circuit board, keeping interconnections as short as possible and so reducing susceptibility to interference. Also on this board is a digital signal processor, purposedeveloped 10-bit and 12-bit analog to digital converter, SRAM and flash memory. On the second board is a 16-bit microcontroller which performs the necessary car speed control calculations. The third board contains the driver modules to allow connection to the car’s electrical and CAN bus communications systems. The module must be aligned in both vertical and horizontal planes. In the horizontal plane Bosch state that a degree of accuracy of better than 0.3° is required, while BMW put the figure at 1° and Cadillac at 2°. The BMW system requires the use of a BMW service tool to perform the alignment, while Cadillac systems can be placed in an ‘alignment mode’ and then automatically aligned by being driven along with a road that has stationary objects either side. Apparently, the more stationary objects (such as light poles, mail boxes, etc) there are, the quicker the alignment occurs. How the system works It is all very well to detect the presence of cars in front but how is it The complexity of the technology of Adaptive Cruise Control systems currently limits them to expensive cars. However, expect a trickle-down to more humble cars to occur in the near future. [DaimlerChrysler] siliconchip.com.au The instrument panel of a BMW using Adaptive Cruise Control: (1) the set cruise control speed, (2) indication that the vehicle ahead is being tracked, (3) indication of the driver requested car-to-car spacing, (4) an indication that the cruise control system is on. [BMW] determined whether the car is in your lane or another? What about when cornering? And what happens when a car cuts into your lane? Fig.5 shows the signal processing architecture of a typical ACC. Once the objects are detected, tracking of them occurs. Both their paths and also the path of the controlled vehicle are estimated, the input commands of the driver are noted and the ACC controls the throttle and/or brakes. In the Bosch FMCW system, positive detection of objects is carried out by comparing consecutive radar modulation cycles. If in the second cycle the object is found where it could be expected to be (on the basis of its previously detected speed and position) it is assumed to be the same vehicle. In other words, the object data is filtered on the basis of historical information. Additional object tracking functions are carried out where there are multiple simultaneous echoes from different distances, which can be the case with large trucks. In this situation the multiple echoes are combined so that the system sees only one object. Object selection occurs in this manner: 1. The lateral position of the object versus the predicted course of the ACC system’s own vehicle is calculated. 2. A calculation is made of the object’s “lane probability”, that is, which lane the object is most likely to be in. 3. Lane probability is a main input into the next step, that of a “plausibility attribute”. Together with the frequency and reliability of object detection, this determines the degree of plausibility that the detected vehicle is in the same lane as the ACC car. 4. The object is selected as the target only if the degree of plausibility is sufficient. This plausibility is based only on moving objects – ACC systems ignore stationary objects when selecting targets. The first step – that of locating the object relative to the predicted course of the ACC car – is most critical. Fig.6: if the trajectory of the car equipped with Adaptive Cruise Control cannot be accurately preA dicted, the system will have problems on corners. Here there are three cars travelling around a curve on a multilane road. Car 3, the car equipped with the ACC, is at the bottom of the diagram. Without an ability to accurately model the predicted course of the ACC car, the system would expect to follow course B and therefore sense car 2 as being ahead of it in its lane. However, the ACC car will actually follow course A and so must sense car 1 as being ahead of it. [Bosch] siliconchip.com.au κ B  1 2 d YC d RANGE   2 α RANGE 3 ACC ACC 1 Fig.7: the effective range of the radar beam is much reduced in corners. This has implications for the required radar beam width and also for the behaviour of the system should it lose sight of the car ahead. [Bosch] September 2005  13 The radar sensor jointly developed by Denso and Toyota uses a different design to the Bosch unit. The transmitting and receiving antennas are separate (although in the one package) and use pulsed output transmissions. [Denso] The Bosch Adaptive Cruise Control system incorporates the radar and control circuits into the one enclosure. Dominating the package is the Fresnel lens which focuses the three beams of the radar. [Bosch] Fig.6 shows three cars travelling around a curve on a multi-lane road. Car 3, equipped with ACC, is at the bottom of the diagram. Without an ability to accurately model the predicted course of the ACC car, the system LEVEL 1 LEVEL 2 RADAR DATA would expect to follow Course B and therefore would sense Car 2 as being ahead of it in its lane. However, the ACC car will actually follow course A and so must sense car 1 as being ahead of it. WHEEL SPEED SENSOR YAW RATE SENSOR RADAR OBJECT DETECTION DETERMINATION OF COURSE CURVATURE LEVEL 3 OBJECT SELECTION COURSE PREDICTION, TRACKING LEVEL 4 ACC CONTROL LEVEL 5 LINEAR SPEED CONTROL LEVEL 6 OTHER SENSORS ENGINE MANAGEMENT DRIVE TRAIN ACTIVE BRAKE INTERVENTION Fig.8: the Bosch Adaptive Cruise Control uses the 6-level control sequence shown here. The first level is the input of data from the radar, wheel-speed sensors, yaw sensor and other sensors. The second level is to identify any moving objects ahead of the car and assess their plausibility of being in the same lane. Once this has been done, the system can calculate the projected trajectory of the Adaptive Cruise Control car and track and predict the course of other vehicles. A target vehicle is established and the required acceleration calculated. The actuation system by which the car’s speed is to be changed is selected (it can be throttle, brakes or transmission) and then finally, this control is exerted. [Bosch] 14  Silicon Chip Course prediction is based on the “trajectory curvature”. That is, the change in direction that the car is undergoing as a function of the distance travelled. This is determined by sensors detecting steering angle, lateral acceleration, yaw and the difference in left/right wheel speeds. The effect of crosswinds, road camber and differences in wheel diameters can all reduce trajectory curvature prediction. Combining the techniques reduces the probability of error. In addition, the ACC system can use the current and past positions of stationary and moving objects to determine the projected course of the car. This can be carried out by analysing the apparent lateral movement of vehicles in front as they enter a bend and analysing near-road stationary objects. Special logic is used in sharp bends. If it is sensed that the car is negotiating a sharp bend, a reduction is made in the maximum permissible acceleration (note that in this context, acceleration also refers to deceleration), so as to maintain vehicle stability. Secondly, as Fig.7 shows, the effective range of the radar beam is much reduced in corners and so the ACC modifies the allowable acceleration to suit this reduced “visibility”. Finally, if the target car disappears from view, logic prevents the ACC vehicle from suddenly speeding up. The Bosch ACC uses the 6-level control sequence shown in Fig.8. The first level is the input of data from the radar, wheel-speed sensors, yaw sensiliconchip.com.au Driving with Adaptive Cruise Control In order that the car reacts adequately quickly to a changed situation but at the same time avoiding uncomfortable braking or acceleration if it is not essential, a non-linear control system is employed. This causes changes in relative speed (eg, a rapid closing speed) to produce a greater reaction than changes in distance. On the road We were able to spend some time with the Audi A8 4.2, a car that features Bosch Adaptive Cruise Control. And what was it like? In a word, brilliant. We didn’t have a chance to test it on tight, winding country roads but in freeway conditions it was superb. Speed selection is available only in 10km/h increments – which is fine when you no longer need to ‘tap-up’ and ‘tap-down’ in tiny increments, trying to maintain a constant gap to the car in front. As you would expect with a system that maintains a constant time gap, at slow speeds the Audi would creep up on the car in front and at higher speeds it would drop back; all automatically, of course. If the car ahead slowed abruptly, the Audi would automatically apply the brakes – and if it was deemed by the system to be an emergency stop, an audible alarm sounded and you were expected to brake. A green symbol showed on the instrument display when the car in front was within the minimum safe distance – and this changed to red when driver braking was needed. Describing the system in step-by-step detail makes it sound more cumbersome than it really is. This is literally a set-and-forget system – on a drive from Sydney to Canberra or Melbourne, it would be simply awesome. If the price of the technology drops as it has for other car innovations, we’re happy to go on record and say that in the foreseeable future – say, in 10 years time – all cars with cruise control will have a radar proximity function. It just works so well…. Most cars equipped with ACC use a similar driver interface. The selected cruise speed is shown by an illuminated segment or LED on the speedometer. The selected gap spacing is shown diagrammatically on a dot matrix or TFT display – for example, by the spacing between two car symbols. When the ACC is tracking a car, another symbol illuminates on the dashboard display. In this way, the requested and actual vehicle speeds, the requested gap and the tracking action of the ACC can all be quickly and easily seen. Current ACC systems are suitable for use primarily on freeways and open rural roads. They will not brake a vehicle to a standstill, even if the vehicle is aimed straight at a roadside obstacle. Furthermore, if the traffic ahead is stopped, an alarm may sound but again the vehicle will not be emergency braked. Such collision avoidance systems are in the pipeline but as was remarked at the beginning of this story, ACC is only the first step on that road. However, it’s a pretty impressive SC step… Which Cars? sor and other sensors. The second level is to identify any moving objects ahead of the car and assess their plausibility of being in the same lane. In this step the data from the other car system sensors is assessed to determine the degree of curvature of the road. Once this has been done, the system can calculate the projected trajectory of the ACC car and track and predict the course of other vehicles. A target vehicle is established – normally it will be the one calculated as being ahead of the ACC car in the same lane. However, this is not always the case: if vehicles ahead of the ACC car (or the siliconchip.com.au ACC car itself) change lanes, a group of several possible target vehicles can be considered. The next step is the calculation of the required acceleration. The actuation system by which the car’s speed is to be changed is selected (it can be throttle, brakes or transmission) and then finally, this control is applied. The driver has control over two functions: the set speed and the distance to be maintained between the ACC car and the car ahead. As mentioned earlier, the distance is set by means of a requested time gap which is generally in the range of one to two seconds. Cars fitted with Adaptive Cruise Control are currently limited to the upper echelons. A brief world list includes: Audi A8 (2004 - current), BMW 7 Series (2003-current), BMW 5 Series (2004 - current), General Motors Cadillac XLR (2003 - current), Nissan Infiniti Q45 (2003 - current), Jaguar XKR (2003 - current), Lexus LS430 (2004- current), Lexus GS430 - current), Mercedes-Benz S Class (2000 - current), Mercedes Benz CL Class (2000 - current), Mercedes Benz E Class (2003 current), Mercedes Benz SL Class (2003 - current). September 2005  15 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au We test by Ross Tester iBurst Mobile Broadband We looked at Unwired a year ago. Now we look at the opposition! H aving now obtained a reasonable amount of experience with Unwired’s wireless broadband offering, we were given the opportunity to test their opposition recently. iBurst sent us one of their “mobile” broadband modems to evaluate. They call it a Personal Broadband Access Card. iBurst actually have two types of wireless broadband modem. The first is designed for fixed systems, not too dissimilar to that offered by Unwired (however, they are certainly not interchangeable as they use different technologies and frequencies – iBurst is on 1.9GHz where Unwired is on 3.5GHz). However, the one which made us sit up and take note was something that Unwired don’t offer – a model designed for laptops and notebooks, claimed to not only offer a completely mobile system but one which could actually be used when mobile – according to iBurst at speeds in excess of 100km/h! The laptop/notebook modem takes the form of a PC-card (once called PCMCIA) which simply slides into a type-2 PC card slot. There is nothing else to connect. Also on this section are a pair of LEDs – one shows power while the The iBurst mobile modem fitted to the PC slot of an IBM notebook. You can have a notebook with both iBurst and WiFi as they are on different frequencies. other (with an antenna logo) shows signal strength with different LED colours showing good (green), marginal (orange) and poor/non-existent (red). Our experience was that you really had to have a green to have any real reliability. But we’re getting a bit ahead of ourselves. Finally, there is an integral antenna. I’ll have a little more to say about this later as well! Installation One of iBurst’s selling points is its quick and easy installation. “Under three minutes”, they claim. Was it? Yes . . . and no! Installation certainly took a very short time – run This page: the iBurst coverage maps (l-r) for Sydney, Canberra and Brisbane. Sydney is fairly well covered, except for great slabs of the north, northern beaches, and outer west. Unwired has a better coverage of Sydney but iBurst also covers other cities where Unwired has yet to start. 22  Silicon Chip siliconchip.com.au The iBurst mobile (laptop/notebook) PC-card modem. The folded-down antenna is hidden along the back. the software, plug in the card when requested, then log on. Except that I couldn’t log on, which sort of made the whole experience just a bit less than satisfactory. When we looked at Unwired, we made the comment that the Northern Beaches of Sydney (while it is God’s country!) is still a telecommunications backwater. And unfortunately, that’s where the SILICON CHIP offices are (as are most of the staff). Depending on where you are, television signals range from good to virtually non-existent. FM radio suffers from multipath and other interference. Even good ol’ AM radio can be plagued by noise and poor signal strength. ADSL is Similarly, here’s the current coverage of the Gold Coast (above) and Melbourne. iBurst admit they have a long way to go – but they’re working on it! siliconchip.com.au often unavailable due to the distances between telephone exchanges and customers – and cable hasn’t quite made it to many areas. All this around 15-20km from the coat hanger! And so it is with iBurst. According to the red areas (good signal) on their coverage map (published elsewhere in this feature), they look after Sydney city, the north shore, eastern suburbs and a good part of the west pretty well. But check out the Northern Beaches: most of it is green – meaning no go (actually it means “planned”, as in sometime in the future. It’s been that way since iBurst was introduced last year!). However, one particular area is all red – Collaroy Plateau. For those who don’t know Sydney, this is an elevated area with good line-of-sight in most directions, including the City. So most of my initial testing was done sitting in a carpark on Collaroy Plateau. Unfortunately I don’t have a car charger for my notebook so this necessitated several trips home to charge the battery. The first time I installed iBurst everything went perfectly, except for one minor detail: it didn’t work at all. “No signal” it said. “No modem”, it said. I tried reseating the modem, just in case – but no go. After an hour or so, I gave up in frustration (actually the battery gave up!) OK, what next? I was loathe to ring iBurst because I’m a technical person and I should be able to follow simple instructions, right? So I tried again. Still no go. Could it be a software problem? I decided to un-install the software from my notebook and re-install it. This time I did it in the carpark where there should be plenty of signal – and lo and behold, it did install properly – and worked. And from go to whoa, it did take about three minutes. Why didn’t it work the first time? Dunno! Put it down to the vagaries of computers! (I’m not going to admit it might have been the nut on the keyboard, am I?) The test The iBurst control panel tells you quite a bit of useful information, such as whether you are connected or not, the relative signal strength, packets sent and received, and so on. It’s a useful addition to the red/orange/green signal strength LED on the modem itself. Our test modem came direct from iBurst (actually, their PR company) so I didn’t have the hand-holding that you would get with, say, Dick Smith Electronics or one of their other “channel partners” (don’t you just love the buzz words? No? Neither do I!) At the suggestion of the PR company, I logged onto another iBurst distributor, Chilli Internet Solutions (www.chilli. net.au.) Their website contains a significantly better coverage “map” than does iBurst itself – you enter the required location (down to street name and number) and it will tell you whether iBurst is available at that particular spot – complete with hi-definition maps. It was here that I found out that NOT all of Collaroy Plateau is covered. I also found that an area, which the iBurst map suggested was not covered, was! But there was something else I had completely overlooked. I had simply plugged the iBurst modem into the PC slot, as the instructions suggested. But then I noticed a couple of photos on the Chilli site showed a little vertical antenna. “Bugger!” I thought “the PR company has forgotten to send me the antenna”. But then real close examination showed that it was integral with the modem and just required unclipping and turning through 90°. Talk about embarrassing! Armed with this information, I went driving (remember, iBurst mobile is guaranteed to be just that, mobile). With my trusty notebook on the front seat, I logged on to a site with free streaming video (OK, I admit it – Big Brother Live Cam! Of course, this was for purely scientific research purposes). All I can say is – it worked. Anywhere that the Chilli site suggested I September 2005  23 Chilli Laptop Modem Speed Download Limit 512/128k 300MB 1Mb/345k 500MB 1Mb/345k 1GB 1Mb/345k 3GB 1Mb/345k 10GB Monthly Price $49.95 $64.95 $99.95 $129.95 $199.95 Chilli Desktop Modem Speed Download Limit 256/64k 200MB 256/64k 400MB 512/128k 400MB 512/128k 1GB 1MB/345k 1GB 1MB/345k 3GB 1MB/345k 10GB Monthly Price $29.95 $34.95 $44.95 $59.95 $64.95 $79.95 $189.95 Chilli’s current iBurst plans for both the laptop modem we featured here or the desktop modem. There’s also a once-only contract charge ranging from $66 to $129 and if you exceed your download limit, you either pay extra or have it “shaped”. could get signal, the streaming video didn’t miss a beat. Signal strength stayed up in the 60+ area. I cannot confirm the 100km/h claim – there’s nowhere I can legally drive that fast in the local coverage area. I had already checked out iBurst at my own place – absolutely nothing (no surprise there). Next I drove down from the high plateau into an area which should have been non-existent, according to iBurst, and patchy, according to Chilli. That’s exactly what it was – patchy. Most of the time it was pretty good but there were places where the signal did momentarily drop out – but usually it reconnected pretty quickly. There were places where I didn’t expect signal – and got it. And there were places, outside the acknowledged coverage area, where connection disappeared completely, as expected. Remember, this test was being done at what would have been called “deep fringe” in TV signal parlance. You’d expect to need a good antenna system to get any signal – but this thing is just a tiny (53mm) whip antenna on a modem in a laptop on a car seat – hardly the best reception environment. I have read all the testimonials from very happy and satisfied iBurst/Chilli customers, about how well it works in the inner city, west, north shore, et al. Fine – all of those areas should be wall-to-wall. I’d be disappointed if it didn’t work there after all the claims made. But for it to work as well as it did at the very edges of expected signal – and even beyond – I have to say I am impressed with its performance. How much? For this sort of flexibility, it’s not unreasonable that you would have to be prepared to spend a little more than your typical ADSL/Cable (ie wired) system. iBurst/Chilli maintain that it’s about the same – that’s advertising talk for both prices starting with a dollar sign. First of all, the modem itself: the mobile version we tried will set you back $299. As we mentioned before, there is a fixed version (but still wireless, along the lines of Unwired) for $199.00. There is also an “activation charge” which, depending on the length of contract you take out, ranges from $66 (12 months) to $129 (no contract). We looked at the Chilli website to find plan prices – plans from other providers are pretty much identical (in fact, many on-sell Chilli plans). We’ve shown the Chilli plans for both fixed and mobile. As you can see, they aren’t as cheap as most broadband (ADSL/Cable) plans available these days. In fact, their top-of-the-line mobile plan, 1Mbs download, 345Kbs upload, 10GB download limit before shaping or excess charges, is a not inconsiderable $199.95 per month. To counter this, iBurst claim that their speed is maintained at a much higher level than ADSL/cable and are even promising speeds of 2Mbs next year and 8Mbs by 2008. That’s fast! Summary Is iBurst for you? If you have a laptop/notebook and don’t want to be tied to a wired modem, obviously. It really is convenient. Even if you have a desktop PC and don’t want to (or cannot) connect to ADSL or cable AND you’re in the coverage area, iBurst could be the answer. One feature/benefit iBurst point out is that with this system, you can get rid of your fixed telephone and make all your calls VoIP calls. The thirty bucks or so a month that the phone rental costs you could be put into a better broadband plan. With the VoIP offerings available these days, that too makes perfect sense, especially if you’re one of Australia’s more “mobile” population. You could even use a mobile phone for incoming calls and iBurst+VoIP for very low-cost outgoing calls. Gives you something to think about! And finally, a plea, albeit a selfish/ parochial one: please, Mr (or is it Ms?) iBurst. Can you PLEASE do something about coverage on the Northern SC Beaches? Reader Feedback on “Unleashing Unwired” I have some feedback for you on the “Unleasing Unwired” article that featured in the July 2005 issue. Firstly, I would like to congratulate Ross Tester on an informative article. I would like to let everyone know that there is a diagnostic program available from Navini, the people who design and manufacture the infrastructure that Unwired uses. Navdiag gives you a whole hoard of information, such as received signal strength, SNR, which antenna currently in use, distance to current base station in meters, 24  Silicon Chip amongst many other parameters. Anyway the software is available for download at:- http://www.navini.com/downloads/ Support/navdiag_windows.exe Note that if you are behind a router or firewall, you will need to directly attach a PC to the Unwired modem to run this software. There is a ‘hidden’ advanced mode that is available in the software which gives far more detailed infomation on the status of the modem. Press Ctrl+Shift+F10 to activate this feature. One thing I really like is the fact that it reports the current BTS id number. (BTS is Navini-speak for Unwired base station) For instance, I can see that the BTS I connect to is number 200352. You can then go over to www.ozunwired. com where there is a list that tells you which BTS id is which base station. I hope you guys find this utility as useful as I have in tinkering with external antennas on Unwired. Kind Regards, Matt Robert VK2TVK siliconchip.com.au Custom-made Lithium Ion, NiCd and NiMH battery packs Smart Chargers www.batterybook.com (08) 9240 5000 High-capacity 280mAh rechargeable 9V 2400mAh NiMH AA cells siliconchip.com.au High-quality single cell chargers with independent channels. Charge any combination of NiCd & NiMH AA and AAA cells High-capacity 9Ah rechargeable D September 2005  25 Build Your Own Seismograph Ever wondered how a seismograph works? Here’s one that you can build yourself. It uses a horizontal swinging pendulum to detect earthquake waves and you can even display the results on a PC. By DAVE DOBESON* M OST AUSTRALIANS are thankful that we are not seriously affected by the large earthquakes and volcanoes that regularly devastate so many other parts of the world. However, few realise just how close we are to much of the tectonic action, or how easy it is to make your own amateur seismograph. The design described here can easily detect the half-dozen magnitude 7 quakes that occur around Australia each year. In fact, the author has observed three major quakes occurring “live” on the monitor, including one from El Salvador. Plate tectonics Before we take a look at the design of our seismograph, let’s first find 26  Silicon Chip out why major earthquakes occur. In particular, we need to have some understanding of “plate tectonics”. The basics are very simple – the crust of the earth is made up of about 20 major “plates” that “float” on semi-liquid layers underneath. In our region, the Australian-Indian plate (including the ocean floor out to NZ, Fiji, PNG, Indonesia, most of the Indian Ocean, and also India) is moving in a north-westerly direction by about 7cm each year. Over millions of years, India (which is at the leading edge of the plate) has “crashed” into Asia, forming the Himalayas. Earthquakes commonly occur at the boundaries of the plates, where they collide and produce stresses in the Earth’s crust . For example, deep ocean faults off the coast of Sumatra produced the magnitude 9.0 “Boxing Day Tsunami” earthquake last year and the related Niass 8.7 earthquake in April, 2005. Also associated with this plate are a number of volcanoes, including Krakotoa, which partly circle Australia from Indonesia, through PNG and down through NZ. Macquarie Island, situated half-way between Australia and Antarctica, had a magnitude 8.1 earthquake on Christmas Eve, the biggest in the world last year until the Boxing Day earthquake. Of course, many large earthquakes go unreported because they occur under the ocean or in sparsely populated areas and have no impact on humans. siliconchip.com.au This seismograph plot shows a magnitude 6.5 quake that occurred in PNG on April 11, 2005. A 6.8 quake near Noumea was detected only five hours later. The detector circuit used was the same as described here but the data logger was one of the types used in NSW high schools. The mechanical section of the seismograph uses parts that are readily available from a hardware store. It’s based on a swinging horizontal pendulum and movement is detected using a vane and light sensor circuit mounted at one end. If you look at the United States Geographical Survey (USGS) home page and click on “Recent Earthquakes” (to show the last seven days’ earthquakes for the US and the world), you will see that many of the larger earthquakes occur near the boundaries of our continental plate – see www.usgs.gov In addition, Geoscience Australia’s website (at www.ga.gov.au) has a table that gives information on recent earthquakes in Australia and significant worldwide quakes (just click on the “Recent Earthquakes” link). Both sites also have detailed information on the tectonic forces causing earthquakes, the design and operation of professional seismographs, records of historically significant quakes and links to records in other countries. siliconchip.com.au Another site that’s worth visiting is www.geonet.org.nz/drums – it shows “live” displays from seismographs around NZ. If your home-made seismograph detects a real earthquake, the event should also be reported within minutes by the above three sites. Designed for schools This do-it-yourself seismograph was originally described in “Scientific American” in 1979 and has been adapted for science teachers to build and use in the school laboratory – see http://science.uniserve.edu.au/school/ Seismograph Movements of the seismograph, which is basically a horizontal pendulum, are detected using a simple light sensor circuit. In operation, a metal vane attached to one end of the pendulum (or bar) partially blocks the light between a LED and an LDR (light-dependant resistor). However, when the bar moves (ie, during an earthquake), the amount of light falling on the LDR is modulated by the metal vane. This signal is then fed to a low-cost op amp circuit which, in turn, feeds into a data logger. Finally, the output of the data logger is fed to a computer to store, display and print the results. All high schools in NSW have edu- cational data loggers for use in experiments. Most of these units cost well over $1000 but a cheap, 4-channel, 10-bit serial data acquisition device (DI-194RS) from DATAQ in the US is available from Turnkey Solution for under $60 plus GST and delivery – see www.turnkey-solutions.com.au There’s an even cheaper way around this problem for the home enthusiast. A PICAXE-based A/D converter and a freeware graphing program called “StampPlot Lite” can do the same job for about $10.00 – provided you also have a PC. Building the seismograph OK, let’s take a look at the mechanical details of our seismograph and find out how it’s built. The seismograph described here is known as a “Lehman” or “Horizontal Pendulum” seismograph. It’s also called a “Swinging Gate Seismograph”, because the bar and its supporting wire look like an old-fashioned farm About The Author* Dave Dobeson is a science teacher at Turramurra High School and the University of Sydney Science Teacher Fellowship holder for 2005. September 2005  27 TOP PIVOT POINT (25-35CM ABOVE LOWER PIVOT POINT) This labelled photograph clearly shows how the Seismograph is built. This version uses a magnetic damper but liquid damping could also be used (see text and photos). Note that the light sensor and A/D converter unit shown here is an early prototype. TURNBUCKLE STEEL WIRE 1-2MM DIA. 2-3KG MASS DAMPER METAL VANE LIMITING BOLTS BAR: 5/16-INCH x 800MM THREADED STEEL ROD LIGHT-SENSOR & A/D CONVERTER CIRCUIT gate. The “hinges” (actually the pivot points) of the “gate” are not quite vertically aligned, with the top hinge just forward of the bottom hinge so that the “gate” will swing shut. In practice, this means that the horizontal pendulum (or bar) swings slowly back to its original resting position The accompanying photos show the basic set-up. As can be seen, it includes an 800mm-long 5/16-inch threaded steel rod that’s fitted with a 2-3kg mass at one end. The other end of the rod is ground to an edge and pivots on the end of a ½-inch bolt – this forms the lower pivot point. The supporting wire is attached to the rod at one end, just before the weights, and to a turnbuckle at the other end. This then pivots about 2530cm above the lower pivot. If we align the seismograph pivots so that the top pivot is less than 1mm forward of the bottom pivot, then the seismograph bar will always swing back to its central position and will have a natural period of about 5-10 seconds. However, if the pivots are exactly vertically aligned, there will be no restoring force and it will never swing back. We cannot move the top pivot too far forward though, otherwise the seismograph will be very insensitive. 28  Silicon Chip This unit is very sensitive to the mostly horizontal motion of earthquake “L-waves” but is insensitive to “P-waves” which are mostly vertical. Kiwis, because they are much closer to the action, might be able to detect P-waves if they use a spring instead of the wire. Perth, Tennant Creek and Yass also have small local quakes every few months, so you might like to experiment with a spring support if you live in these areas. By t he way, it’s important to remember that although we often talk about the bar (or pendulum) of the seismograph “swinging”, it’s really the room that moves during an earthquake. The bar, because of the inertia of a heavy mass attached to one end, initially stays still. In effect, the unit and its associated logger act as a low-pass filter which renders the unit insensitive to everyday events (footsteps, doors closing, passing traffic, etc). The accompanying photos show most of the construction details. The only critical dimension is that the top pivot must be less than 1mm in front of the lower pivot. As well as the wooden frame shown, the unit could be built into any strong cupboard, bookcase, shelf or even a strong, metal frame. In that case, the brackets and wooden frame would not be needed. Any type BOTTOM PIVOT POINT TILT ADJUSTMENT BOLTS RIGHT-ANGLE BRACKETS WITH DIAGONAL STAYS of metal rod could be used (as long as it’s strong enough) and the same goes for the mass at one end. Note that you will have to “re-zero” the seismograph for the first few weeks after building it, as the wire, brackets and wood flex under the strain. After that, it will be a matter of making routine adjustments every few months. Top pivot point The top “hinge” (or pivot point) is made by drilling a 5mm diameter hole about half-way through the outer section of a large, thick washer – ie, to make a “dimple”. Smaller washers and a nut are used to hold the large washer in position, while a nut and lockwasher behind the wooden upright panel lock the bolt in place. As shown in the photos, the hook at the end of the turnbuckle sits in this dimple, so that it can freely pivot. In operation, the turnbuckle adjusts the tilt of the bar and is set so that the bar is horizontal. The securing bolt can be screwed in or out to move the top pivot point relative to the bottom pivot. This is important for the overall functioning of the seismograph because it affects the natural period of the bar (ie, the time for one complete swing from the centre to one side, then back through the centre to the other side and finally siliconchip.com.au back to the centre again). A period of about five seconds seems to work best for my seismographs in Sydney. The pivot end of the 5/16-inch threaded rod is ground to a knife-edge and this sits vertically against the end of a ½-inch bolt. Wind a nut onto the rod before you cut and grind it, so that the thread is restored when the when the nut is removed. Be sure to use safety goggles when drilling, cutting or grinding metals – you only have one pair of eyes. Note that the lower mounting point must be directly below the upper mounting point. The best way to ensure this is to use a plum-bob made from fine fishing line and a lead sinker. The two rear-most vertical bolts that go through the support brackets are used for tilt adjustment – see photo. These both screw into threads that are tapped through the wooden base and the brackets (nuts under the wooden base will do) and each has a screwdriver slot cut into its end. This allows you to use a screwdriver to tilt the seismograph sideways and forwards or backwards, to alter the position of the bar and thus its period and sensitivity. The far end of the seismograph wooden frame has a single central support. A sheet of plywood or particleboard underneath will stop the three supports from sinking into the carpet when the unit is positioned on the floor. Swinging the weight Just about any mass of 2-3kg will provide sufficient inertia to initially keep the bar still during an earthquake, provided it doesn’t hang too far below the bar. A pair of 1.25kg barbell weights are ideal for the job. They cost less than $3 each from a sports store and come with a ready-made hole through the middle. This means they can be simply slipped over the end of the bar and clamped in position using nuts and washers on either side. Damping Once earthquake waves set the bar swinging, it will keep swinging for hours unless it is damped. Perfect damping would stop the bar with a few swings but in practice, under 2-3 minutes is OK. You can use either liquid or magnetic damping. For liquid damping, a 40 x 50mm plastic paddle dipped into a rectangular container of water will do the job. You can use a small bulldog clip to attach the paddle to the bar. The water will need topping up each week or so. Magnetic damping involves attaching one or two super magnets to the end of the bar using a U-shaped bracket. A thick sheet of aluminium or a coil of wire with the ends joined is then placed in the magnetic field. When the bar moves (ie, during an earthquake), current is induced into the aluminium or wire coil. This in turn produces a magnetic field that counters the magnets and so damps the motion of the bar. Discarded computer hard disks are a good source for super magnets but be careful – supermagnets are dangerous and the author has been badly cut when a pair decided to play “north attracts south with my hand in be- The hook at the end of the turnbuckle sits in a 5mm dimple that’s drilled into a large washer to form the top pivot point. The lower pivot point is formed by first grinding the end of the bar to a sharp edge. This sharp edge then rests vertically against the end of a 1/2-inch x 40mm-long bolt. tween”. They can also be a disaster if they get too close to your credit cards or a computer monitor! On the other hand, the good thing about magnetic damping is that once Above & right: these two views show the alternative damping methods for the swinging bar. Magnetic damping (above) uses a couple of super magnets and a coil of wire, while liquid damping (right) uses a 40 x 50mm plastic paddle dipped into a rectangular container of water. siliconchip.com.au September 2005  29 This side-on view clearly shows the tilt adjustment bolts. These are set so that the base is perfectly horizontal (both east-west and north-south), so that the pivot points are in the same vertical plane. The turnbuckle is then adjusted so that the bar is also horizontal. TILT ADJUSTMENT BOLTS you get it right, it stays right. Old aquarium air pumps have coils of fine wire, which can be used for magnetic damping if the ends of the wires are joined together. A 400g coil of 0.7mm enamelled wire with the ends joined together and a super magnet that moves inside the coil gives almost perfect damping. Use your multimeter to check that the winding hasn’t burnt out before using the coil. The perfect location for your seismograph is on a concrete block that’s set into bedrock at the bottom of a sealed mine shaft! If you don’t have access to a mine shaft(!), the seismograph should be installed in a closed room or cupboard, or in a strong bookcase surrounded by a Perspex cover (to prevent air movement over the unit). Circuit details Many different seismograph detector and A/D (analog-to-digital) converter circuits are available on the net. The best-known site is called the Public Seismic Network at www. psn.quake.net (in California). It has designs that go from pens writing on rolls of paper to very complex circuits with low-noise op amps, 16-bit A/D converters and damping using negative feedback. By contrast, the circuit used here is quite simple – see Fig.1. As previously stated, it’s based on a light sensor circuit that’s interrupted by a metal vane attached to the end of the bar. In practice, the unit is set up so that the vane normally blocks about half the light from the LED to its LDR. The light detector and its associated op amp circuit is exactly the same as the one designed for use with school data loggers. The logger output is simply taken from the output of IC1, as shown. Alternatively, you can add your own data logger, based on A/D converter stage IC2 (a PICAXE-08M). In greater detail, power for the circuit comes from a 9V DC plugpack supply. Diode D1 provides reverse polarity protection, while the associated 100W resistor and 470mF capacitor provide decoupling and ripple filtering. The filtered DC rail is used to power LED1 via a 1kW current limiting resistor. The LDR and its associated 10kW resistor effectively form a voltage divider across this supply rail, the voltage at their junction varying according to the resistance of the LDR. This in turn depends on the amount of light reaching it from the LED. The output from the LDR is fed to the inverting (pin 2) input of op amp IC1 (741) via two back-to-back 470mF capacitors. These capacitors block the DC component at the output of the LDR while allowing signal fluctuations to be fed to the op amp. They also block any slow variations in the LDR signal due to thermal variations in the room. IC1 functions as an inverting amplifier stage. Its non-inverting input (pin 3) is biased to half-supply using two In the prototype, the LED & the LDR were brought out through holes in the case, with the vane sitting between them – see above. By contrast, in the final version, the LED & LDR are inside the case and the vane rides in a slot. The vane is positioned so that it normally “shadows” about half the LED body. 30  Silicon Chip siliconchip.com.au 10kW resistors, while its gain can be varied from 0-10 using potentiometer VR1, which is in the feedback loop. Note that although the circuit shows a 741 op amp, you could also use an OP27 device for improved accuracy. IC1’s output appears at pin 6 and is fed to a voltage divider consisting of two 3.3kW resistors. The top of this divider (ie, at pin 6) can be used to directly drive an external data logger. Alternatively, the divider output (at the junction of the resistors) can be used to provide a nominal 0-5V signal, which may be required by some loggers. Pin 6 of IC1 also drives trimpot VR2 and this is used to set the maximum signal level into pin 3 of IC2 (to about 4V). IC2 is programmed to function as an A/D converter, using the simple program shown in the accompanying panel (more on this later). Its output is taken from pin 7 (P0) and fed to pin 2 of DBF9 socket CON2. This socket is in turn connected to the serial port of a PC, to provide the alternative data logger. The PICAXE-08M is programmed via pin 3 of the DBF9 socket. The incoming data signal is fed to pin 2 (SER IN) of the IC via a voltage divider consisting of 22kW and 10kW resistors. Power for IC2 is supplied via 3-terminal regulator REG1. This provides a regulated +5V rail to pin 1. Building the circuit Building the circuit is easy since all the parts are mounted on a small PC board coded 04105091. Fig.2 shows the assembly details. Note that REG1 and the PICAXE (IC2) are required only if you don’t already have a data logger. If you do have a logger, these parts can simply be left out, along with the DB9F socket, trimpot VR2, the 100nF capacitor and the 22kW and 10kW voltage divider resistors from pin 2 of IC2. Begin by installing the re- Par t s Lis t 1 PC board, code 04105091, 123 x 57mm 1 9V DC plugpack 1 2.1mm DC power socket, to suit plugpack (CON1) 1 DB9F connector, PC mount 1 plastic utility box, 130 x 67 x 44mm (UB-3 size) 4 9mm-long untapped spacers 4 M3 x 15mm machine screws 4 M3 nuts 3 PC stakes 1 serial computer cable (see text) 2 8-pin IC sockets 1 100kW linear potentiometer (VR1); Jaycar Cat. RP-8518 1 5kW horizontal trimpot (VR2) 1 Light Dependent Resistor (LDR1) 1 3-way pin header 4 10kW 1 100W 1 3.3kW Plus 1 x 10kW or 1 x 3.3kW or 1 x 1kW to match LDR resistance – see text Mechanical Parts 1 800mm-long x 5/16-inch threaded steel rod 5 5/16-inch nuts and washers to suit rod 1 50mm-long x 1/4-inch bolt 3 1/4-inch nuts and washers 1 40mm-long x 1/2-inch bolt 1 1/2-inch nut and washers 1 3/8-inch washer 1 1-metre length 1-2mm diameter steel wire 2 bull-dog clips to suit 1 2-2.5kg mass (eg, 2 x 1.25kg barbell weights) 1 piece of thin aluminium sheet (to interrupt light beam) 1 50 x 50mm piece of aluminium or rigid plastic for paddle (see text) 2 small bolts & nuts to fasten paddle to bulldog clips 2 braced right-angle brackets, 250 x 250mm 8 1/4-inch x 40mm bolts, nuts & washers 3 5/16-inch x 100mm roundhead bolts, nuts & washers 1 wooden base, 900 x 250 x 20mm 1 wooden back, 400 x 250 x 20mm Semiconductors 1 741 or OP27 op amp (IC1) 1 PICAXE-08M microcontroller (IC2) 1 7805 3-terminal regulator (REG1) 1 1N4004 diode (D1) 1 red or white high-brightness LED (LED1) Capacitors 3 470mF 25V electrolytic 1 100nF MKT (code 104 or 100n) Resistors (0.25W, 1%) 1 22kW 2 1kW sistors and capacitors. Table 1 shows the resistor colour codes but it’s also a good idea to check each resistor using a digital multimeter before soldering them into circuit, just to make sure. Follow these parts with diode D1, the two IC sockets (don’t install the ICs yet) and trimpot VR2. Take care to ensure that D1 and the electrolytic capacitors go in the right way around. LED1 can go in next. Bend its lead down through 90° close to its body before installing it at full lead length on the PC board – ie, the centre of the LED should be about 22mm above the PC board (see photo). Again, take care to ensure that it’s oriented correctly. That done, you can install the LDR but there’s just one wrinkle here. The 10kW resistor shown in series with the LDR on Fig.1 is correct for most LDRs. However, some LDRs have a Table 1: Resistor Colour Codes o o o o o siliconchip.com.au No. 1 4   2   1 Value 22kW 10kW 1kW 100W 4-Band Code (1%) red red orange brown brown black orange brown brown black red brown brown black brown brown 5-Band Code (1%) red red black red brown brown black black red brown brown black black brown brown brown black black black brown September 2005  31 REG1 7805 100 LED1 K  OUT 100nF 10k LDR1 K 470F 9V DC IN 1 6 470F 10k VANE ON SEISMIC MASS CON1 SERIAL OUTPUT CON2 DB9F SENSITIVITY VR1 100k A 470F 25V 7805 GND GND A  D1 1N4004 IN +5V OUT IN 2 7 3 IC1 741 4 6 VR2 5k 4 3.3k 10k* (SEE TEXT) 1k 3 Vdd P0 P1 P3 2 3 IC2 5 PICAXE P2 -08M SER 2 IN P4 Vss 5 22k 8 H L E 10k 7 3.3k 10k LED SC  2005 LOGGER OUTPUT SIMPLE SEISMOGRAPH 1N4004 A K K A 22k IC2 PICAXE 3.3k IC1 741 5 470F 470F E L H 5k 10k VR2 3.3k 470F 2 3 100nF 10k K CON2 LDR1 10k A LED1 (SLOT IN BOX ABOVE) CON1 REG1 7805 10k 100 5002 © 1k 9V DC IN D1 19050140 (BEND LEADS SO LED FACES LDR1) 10k 1N4004 Fig.1: the circuit uses a light detector based on LED1 & LDR1 to detect movement of an interrupter vane placed between them. The resulting signal is then amplified by IC1 and fed to the logger output. IC1 also drives IC2, a PICAXE-08M chip programmed to function as an A/D converter. Its output can then be fed to the serial input of a PC, to provide an alternative data logger. DB9F VR1 100k LOGGER OUT Fig.2: install the parts on the PC board as shown here, making sure that all polarised parts are correctly oriented. IC2, REG1, VR2 and CON2 can be left out if you already have an external data logger. 04105091 © 2005 Fig.3: this is the full-size etching pattern for the PC board. 32  Silicon Chip lower resistance than others in the presence of light and you may have to adjust the value of the series resistor accordingly. That’s easy to do – just measure the resistance of the LDR in a brightly lit room and use a series resistor that’s about the same value. The value isn’t all that critical. In practice, you can buy 1kW, 3.3kW and 10kW resistors and use the one that’s closest to the measured LDR value. The LDR is mounted in similar fashion to the LED – ie, bend its leads down through 90° before installing it. It should be mounted so that its face is siliconchip.com.au This view shows the fully assembled PC board. Note the arrangement for the LED & the LDR. directly aligned with the LED. Regulator REG1 is mounted with its metal tab flat against the PC board. To so this, bend its leads downwards by 90° about 5mm from its body, then secure it to the board using a 3M x 6mm machine screw and nut before soldering its leads. There’s no need for a heatsink, as it supplies just a few milliamps to IC2. The board assembly can now be completed by fitting CON1, CON2, potentiometer VR1 and a 3-pin header for the external logger interface. Serial cable options A standard serial cable is used to connect the PC board to the computer (if you’re using a PC as the data logger). There are several options here. First, you could go out and buy a serial cable but that’s the expensive way of doing things. It’s far better to scrounge a cable instead. For example, if you have an old modem (left over from your dial-up days), you can use its serial cable (you did keep it, didn’t you?) to connect to the PC. Another possibility is to use a serial cable from a discarded mouse. Just cut the cable off close to the mouse, then strip the wires back and use a multimeter to identify which lead goes to which pin on the socket – you need to use the leads that go to pins 2, 3 & 5 (the rest can be trimmed off). These leads can then be soldered directly to three PC stakes mounted at the appropriate points on the PC board. As a bonus, you don’t need the siliconchip.com.au Above: a slot is cut into one end of the case to provide access for the metal vane that’s attached to the seisomograph bar. on-board DBF9 socket, which means you can save even more money. Checks & adjustments Before fitting the two ICs, it’s necessary to make several voltage checks. First, connect a 9V DC plugpack supply and switch on. The LED should immediately come on. If necessary, adjust it so that it shines directly on the LDR. Next, use a digital multimeter to check the voltages on IC1’s socket pins. Pin 7 should be at the supply voltage (about 9V, depending on the plugpack), pin 2 should change when the light to LDR is suddenly inter- rupted and pin 3 should be at half supply voltage. That done, check for +5V on pin 1 of IC2’s socket and for 0V on pins 2, 3, 7 & 8. If it all checks out so far, disconnect the plugpack and install IC1 (but not IC2). You now have to adjust trimpot VR2 so that the voltage on pin 3 of IC2 can never exceed 5V. This is done as follows: (1) Connect a clip lead across the two back-to-back 470mF capacitors (ie, short them out); (2) Set both VR1 and VR2 to their midrange positions; (3) Place a piece of thick cardboard (or other opaque object) between the LED September 2005  33 Tectonic Plates, Earthquake Waves & The Richter Scale ”An earthquake is the way the Earth relieves its stress by transferring it to the people who live on it.” – Dr Lucy Jones, USGS. E ARTHQUAKES occur when adjacent blocks of the Earth’s crust slide past each other along a fracture we call a fault line. Most active faults are located near the boundaries of the Earth’s tectonic plates. These plates move in several ways: (1) they can slide past each other; (2) they can move away from each other (diverge); or (3) they can move towards each other (converge). For example, the west coast of New Zealand’s South Island – which is at the eastern edge of the AustralianIndian plate – moves north along the Alpine Fault. This movement is relative to the eastern side of the island, which is part of the Pacific plate. This area experiences several magnitude five quakes every year, as well as much larger but less frequent earthquakes. Plate divergence generally occurs at mid-ocean ridges such as the Atlantic’s, which rises above sea-level to form Iceland’s central rift valley. Convergence occurs at “subduction zones” like the one that caused Aceh’s Boxing Day earthquake. Here, the northern edge of the AustralianIndian plate is descending under Indonesia, which is part of the Eurasian Plate. While most active faults are located near plate margins, about 10% of active faults occur well away from the plate margins. The earthquakes generated in these locations are known as intra-plate earthquakes and are mostly thought to occur either as a response to stress transmitted through the plate from its interaction with adjacent plates or from thermal equilibration, which can cause con- and the LDR (to block the light); (4) Reapply power and check the voltage at pin 6 of IC1. It should be about 1V less than the supply rail; (5) Monitor the voltage at pin 3 of IC2’s socket and adjust VR2 for a reading of 4V (or slightly less). 34  Silicon Chip traction as the plate cools down or expansion as the plate warms up. The Northern Territory’s Tennant Creek fault is a world-famous example of one of these intra-plate structures and generates a number of generally small earthquakes each year. Several types of vibrations are generated as blocks of rock grind past each other during an earthquake and these propagate around and through the planet as different types of earthquake waves. The fastest (and the first to arrive) are “Primary” or P-waves, which are longitudinal compressional waves that propagate at speeds of 1.5-8km/s (depending on rock density). The next fastest are the “Secondary” or S-waves which are shear waves (or transverse waves) and these propagate at speeds of about 3.2-4.8km/s. Both P and S-waves move through the body of the planet and are refracted and reflected as they encounter rock density and composition changes. However, S-waves cannot propagate through the liquid part of the Earth’s core. In fact, it was by examining the geographic pattern of P-waves and S-waves that led to the formulation of the core-mantle-crust model of the Earth. The slowest waves are surface waves, which propagate at speeds of about 2-5km/s. There are two types of surface waves: Rayleigh and Love (L) waves. It’s the shear and surface waves that generally cause the damage associated with earthquakes. By measuring the time gap between the arrival of the P and S waves, it’s possible to calculate how far away the earthquake was from the seismograph. This is roughly 500km for every minute between their arrival. The location of the epicentre is determined by a form of “triangulation”. To do this, a circle corresponding to the calculated distance is drawn Once that’s done, disconnect the plugpack and install the PICACE-08M, with its notch facing to the left – see Fig.2. Final assembly The PC board is designed to fit around at least three different seismograph locations on a map of the region. Where the circles intersect is the likely epicentre. Most earthquakes occur at depths of less than 100km. P waves have higher frequencies and are best detected with a “Short Period (one second or less) Vertical Seismograph”, while S, L and Rayleigh waves have lower frequencies and are best detected by a “Long Period (10 seconds or longer) Seismograph”, such as the design described here. Professional seismic stations have short, long and wideband seismographs mounted northsouth, east-west and also vertically, with both low and high-sensitivity detectors. Analysis and filtering of the seismic patterns allows the arrival of each type of wave to be determined from the mixture of P, S, L and Rayleigh waves, reflections (PP and SS waves), refracted waves and alternative path surface waves. Our seismograph with a 1-second (or 10 second) sample rate, will probably only detect S waves and the much larger displacement L waves and Rayleigh waves. If you live very close to the action, such as in NZ or PNG, you might also detect P waves. The Richter value, devised by Charles Richter in 1935, is basically a logarithmic measuring scale. It’s calculated according to the largest ground motion waves that are detected 100km from the epicentre of the earthquake. Because the scale is logarithmic, a magnitude 7 earthquake has 10 times the ground motion (and more than 30 times the energy) of a magnitude 6 quake. The Aceh Earthquake measured 9.0 on the Richter scale and released many thousands of times more energy than the 5.6 Newcastle earthquake of 1989. inside a standard UB3 utility case. It’s mounted on the lid on four 9mm untapped spacers and secured using M3 x 15mm long screws and nuts. That done, you have to make a cutout in one end of the case to provide clearance for the DBF9 socket (CON2) siliconchip.com.au and the pot shaft. This cutout measures 45mm long x 12mm high and is about 12mm from the lip of the base. Alternatively, if you’re not using CON2, the serial cable can be run through a small hole in the case and secured using a small cable tie. The same applies if you are connecting an external logger to the 3-pin header. You also need a hole directly in-line with the DC power socket (CON1). This is horizontally centred 17mm from the lip of the case and should be drilled and reamed to 8mm. Finally, a slot must be cut in the case in line with the light sensor to provide access for the vane that’s attached to the bar. This slot should be positioned 37mm from the end of the case and can be about 4mm wide. The unit can then be assembled into the case and attached to the base of the seismograph. Position the vane so that it normally blocks about half the light between the LED and the LDR. Programming the PICAXE To program the PICAXE, you first have to download the free “Programming Editor” from www.rev-ed.co.uk/ picaxe That done, connect the board to your computer via the serial cable (this should be done with the computer off) and download the simple program shown in Listing 1 into the PICAXE chip. If you increase the logging interval to 10 seconds by changing line 5 to “wait 10”, you can keep a continuous seismograph record for up to a week. You could also hang a piezo transducer off the PICAXE and add an “Alarm” loop to the program to warn you if b1 exceeds a certain value. Once the program is loaded and running in the PICAXE-08M (check by looking at the “debug” screen), you must close down the PICAXE Programming Editor to free the COM Port, so that the StampPlot Lite program can use it. StampPlot Lite is available free from www.selmaware.com Fig.3: this simulated plot of an earthquake was produced during final sensitivity tests of the seismograph. A gentle puff of air aimed towards the seismograph masses from two metres away produced the first “earthquake” waves, while similar puffs from one metre gave the full scale deflection. (3). Click on “Connect” and “Plot Data” – the program should immediately begin to graph the values sent by the PICAXE-08M. You can test this by blowing on the bar from a distance of about one metre. Adjust the sensitivity control (VR1) for full-scale deflection. The “action” near the bottom of the screen indicates that data is being collected. (4). Set the maximum number of points to 200,000 or higher. (5). A “Time Span” of 400 seconds will show each swing of the bar during testing but increasing this to 25,600 will let you see most of a night’s recording. Australia is normally a long way from the action and different types of earthquake waves will continue to arrive for more than an hour after a distant quake. (6). Click on “Save data to file” so the program saves the data as a .txt file. siliconchip.com.au Acknowledgement: thanks to Dr Tom Hubble of the University of Sydney for his geological knowledge and neighbours Jo and Manfred for computing and design assistance. Program Listing 1 Using StampPlot Lite StampPlot Lite is the logging program. Once it’s installed, you need to carry out the following steps: (1). Set the COM port so that it’s the same as the port that connects to the PICAXE. (2). Change the Baud rate to 4800. (7). Click on “Clear min/max on reset” and you will be able to see if any values have been detected that are significantly above the background line (ie, an earthquake) and when this occurred (approximately). If you deselect “Connect” and “Plot Data” to stop the recording, you can look back at stored parts of the graph by moving the bar next to “Enable Shift”. The running graph can be seen on the screen and “.txt” values can be exported to Excel and graphed. (8). Click on “Time Stamp” so that Excel will show “Time” on the graphs. Good luck and I hope that the Earth SC moves for you. main: readadc10 4, b1 debug b1 sertxd (#b1,cr,lf) wait 1 goto main 'makes an A-D conversion of the value at input 4 and sends to b1 'allows you to see the value at b1 on the Picaxe debug screen 'sends the value of b1 out to the StampPlot Lite program 'sets the time gap in seconds between readings 'makes the program loop back to the start September 2005  35 Minimise the risk of boating explosions Bilge Sniffer by John Clarke Messin’ about in boats is one of the world’s favourite leisure activities. Yet far too regularly, we see in the news stories about injuries and deaths when boats blow up due to fuel vapours in the bilges. This little sensor/alarm unit is designed to let you know about this danger before you turn the key . . . M otorboat explosions and fires are the largest single cause of marine property damage. The hazards are due to the presence of flammable liquids within poorly ventilated spaces, such as the bilge. Petrol is the major hazard, whether by leakage, spills, the use of poor storage containers or even downright stupidity. With the right mixture of petrol and air, a small spark (even from a switch), a cigarette or match, 36  Silicon Chip or even electrical failure can cause an explosion that can literally blow the boat apart. As an extra danger, the petrol vapour is heavier than air and tends to collect in lower areas of the boat. Consequently, a small leak or spill can present a significant hazard for explosion and fire. To blow up, the mixture of petrol vapour and air must be within a certain (and quite limited) range of fuel-to-air ratios. The lower explosive limit (LEL) is 1.4% by volume and the upper explosive limit (UEL) is 7.6%. Above and below these limits, the fuel will not explode. With diesel fuel, the explosion risk is significantly reduced – although it is still significant. This is due to diesel’s higher flash point, which prevents it from readily evaporating and producing a flammable mixture. The LEL for diesel fuel is typically 3.5% by volume siliconchip.com.au It’s very cheap insurance! Fit it to your boat and it could save it – or your life. It can automatically turn on bilge exhaust fans when explosive gases are detected. and the UEL is 6.9%; ie, a higher LEL and a smaller range than petrol. While the reduced range makes it harder for diesel fuel to explode, it can still happen. In the heat of summer, for example, temperatures within the boat compartments may be raised sufficiently to provide the right conditions for an explosion. In addition to engine fuels, boats often have propane gas cylinders for fuelling stoves, on-deck barbecues, and so on. This too can be a fire and explosion hazard. Propane will explode with an air/fuel ratio by volume of between 2.5% and 4.5%. Once again, because propane is heavier than air, a leak can create an explosive mixture in lower boat compartments. The bilge Ahoy, me hearties. Throw ’em down in the bilges. . . OK, pirate movies are about as close as the great unwashed ever come to a bilge. But what is it? It’s the lowest area of the boat, closest to the water. Often the bilge is actually under a floor (between the floor and the outer hull), so it can be almost inaccessible. In a large motor siliconchip.com.au boat, it’s almost certainly right under the engine. Being the lowest point in the boat, the heavier-than-air fuel mixture tends to concentrate here. Any ingress or leakage of water through the hull (and there almost always is some, especially in timber boats!) congregates there (and that water can really go “off”!). On a big ship, it’s where the rats love to nest. With a mixture of rancid water, oil, fuel and all manner of dirt, it can often be an unpleasant, foul-smelling place. All boat owners should be aware that the bilge is by far the most dangerous area of the boat, as far as explosive gasses are concerned. Even if the fuel is mixed with the bilge water there is no guarantee of safety: all fuels float on water and so vapours are still likely be released into the air. Ideally, boats should include bilge ventilation to expel any inflammable gases that will inevitably accumulate, even if correct refuelling methods are used and leaks/spillage minimised. However, ventilation on its own is usually not enough to guarantee safety. Exhaust fans should also be used to remove the potential explosive gases before starting the engine. Many boat owners have bilge exhausts that are run “as a matter of course” for perhaps a minute or so before the engines are started – just in case. But wouldn’t it be better to know for certain, one way or the other, if there are dangerous gases down below? That’s what the SILICON CHIP Bilge Sniffer is designed to do. What’s more, it can be set up to automatically start an exhaust fan if dangerous levels of hydrocarbons – that’s any fuel or gas – are detected. It could also be made to be part of the engine start or ignition circuit, locking out the engine if hydrocarbons were detected. That could be a boon for hire craft operators who cannot guarantee hirers will wait for gases to be cleared before starting the engine. The “on” time of any exhaust fan is important because bilge fuel levels might be above the upper explosive limit and therefore offer little risk of explosion. If the fan sucks out only some of the gases, the level might be reduced to where it is bang (literally!) in the middle of the danger zone. September 2005  37 REG1 7805 +5V OUT IN GND 10 µF + 100 µF 16V D1 1N4004 10Ω +11.4V (nom) ZD1 16V 1W OPTIONAL 12V DASH SIREN K A +12V (nom) 0.5W 0V – +11.4V A +5V K SENSOR1 MG-3 HYDROCARBON SENSOR H A B H CALIBRATE 8 2 IC1a 2.2k 1 K A 5 6 IC1b 4 MG-3 BILGE SNIFFER/ALARM A 10k IN4004 A H SC 10k 7 LED B NC COM NO HYSTERESIS D2 1N4148 VR2 500k ALARM LEVEL VR3 10k 10k 2005 NC COM NO IC1: LM358 3 VR1 50k D3 1N4004 A 2.2k 10 µF 16V RLY 1 K λ 100 µF 16V LED1 B C E BC337 Q1 BC337 E B C GND K OUT B H A A K ZD1 1N4148 A K 7805 IN A K Fig.1: the hydrocarbon sensor’s resistance is monitored by op amp IC1a. When gas is detected, transistor Q1 is switched on, pulling in a relay. What you do from then on is up to you! The dash siren is optional – see text. Therefore, the sniffer is designed to keep removing gases while ever it senses any hydrocarbons; ie, until they are well under the lower explosion limit. The hydrocarbons that can be detected include iso-butane, propane and LPG, as well as petrol and diesel fuel. The sensor itself is encapsulated in a plastic housing with a stainless steel mesh cover which provides antiexplosion protection. It has an aluminium oxide ceramic tube that is coated with a tin dioxide sensitive layer, along with a heating element. Electrodes attached to the sensitive layer provide the gas sensing terminals. The semiconductor sensor changes its resistance between two measuring electrodes in the presence of the appropriate vapour, with the resistance decreasing with increasing gas concentration. Circuit details The circuit for the Bilge Sniffer is shown in Fig.1. Operation is quite 38  Silicon Chip simple: the sensor is monitored by IC1, which controls transistor Q1. This switches the relay at a preset hydrocarbon concentration. One of the electrodes from the sensor connects to the 5V supply while the other end connects to the calibration potentiometer (VR1) and series 10kW resistor. In operation, the sensor electrodes present a certain resistance at various hydrocarbon concentrations and this resistance sets a voltage due to the divider action of VR1 and the 10kW resistor. Typically, the voltage is around 2V at 0.1% hydrocarbon concentration when VR1 is set at 10kW. IC1a is an op amp connected as a unity gain buffer, which monitors the sensor voltage at the top of VR1 and the 10kW resistor. IC1a’s output drives the non-inverting input of IC1b which is wired as a comparator. Pin 6 of IC1b connects to the alarm level trimpot, VR3. Wired directly across the 5V supply, this trimpot can set the level anywhere between 0V and 5V. When the voltage at IC1a’s output goes above the voltage set by VR3, then IC1b’s output goes high, to a little less than 12V. Diode D2 then conducts and the pin 5 input of IC1b is pulled slightly higher than the pin 1 output of IC1a due to the voltage divider action of VR2 and the 2.2kW resistor connecting to pin 5. Built-in hysteresis, set by VR2, prevents IC1b’s output from “hunting”, or switching high and low at a rapid rate at the threshold where IC1a’s output equals the level set by VR3. The output of IC1b drives the base of Q1 via a 10kW resistor. The 10kW resistor from base to ground ensures that Q1 is off when IC1b’s output is low. Transistor Q1 drives relay RLY1. The common and normally open contacts close, turning on the ventilation fans. LED1 also lights to indicate whenever the relay is on. Diode D3 quenches the back-EMF produced by the relay coil when Q1 switches off. Note the relay should be a sealed (ie flameproof) type if it is to be used anywhere near explosive gases. siliconchip.com.au K K A 100 µF H 10 µF 500k 2.2k B VR1 50k K D2 C CN 4148 10k 100 µF 10 µF K A D3 Q1 siliconchip.com.au ON A 10k We have also shown an optional 12V siren wired across the relay coil. There would almost certainly be times when a LED might not be noticed (especially in daylight) and we would imagine that the skipper would like to know that there is something not quite right down in the bilges just as soon as it happened! Any small 12V warning siren or buzzer would be satisfactory here – they draw very little current for a lot of noise! No provision is made on the PC board for this – it would most easily be connected directly across D3. If the buzzer or siren is polarised, the “+” side would connect to the cathode of the diode. Of course, such a buzzer could also be switched by one of the sets of relay contacts if you didn’t need them for something else. Power for the circuit is provided from a 12V supply. This would normally be from the boat’s 12V battery. The supply is reverse-polarity protected using diode D1 and protected from transient voltages using a series 10W resistor and the 16V zener diode, ZD1. K rab/tod VR2 A SENSOR1 H A 2.2k ZD1 LED1 10k 10k K 0V A VR3 IC1 LM358 REG1 +12V NO RELAY 1 15090150 The 100mF capacitor filters the incoming voltage and REG1 regulates the voltage down to 5V for the sensor’s heater coil. This coil has a resistance of 33W, so the current drawn from the 5V supply is around 150mA. Note that both the 12V supply (and indeed the 11.4V supply) are labelled “nominal” because these could be higher, depending on the state of charge of the boat battery – up to about 14V. The 11.4V rail is simply 0.6V less than the supply rail (the 0.6V being dropped across D1). 24 or 48V boat supplies If you are really well-heeled, you might have one of those floating palaces with a 24V or even a 48V DC boat supply. . . in which case, you have even more to lose than those of us with little putt-putts and tinnies. You really need the Bilge Sniffer! Naturally, the Bilge Sniffer cannot be powered from these higher rails direct but it would be a very unusual “big boat” not to have a derived 12V(ish) supply somewhere for such things as two-way radios, entertainment R OS NES GPL/L O H O CLA 10Ω CN D1 C ON A COM CONTACTS 1 NC NO COM CONTACTS 2 NC Fig.2: component overlay and matching photograph below. The gas sensor is the large silver object at lower left. The relay needs to be a completely sealed type if you are going to mount the PC board anywhere near where explosive gases might congregate. Don’t worry about the unused holes in this PC board – we explain why in the text! systems, etc. We’re only talking a few hundred milliamps maximum so it shouldn’t cause any overloads! Failing this, you could add a suitable DC-DC converter. Construction The Bilge Sniffer is constructed onto a PC board coded 05109051, measuring 123 x 60mm. It has its four corners removed and shaped to allow it to fit into a plastic UB3 box measuring 130 x 67 x 44mm. Power is connected via a figure-8 lead that attaches to the boat’s 12V supply via an in-line fuse. Begin construction by checking the PC board. Check that the corners of the PC board have been shaped correctly so that the PC board can be fitted into the box. First, install the six resistors, making sure the correct value is placed in each position. You can use the accompanying resistor colour-code table to check the values or use a multimeter to measure them. When placing the regulator and IC, make sure they are oriented correctly. A heatsink is attached to the regulator September 2005  39 the power screw connector and relay contact connections. Connect the figure-8 power lead to the 12V terminals. We didn’t find any need to screw the PC board into the case – it sits snugly inside the four corner pillars and on the recesses in the moulded slots in the case side. When the lid is scrwed on, it virtually locks the PC board in place. Parts List – Bilge Sniffer 1 PC board, code 05109051, 123 x 60mm 1 UB3 box (130 x 67 x 44mm) 1 MQ-6 hydrocarbon gas sensor (Jaycar RS-5610) (Sensor 1) 1 12V 5A DPDT PC-mount sealed relay (RLY 1) 1 mini heatsink, 19 x 19 x 10mm 1 M3 x 10mm screw and nut 4 2-way PC-mount screw terminal blocks 6 PC stakes 1 200mm length of light-duty figure-8 polarised wire 1 150mm length of 0.8mm tinned copper wire Semiconductors 1 LM358, TL072 dual op amp (IC1) 1 7805 5V regulator (REG1) 1 5mm red LED (LED1) 1 BC337 NPN transistor (Q1) 2 1N4004 1A diodes (D1,D3) 1 1N4148 diode (D2) 1 16V 1W zener diode (ZD1) Capacitors 2 100mF 16V electrolytic 2 10mF 16V electrolytic Resistors (0.25W, 1%) 3 10kW 2 2.2kW 1 10W (0.5W) 1 500kW horizontal trimpot (VR2) (code 504) 1 50kW horizontal trimpot (VR1) (code 503) 1 10kW horizontal trimpot (VR3) (code 103) using an M3 x 10mm screw plus an M3 nut, with its flanges oriented so that they point towards the edge of the PC board. When mounting the electrolytic capacitors, ensure they are oriented as shown on the overlay diagram. Similarly with the diodes: solder them in place with the orientation shown. Terminal blocks for the power connection and relay contacts can also be installed, along with the trimpots. Use PC stakes and tinned copper wire (eg, resistor lead cut-offs) to hold the sensor in position above the PC board (see photo). The sensor can be mounted either way around, as the pin connections are symmetrical. The top of the sensor should be 40  Silicon Chip Testing The gas sensor itself is mounted up off the PC board, on PC stakes and tinned copper wire, so its “nose” pokes through the lid of the box. 35mm above the PC board to allow it to poke through the jiffy box lid. For the same reason, mount LED1 so that its top is 32mm above the PC board. Construction of the PC board is now complete. Check that your board agrees with both the overlay diagram and the photographs, and also check your soldering for bridges or dry joints. Don’t worry about the large number of unused holes in the PC board – this board will also be used for another project in a coming issue (the holes are primarily for a LED bargraph and driver IC). Using the front panel artwork as a guide (a photocopy temporarily stuck to the lid is ideal), drill or ream a 16mm diameter hole in the box lid for the sensor and a 5mm diameter hole for LED1. Also drill out a hole in each end of the box adjacent to the terminal blocks suitable for the wiring entry to Apply power to the Bilge Sniffer and check that there is +5V at the output of REG1 with respect to the ground. Similarly, check that pin 8 of IC1 is around 12V. Before further use, the Bilge Sniffer should be left powered up for about 24 hours. This allows the heater inside the hydrocarbon sensor to burn off impurities that have collected onto the sensing element during manufacture and while in storage. The Sniffer can be tested after a few minutes of purging by waving an open bottle of air and petrol over the sensor. Just a couple of drops of petrol in an empty 2-3 litre milk bottle will be sufficient (but take care as this mixture can be explosive!). With VR1 set mid-way, exposure to this mixture should see the voltage across the sensor (measured at pin 3 of IC1a) rise to around 1V or so. Setting up The Bilge Sniffer should be set up so that the relay switches on when it detects even small amounts of hydrocarbons in the air. In this way, the The shaped PC board slots into the recesses in the vertical mouldings inside the jiffy box and is held in place when the lid is screwed on. siliconchip.com.au exhaust fan can be operated to keep the remnants of hydrocarbons to a minimum. First, set VR3 so that the ALARM wiper is at 200mV and set VR1 to its maximum (fully clockwise). This will provide maximum sensitivity for the sensor. Now set VR2 to mid setting and test that the relay switches on when the sensor is exposed to the milk bottle petrol vapour and that the relay switches off not long after the bottle is taken SILICON away (ie, when the sensor is exposed to fresh air). CHIP www.siliconchip.com.au Set trimpot VR2 more anticlockwise if the relay does not Fig.3: same-size artwork for the front panel and the PC board. The panel artwork is also useful as a template for drilling the holes in the lid for the sensor and LED. switch off. The common and normally K A open relay contacts are wired in series with the exhaust fan wiring so that the fans will run when these contacts close. For a belt’n’braces approach, a dot/bar NO separate switch can be installed in parallel with the relay contacts so C that the fans can be run manually NC before starting the boat’s engine. Note that each relay contact is rated at 5A, which should suit all but the highest-volume fans. There are two sets of contacts which can 05109051 be wired in parallel if more current than the 5A is required – or additional fans powered. Ignition cutout If you find that the exhaust fans a false sense of security and becomes run continuously, you may need to It has been suggested that the Bilge too complacent to actually check the increase the alarm level by turning Sniffer could be incorporated into bilges before starting out (every good VR3 further anticlockwise. This will the boat’s ignition circuit so that the boat owner should know the value of cause the fans to run less often. motor couldn’t even be turned over if the “nose test” before starting engines Trimpot VR2 may need to be turned – you should never rely on electronics hydrocarbons were present. further anticlockwise to reduce hysFrankly, we are in two minds about alone!). teresis and cause the fans to run for a If you do want to wire the Bilge this – especially in the “what if” deshorter time. But before you do this, Sniffer to disable the engine(s) on a partment. make sure the Bilge Sniffer is not trying What if the relay (or sensor) failed fuel vapour alarm, you would wire the to tell you that you have a problem! and you couldn’t start the boat when boat’s ignition switch (not the starter To run the fans for a longer time, set or the high voltage line!) via the “noryou needed to? VR2 more clockwise – but make sure What if the Bilge Sniffer sensed a mally closed” sets of contacts. that the fans will switch off when the This would have the motor powered fuel spill and operated correctly, cuthydrocarbon levels are reduced. ting the engines – but at the time the in the normal way but when hydrocarSetting VR2 too far clockwise will boat was, say, crossing a bar? What bons were detected, the relay would pull cause the fans to run all the time once in, opening the normally closed contacts would be the worst evil? SC the alarm level has been reached. What if the owner gets lulled into and shutting off the engine. BILGE SNIFFER NO C NC ALCOHOL/LPG SENSOR Resistor Colour Codes 1 1 1 No. 3 2 1 siliconchip.com.au Value 10kW 2.2kW 10W 4-band code (1%) brown black orange brown red red red brown brown black black brown 5-band code (1%) brown black black red brown red red black brown brown brown black black gold brown September 2005  41 CIRCUIT NOTEBOOK Interesting circuit ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates. Antenna input & audio line-out adaptor for portable radios Here is an idea for a simple lowcost adaptor that allows a portable FM radio (or MP3 player with FM tuner) to be connected to an external antenna and to audio equipment such as a hifi system or PC sound card. Portable FM radios and some MP3 players typically provide a 3.5mm stereo jack socket for the headphone connection, with the shield conductor of the headphone cable doubling as an antenna. The problem Recently, the author bought a cheap FM radio with a USB connector, designed to be operated with a PC. The package included an audio cable with a 3.5mm stereo phone plug at each end. The plug that goes into the radio has an additional wire (about 2m long) hanging out of it, which is meant to serve as an indoor antenna. When using the supplied cable, the system suffered from poor radio reception (too much interference), 42  Silicon Chip and poor audio quality (lack of bass). The first problem was easily explained, as the radio was used in a marginal TV/FM reception area. When the cable was “buzzed out”, the reason for the second problem became apparent. There was no audio ground connection, as the cable screen is not connected to anything at the radio end! As mentioned, the antenna wire in these units is connected to the “common” terminal of the 3.5mm socket, which normally doubles as the audio signal return path. If this terminal were to be connected to the ground of external audio equipment, the antenna signal would be clobbered. Perhaps the designer of this cable assumed that an adequate audio ground connection would be made indirectly via the USB cable – a poor assumption! The challenge The challenge then was to pro- Michae vide a good l is this m Bauer antenna signal on winner th’s for the radio Peak At of a las while at the Instrum Test ent same time making a good audio ground connection to external equipment. Preferably, this was to be achieved without relying on the USB connector (because not all FM radios have one) and without having to mess with the radio’s internal works. The accompanying circuit diagram shows how this can be achieved. The radio-frequency choke (L1) has a low impedance at audio frequencies, thereby making an audio ground path to the line output sockets from the radio’s antenna input (“common” terminal). Conversely, the RFC presents a high impedance to the RF antenna signal, so preventing it from being shorted to ground. The antenna signal is coupled to the radio via two 220pF polystyrene (or ceramic) capacitors, which also block low-frequency interference (eg, mains hum). Note that the design relies on the capacitance in the audio cable to couple the antenna “ground” (cable shield) to the radio’s internal “ground”. Building it To build the adaptor, simply mount the parts in a small plastic box and wire up as shown. A suitable choke is available from Jaycar (Cat. No. LF-1534). The leads going to the 3.5mm plug should be no longer than about 100mm and need not be shielded. With a good TV/FM antenna, the author’s unit performed remarkably well, even in a poor FM reception area. The audio frequency response and signal-to-noise ratio were surprisingly good considering the low cost of the radio (about $40). Michael Bauer, Prahran, Vic. siliconchip.com.au Automatic alternate motor switch This circuit was designed to allow two motors to run on an alternate day-by-day basis. An off-the-shelf time clock dictates the running time and frequency of operation. In the author’s application, the circuit uses two 240VAC, 16A relays (RLY2 & RLY3) for motor control but these do not directly switch power to the motors. Instead, the relays control two 415VAC contactors which themselves provide power to two high-voltage motors. Power for the control circuit is provided by a small 12VAC mains transformer. Its output is rectified, filtered and then regulated to +12V and +5V by REG1 and REG2. Operation begins with the closing siliconchip.com.au of the remotely located time-clock contacts (S2). With mode selector switch S1 in the “Auto” position, this energises 5V relay RLY1 and provides +12V to the top of the two output relays (RLY2 & RLY3). When RLY1 changes over, the logic levels of pins 2 & 6 of the NOR gates in IC1 reverse, causing the output at pin 4 to go low. The purpose of IC1 is to remove the effects of relay contact bounce, so that a clean clock signal is fed into pin 3 of J-K flipflop IC2. As both the J and K inputs of the 4027 are connected to +5V, it functions as a toggle flipflop. When power is first applied, either one of it’s outputs (Q or Q-bar) will be high, switching on transistor Q2 or Q4 and energising the associated motor relay. After the programmed motor run period, the time-clock contacts open and RLY1 switches off. The output (pin 4) of IC1 now goes high, toggling the flipflop and effectively enabling the alternate motor relay for the next time cycle. Each output circuit also features a separate LED indicator (LED1 & LED2, driven by Q1 & Q3). These are powered from the +5V rail and indicate which motor will run next in the cycle. Provision has also been made for remote mounting of a pair of indicator LEDs, where required. Finally, the 3-pole, 4-position rotary switch (S1) includes two manual settings to provide a means of “locking out” an out-of-service motor. By switching to either the “Manual 1” or “Manual 2” positions, only the in-service motor will run at each closure of the time-clock contacts. Jeff Jorgensen, eptember Bundaberg, SQld. ($50) 2005  43 Circuit Notebook – Continued Filter for “ripple control” mains tones Ever since the 1950s, electric power utilities have been using a technique known as “ripple control” to remotely manage the operation of off-peak water heaters, street lighting and other reduced-tariff loads. Ripple control involves low-speed signalling over the power lines, using bursts of relatively low frequency audio tones superimposed on the AC mains voltage. You can often hear “beeps” resulting from these tones emanating from the tone-operated relays or sequencers on domestic power switchboards, and sometimes even from radiators, fluorescent light ballasts and electric fan motors. The following tone frequencies are used in Australia for ripple control, depending on the distribution company and area: 1050Hz, 750Hz, 492Hz, 396Hz, 283Hz and 167Hz. Some readers have reported problems caused by these tones finding their way into home theatre and PA systems (and even some computers) and have asked for information on building suitable filters. This isn’t as easy as it sounds, partly because of the number of different frequencies involved. The filter also needs to have very low insertion loss for the 50Hz mains power itself, so it doesn’t waste energy or lower the voltage fed to the load. After carrying out several tests, we developed the circuit shown. Although simple, it’s very effective and provides about 34dB of rejection (ie, 50:1 attenuation) for the tone frequency you want to reject, coupled with almost no insertion loss at the 50Hz mains frequency. The filter uses the bridged-T notch filter configuration, with the 15V secondary winding of a small power transformer acting as the inductor. The winding is straddled with a pair of equal-value capacitors (C1 & C2) wired in series. A variable resistor (VR1) connected from the junction of the capacitors to the neutral line forms the tuning/balance control, allowing you to fine-tune the filter for maximum rejection at the desired control tone frequency. The capacitor values shown in the table for the four highest control tones used in Australia were found experimentally using a “2155” type transformer sold by Jaycar Electronics (Cat. No. MM-2002). The values for the two lowest frequencies have been estimated from the measured inductance of this transformer’s 15V secondary winding but should be reasonably close. Note that all capacitor values may need to be changed if you use a different transformer. The capacitors should be metallised polypropylene types rated Use this table to select the capacitor values to suit the control tone frequency in your area. 44  Silicon Chip for 250VAC operation and preferably with a “class X2” rating. However, the higher capacitance values may be difficult to obtain with a 250VAC rating, so you may have to substitute 630V DC rated types instead. We’ve included a table to show how parallel combinations of smaller values could be used to achieve the necessary capacitance, all when using the Jaycar MM-2002 transformer. If you do use a different transformer, you will need to select the correct capacitor values experimentally. This isn’t as difficult as it sounds. First, feed the output of an audio oscillator or signal generator through a small amplifier to provide a good low impedance source of the tone frequency you need to reject. An output level of about 10-20V RMS will be sufficient. Next, connect the amplifier output to the input lines of the filter (in place of the mains supply) and connect a 220W 5W resistor across the output lines as a dummy load. You can then hook up your digital multimeter or ’scope across the load resistor to monitor the output signal level. You will then be able to experiment with the values for capacitors C1 and C2 (and settings for VR1) until you achieve maximum rejection of the tone frequency. Ideally, the correct capacitor values will reduce the output voltage to about 1/50th of the input voltage at the test frequency. One last point; how do you find out which tone frequency is being used in your area? The first place to look is the ripple control decoder box on your own power board. These often have a nameplate showing the control frequency in use. However, if this isn’t the case, you could try asking your power utility company. WARNING: Do not use this circuit. Due to a major oversight, this circuit was not tested at 240VAC which would have highlighted the following drawback. Regardless of the values of the capacitors selected for the ciruit, their reactance will be quite low, resulting in the application of high voltage to the 2W potentiometer which will fail at switch-on. Jim Rowe, SILICON CHIP. siliconchip.com.au PICAXE RGB LED display Having seen the 5mm RGB LEDs that automatically cycle through 7 colours (red, blue, light blue, pink, white & yellow), one of our readers has asked how this could be improved upon using a PICAXE08M. Shouldn’t it be possible to generate many more colours using the power of the PICAXE and an ordinary RGB LED? While it is possible to generate a range of colours (many more than 7) using pulse-width modulation to vary LED intensity, the PICAXE08M supports full-function PWM on one pin only (using the pwmout command). Nevertheless, there are a number of other ways that three PWM outputs can be generated. PICAXE BASIC is not particularly fast for a task like this, so you could resort to programming the PIXAXE08M in native (PIC12F683 assembly language) mode. Another way is to compromise and use the more limited pwm com- mand. It works on any of the -08M output pins but as it only operates on one pin at a time, it’s necessary to multiplex between the three LEDs (colours). An example program demonstrating this is below, while the circuit shows the LED connections. The program could easily be expanded for a more elaborate display. Using this method (each LED on for about one third of the time), the average LED current is about one third maximum, so you could run the LEDs at higher than their maximum continuous current rating to obtain a brighter display. The red LED current may have to be trimmed to get a good colour balance. SILICON CHIP. Program Listing ' RGB LED Demo for PICAXE-08M ' Change next three lines to suit ' LED to PICAXE pin assignments. symbol red_led =1 symbol green_led = 4 symbol blue_led = 2 setfreq m8 b0 = 0 b1 = 0 b2 = 0 main: for b3 = 0 to 254 b0 = b0 + 1 pwm red_led,b0,1 pwm green_led,b1,1 pwm blue_led,b2,1 next b3 loop: for b3 = 0 to 254 b1 = b1 + 1 pwm red_led,b0,1 pwm green_led,b1,1 pwm blue_led,b2,1 next b3 for b3 = 0 to 254 b2 = b2 + 1 pwm red_led,b0,1 pwm green_led,b1,1 pwm blue_led,b2,1 next b3 for b3 = 0 to 254 b1 = b1 - 1 pwm red_led,b0,1 pwm green_led,b1,1 pwm blue_led,b2,1 next b3 for b3 = 0 to 254 b2 = b2 - 1 pwm red_led,b0,1 pwm green_led,b1,1 pwm blue_led,b2,1 next b3 Contribute And Choose Your Prize As you can see, we pay good money for each of the “Circuit Notebook” items published in SILICON CHIP. But now there are four more reasons to send in your circuit idea. Each month, the best contribution published will entitle the author to choose the prize: an LCR40 LCR meter, a DCA55 Semiconductor Component Analyser, an ESR60 Equivalent Series Resistance Analyser or an SCR100 Thyristor & Triac Analyser, siliconchip.com.au with the compliments of Peak Electronic Design Ltd www.peakelec.co.uk So now you have even more reasons to send that brilliant circuit in. Send it to SILICON CHIP and you could be a winner. You can either email your idea to silchip<at>siliconchip.com.au or post it to PO Box 139, Collaroy, NSW 2097. September 2005  45 Circuit Notebook – Continued Morse code practice oscillator This simple circuit uses an LM4871 3W bridged audio amplifier IC from National Semiconductor to create a very simple code practice oscillator. The LM4871 is unity gain stable, requires no output coupling capacitors and can develop over 1W into an 8W load. Undoubtedly, this circuit could be adapted for use in other audio oscillator applications where space is at a premium. A phase shift network comprised of three 16kW resistors and three 10nF capacitors is used to generate the conditions necessary for oscillation. With the values shown, we would expect the circuit to oscillate at about 400Hz. A trimpot (VR1) provides a means of adjusting the amplifier gain. Following usual practice, the combined value of the trimpot and 470kW series resistor must be at least 29 times greater than the 16kW value connected to pin 4 of IC1 to achieve oscillation. The LM4871N is available from RS Components (stock no. 349- Craig Kendrick Sellen, Carbondale, Pennsylvania, USA. ($35) 4969), on the Internet at www. rsaustralia.com or phone 1300 656 636. The Latest From SILICON CHIP NOT A REPRINT – Completely NEW projects – the result of two years research & development • Learn how engine management systems work • Build projects to control nitrous, fuel injection and turbo Fro m the pu bli sh ers 160 PAGES 23 CHAPTE RS of boost systems • Switch devices on and off on the basis of signal frequency, temperature and voltage • Build test instruments to check fuel injector duty cycle, fuel mixture and brake and coolant temperatures • Speedo Corrector, Turbo Timer & Digital Thermometer Projects Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas: $A26.00 via airmail. Intelligen t turbo timer I SBN 095 852 9 7809 5 294 - 4 $19.80 (inc GST) NZ $22.00 (inc TURBO B OOST & ni trous fuel 8 5229 46 GST) controllers How eng in managemene t works Order by phoning (02) 9979 5644 & quoting your credit card number; or fax the details to (02) 9979 6503; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 46  Silicon Chip siliconchip.com.au THE AMATEUR SCIENTIST Two incredible CDs with over 1000 classic projects from the pages of Scientific American, covering every field of science... Arguably THE most IMPORTANT collection of scientific projects ever put together! This is version 2, Science Fair Edition from the pages of Scientific American. As well as specific project material, the CDs contain hints and tips by experienced amateur scientists, details on building science apparatus, a large database of chemicals and so much more. “A must for every science student, science teacher, science lab . . . or simply for those with an enquiring mind . . .” ONLY 49 $ 00 PLUS $7 Pack and Post within Australia (Overseas orders: please refer to Page 91 of this issue) Just a tiny selection of the incredible range of projects: ! Build a seismograph to study earthquakes ! Make soap bubbles that last for months ! Monitor the health of local streams ! Preserve biological specimens ! Build a carbon dioxide laser ! Grow bacteria cultures safely at home ! Build a ripple tank to study wave phenomena ! Discover how plants grow in low gravity ! Do strange experiments with sound ! Use a hot wire to study the crystal structure of steel ! Extract and purify DNA in your kitchen !Create a laser hologram ! Study variable stars like a pro ! Investigate vortexes in water ! Cultivate slime moulds ! Study the flight efficiency of soaring birds ! How to make an Electret ! Construct fluid lenses ! Raise butterflies as experimental animals ! Study the physics of spinning tops ! Build an apparatus for studying chaotic systems ! Detect metals in air, liquids, or solids ! Photograph an ant's brain and nervous system ! Use magnets to make fluids into solids ! Measure the metabolism of an insect . . . ! and many, many more (a thousand more, in fact!) See the review in SILICON CHIP, October 2004. . . or read on line at www.siliconchip.com.au HERE’S HOW TO ORDER YOUR COPY: BY MAIL:# BY INTERNET:^ BY PHONE:* (02) 9979 5644 9-4 Mon-Fri BY FAX:# (02) 9979 6503 24 Hours 7 Days <at> BY EMAIL:# silchip<at>siliconchip.com.au 24 Hours 7 Days PO Box 139, Collaroy NSW 2097 * Please have your credit card handy! # Don’t forget to include your name, address, phone no and credit card details. siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information There’s also a handy order form on page 91 of this issue (SILICON CHIP Bookshop pages). Exclusive in SILICON Australia to: CHIP www.siliconchip.com.au siliconchip.com.au September 2005  47 SERVICEMAN'S LOG Oh, Goodie – A VCR To Fix With the prices of new DVD players and VCRs reaching record lows, I don’t get to see many for repair these days. Recently, though I had a VCR to fix – ahh, the good old days! As predicted, the GST not only crippled the service industry but has also contributed to an unprecedented pollution problem. In NSW, we currently dump about 115,000 tonnes of electronic equipment per year, with huge piles of unwanted gear containing dangerous chemicals going directly into landfill and eventually into the water table. Did you know, for example, that every large-screen TV tube has about 2kg of lead in it? Or that other components may contain cyanide and other poisons? Perhaps it’s time to consider the real costs of disposing of electronic equipment and build those costs into the purchase price. One suggestion is to sell consumer electronics with a prepaid voucher system – say $50 to dispose of your television thoughtfully and another $50 in refundable coupons towards the cost of maintaining and servicing the set, thereby prolonging its life. But enough of these musing! Re- Items Covered This Month • • • • • • • Marantz SR19 AV receiver Samsung SV-631B hifi VCR Sony KV-EX29M39 TV set (AG3E chassis) Sony KV-3400ASD TV set (GP2-A chassis) Panasonic TX68PS12A TV set (MX10A chassis) Philips 29PT9418/79G TV set (MG3.1A chassis) Sony KV-ES29M31/SAU3 TV set (AG3 chassis SCC-P92A-A) 48  Silicon Chip cently, Michael Bebbington brought in a Samsung SV-631B hifi VCR which was built in 2000. He was rather vague about precisely what was wrong with it but did mutter something about it not recording and chewing tapes. He didn’t want to buy a new one as it matched the rest of his Samsung gear, which is fair enough. When I got it on the bench and removed its cover, everything initially appeared to be OK. The tape went in and all the functions worked. However, on closer examination, I noticed that when the tape was inserted, it sometimes made scraping noises within the cassette case. What’s more, in fast forward and rewind modes, the pinch roller remained in contact with the tape and capstan shaft, making it run very slowly. I also found that after playing a tape, it wouldn’t automatically go into rewind mode, nor would the “express” or “jet” rewind modes work. To begin with, I thought that this might be a mode select switch problem. As a result, I removed the deck mechanism to expose the switch, sprayed expensive switch cleaner into it and rotated the switch through 360° several times. Unfortunately, this made no difference so I tried cleaning the heads (especially the ACE head) but this had no effect either. Next, I removed the deck again and took a much closer look at the mechanism. I then noticed that the frontloading lever arm assembly, which connects the two sides of the cassette cradle housing, had plastic receptacles on either side. These both had cracks in them and this in turn meant that the cassette was a rather sloppy fit as it went down onto the deck. Initially, I tried re-gluing them with superglue but in the end was forced to concede that they needed replacement (KS30 part no: AC66-30546A).The question was, did they fail of their own accord or because Michael had tried to force out a jammed cassette? Next, I examined the reel assembly, as this is a classic area for faults in video cassette decks. I removed the belt, pulley and reel brakes until I got to the centre gear assembly. Here I discovered three minute cracks in the clutch assembly – just the sort of fault I was looking for. As a result, I ordered a new part for this (K221 Part No: AC66-20581A), as well as a new clutch holder assembly (K200, Part No: AC61-21012A). When the parts (now coloured blue) arrived, I reassembled them but this took several attempts to get it all right. The fact is, it’s rather difficult to remember how everything goes back together again, because of all the springs and plastic lever clips. However, once done, the performance difference was huge. Not only did the pinch roller no longer engage the capstan shaft during fast forward or rewind but the speed was at least 10 times faster. Unfortunately, Michael could only point out that the repair cost about half as much as buying a new VCR so he wasn’t entirely happy – not for something he perceived as “a small adjustment”! However, he had (rather begrudgingly) accepted the quote beforehand, so he couldn’t complain too much. Marantz AV system Bill Douglas brought in his 1999 Marantz SR19 AV surround receiver, complaining there was no sound. This rather impressive unit features Dolby AC-3 5.1-channel surround sound and is capable of 125W RMS into 8 ohms per channel. As can be imagined, those specifications didn’t come cheap back in 1999 – not at around five grand! The fuses were all OK and a quick siliconchip.com.au check for DC offset on each of the outputs showed close to 0V, suggesting that the outputs hadn’t blown. The power supplies were also all OK, the B+ rails measuring ±64V (these should be ±56V on load). The tuner mode also checked out. However, there was no signal on the PL04 pre-out sockets and after tracing the signal to the digital pro-logic board, it was apparent that the muting relays weren’t working. So the fault was somewhere in the mute circuit. This Marantz receiver/amplifier is a very complex unit. The muting circuits on their own are quite extensive and include the protection circuits. In fact, there are no less than nine relays in this unit! The circuit shows that the relay driver IC (QN01, TA7317P) – which is on board P754 – drives transistor QN02 (DTC144ES). This in turn controls QN04 and LN01 and also dovetails into the relay control bus. Transistor QN03 (2SA970) is part of the protection circuitry and monitors five current sensor detection transistors – Q729, Q730, QT29, QP29 & QP30 – at the output of each amplifier. This transistor then controls pin 9 of IC QN01. However, the voltages here were not correct and measured considerably less that the 3V shown on the circuit. One problem with this receiver is that the internal access is difficult, simply because it has so much circuitry. This means that you have to dismantle some of the assemblies to get to individual PC boards, in order to make detailed DC measurements and check components. This all takes time and so you need to approach the job logically to avoid going over the same ground twice. Although the transistors on the P754 board all measured OK, I decided to replace them and any nearby electrolytic capacitors as well. That done, I moved on to the power amplifier board which is designated P704. First, I removed the five plugs to the top boards and noticed that the BIAS plug (JY13) was dry-jointed. I then checked all the other plugs and also found the connections to JT13 to be poor. Apart from that, everything looked OK and because I had actually identified a problem, I reconnected everything for a quick test. Amazingly, the receiver powered up but only two channels were worksiliconchip.com.au ing – front-right and rear-left. It was then that I noticed I had forgotten to reconnect one of the plugs (J703) to the main ±B rails. However, when I reconnected that, the protection circuit immediately cut in and I was back to square one again. Rats! Fortunately, though, I now had a clue – the problem obviously lay in one or more of the three amplifiers that weren’t working. As a result, I disassembled them completely and found that two of the amplifiers had been seriously damaged despite there being no visible evidence. Changing all the transistors and some of the resistors fixed the problems, however it was a bit of hit or miss affair. Basically, you have to make sure you change all the faulty parts at one go, otherwise the whole lot will have to be removed again. Fairly obviously, these two amplifier stages were damaged by the dry joints to the bias plugs. Fixing them took a lot of time and effort and I really don’t think Bill appreciated just how much work went into his receiver. The reluctant Sony Arthur Beecroft’s Sony KV-EX29M39 TV set (AG3E chassis) was under extended warranty and had to be picked up. The problem was that the set turned itself off after five seconds – or so said Arthur. In practice, I found that it really didn’t quite get that far, as there was never a picture for me. However, I did notice that the red LED was flashing six times, which denotes a problem in the horizontal deflection circuit. The protection circuit for the line output stage is fed from the collector of transistor Q6808 via two series capacitors – C6837 and C6838. As for the service manual, it suggests that the fault condition could be due to C6831 (6200pF 1.5kV, part No. 111783521) going open circuit, in turn causing excessive EHT. This capacitor checked out OK but I replaced it anyway – it made no difference! By disabling the protection circuit a bit at a time, I eventually found that removing the x-ray protect from pin 27 on CN6819 to the D1 board restored the picture and sound. However, there was no east-west correction, either in pincushion or width. I checked the 9V supply to the D1 board and this was OK. This board has a series of quad AND gates (LM393N Want cheap, really bright LEDs? We have the best value, brightest LEDs available in Australia! Check these out: Luxeon 1, 3 and 5 watt All colours available, with or without attached optics, as low as $10 each Low-cost 1 watt Like the Luxeons, but much lower cost. •Red, amber, green, blue and white: Just $6 each! Lumileds Superflux These are 7.6mm square and can be driven at up to 50mA continuously. •Red and amber: $2 each •Blue, green and cyan: $3 each Asian Superflux Same as above, but much lower cost. •Red and amber: Just 50 cents each! •Blue, green, aqua and white: $1 each. Go to www.ata.org.au or call us on (03)9419 2440. Select your microcontroller kit and get started... From $295* RCM3400 Fax a copy of this ad and receive a 5% discount on your order! Feature rich, compiler, editor & debugger with royalty free TCP/IP stack • Prices exclude GST and delivery charges. Tel: + 61 2 9906 6988 Fax: + 61 2 9906 7145 www.dominion.net.au 4007 Ozitronics www.ozitronics.com Tel: (03) 9434 3806 Fax: (03) 9011 6220 Email: sales2005<at>ozitronics.com USB PIC Programmers - $68.20 K128 – Flash PICs only, powered from USB K149 – USB or Serial, ICSP, 17VDC K150 – USB only, ICSP, 17VDC K182 – ICSP only, fully assembled - $61.60 40 Pin Wide Slot ZIF Socket - $16.50 If purchased with PIC programmer - $13.20 PIC Microcontrollers PIC16F84A-04/P, PIC16F628-20/P - $8.80 each USB cable, A-B, 2 metre - $8.80 Prices include GST – shipping extra. Full documentation available from website. September 2005  49 Serviceman’s Log – continued and µPC358C) which have been known to fail, so I replaced IC4800 through to IC4804 with sockets and ordered replacement ICs. I then left the set on the bench plugged into the power point which was turned off and with the D1 board unplugged. Unfortunately, while I was out, someone unplugged the TV, used another appliance, then plugged the set back in again with the power on. The effect of this was to change the LED flashing from 6x to 2x, which denotes a +B overcurrent (OCP) mode. The manual suggests that Q6807 and Q6810 are probably the cause in this case. However, I found that it was in fact Q6808 (2SC5480-01) and Q6810 (IRF1830G) that were at fault, having gone either short circuit or very leaky. Replacing both these not only restored the picture but also fixed the east-west problems, even when the x-ray protect pin was resoldered. I guess you have to be lucky sometimes. By the way, Q6807 and Q6808 are a real pain to remove in this set. They are vertically mounted on heatsinks and Q6807 cannot be removed without first removing Q6808 and its heatsink. And that’s because the mounting screw cannot be accessed unless you have a custom tool for the job. Large-screen Sony Sam Pritchard’s Sony KV-3400ASD TV set came in on the back of his ute, as it was too big to fit in his car. This 50  Silicon Chip 80cm set was built around 1989 and the problem was that it turned itself off after about half an hour. Unfortunately, the fault proved to be very haphazard. Sometimes, the set would work all day without problems, while on other days it would switch off seemingly at random. This set employs a GP-2A chassis and this has been pretty reliable over the years. What’s more, I hadn’t ever encountered an intermittent fault like this so where was I to start? I couldn’t sit around all day waiting for the fault to occur, so I decided to start with a few basic checks. The power supply appeared to be OK, with all five voltages being present. When the set is “off”, the 135V rail rises to nearly 150V. However, this isn’t surprising as two transistors (Q651 and Q652) switch in a 2kW load resistor (R603) in the standby mode. Because the power supply is one of the few areas that can cause strife (and is buried in the bilges of the set), I decided to start getting serious here. This initially involved replacing all the electrolytic capacitors, after which I resoldered the PC board to within an inch of its life! Off course, this made no difference but it made me feel that I could at least cross two jobs off my “to-do list”. I also checked Q651 and Q652 out of circuit and replaced C655 and C656 on the 7V and 15V lines. Next, I examined the deflection board (D). I checked for cracks in the board tracks near the clips and hinges and also kept an eye out for any suspicious solder joints and dried out electros. In particular, I concentrated on resoldering L801 and L806 in the east-west circuitry, as well as the flyback and IC regulators (IC1704 and IC503). None of this made any difference, so I moved on to the 47kW resistor between Q806e and Q807c. This resistor isn’t shown on the circuit diagram and had a piece of black insulation beneath it. Eventually, after many years, this insulation becomes conductive, causing symptoms similar to the ones I was experiencing with B+ protection. Again, this made no difference. Instead, the work I had done had actually made things worse. The set was getting harder to switch on, which was great because it meant that I could start getting to grips with the problem. Checking further, I found that IC503 wasn’t always delivering 12V on its pin 3. This device is an STR90120 12V “controllable” (or switchable) IC regulator and is fed from the 15V rail. However, I wasn’t sure whether it was the IC itself or the standby circuitry that was at fault, as the voltage on pin 2 and the ST-BY bus wasn’t changing and was low. The ST-BY bus originates from pin 41 of the “System Control Microprocessor (IC001). The circuit shows this voltage to be 7.4V, which must be a mistake as it is pulled high by R010 and CP005 to the 5V rail. However, on other circuits for similar models, it is shown as being pulled high to the 5V rail by R010 and to the 12V rail by CP005! The ST-BY bus wanders all over the K board, performing all sorts of muting tasks, before going over to the F1 power board and to pin 2 of IC503 via R5512. I spent a lot of time analysing this ST-BY bus, looking for shorts and disconnecting it all over the place, until I finally woke up that it should be high in the “Standby” mode and low in the “On” mode. However, in this set, the micro was unable to switch it from “On” to “Standby” and that just left IC503, which I then ordered (Part No. 874992060). siliconchip.com.au When fitted, it finally fixed Sam’s problem for good. I also replaced the 1mF capacitor (C5501) on control pin 2 and C55602 on pin 4, just for good measure. Intermittent Panasonic I had a 2001 Panasonic TX68PS12A (MX10A chassis) arrive on my workshop bench with a litany of intermittent faults. These included low height, a faint on-screen display (OSD), over-brightness and no tuning. Apparently, these faults all appeared after a “power surge”. So what could be a common factor with all these symptoms? Well, when in doubt, always measure all the power supply B+ rails. Unfortunately, there are a lot of supply rails in this set and some are difficult to access but I persevered. I checked the 140V, 12V, 9V and 5V rails, plus a second 5V rail, and all were OK. Well, not quite – the second 5V rail on TPA323 was varying slightly. I used an old-fashioned analog meter, a can of freezer and a hairdryer to track this fault down. And it didn’t take long to determine that regulator IC884 (PQ05RD1B) was unstable. A new one fixed the problem. A haughty customer Mr Symons came in with his Philips 29PT9418/79G TV set (MG3.1A chassis), complaining rather haughtily that he was disgusted his set had had the temerity to (intermittently, mind you) turn itself off – without permission even! Well, I said, I would look into it for him as soon as possible. As it happened, I was having one of those rare days when everything was going right (I should have bought a lottery ticket) and I stumbled upon the cause fairly rapidly. After a few quick voltage checks, I noticed that the +11V rail was varying intermittently on the cathode of D6237 on Board B and when I finally worked out how to disassemble the power board, I found an almost invisible hairline fracture around pin 2 of transformer T5204 in the DC-to-DC converter circuit. siliconchip.com.au September 2005  51 Serviceman’s Log – continued I was quite chuffed with myself for finding the fault so quickly but Mr Symons was less impressed. He duly collected it with bad grace, probably upset that he hadn’t had the chance to have an even longer whinge than he did when he first arrived. Anyway, I thought that would be the end of him until a couple of weeks later, when I heard his voice again at the front counter, demanding immediate attention. He immediately made it clear that I was obviously the incompetent who was masquerading as a TV technician and who should obviously be sacked – but only after rectifying the problem that I had created on his telly! Well, when we got down to brass tacks, the fault he now had was in fact entirely different (which he was not prepared to concede). This time, the vertical deflection was intermittently scanning and causing bottom fold-over. Unfortunately, this fault didn’t show up immediately and just when I was about to put it down to a quirk of his imagination, I saw the problem. And now that I had seen it, it wasn’t too long before I found the problem to be a number of dry joints on IC7600, the vertical output IC on board A3 underneath the set. 52  Silicon Chip Well, despite the fact that this fault was totally unrelated to the first and was in a completely different part of the set, I couldn’t get it into Mr Symons’ thick head that I was in no way responsible for the problem. In the end, I had to wear the repair because he was one of those idiots you just can’t reason with. But I had the parting shot – I told him that in future, he would have to take his service problems elsewhere. I don’t enjoy working for nothing! The reluctant Sony Paul Sandringham brought in his 1999 Sony KV-ES29M31/SAU3 (AG3 chassis SCC-P92A-A), complaining that there was no picture and the set would try to start and then switch off. When I tried it, it also gave a LED error code 4 (ie the LED was flashing four times). Based on my previous experience (this chassis is similar to the AE5), I went straight to Q68087 (2SC5480-01) and replaced it as it was short circuit. The set was now able to start but there was still no picture, Instead, it just showed a rolling raster or, at least, one with a vertical jitter with OSD menus. What’s more, I couldn’t tune in any stations, nor could I get any signal input up on the screen. I decided to start with the J Board and trace a colour bar signal I injected into AVI with the oscilloscope. Well, I didn’t get very far, because there was no 5V rail anywhere on the J Board. This rail is supplied via IC8304 (LF50 CDTTR), an SMC 5V IC regulator, which is in turn fed with +6.5V via pins 12 & 1 3 of plug CN8304. It was then that I also noticed IC8304 was getting extremely hot, no doubt due to a short circuit on the 5V rail. The J Board has 10 3-pin feedthrough inductors (for EMI suppression) which are susceptible to going short circuit. Fortunately, there are only six on the 5V rail but it still took some time to remove them from the double-sided PC board and replace them. However, this wasn’t the problem area; instead, it was one of the three modules (BC4, A1 and IC8314) which are soldered onto the J Board. These too are difficult to remove and you have to remember which way the metal screens go on when removing them. If you don’t, you will find (as I did) that there are two ways the IC cover can be fitted – one of which won’t allow the J module to fit back onto the main chassis. There is also a little fibro insulating washer that prevents the IC8314 module from shorting to ground, so care has to be taken to ensure this goes back in. By the way, the circuit for this module isn’t shown in the service manual. When I removed the BC4 module (Y/C separator and comb filter), the short cleared. Inside the module, almost everything was surface mounted and not easy to remove and replace without damage. Eventually, I found that the 37mH EMI feedthrough (FL2007), which feeds the 3.3V IC regulator, had shorted. Unfortunately, in the course of all this, I also managed to damage L2004 and Q8313, as considerable force has to be used in prying some of the components out. These parts were also replaced, after which the unit was reassembled. It now all worked perfectly – much to my relief. SC siliconchip.com.au 40Ch UHF CB Transceiver Wireless Internet Antenna Having trouble getting unwired? This wireless modem antenna replaces the existing 'rabbit ear' on your wireless broadband modem and boosts the signal to improve coverage. It can also improve performance in difficult areas. The antenna can be mounted inside the house or in a modem not included protected outside location for optimum reception. Supplied with Cat. AR-3274 N type to MCX lead & mounting bracket. $ .95 •Size 135(W) x 160(H) x 30(D)mm. Illuminated House Number Solar powered illumination! This clever idea makes house numbers easy to see at night. It works by illuminating the number from behind with a bright LED & is charged by a built-in solar cell (Number inserts included). Several modules can be clipped Cat. GH-1830 .95 together to form multiple digit numbers. $ 129 MPEG4 Player 14 NEW STORE IN SUNSHINE VICTORIA OPEN 204 MCINTYRE ROAD SUNSHINE VIC 3020 DAYS Ph: 03 9310 8066 Fax: 03 9310 8077 Great for the car or home! Here is a great way to enjoy movies, music and picture slide shows on your TV or PC monitor. It accepts most memory cards so all you need to do is load the files on the card, pop it in, and you’re away! Supports MPEG4 encoded files in MPG, DAT and AVI formats and can also play music and image files. Cat. XC-4865 See our website for details. $ .00 •125(W) x 22(H) x 83(D)mm. 199 Mini Digital Video Camera A digital camera for under $200! This easy to use camera fits in the palm of your hand. The recorded video can be transferred to a computer for editing or simply viewed directly on any TV with AV inputs. Features include a 3.1 Megapixel software resolution for stills, 1.5" colour LCD screen, 5 layer glass lens; 32MB internal memory, SD/MMC expansion slot, 4 x digital Cat. QC-3230 SAVE zoom, internal microphone $ .00 $20 and lots more! Was $199 179 7 NEW KIT - Bilge Sniffer Minimise the risk of boating explosions Ref: Silicon Chip September 05 Fit the bilge sniffer to your boat and it could save the boat and your life. It automatically turns on bilge exhaust fans when explosive gases are detected when incorporated with the engine starter or ignition circuit, locking out the engine if hydrocarbons are detected. Detects iso-butane, propane, and LPG the three main sources of A MUST hydrocarbons from petrol, FOR PETROL diesel fuel and propane gas. BOATS •Power source: 12V DC •Recommended enclosure: Cat. KC-5416 UB3 HB-6013 $3.50 ea. $ .95 39 DON’T FORGET YOUR FREE BATTERIES REDEEM YOUR SEPTEMBER COUPON FROM INSIDE YOUR 2005 CATALOGUE TODAY! STOP PRESS STOP PRESS STOP PRESS STOP PRESS STOP PRESS 1GB Portable MP4 / MP3 Player with Voice Recorder FM Radio and Picture Viewer Watch full length movies on the go Check this out! This blows conventional MP3 players and solid state flash disks out of the water! At first glance, you might think that it is just an MP3 player with a LCD screen, but that is just the tip of the iceberg. This unit is feature packed, just check out the line-up! •MP3 player of course, the most obvious feature, the 1GB capacity allows storage of a few hundred songs! •JPEG picture viewer - you can run slideshows for you and your friends - great in this digital age. •Built-in FM radio - so you can catch up on the news, or listen to the latest chart-topping hits. •Voice recorder - so you can take voice notes or record conversations (with permission of course). •MPEG-4 player - so you can watch full length movies on the go! NOW AVAILABLE It measures just 75 x 37 x 14mm, and weighs less than 40g! Cat. GE-4006 The 1.3" high resolution TFT LCD screen provides crystal clear $ SAVE pictures, and is the perfect way to keep yourself entertained. $50 See our website for full details. Was $399 349 New low price! This lightweight handheld transceiver is suitable for all manner of professional and leisure activities. This is a quality UHF radio and, whilst just 0.5W output, it is NOT a toy. Open field transmission range is up to an incredible $34.95ea 5km, with typical city or buy 2 for range up to 1km. $59.95 Was $39.95 Cat. DC-1010 SAVE $5 Wireless Weather Station with Wind Direction & Rain Gauge Wireless sensors! The system monitors inside and outside temp, air pressure, rainfall, humidity, wind speed and direction, and wind chill factor. Check our website Cat. XC-0293 for all the $ .00 features. 249 Lead Acid Battery Zapper Kit Extend the working life of your lead acid battery! Ref: SC July ‘05 This simple circuit is designed to produce bursts of high-energy pulses to help reverse the damaging effects of sulphation in "wet" lead acid batteries. This is particularly useful when a battery has been sitting for a length of time without use. Its effects are dependent on the battery’s condition and type, but the results can be quite impressive. Kit supplied with case, Cat. KC-5414 silk screened lid, leads, inductor and $ .95 all electronic components. 39 Attn: All You “Tim The Toolmen” (The Wealthy Ones Anyway) We now stock the US-Designed Grabit damaged screw removal tool, but BOY it’s expensive!! What it does. If you have a typically, (but not necessarily) countersunk screw that is slotted, Phillips, Posidrive, Torx, Tri-Wing, tamper resistant, etc that is totally stripped out, this product will get it out - even if the head is totally hollow! All of us “Tims” have experienced this! The extraction bit consists of a burnishing bit that basically preps a tapered hole in the screw head. You turn the bit around with the extractor bit out, reverse the cordless drill direction and the extractor bit bites into the prepped hole with tremendous force. Works equally well on brass, steel, stainless screws etc. The TD-2059 consists of two 1/4” hex drive bits that cover screws from #6 to #14 gauge. In days when a 12V cordless drill can retail for $25 this Cat. TD-2059 $ .95 product may seem expensive. What it can do for you is priceless. 49 STOP PRESS STOP PRESS STOP PRESS STOP PRESS STOP PRESS FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au 1 Great New iPod Accessories! iPod USB Data Cable Attention PC users! A replacement cable for a lost or broken iPod data cable. Works with all iPods that use the 30 pin Apple connector. Commonly used on Windows computers. Cat. WC-7692 $ .95 14 iPod Firewire Data Cable Attention Mac users! A replacement cable for a lost or broken iPod data cable. Works with iPods that use the 30 pin Apple connector. Commonly used on Macintosh computers. Massive portable storage! Instantly add gigabytes of storage to your PC or notebook. You can use any 2.5" IDE HDD, and then plug it into your USB 2.0 port for super fast backup, transfer, and storage. Includes carry pouch, Cat. XC-4678 $ .95 cable, and drivers (only required for Win98). 49 Notebook Docking Station USB Powered Battery Charger Cat. WC-7690 $ .95 14 Very useful! Charge and update your iPod easily with this cradle. It will charge the battery and you can connect the USB or Firewire cable to update your Cat. XC-4930 iPod not .95 playlists etc. $ SAVE $4 Recharge your batteries while you download your photos! Why use another mains outlet when you can utilise the USB power at hand. Charge up to 4 x AA or AAA, Ni-MH or Ni-Cd batteries. Was Cat. XC-4950 $ .95 $19.95 300k Pixel SurfCam USB Web Camera 128MB USB 2.0 Flash Disk with Memory Card Reader Portable iPod / MP3 Player Dock and Speakers Very handy! Not only is this a handy USB 2.0 flash disk, it also houses a card reader that can read Memory Stick, Secure Digital, and Multimedia cards. Fully compliant with USB 2.0 specification for ultra fast data Cat. XC-4750 $ .95 transfer. Cat. XC-5163 $ .95 89 Computer Speakers These speakers sound as good as they look! •Subwoofer: 3” driver 10WRMS 133(W) x 145(D) x 252(H)mm •Satellites: 2” drivers 1.5WRMS 114(W) x 80(D) x 195(H)mm •12 volt plug pack included Cat. XC-5167 $ .95 39 69 Desktop Multimedia Microphone 179 PCI Wireless Network Interface Card •IEEE 802.11g wireless network compatible. Interoperation with IEEE 802.11b 11Mbps networks. •64 / 128 Bit WEP encryption. •54Mbps high speed transfer rate. •40 - 100m indoor range. •100 - 300m outdoor range. Cat. YN-8066 •Low power consumption. $ .95 •Plug and Play compatible. •Compatible with Win98/SE/2000/ME/XP 69 USB 2.0 Wireless Network Card •54Mbps Cat. YN-8067 $ .95 89 2 35 19 Key USB Numeric Keypad Great for laptops! One key feature that doesn’t come with a notebook computer is the numeric keypad. Sure it is overlayed on other keys, but it just isn’t the same. This unit is compact and Plug n Play, so it is very easy to use. Cat. XC-5155 $ .95 USB Magnifier Lamp Ideal for voice recognition! It can sit on your desktop, or be attached to your monitor. It produces low noise and has a wide frequency response for more natural sound. 3m lead Cat. AM-4087 to 3.5mm plug. $ .95 Utilise USB power and take the strain off your eyes. A 50mm diameter glass lens provides great magnification while a built in lamp lights your Cat. ST-2809 work. $ .95 12 19 Laser Pointer with Line and Arrow PCMCIA Wireless Network Card Installing network cables can be a hassle, and what if you are renting? This router allows communication with up to four wireless networked computers. It includes support for WAN, web-based and remote management, auto detection and configuration of ISP, Cat. YN-8086 built in firewall, and more! $ .00 •IEEE 802.11g and IEEE 802.11b compatible. •Up to 54Mbps data rate. •Static and dynamic routing. •VPN pass through. Video conferencing and more! It uses a 300k pixel colour GREAT CMOS sensor with auto VALUE exposure and white balance for optimum performance. Software included for creating greeting cards and photo albums. Cat. QC-3223 $ .00 29 WIRELESS NETWORK PERIPHERALS Wireless Network Access Point 802.11G with 4 Port Switch No more cable tangles! Leave your peripherals connected to the dock, and just plug/unplug a single Cat. XC-4860 cable! Includes 4 port USB 2.0 hub, $ .00 Ethernet, serial, and 2 x PS/2 connections. 139 15 included Featuring 1.5" micro speakers, & an internal amplifier, they sound great. It all folds up to a neat 286g package when not in use too. Powered by 4 x AAA batteries not included. •iPod not included. 2.5" IDE - USB 2.0 Hard Disk Drive Case Relax at your computer! The USB powered device contains lavender scented wax that fills your workspace with a calming fragrance that is said to soothe the mind and heal the body. Works with your own fragrances too! Cat. GH-1044 $ .95 19 iPod Data / Charging Cradle and Cables 29 USB Aromatherapy Diffuser The laser image changes as you turn the tip of the pen from arrow, to a line or to the normal red laser dot. Use the laser line to emphasise a word, Cat. ST-3106 $ .95 direct movement using the laser arrow or simply point out aspects of your presentation with the conventional red dot. Made from sturdy metal and uses 2 x AAA batteries (not included) •54Mbps 80211G SAVE $20 Was $89.95 Cat. YN-8068 $ .95 29 69 WiFi Hot Spot Finder Check for the presence of wireless network hotspots without the hassle of unpacking & booting-up your notebook computer. This key-fob sized device will tell you when you are in a WiFi capable location and indicate the strength of the signal at the press of a button. Will also detect the signals transmitted by wireless surveillance cameras they may be observing. Cat. XC-4885 •Size:75(L) x 37(W) x 10(D)mm. $ .95 •2 x CR2032 batteries included. 39 USB Bluetooth Dongle Class 2 SAVE $10 Supports Windows 98SE, 2000, & ME. Get short range wireless connectivity with mobile phones, PDAs, some keyboards and mouse Cat. XC-4890 products with this USB Bluetooth $ .95 dongle. Was $49.95 39 Laser Pointer with Power Point Remote Control SAVE $5 Power Point presentations are a great way to get information across to a large audience. This excellent device incorporates "Page Up" & "Page Down" buttons into a stylish laser pointer. The combination allows you to move around the room and still run your presentation and point-out items of interest. This is one of those truly useful devices that make a job so much easier and with Cat. ST-3108 $ .95 a transmission range over 15m you can’t go wrong. Was $49.95 44 4 in 1 Pen/PDA Stylus/Laser/Torch Looks like an ordinary biro but includes a laser pointer, torch and PDA stylus. Presented in a metallic silver case that Cat. ST-3101 would make an ideal gift for the $ .95 lecturer or student. 24 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au LCD Virtual Goggles 2.4GHz Wireless Audio Video Senders Noise Cancelling Headphones Watch cable TV all over the house! Send a signal from a DVD player, settop box etc., to another room, without the use of any cables! You can use as many receivers as you like, without degrading signal quality. Each unit comes supplied with stereo audio and video transmitter and receiver, mains plugpacks & RCA cables. Transmission range is up to 100m, but depends on the type of construction materials used. Cat. AR-1832 SAVE $ .95 Was $99 $29.05 Take the cinema screen with you! Enjoy private viewing of your TV/DVD/VCR or games console with these lightweight goggles. So portable they can be used in a car to enjoy DVD player entertainment, or connect it to a video games console such as PLAYSTATION, XBOX, etc. Supplied with cables & power adaptor. 800 x 225 (180,000) pixel resolution. Cat. QM-3790 SAVE $ .00 Was $399 349 $50 69 Sleep soundly! Designed for use in noisy environments such as an aircraft or in cars. Can reduce background noise Cat. AA-2054 by as much $ .95 as 15dB. Extra receiver to suit Cat. AR-1833 Was $69 49 49 HIGH DEFINITION Digital Terrestrial TV Card for PCs HDTV on your computer! Watch high or standard definition TV on your PC! It supports wide-screen (16:9) and standard (4:3) aspect ratios. •PCI Card version Cat. XC-4819 Was $179 $ .00 NOT AVAILABLE IN NZ With the addition of an IR remote control repeater you can change the channel of the source device etc from the Cat. AR-1830 other room. $ .95 Was $139 SAVE $10 Top quality reception! No need for physical hardware installation, just plug it into your USB 2.0 port for HDTV. It operates in enhanced 16:9 format with software supplied for DVD making and manipulation. See our website for Cat. XC-4814 system requirements. $ .95 NOT AVAILABLE IN NEW ZEALAND 249 XPERT DVD Maker SAVE Convert all your old VHS tapes and $50 camcorder cassettes to DVD! XPERT DVD Maker converts on the fly, so there is no need for excessive amounts of free disk space. All you need is a DVD Cat. XC-4811 $ .00 burner and you can store your memories forever! Was $149 99 USB 2.0 DVD Maker Cat. AR-1831 $ .95 69 800WRMS Class D • 1 x 400WRMS <at> 4 ohms. • 1 x 700WRMS <at> 2 ohms. • 1 x 820WRMS <at> 1 ohm. AA-0428 399.00 $ Kevlar Cone Coaxial Speakers Fantastic quality! This new range of coaxial speakers offer high performance and great looks. They retain the large super tweeter that made last year’s range great, but the new Kevlar cones take them into a realm of their own. Check out our catalogue on page 229 or our website for full details. 4" Kevlar 2 Way Cat. •40WRMS power. CS-2320 •86.5dB sensitivity. $99.95 5" Kevlar 2 Way Cat. •50WRMS power. CS-2322 •89.5dB sensitivity. $109.95 Cat. 6.5" Kevlar 2 Way CS-2324 •75WRMS power. USB 2.0 Video Capture Box Fantastic sound! A new design of our previous Kevlar split speakers, they sound great. They have a great sounding 25mm soft dome tweeter, as well as separate crossovers for optimum performance. Cat. QV-3090 $ .00 99 •91.3dB sensitivity. 6" x 9" 2 Way •80WRMS power. •93.5dB sensitivity. 119.95 $ INTERNET> www.jaycar.com.au Affordable at last! Spectacular U.S. Stock Purchase All Audiophiles know that Don’t ribbon tweeters Miss are the ultimate speaker Out! for smooth high (and very high) frequency performance. Unfortunately, a good ribbon tweeter can cost between $100 and $500 - to thousands for some custom German ones. Even high-end enclosure manufacturers all opt for dome tweeters simply because "ribbons" add too much to system cost. Jaycar have made a massive stock purchase from a major US organ manufacturer who makes both pipe and electronic organs. They are an 80+ year old company and we cannot tell you who they are! They are restructuring their production of their high-end organs and their stock of ribbon tweeters has been sold to us far, far below the 10,000+ factory gate price! Their massive loss is your gain. The tweeter is made in Japan by the venerable manufacturer, Foster. The device itself has multiple ribbon "diaphragm" components in same phase configuration. There are two basic types of ribbon tweeters, static or dynamic type. This product is the dynamic type which has conventional impedance 8Ω and is more efficient. Each speaker is supplied with a datasheet and securely packed. Even if you do not have any specific need for a ribbon tweeter at the moment, we strongly urge you to consider purchasing it for future use. At the price we are offering, we expect OEM (manufacturer) interest. As it is a distress stock buy, quantities are limited. On many occasions in the past we have warned customers of this and the slow ones miss out. Finally, we think that technically, two tweeters per enclosure would be the way to go. They should not be overdriven. Note also the fairly high crossover frequency. In keeping with this suggestion, we have a special price for a set of 4 pieces. Type: Regular-phase 100mm ribbon tweeter Power: 20 Watts RMS (cont), 50W max. SPL: 92dB/Watt. Freq Resp: 6K-40KHz +/-2dB (SUBLIME!). Impedance: 8Ω. Crossover Frequency: 6,400Hz (12dB / Octave). Normally a speaker of this quality would sell for over $100. Because the factory’s loss is your gain we are offering this product for only $39.95 each, or a set of 4 for only $136 – only $34 each! You will KILL yourself if you miss out and you will if you delay. Cat. CT-2023 $ .95EA 39 Cat. CS-2328 or buy as a set of 4 for $136.00 That”s only $34 each! Carbon Fibre Subwoofers 139.95 $ New range! Featuring high quality Carbon Fibre cones and dual voice coils, these new subwoofers offer great performance and durability. See website for full details. 6.5" Kevlar Split Speakers FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 SAVE $19.05 Check out our massive amplifier range No more fading memories! Transfer all of your VHS, Betamax, and camcorder tapes to DVD using your computer’s DVD burner. With editing software to add colour and transitional effects, as well as sound tracks. Supports composite Cat. XC-4809 SAVE & S-Video inputs & PAL or $ .00 $20 NTSC sources. Was $149 129 SAVE $49.05 89 Extra receiver to suit Cat. AR-1831 Was $89 USB 2.0 HIGH DEFINITION Terrestrial TV Tuner for PCs Streaming full resolution video on your PC! Preview, record and playback video, or burn to CD or DVD. This is a great way of making DVDs if you own an analogue video camera. Includes capture and editing software, supports MPEG1 and MPEG2. SAVE $19.05 As Above but with Remote Control Extender TV/Video Capture Systems 169 Cat. AR-1833 $ .95 RIBBON TWEETERS 10" Subwoofer •250WRMS power handling. •Dual 4-ohm voice coils. CS-2278 $ •87.1dB sensitivity. 179.95 12" Subwoofer Cat. CS-2329 $ .95 pr 149 •300WRMS power handling. •Dual 4-ohm voice coils. CS-2279 •88.2dB sensitivity. $ .00 219 3 H E A LT H A N D F I T N E S S G A D G E T S Pedometer with 128MB MP3 Player Time flies when you're exercising! This pedometer has a built-in MP3 player which stores up to two hours of music. More than enough for most fitness programs! Pedometer functions include calorie counting, distance monitor, as well as a clock. •With USB cables and earphones. Was $119.95 SAVE $20 Cat. GE-4012 99.95 $ Cat. XC-0267 19.95 $ Pulse and Calorie Digital Watch Keep track of your pulse rate and energy consumption with this easy-to-use digital watch. Simply place your finger on the sensor and the watch will tell you your pulse rate. It can even work out the number of calories consumed and the heart rate 'zone' you’re exercising in. The watch has an alarm and a stopwatch with split-time SAVE function as well as rubber mounting $10 clamps to attach to bicycle handlebars. Batteries 2 x LR44, included (for Cat. XC-0266 replacements use our SB-2516). $ .95 Was $39.95 29 Battery Free Torch No batteries needed. Just shake and the mechanism SAVE produces a current $2 to run the torch's LED. If the torch dims, shake it again. This compact torch will fit easily into you glovebox or around the house for those times you need a light in a few "shakes". 165mm in length, waterproof, weatherproof and it floats in water! Was $14.95 Cat. ST-3340 ST-3344 12” version also $ .95 available for $24.95 NEW 12 The Amazing Flygun! Keep the kids entertained! The Amazing Flygun is a safe, fun, and effective method of killing flies and mosquitoes. Launch the spring powered swatter at your target! It is safe, fun and really does work! Cat. YS-5545 SAFE $ .95 FOR AGES 8 AND UP 7 5 Piece Bicycle Tool Set with Bag Keep your bike in top condition! The set includes: a hand pump, puncture repair kit, two piece tyre lever, Allen keys, a stainless steal muli tool and a canvas carry bag which attaches to the frame of your bicycle with velcro straps. 4 Cat. TH-2137 29.95 $ Four powerful magnets work to provide stress relief. With the hand controller, you're able to control the type of massage you like. Also featuring dual speakers on the top of the unit, you can use the hand controller to select between 8 soothing environmental sound recordings. Great to use in the home Cat. GH-1757 or office. Portable and powered by $ .95 4 x AA batteries or supplied plug pack. 39 Toothbrushes and shaving razors are personal items which can attract and breed bacteria easily. This cleaner will keep your toothbrush and razor clean and fresh. It emits ultra-violet rays which will sterilise the bacteria that build up in these items as well as deodorises, thus eliminating unpleasant odours. The unit holds up to 4 toothbrushes and 1 razor at one time. The light will automatically turn off when the lid is opened. Cat. GH-1507 •Requires 6 x AA batteries (not inc) $ .95 •Size: 141(W)x60(D)x105(H)mm 24 3kg Nutrition Scales SAVE $10 Ideal for those who need to monitor their food intake or are watching their weight. These kitchen scales double as a nutrition calculator for over 470 common food items. They calculate calories, kilojules, cholesterol, protein, fat, carbohydrates and glycaemic index. Was $79.95 Relax and enjoy an eye massage which combines gentle air pressure and warm compressions to give you the ultimate in stress relief. Using the remote control you can select three functions: Massage reduce fatigue & stress; Warm compressions - to facilitate circulation to increase Cat. GG-2262 oxygen supply to the eye area and $ .95 Gentle air pressure - to reduce eye strain. 99 Anti Bacterial Toothbrush Holder Pedometer with FM Radio and Calorie Counter Keep track of your calories! You can input the food you have eaten, and it will count down how far to go until you have walked it off. Many other functions, see our website. Eye Massager with Heater Neck Massager with Nature Sound Travel Sized Anti-Fog Shaving Mirror with LED Alarm Clock This innovative unit is slim, compact and easy to take travelling. It features an anti-fog mirror so it can be used in the shower where a fold down shower caddy is available to place shaving equipment or toothbrushes. It also comes with an LED Alarm Clock. The suction cups and clip Cat. GH-1512 $ .95 hanger allows for easy installation. 39 Alcohol Breath Tester with LCD Readout Stay safe and under the limit on the roads! This unit is very compact & features an integrated LCD to give you an actual readout of your blood alcohol content. Cat. QM-7240 69 $ .95 5 in 1 Dynamo Power Bank with Radio and Lamp Very versatile! Not only does this dynamo powered device have an AM/FM radio and incandescent lamp, there is a host of other functions. There is a 3, 6, 9, and 12VDC output socket to provide emergency power, and a plugpack can also be used to charge the internal battery. It also has two-way charging; wind the handle to charge Cat. ST-3370 your car battery, or let you car $ .95 battery charge it! 59 LED Solar Balls Create a party atmosphere or add charm to an intimate setting with these environmentally friendly lights. Made from water resistant clear plastic, they feature a solar panel and an extra bright Light Emitting Diode (LED). Charge them up in sunlight for at least 12 hours and enjoy up to 24 hours of continuous use. They have a light sensor so they will remain lit in the dark. The solar ball looks fantastic hung from the ceiling or trees, you can even float them in the pool or pond. ALL COLOURS ST-3120 Solar ball red $ .95 ST-3122 Solar all blue ST-3124 Solar ball white 24 While providing a good indication of BAC, it should not be relied on for precise results, and you should never drink and drive. Cat. QM-7294 69.95 $ Air Powered Rocket Launcher and Pump Great fun for the whole family! With the use of the hand pump the missiles can launch over 30 metres into the air! •Pump included Cat. GT-3006 29.95 $ Air Powered Jet Hawk Glider SAVE Launch it like a rocket and $5 watch it soar like a hawk! Pump up the air powered launcher and send your Jet Hawk glider soaring 500 feet (150m) into the wild blue skies! It includes a safety feature to disable launching in horizontal or vertical positions. Cat. GT-3440 610mm wing-span. $ .95 Was $59.95 54 Battery Free Calculator No more flat batteries or fading screen on your calculator! Simply shake the calculator side to side and it will be ready to use in Cat. QM-7275 no time. $ .95 14 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au MOOD LIGHTING & LIGHTING KITS Magic Eggs Create an intimate party atmosphere these egg shaped lights. Watch in amazement as they change from one colour to the next. The egg can be lifted from their recharging base and placed anywhere around the house or outdoors. They are lot safer to use than traditional candles with the added benefit of coloured lighting that lasts up to 6 hours when fully charged. No batteries or wires required. Includes charging station and mains adaptor. •Size of egg 95(H) x 65(W) x 70(dia)mm Single Three Piece Cat. GH-1806 Cat. GH-1804 49.95 24 $ $ .95 Desktop Mood Lamp with Sound Modulation This flat panel disk produces an amazing display of blue light which responds to your touch, voice or music. Comes with a removable stand & can be wall mounted. Mains power adaptor included. •254mm/10" (dia.) •6” version also available GH-1530 $39.95 BE ON TIME WITH THESE CLOCKS & WATCHES Talking Watch Cat. GH-1532 49.95 $ Colour Master Colour Changing LED Lighting Kits Includes 4 x round LED fittings, 12.5m of cable, and controller. Eight Light Pack Includes 8 x round LED fitting, 22.5m of cable, and controller. Cat. ST-3880 79.95 $ Cat. ST-3882 139.95 $ Colour Morphing Disk This exciting colour morphing disk features a sound modulation system that creates unique light patterns that change in sync with the sounds or music around it. Requires 4 x AAA batteries (Available separately). It measures approx. 80mm dia. x 30mm thick. Cat. GH-1049 34.95 $ This watch makes telling the time easy! Announces the time at the touch of a button. 3 different alarm sounds - a beep, cuckoo or a rooster crow. It also Cat. XC-0258 has a snooze $ .95 function! CR2016 battery included. 19 Fun and funky! Mount them in laminate or wooden floors, walls, or even ceilings for great mood lighting. They can be changed from red, blue, or green, auto changing or static. Supplied with controller and mains plugpack. Lights measure 80(Dia) x 6(H)•mm. •6mm protruding from mounting Two packs available: Four Light Pack This great looking lamp changes from hues of red, purple, blue, green and pink. It can be automatically set up to change colours at various speeds or see it morph to the sound of your voice or music! It’s perfect for creating soft ambient lighting in your bedroom, living room, dining area or outdoors. Was $39.95 SAVE $5 10" Plasma Disk Cat. GH-1800 19.95 $ Under Cabinet Alarm Clock Great in the workshop! This alarm clock can bolt under an overhead cabinet, or simply sit on a desk. Includes an AM/FM radio so you can wake up to the morning news or a simple buzzer. The radio has a bright red display and measures 185(W) x 50(H) x 110(D)mm, including the cable-tidy Cat. XC-0248 $ .95 at the rear of the radio. •Mains powered. 24 Oscillating Message Board This futuristic unit displays a message, time, or date, without a solid display. It uses a fast oscillating arm with LED's.Using precision timing, and clever calculations,it appears to display the message in thin air!It can be programmed to cycle through the user programmed messages, or simply display the time and date. Cat. XC-0198 69.95 $ GREAT NEW 2.4GHZ WIRELESS SYSTEMS & SURVEILLANCE EQUIPMENT 2.4GHz 4 Channel Wireless Receiver with Remote Control 2.4GHz Wireless Colour CCD Pinhole Camera High quality picture! A Sharp 1/4" CCD sensor provides clear 420TV line resolution picture, and can transmit it up to 100m to the receiver (use QC-3588). A mains plugpack is included, and there are two channels available: Both Types Channel 1 Cat. QC-3560 $ EA Channel 2 Cat. QC-3561 Audio and video! Receiving up to four 2.4GHz cameras (any of the cameras shown left), you can switch between cameras manually, or set it to automatic. Composite video output allows display or recording on any device. A mains plugpack and RCA cables are also supplied. 2.4GHz Weather Resistant Wireless Colour CCD Camera with IR LEDs 2.4GHz 4 Channel Wireless USB Receiver 229 Night vision! As well as 420TV line resolution, this camera has 27 integrated infrared LEDs to see in the dark. It is weatherproof, great for mounting under eaves, and a mains plugpack is included. QC-3588 receiver required. Two channels available: Both Types Channel 3 Cat. QC-3564 $ EA Channel 4 Cat. QC-3565 269 2.4GHz Wireless Colour CCD Rechargeable Camera with Audio The ultimate in portability! This camera features an internal Lithium-Ion rechargeable battery that can operate the camera for up to 5hrs per charge. Channel selectable to use with Cat. QC-3595 .95 QC-3588 receiver, see $ website for details. 169 129 Surveillance on your computer! This tiny four channel receiver takes the pain out of surveillance.Just plug it into your PC’s USB port and you’re set. You can view cameras on the PC, with a composite option for a TV or monitor too. There is a host of on-board functions such as email alert on motion detection, and a whole lot more. See page 313 of our 2005 catalogue for more info. Cat. QC-3597 $ .95 249 2.4GHz Wireless Colour LCD Receiver Roam while monitoring! Now you can take your surveillance monitor with you to watch the kids, or keep a lookout for potential thieves. It has a 65cm LCD and a speaker for audio. See 2005 catalogue Cat. QC-3596 page 312 for compatible $ .00 cameras. 299 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 Cat. QC-3593 $ .95 INTERNET> www.jaycar.com.au 5" B&W Surveillance System Quick and simple! Consisting of a 5" B&W surveillance monitor, two cameras, and two dummy cameras, you can keep an eye on your premises. The real cameras simply plug in with their 10m lead, and the dummy cameras look identical. Great for small shops. Cat. QC-3446 $ .00 149 Four Zone Security Alarm System with Simple Two Wire Hookup The alarm is so simple to set up you DIY enthusiasts will love it! All system components (sensors, sirens) are connected to the control unit via a two-core non-polar flat wire. The unit has a built-in keypad with status LED and three modes or operation (Home, Out, Off). All sensors and sounders are line protected so any attempt to interfere will sound the alarm. Supplied with: •Main control unit •Two PIRs •Four Door or Window contact reed switch •External Siren •240VAC Adaptor •50m two-core flat wire and clips •Screw/wall plug packs •Main unit: 160(H) x185(W) x35(D)mm Cat. LA-5475 $ .00 •Extra PIR to suit LA-5476 $29.95 199 5 Buy in Bulk and Save We have a massive range of rechargeable high capacity batteries and chargers! Check out these NiMH AA/AAA individual and bulk prices. Cat. # Terminal Type SB-1723 nipple AAA SB-1724 solder tag AAA SB-1700 nipple AA SB-1706 nipple AA SB-1708 solder tag AA SB-1727 nipple AA PACKETS OF FOUR SB-1739 nipple AAA SB-1737 nipple AA SB-1735 nipple AA Capacity 900mAh 900mAh 1650mAh 2000mAh 2000mAh 2400mAh Qty 1+ BUY 10 FOR $2.79 ea $2.45 ea $3.78 ea $3.30 ea $2.95 ea $2.60 ea $3.95 ea $3.45 ea $5.75 ea $4.95 ea $5.95 ea $5.25 ea 900mAh $11.95 ea 2000mAh $15.95 ea 2400mAh $19.95 ea Bulk Pack Alkaline Batteries These bulk packs of alkaline batteries represent excellent value for money. We have them made to the same specifications of those well known expensive brands advertised on TV, but at a realistic price. With a shelf life past the year 2010 you cannot go wrong! AAA Alkalines Cat. SB-2331 Bulk Pk of 24 $12.95 AA Alkalines Cat. SB-2330 Bulk Pk of 24 $12.95 AA Alkalines Cat. SB-2332 Bulk Pk of 40 $19.95 AA/AAA Ni-Cd/Ni-MH Battery Charger with LCD Recharge either four of, AA, AAA Ni-Cd, NiMH, or rechargeable batteries. Features a quick and easy logic-controlled function to discharge the batteries before the charging cycle starts to extend battery service life and maintain storage capacity. The charger has an LCD display that shows the battery charge state and is supplied with a mains plug-pack. •Charging Time: 1 - 2 hours Cat. MB-3542 •LED & LCD Display $ .95 •Automatic Discharge function 49 Great reliability! Pure Sine Wave inverters provide a mains waveform that is much closer to that of conventional mains supplies. This is much better and sometimes required when powering sensitive equipment, some switchmode power supplies etc. $1.25 ea $1.60 ea $2.25 ea 1 Hour Super Fast Battery Charger Ni-Cd/Ni-MH w/car Adapter SAVE $7 Never find yourself with flat batteries again. This battery charger recharges 1 to 4 pieces of AA or AAA batteries in one hour. Along with the AC adaptor is a 12V Cat. MB-3537 .95 cigarette car adaptor. Voltage input of $ 100-240VAC Was $69.95 62 Battery Fighter® Chargers Designed to fully charge and maintain a lead acid battery at the correct storage voltage without the damaging effects caused by trickle charges. Ideal for vintage cars, boats or planes that sit for months at a time without use. Lack of use causes a lead-acid battery to self discharge and may result in a destroyed cell. A replacement battery will cost Cat. MB-3600 more than these chargers. .95 12V 750mA Battery Fighter® Charger $ 49 Cat. MB-3602 $ .95 12V 1.2A Battery Fighter® Charger Battery, Bulb and Fuse Tester A no-fuss battery tester with fuse and bulb checker. It checks bulbs and fuses, giving a 'good' or 'replace' indication, and will also test larger 1.5V button batteries like the CR2032. There is also a handy compartment to store spare fuses, bulbs and button cells. Cat. QP-2252 $ .95 A must for every toolbox. Remote switching of appliances! This wireless mains system can support up to five outlets, each with their individual On/Off buttons on the remote control. They are rated at a maximum of 1,000 Watts, so please check the power consumption of high current devices. Supplied with one remote control, and one mains switch. Cat. MS-6100 SAA APPROVED. $ .95 Battery Charger & Alternator Tester Quickly indicates the condition of your 12V battery, charger or alternator. It uses 3 LEDs (12.6V Full, 12.0V 50% and 11.5V Low, to indicate battery condition), and 3 LEDs (15.5V Over voltage / Regulator failure, 14.5V Max. Charger Voltage, 13.2V Charger and Alternator Cat. QP-2258 Charging) to indicate $ .95 Charger/Alternator output. 39 Extra mains switches Cat. MS-6102 $29.95ea. 9 Lead Acid Battery Conditioner Sealed Lead Acid Batteries High quality batteries! Our range of SLA batteries represent excellent value for money. They feature leak proof construction, long service life, high discharge capability, deep discharge recovery, and more. Don’t use low quality SLA batteries to save a dollar or two, you will just end up replacing them even sooner. Capacity Cat. No. Voltage 6 Volts 4.2Ah SB-2496 6 Volts 12Ah SB-2497 12 Volts 1.3Ah SB-2480 12 Volts 2.2Ah SB-2482 12 Volts 4.2Ah SB-2484 12 Volts 7.2Ah SB-2486 12 Volts 18Ah SB-2490 79 Remote Controlled Mains Switch 9 6 $10.70 ea $14.35 ea $17.70 ea SAVE $$$ SAVE $0.34 ea $0.48 ea $0.35 ea $0.50 ea $0.80 ea $0.70 ea $12.95 $29.95 $19.95 $24.95 $35.00 $36.50 $44.95 STOP PRESS STOP PRESS W E HAVE A MA S S IVE RANGE OF INVERTERS Pure Sine Wave Inverters Removes or reduces sulphation which kills batteries. As many of you know, when wetcell lead acid batteries are allowed to sit around they will sulphate up in as short a time as 6 months. The sulphate builds up on the plates and separators. This product basically dissolves the sulphation. The product is so good that the manufacturer will extend the warranty on a new battery by a year if used when the battery is new. One bottle will do up to a N7OZ size battery (4WD, boat, truck, etc.) Power Surge VDC VAC Cat. No. Price 150W (300W) 12 to 230 MI-5080 $229 Suits battery chargers, fax machines etc. 300W (500W) 12 to 230 MI-5082 $289 Suits laptops, lamps and fluorescents up to 300W, 34cm TVs etc 500W (1000W) 12 to 230 MI-5085 $329 Suits power tools, laptops, microwaves, blenders, small fridges etc 1000W (2000W) 12 to 230 MI-5088 $799 Suits Hi-Fi systems, computers, 68cm TVs, lighting, fridges etc! 1500W (2500W) 24 to 230 MI-5089 $999 Suits large TVs, many power tools, lighting, computers and more Modified Square Wave Inverters Great value! With a host of safety features such as overload & short circuit protection, dielectric isolation between the battery and secondary voltages and more. They all have excellent surge ratings and boast over 90% efficiency. Power Surge VDC VAC Cat. No. Price 100W (300W) 12 to 230 MI-5100 $44.95 Suits battery chargers, small lights, and low power devices 150W (450W) 12 to 230 MI-5102 $48.95 Suits battery chargers, fax machines etc! 300W (1000W) 12 to 230 MI-5104 $119.95 Suits laptops, lamps & fluorescents up to 300W, 34cm TVs etc 400W (1200W) 12 to 230 MI-5106 $159.95 Suits laptops, lamps & fluorescents up to 400W, 54cm TVs etc 400W (1200W) 24 to 230 MI-5107 $169.95 Suits laptops, lamps & fluores to 400W, 54cm TVs & more from 24V 600W (1500W) 12 to 230 MI-5108 $249.95 Suits power tools, 68cm TVs, laptops, microwaves, small fridges etc 800W (2000W) 12 to 230 MI-5110 $299.95 Suits power tools, 68cm TVs, blenders, small fridges, microwaves etc 1000W(2500W) 12 to 230 MI-5112 $399.95 Suits Hi-Fi systems, computers, 68cm TVs, lighting, fridges etc 1500W(3500W) 12 to 230 MI-5114 $599.95 Suits large TVs, many power tools, lighting, computers etc STOP PRESS STOP PRESS IEC320 to Mains Socket – UPS Lead Cat. NA-1420 $ .95 8 Here at last! After countless requests we have a lead to plug mains devices into a UPS which has IEC320 sockets. 150mm long. Cat. PS-4100 $ .95 9 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Mini Laboratory Magnifier Lamp SAVE $20 90mm diameter lens and a 12 Watt circular globe enclosed behind a clear protective housing mounted on a 300mm flexible gooseneck. Lens magnification is 3 dioptre and the lens includes a hinged cover to protect the top of the lens when it's used as a lamp or not in use. (Replacement fluoro tube Cat. QM-3520 $ .95 QM3521 $9.95). Was $69.95 49 Bench Laboratory Magnifier Lamp 115mm diameter lens with a 3 dioptre magnification, a quality steel cantilever arm and two swivel joints and a 22 Watt circular fluoro light. Max reach of the head is over 450mm. The base measures 200(W) x 280(D) x 40(H)mm. The lamp is 240VAC operated. (Replacement fluoro tube QM-3523 $13.95). 1 Farad 5.5V Super Capacitor 10mW Green Laser Module Extremely bright! This laser module consists of a 10mW laser diode, lens, and driver PCB. Simply connect a 3VDC supply, & you have a great high Cat. ST-3117 power laser. •Datasheet included. $ .95 •Measures 65(L) x 11(dia)mm. Massive capacity! These are high capacity 1 Farad capacitors made by ELNA in Japan. Very useful for 5V memory retention in volatile chips. PCB mount. Cat. RU-6705 $ .95 Special introductory price! Cat III Auto Ranging DMM Coax Seal Tape 149 No more water ingress! Seal your outdoor coaxial connections to prevent moisture entering the connectors which hampers signal quality and causes corrosion. Simply wrap it around the connector and cable, and it will turn into a removable water Cat. NM-2828 resistant seal that lasts for years. $ .95 •12mm wide As used by NASA and the US military •1.5m length. Double moulded housing! It features large digits, Cat III 600V certification, and is designed for the professional and serious enthusiast. •Capacitance. •Frequency. Cat. QM-1539 •Relative $ .95 measurement. 69 Cat. QM-3522 $ .00 149 Desk Clamp Magnifier Light This is a high quality, all metal frame construction magnifier which features a 22 watt circular fluoro built inside the magnifier head. The magnifier itself is a 3 dioptre lens. Total extended length 990mm. Cat. QM-3525 (Replacement fluoro tube $ .00 QM-3523 $13.95) 109 IDEAL Non - Contact 60 to 400VAC Tester Great for every tradesman’s pocket! Gives an audible and visual indication on energised circuits. It has an unlimited lifetime warranty, and is rated at CAT III 600V. Cat. QP-2274 $ .95 29 9 Mini AC/DC Current Clamp Meter Includes voltage detection! Rated at Cat II 600V, this clamp meter can measure AC or DC current up to 200A, and features an integrated non-contact Cat. QM-1564 .95 voltage sensor. Supplied with a leather $ like belt pouch. 99 Laser Level with Tape Measure Whether you are a handy person around the house or a professional, you’ll love this laser level with tape measure. Use this tool to hang pictures, paintings or mirrors in your home, install shelving, lay tiles etc. The range of the laser line projects up to 6m indoor and covers an arc of 45 and 90 degrees. The unit incorporates a horizontally spread laser to create illuminated guide lines along walls, Cat. ST-3113 horizontal and vertical levels. It also $ .95 includes a handy 2.5m tape measure as well as a ruler on the side. 39 90 - 300VAC / DC Voltage Tester Handy Laser Level A quick go / no go indication. Great for simply testing to see if a wire is live. High quality Cat. QP-2240 insulated probes, $ .95 neon indication. 3 GPO Mains and Earth Leakage Tester Make GPO installation and checking a breeze! Identifies problems with wiring, and checks earth leakage circuit breakers using Cat. QP-2000 selectable trip $ .95 current. 19 Looks like an ordinary spirit level, except that it has a laser fitted in one end. The laser projects a straight line that covers about 15° of arc and can be viewed over many metres, thus enabling a very SAVE accurate level to be maintained over $5 quite a distance. Fitted with magnets in the base so it can be 'stuck' to steel frames and comes with its own small tripod. Dual bubbles ensure that levels can be maintained in both vertical and Cat. ST-3114 horizontal planes. Measures $ .95 170(L)x45(H)x20(W)mm. Was $29.95 Solder Sucker and Blower Bulb Quick and simple! Cheap, compact and effective, you can buy a few so you always have one handy. Measures approx 50(D) x 110(L)mm. Cat. TH-1850 $ .95 3 Fibre Optic Adaptor for Maglites Light only travels in straight lines, but you can make it bend with this Fibre Optic adaptor. A small attachment fits right over the head of your torch, and is attached to a 180mm (7") fibre optic cable. It gives you a flexible light source to get into those places your Maglight won't go. With a diameter of just 3mm, it really can get into those tight spaces. Cat. ST-3410 $ .95 14 LED Upgrade Kit for Maglites Better efficiency! Upgrade the bulb in your AA Maglite™ to this unit that has 3 LEDs. Because LEDs are so efficient, you get four times longer battery life, and LEDs don’t blow! This is the single best upgrade to a torch you can make! 24 PORTASOL SOLDERING IRONS Portasol Technic Gas Soldering Iron Portasol 50 Gas Soldering Iron SAVE Great entry level iron! $15 With a fixed tip temperature of 350°C, it is suitable for a range of applications. 35W approximate electrical Cat. TS-1300 equivalent, with a 30min run-time $ .95 from a refill. Limited qty. Was $39.95 24 The Portasol Technic combines compact power, and convenient reliability, making it one of the most versatile gas soldering irons available. It offers a run time of around 60 minutes, and tip temperature is adjustable up to 450°C. With equivalent electrical power of between 10 and 60 Watts, it is ready to tackle just about anything. The protective end cap features a built in flint type ignitor, and if the gas is left on, it will turn it off when replaced. If a compact, versatile, and reliable gas iron Cat. TS-1305 is what you’re after, then the $ .95 Portasol Technic is for you. 49 Portasol Pro Piezo Gas Soldering Iron Adjustable temperature control up to 580°C. It incorporates a viewing window at the end of the gas tank, to keep an eye on the fuel level. The fuel tank fills in around 20 seconds, and will provide approximately 45 minutes of run time. Ignition is via the built in Piezo crystal mechanism, and the end cap provides safety gas shut off when replaced. The Portasol Pro Piezo is a Cat. TS-1310 dream to use, and will not let you down. $ .95 Supplied with a 2.4mm double flat tip. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 4 INTERNET> www.jaycar.com.au 84 Cat. ST-3400 $ .75 14 Portasol Super Pro Gas Soldering Iron The big brother of all irons in the range. It features adjustable tip temperature up to 580°C, with equivalent electrical power of between 25 and 125W! Ignition is achieved with the internal Piezo crystal mechanism, and run time is around 2 hours on a 30 second refill. With the various tips available Cat. TS-1320 and huge power at hand, no job is a $ .00 match for the Portasol Super Pro. 99 FREE 150G BUTANE GAS* Use it for filling up your gas iron, flame torch, cigarette lighter etc. *Buy any Portasol gas soldering iron during the month of September and receive this 150 gram can of butane gas can, free! NORMALY $5.95 Cat. NA-1020 Cannot be sent by post 7 VELLEMAN USB Controlled Interface Kit No parallel, no problems! This interface kit offers 5 digital and 2 analogue inputs, as well as 8 digital and 2 analogue outputs! That is plenty for experimenting and interfacing with your home or devices in many ways. It is powered straight from the USB port, and even has on-board test functions. The kit is supplied with all components, silk screened PCB, assembly manual, and Cat. KV-3600 software. You will not be disappointed. $ .95 69 Digital Fuel Mixture Display Kit Monitor your car’s air:fuel ratio in real time. Ref: Silicon Chip Sept/Oct 2000. This brilliant dash mounting unit features a three digit LED display, as well as a bargraph for readings at a glance. It indicates air:fuel in real time of 11.8 - 20.6 for petrol, and 12.7-21.5 for propane/LPG. It has loads of great features, just check out our Cat. KC-5300 website. Kit includes PCBs, laser cut $ .95 panels, pre-programmed PIC, and all electronic components. 62 This clock is hypnotic! Ref: SC June 2005. It consists of an AVR driven clock circuit, and also produces a dazzling display with the 60 LEDs around the perimeter. It looks amazing, but can’t properly be explained here. We have filmed it in action so you can see for yourself on our website, so check it out! Kit supplied with double sided silkscreened plated through hole PCB, and all board components as Cat. KC-5404 EXCLUSIVE well as the special $ .00 TO JAYCAR clock housing. EXCLUSIVE TO JAYCAR! This kit enables you to make a full-sized electronic scoreboard, in particular for Basketball but also adaptable for netball and other games. Ref: Silicon Chip March/April/May 2005. It can be built for a fraction of the cost of commercial equivalents and has a completely wireless scoring console that can Wine Cooler Kit control one or multiple scoreMake a cheap wine cooler! boards. You can mount the scoreRef: SC June 05. This project turns boards high up in the court, plug it a regular fridge or freezer into a in to a 240VAC power point and then wine cooler by accurately controlling control them from a table courtside with no messy the temperature to make it suitable for wiring. It features Home/Away team scores 0 to 199, wine storage. A much cheaper option than game period, countdown time, Home/Away time and commercial units. Kit supplied with PCB, Cat. KC-5413 the addition of a new 'foul' feature. It measures 900 x .95 600mm and comes with all pre-cut scoreboard case, mains plug & all elec. components. $ woodwork, screen printed face, display filters, AC/DC Current Clamp Meter mounting plates, pre-programmed microcontroller, Kit for DMMs printed circuit boards, 2.4GHz transmitters & receivers, A cheap alternative! pre-punched control console with special piezo end-ofRef: SC Sept ’03. It works with game quarter sounder, and all electronic Cat. KC-5408 your DMM just like a professional $ .95 components to make one scoreboard. clamp meter. Kit includes PCB, case, Cat. KC-5368 Extra Scoreboards Available $ .95 hall effect sensor, pre-cut core, and Contain everything included in the original kit without electronic components. parts for the control console. Cat. KC-5409 $649 129 39 NEW SOUTH WALES Albury Ph (02) 6021 6788 Alexandria Ph (02) 9699 4699 Bankstown Ph (02) 9709 2822 Bondi Junction Ph (02) 9369 3899 Brookvale Ph (02) 9905 4130 Campbelltown Ph (02) 4620 7155 Erina Ph (02) 4365 3433 Hornsby Ph (02) 9476 6221 Newcastle Ph (02) 4965 3799 Parramatta Ph (02) 9683 3377 Penrith Ph (02) 4721 8337 Silverwater Ph (02) 9741 8557 St. Leonards Ph (02) 9439 4799 Sydney City Ph (02) 9267 1614 Taren Point Ph (02) 9531 7033 Wollongong Ph (02) 4226 7089 VICTORIA Coburg Ph (03) 9384 1811 Frankston Ph (03) 9781 4100 Geelong Ph (03) 5221 5800 Melbourne Ph (03) 9663 2030 Ringwood Ph (03) 9870 9053 Springvale Ph (03) 9547 1022 Sunshine Ph (03) 9310 8066 QUEENSLAND Aspley Ph (07) 3863 0099 Brisbane - Woolloongabba Ph (07) 3393 0777 Gold Coast - Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 AUSTRALIAN CAPITAL TERRITORY Canberra Ph (02) 6239 1801 TASMANIA Hobart Ph (03) 6272 9955 SOUTH AUSTRALIA Adelaide Ph (08) 8231 7355 Clovelly Park Ph (08) 8276 6901 WESTERN AUSTRALIA Perth Ph (08) 9328 8252 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Hamilton Ph (07) 846 0177 Newmarket - Auckland Ph (09) 377 6421 Glenfield - Auckland Ph (09) 444 4628 Wellington Ph (04) 801 9005 Christchurch Ph (03) 379 1662 Freecall Orders Ph 0800 452 9227 8 Ref: SC Jan ‘05. Be the envy of your mates as they hear the rumble when they press your doorbell. You may have seen commercially available units, but nothing like this. It sounds just like a V8, & has variable background noise for tappets & valves etc for an even more realistic effect. 2 versions available: Full V8 Doorbell Kit Supplied with PCBs, silk-screened and machined case, push button bell switch, speaker, hook-up wire, and all electronic components. Includes optional 120mm length of 100mm dia.pipe Cat. KC-5405 $ .95 for that extrarumble! 79 Short Form V8 Doorbell Kit Contains the working electronics only. Supplied with PCBs, and all electronic components. No case, Cat. KC-5406 speaker, or pushbutton $ .95 etc supplied 49 Regulated Voltage Adaptor Kit Very versatile! Ref: EA Aug ’97. Get a regulated 3 to 15VDC voltage at up to 1.5A from a car battery or ATX power supply. Includes PCB and components. 799 34 YOUR LOCAL JAYCAR STORE V8 Engine Door Bell Kit Freecall Orders: Ph 1800 022 888 Wireless Basketball Scoreboard Kit "Clock Watchers" LED Clock Kit Cat. KA-1797 $ .95 6 The SHORT CIRCUITS LEARNING SYSTEM Short Circuits is a great way to learn electronics. It is fun, informative, & you build great projects along the way. Here is just one from Short Circuits 3 FM Microphone This FM transmitter has many possible uses including baby room monitor, wireless microphone or spy bug. It can be picked up on any FM radio. •Kit includes PCB, electret microphone and electronic components. Nitrous Fuel Mixture/ Motor Speed Controller Kit Ref: High Performance Electronic Projects for Cars - Silicon Chip Publications. Pulse a fuel injector in a nitrous system. When activated, it will fire the injector at a preset duty cycle, adding a fixed amount of nitrous fuel. This is a far cheaper alternative to a dedicated fuel solenoid and jets. It also makes a great motor controller, to control an electronic water pump, additional fuel pump, cooling fans and more. It is suitable for use with most fuel injectors, or pumps and motors up to 10 amps. Kit supplied with PCB and all electronic components. Cat. KC-5382 • Please note that the use of $ .95 Nitrous Oxide systems is for race use only. Use of these systems on the street is illegal. 24 Performance Electronics for Cars Book Universal Voltage Switch Kit PRICES VALID TO END SEPTEMBER 2005 9 High Energy Ignition Kit Less emissions! Ref: SC June ’98. A high energy 0.9ms spark burns fuel faster and more efficiently to give you more power! Includes PCB, case, and all electronic Cat. KC-5247 components. $ .95 •Limited quantity 52 Fuel Mixture Display Kit Is your car running right? Ref: SC Nov ’95. It gives an indication of fuel mixture via 10 LEDs. Kit includes PCB and all electronic components. Cat. KC-5195 $ .95 14 Car Turbo Timer Kit Over 160 pages! The Performance Electronics for Cars Book from Silicon Chip publications has chapters on modification and theory, as well as the 16 projects. Here is just one… Cat. BS-5080 $19.80 Automatic device switching! Use it to trigger cooling systems, fans, and more from sensors. This can include temperature sensors, throttle position sensors and more. Kit includes PCB and all electronic components. Cat. KJ-8078 $ .95 Cat. KC-5377 $ .95 29 Save your turbo! It idles your car for a set time after the ignition is switched off to aid in turbo cooling. Includes PCB, case, relay, and all Cat. KC-5254 electronic $ .95 components. 29 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au SILICON CHIP Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 www.siliconchip.com.au PRICE GUIDE: SUBSCRIPTIONS YOUR DETAILS (Note: all subscription prices include P&P). (Aust. prices include GST) Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Please state month to start. Australia: 1 yr ....................$A83 1 yr + binder .....................$A96.50 NZ (air): 1 yr .....................$A89 Overseas (air): 1 yr ...........$A135 2 yrs .....................$A160 2 yrs + 2 binders ..$A186 2 yrs .....................$A178 2 yrs .....................$A260 Address__________________________________________________________ PRICE GUIDE: OTHER PRODUCTS __________­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­___________________­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­____________________________________ Postcode_____________ Daytime Phone No. ( )_____________________ Email address (if applicable) ___________________________________________ Method of Payment: (all prices include GST on Aust. orders) *SILICON CHIP BACK ISSUES in stock: 10% discount for 10 or more issues or photocopies. Australia: $A8.80 ea (including p&p). Overseas: $A10 each (including p&p by air). *ELECTRONICS AUSTRALIA: project photocopies, limited back issues. 10% discount for 10 or more issues or photocopies. Australia: $A8.80 each (including p&p). Overseas: $A10 ea (including p&p by air). o Cheque/Money Order o Bankcard o Visa Card o Master Card *BINDERS: BUY 5 or more and get them postage free.   (Available in Aust. only): $A12.95 each plus $7 p&p per order. Card No. *ELECTRONICS PROJECTS FOR CARS, VOL.2: Aust. $A14.95; NZ/Asia/Pacific $A18.00 including p&p (air); elsewhere $21.50. (All prices include p&p). Card expiry date: Signature_____________________________ *PERFORMANCE ELECTRONICS FOR CARS: Aust. $A22.50; Overseas $A26.00. (Prices include p&p & GST where applicable). SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS* * except subscriptions/renewals Qty Item Price Item Description Subscribe to SILICON CHIP on-line at: www.siliconchip.com.au Both printed and on-line versions available Total TO PLACE YOUR ORDER siliconchip.com.au P&P if extra Total Price BUY MOR 10 OR ISSU E BACK ES A 1 0 & G ET DISC % OUN T $A Phone (02) 9979 5644 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9979 6503 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, S eptember 2005  61 Australia 2097 09-05 PRODUCT SHOWCASE Bargain oscilloscope has 10MHz bandwidth For most electronic enthusiasts, an oscilloscope is pretty much out of reach, as they cannot justify the cost for a reasonable instrument, particularly if it has two channels. But this single channel 10MHz oscilloscope is certainly within the reach of a majority of enthusiasts and will be of considerable interest to many technicians as well. Apart from an accurate digital multimeter, the most desirable test instrument for any technician or enthusiast is a modern oscilloscope. Up till now, the only way that most enthusiasts could afford a scope was to purchase a very old, secondhand unit but these would of doubtful reliability and parts can be impossible to obtain. Now the equation has changed with the introduction of this compact single-channel oscilloscope from Dick Smith Electronics. Measuring 220mm high, 92mm high and 293mm deep (including front panel knobs), the scope will easily fit onto most workbenches or a small shelf above. It has a small screen with a graticule measuring 48 x 60mm. The graticule is not illuminated but is easy to see, being divided into 10 horizontal and eight vertical divisions (one div = 6mm). Vertical sensitivity can be switched in 10 steps from 5mV/div to 5V/div, in a 1-2-5 sequence. The vertical sensitivity can be further reduced to 50V/ div when using the supplied probe in the x10 attenuation setting, giving a maximum input signal of 400V peakto-peak. Apart from the vertical sensitivity control, other Y-input controls are a variable sensitivity control (2.5:1 range), a vertical position control and an input-coupling switch to give AC or DC coupling or GND (grounding the input signal to allow precise trace positioning on the screen. The horizontal timebase switch has a range from 0.1uS to 0.1S/div, again in a 1-2-5 sequence. Also in timebase section of the front panel are three knobs for variable timebase (2.5:1 range), a horizontal trace position control and the trigger level control. As well, there slide switches for trigger mode (Auto, Normal and TV sync), Slope (positive or negative slope triggering and trigger source (Y input, Line or External) and there is a BNC socket for an external trigger source. Just next to the screen are two knobs for focus and brightness controls and these can be adjusted to give a very satisfactory bright and finely focussed display. There is also a contact for an internal 1kHz 0.5V p-p square wave signal which is useful for adjusting the probe compensation and checking timebase settings. Inside, the unit appears to be very well made with good quality discrete components and a few 7400-series logic chips. No surface-mount chips are present and the power supply is all analog, not switchmode, so servicing, if it is eventually required, should be straightforward. What more could you want? A brief check of its performance shows that its –3dB bandwidth is close to 10MHz, as stated. In fact, it has quite useable response to 15MHz. And the price? An almost miraculous $158 including GST. How do they do it? Made in China, no doubt but a bargain nonetheless. See it at your local Dick Smith Electronics store. Contact: Dick Smith Electronics (all stores) PO Box 500, Regents Park DC NSW 2143. Tel: 1300 366 644 Fax: (02) 9642 9155 Website: www.dse.com.au STEPDOWN TRANSFORMERS 60VA to 3KVA encased toroids Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 62  Silicon Chip siliconchip.com.au Asus WL-330 Pocket Wireless Access Point Imagine having an office meeting and, as is typical today, everyone arrives with their research and reports on their laptops/notebooks. Instead of printing out hard copies of everything, each person was able to view each other’s reports on their own wireless-equipped laptops in just a couple of minutes. Want information from the company PC or network? Easy! Want to transfer files back and forth? Easy! And if you really needed a hard copy, you simply went into the print menu and printed on the network printer! Or perhaps you’re travelling overseas on business. The hotel has thoughtfully provided an Internet (RJ45) socket on the wall – but not wireless. You don’t want to be tied to the wall socket when you could be outside on the balcony, working wirelessly on your laptop. Well, just do it! Or perhaps the wireless internet access in your home or office doesn’t quite make it as far as you’d like. You’d really like a device which could extend the range without losing the wireless flexibility you now enjoy. Well, just do it! If all this sounds a bit fanciful, it’s not: all you need is this multi-skilled, tiny WL-330 Pocket Wireless Access Point from Asus. As we will see, it’s much more than even its name suggests! With it, you can very quickly set up a wireless network – anywhere, anytime. It will enable any Ethernetcapable devices to go wireless themselves. It will act as a bridge/repeater to extend your wireless coverage. It’s a cost-effective, simple way to integrate multiple wireless networks. The WL-330 is not a new device – it has been around for the best part of a year (maybe even a bit more overseas). But we were intrigued by the “rave” reviews we’d seen on this, especially in comparison to its big brothers, that we just had to grab one and find out for ourselves when the opportunity arose. And arise it did, via a flit through eBay looking for nothing in particular! We spotted this device and were immediately interested. So we contacted the supplier, XPMicro, and found that even the retail price wasn’t too bad, either (it was even better on eBay!). Perhaps its low price is because the WL-330 is an 802.11b device - and these days, everyone knows you just gotta have the latest 802.11g! But as we have discussed in recent issues of SILICON CHIP, “b” is more than adequate when it comes to ’net access and isn’t all that shabby for such mundane things as file transfer, either. Back to this device. First of all, it’s tiny – about 85 x 63 x 18mm. They say about the size of a deck of cards, which isn’t too far wrong. It almost feels as light as a pack of cards – pick it up and you’d swear it was an empty case! Second, it’s fully self contained – the two antennas are inside the case and it can be powered by the computer’s USB port if you wish (adaptor cable supplied). There is also a 100-240V AC “universal” 4V DC adaptor included, as is an Ethernet cable. All this comes in a handy 150 x 130 x 35mm “travel pack” – large enough to fit everything except the setup CD and instructions. siliconchip.com.au While that might seem like an oversight, once you have set the WL-330 up once, you probably won’t need the CD and instructions again! A web configuration utility allows you to configure the WL-330 using your web browser. You can run it in access point mode or Ethernet mode, simply by flipping a switch on the bottom of the unit. You don’t need any knowledge of TCP/IP to use it, unlike some adaptors which assume you are a genius! The WL-330 is obviously intended for a mobile (ie, travelling) market (it’s way under half the size and weight of most access points) but it is just as viable at home or in the office. Performance is pretty well “as expected” from an 802.11b device – a bit over 5Mb throughput (which is getting close to the maximum – the rest is taken up with overhead). Range was a surprise – for something with internal antennas we weren’t expecting to realise Asus’s claim of 40m indoors because this is under ideal conditions with “indoors” usually meaning one end of a large room to another with no intervening walls, filing cabinets, people, etc. However, in a typical house and office it reached better than 15m. That figure is important for home users, because the average Aussie suburban house sits on a 15m-wide block – enough said? One thing, though: the WL-330 does run fairly hot, so we’d ensure good ventilation around it. And that heat has to be powered by something – so we’d suggest running from the plugpack where possible, not the laptop batteries via the USB port. The WL-330 has a retail price of $69.00. Contact: XPMicro Unit 2, 101 Derby St, Silverwater, NSW 2128 Tel: (02) 9748 6439/6469 Fax: (02) 9748 6489 Website: www.xpmicro.com.au September 2005  63 Altronics opening this month in Melbourne, looking for staff . . . After their successful move into the Sydney retail electronics market last year, Altronics are further expanding with a new retail store in Melbourne. Located at 891 Princes Highway, Springvale, the new store will be their largest to date and will be opening at the end of September. Keep your eye on the Altronics website at www.altronics.com.au for more information. Altronics are looking for motivated individuals to man their new operation starting early to mid September. Positions include a full time retail manager, full time and casual retail sales staff, plus full time and casual warehouse staff. Applications for sales positions must have a sound knowledge and an interest in electronics. Warehouse staff should have relevant warehouse experience. If you are interested in working for Altronics, you can contact Paul Zervaas on 03 9574 6211 or via email at paul.zervaas<at>altronics. com.au LED Light Fittings Wall Mount Various colours and types – - Bullet - Square - Round in Gold - Chrome - Satin Chrome - White - Black. Please view website. We stock a complete range of especially selected quality light fittings for most applications. These fittings complement our LED-based MR16 lamps and are factory assembled for long life operation. Direct connection to 12V (AC or DC) makes these lights ideal for back-up or emergency lighting and for use in low-power (energy saving) systems. All light fittings are supplied fully assembled and fitted with 3Watt High-Power LEDs, withlow power consumption, typically 300mA <at>12V Ideal for Caravans, Motorhomes, Boating and Camping applications. Waterproof/ Outdoor Various types available – - Brass - Bronze - Stainless Steel - Black - Green Ceiling Mount (Stainless Steel) We also stock a full range of other Ceiling, Wall mount and Outdoor type light fittings. Please visit our web site to view a full and detailed colour brochure of all fittings available and request further information. Hi-Output MR16 LED LAMPS Uses 3 Watt Hi-Output LED with Expected Life 50,000 hours plus Input 12-24VDC or 12-18VAC (low power consumption, 300mA <at>12V) Up to 60 Lumens light output Wide beam angle 110° (Narrow beam angle available soon) Total height 39mm (+ Pins) (colour changing longer) Standard 50mm diameter. Drop-in for MR16 lamp housing No UV or Heat radiation (Run much cooler than standard halogens) Conforms to IEC, CE & EN standards For use with “iron core” transformers (electronic type not recommended) 64  Silicon Chip COLOURS: 3 Shades of white & 10 colours available: Sun White, Cool White, Warm White, Red, Amber, Orange, Purple, Magenta, Green, Grass Green, Blue, Light Blue, Cyan PLUS: Multicolour changing lamp with RGB LED (cycles through various Red, Green, Blue colour changing routines) Colour control option via IR Remote or RS485. Fully Dimmable siliconchip.com.au Electricity out of thin (moving!) air Although the global move towards energy wind farming is certainly welcome (and likely to increase in scale), those huge MegaWatt-sized developments may have left a learning void. Although it’s easy enough to grab a few batteries and then learn all about electrical concepts, how can you get “hands on” so readily when it comes to the wind? Wind energy exploitation relates to variables such as blade size and type, wind speed and consistency and even mechanical issues such as noise, balancing and tower height – all usually too involved for educational consideration. Although many well-meaning tinkerers (myself included!) have devised small home built wind generators (typically based around bike dynamos or small electric motors) these often are large and inefficient with dangerous, high-speed blades. Additionally a lack (or excess) of wind at a time when experiments are scheduled may naturally frustrate, as many an America’s Cup race has verified! Hence it’s admirable that Jaycar have just released a ~$50, desktop sized “WindLab Junior” generator kitset (KJ6696), lending itself to all manner of experiments, even indoors when placed near a fan. It’s fitted with a very efficient 3-phase brushless alternator whose output is rectified by 6 inbuilt diodes to deliver up to a Watt (10V DC at 100mA) via convenient terminals. A switched 5.5V 0.33F gold cap can also be charged for later work. Useful output, indicated by a small LED, starts at only a few km/hr wind speed – easily provided by most cooling fans at about half a metre distance – and a good indoor air flow will fully light a 3.6V 30mA white LED. Higher wind speeds, such as those around a moving car, can be utilised as well, although naturally with caution. It’s recognised wind generators perform best at fresh breeze speeds of 10m/s (around 30km/hr ) anyway. Safety issues concerning youthful fingers near the 315mm disiliconchip.com.au ameter spinning blades arise but thoughtfully the supplied soft plastic ones are pliable enough to be harmless at indoor wind speeds. A further design feature relates to the ability to cut, shape and mount ones own blades – perhaps even out of cardboard. Assorted experiments however failed to better the output than from the 3 supplied, although a taller support tower would have allowed a greater diameter sweep. The generator is likely to appeal to a wide age group, ranging from sheer fun with curious youngsters to perhaps senior students out to explore wind speed versus output relationships. (The power available is related to the blade area radius squared and the wind speed cubed – hence a 20km/hr breeze will have eight times the energy of a mere 10km/ hr zephyr). It’s of course feasible to use the wind turbine as a battery charger, perhaps for cell phones when darkness prevents PV use. The blades could even be removed and the shaft then coupled to make a small water jet driven turbine – pico hydro? All you big kids just bursting to try this should first get a clearance from mum before you flood the kitchen. And you’d better get an OK before you cut blades from plastic sheeting with her dress making scissors too! Footnote: A hands-on High School level lab sheet (with modest maths) is being written for this kitset, to be eventually hosted at www.manuka. orcon.net.nz/windgene.htm Stan Swan Contact: Jaycar Electronics PO Box 6424, Silverwater NSW 1811. Tel: 1800 022 888 Fax: (02) 9741 8500 Website: www.jaycar.com.au SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINKinSC WEBLINKa SC WEBLINK SC WEBLINK SC WEBLINK WeSCspecialise providing range of SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Low SC Power RadioSC solutions forSC OEM’s to SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK WEBLINK WEBLINK SC WEBLINK SC WEBLINK SC wireless WEBLINKtechnology SC WEBLINK SC WEBLINK SC WEBLINK incorporate in their SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK based products. SC TheWEBLINK innovative SC WEBLINK SC WEBLINK SC range WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC products WEBLINKfrom SC WEBLINK SC WEBLINK includes MK Consultants, the SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK world-renowned specialist manufacturer. SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tel:(07) 4934 0413 Fax: (07)SC 4934 0311 SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK JEDSC designs and SC manufactures a WEBLINK range of SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK WEBLINK SC SC WEBLINK SC WEBLINK SC WEBLINK single board computers (basedSConWEBLINK Wilke SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tiger and Atmel AVR), as well as LCD SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK displays and analog digitalSC I/OWEBLINK for PCs SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCand WEBLINK SC WEBLINK SC WEBLINK SCalso WEBLINK WEBLINK and controllers. JED makesSC a PC PROMSC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK programmer and RS232/RS485 converters. SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK Tel: (03) 9762 3588 Fax: (03)SC9762 5499SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK OurSC website is updated daily, SC with over SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK SC WEBLINK WEBLINK SC WEBLINK SC WEBLINK WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK 5,500 products SC available through our SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK secure onlineSCordering facility. SC WEBLINK SC WEBLINK WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCsemiconductor WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Features include data SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK sheets, media releases, software SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK and much more SC WEBLINK SCdownloads, WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tel: 1800 022 888SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tel: 1800 022 888 SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINKeptember SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK TeleLink Communications WebLINK: telelink.com.au Jed Microprocessors Pty Ltd WebLINK: jedmicro.com.au JAYCAR JAYCAR ELECTRONICS ELECTRONICS WebLINK: WebLINK: www.jaycar.com.au www.jaycar.com.au S 2005  65 Getting the most from your It’s pretty much commonsense, right? What can go wrong? Sometimes, the experts can tell you things you really hadn’t considered . . . like what do you do if you accidentally “wash” your card? I f you’re getting ready to pack your suitcase, your sunscreen lotion and your digital camera for a quick getaway, don’t forget to pack extra flash memory cards. And, since you’ll be capturing plenty of magic moments, the experts at SanDisk Corporation, the world’s largest supplier of flash memory cards, have some tips on how to get better results from your photography and protect your images from heat, rain and even accidental erasure. Despite our publisher’s reservations about the value of digital cameras (July SILICON CHIP, P2), the world, it seems, does not agree. Digital cameras now outsell film cameras by a very significant margin. And recent reports even suggest camera phones are outselling both – though one would have to wonder whether travellers using camera phones to capture their memories will be all that happy when they see the image quality most phones, at 1.3 megapixel or thereabouts (and many much less), still produce. However, both digital cameras and camera phones are continually improving. Samsung recently announced a 7MP model and many camera phones now accept flash memory cards, just like their “ordinary digital camera” cousins. So a modern camera phone and a few flash memory cards could be a proposition. Here’s what SanDisk recommend: Get higher capacity cards With card prices falling and digital camera resolutions rising, consider upgrading your memory, so to speak, with cards that are at least double your previous capacities. If you’ve been using 256MB cards, move up to a 512MB or even a 1GB model. If you want sharper and larger photos, you’ll need to set your camera 66  Silicon Chip the future (and you will!). Get a faster digital camera?      Sandisk’s 1GB CompactFlash card – now available up to 4GB and also in Ultra II and Extreme III versions which offer much better performance. at higher resolutions and this, in turn, will consume more memory. Consider using a high-capacity, high-performance card such as the SanDisk Ultra II 1GB. But first make sure the firmware of you camera can handle the larger cards – some early cameras are limited to, say, 256 or 512MB. Some cameras may offer a firmware upgrade: check their website. Get faster cards All flash cards are not the same. If you have a late-model digital camera with a rating of, say, 5MP or higher and/or if you like to shoot moving objects, you have a better chance of capturing the specific moment from a faster card. For example, moving from a standard card to a SanDisk Ultra II card (available in SD, Memory Stick PRO and CompactFlash formats) provides up to three times faster writing speeds in many of the newer digital cameras that have fast internal processors. Actual speeds depend on the image processing ability of your camera and the make of your existing flash card, however. Even if your camera is not fast or high-resolution, having the faster cards will be welcome when you do upgrade to a new camera in Perhaps your camera is a few years old; maybe it was your first digital camera. If so, think about purchasing a newer model – and look for information on the buffer processing times of the camera. Some manufacturers now offer, for under $1,000, digital single-lens reflex cameras that can record higherresolution images faster than their predecessors. Even many new, small digital cameras of 5MP resolution currently retail for under $300. Most of these newer cameras noticeably reduce the hesitation you may have experienced when you click the shutter. With a new camera and a faster card, you’ll have a better chance of freezing the action. Handling the card Any card with exposed metal contacts should be handled by the edges, just as you would handle a CD. On most cards, the contacts are gold-flashed to prevent corrosion but they can get dirty, especially if touched by oily hands. One easy and relatively safe way to clean them is to give them a once-over with a standard, soft pencil eraser (don’t use a too-hard one, nor one intended for ink). On cards with internal connec- The card comes with a protective case: use it ! siliconchip.com.au digital camera card tors, such as CompactFlash, avoid at all costs getting dirt or sand in the contacts. Once in, it is very difficult, if not impossible, to remove. Whenever the card is out of the camera, use the protective pouch it came with to protect it. Airport X-Ray machines and metal detectors You can put full or empty flash cards in your checked baggage or in your carry-ons with little risk of damage from airport scanners. The International Imaging Industry Association conducted tests last year with security devices used in US airports and found that no damage to the cards resulted with normal travel frequency. As an added precaution, SanDisk recommends that you take the card out of your camera before passing through security devices. What if you get the card wet? Like anything electronic, getting a card wet should be avoided at all costs. But what if you do? It happens (and not infrequently), that people accidentally leave a card in a pants pocket and then wash the garment. Or they might drop the card in a swimming pool or even a puddle. Don’t despair. Let the card dry for a couple of days – you can even use a hairdryer with a non-heat blower (don’t be tempted to speed it up by using heat: even if it doesn’t damage the chips inside the card, it may distort the package making it difficult, if not impossible, to make the required contacts). There’s a good possibility, based on experience reports from SanDisk customers, that the card might still function. On cards with exposed contacts, a bit of a clean and polish might help (note the earlier comments about a pencil eraser). And we wouldn’t siliconchip.com.au put the card straight back inside an expensive camera – once completely dry, we’d first test it in the card-reader of a personal computer (and if possible, a cheap, external one). Coping with heat If you leave rolls of traditional film on the back seat of a closed, parked car, you stand a good chance of ruining them, especially during the heat of summer. Although it’s advisable to keep flash cards at room temperature, SanDisk’s standard flash cards are designed to withstand relatively high temperatures – up to 60° Celsius or 140° Fahrenheit – without loss of stored images. SanDisk’s Extreme III cards are even better – they’re designed to operate in extreme temperature conditions at the limits of human physical endurance. Make sure you have enough battery left Although no battery power is required to actually store pictures, it is required when reading from or writing to the card. So it’s important to have sufficient battery power when your camera is transferring captured images to your card. If the battery is too low, you could lose one or more images during the transfer, so it’s a good practice to keep a spare, recharged battery on hand. Also, never remove a card while a camera is writing to it or while formatting the card in a camera. Recovering deleted images Suppose that, in sorting through your images, you accidentally delete a picture that you really wanted to keep. Or perhaps you’ve reformatted your card by accident and wiped out all of your photos. They are gone from sight but until you write a new image to the card, they usually they remain stored on it, (although in normally inaccessible memory locations). Using a software program such as SanDisk’s RescuePRO®, which you can purchase for US$40 through SanDisk’s website (www.sandisk. com) and install in your computer, you can often recover so-called “lost” images by selecting “Full Recovery.” In most respects, the card in its reader acts like another hard disk on your PC so many other data recovery programs are also likely to work. At least it’s worth giving it a go – you have nothing to lose if you think you have already lost it! Make backups “on the fly” Be careful, especially in some areas! If you’re anxious to print your photos while travelling, before you drop off a card at a photo processor or use a self-print kiosk, back up your images on a laptop PC or burn them to a CD or another storage medium. That way, if your card is lost or damaged, you can still have another set of pictures. And here’s one last thing to keep in mind: in many areas around the world, you can buy cards at odd times, in odd places. If you run out of memory and need to find a card or two early in the morning or late at night, head for a supermarket or chemist/drug store. SanDisk produces a line of readily available and inexpensive cards, called SanDisk Shoot & Store, which come in capacities of up to 128MB in formats of SD, CompactFlash and SC Memory Stick PRO. September 2005  67 Words and graphics by Ross Tester Want to use an old phone for VoIP calls? Build this cheap adaptor! VoIP (Voice over Internet Protocol) Analog Phone Adaptor Regular SILICON CHIP readers would be no strangers to VoIP and the myriad of services now available (such as Skype). And you would no doubt recall that to take advantage of free or very low cost long-distance calls you’ve needed a special VoIP phone for your PC – or at least a headset with mic and earphone. I n fact, we featured such a phone, from Microgram Computers, in the “new products” section in August 2004 (followed by a full article on VoIP and Skype in September ’04). Those phones are still available and just as viable as they ever were. But they aren’t all that cheap. And using a headset/microphone, while once again perfectly viable, can be both a help and a hindrance. It might free your hands but it just ain’t the same as holding a phone to your ear. You can also buy “internet phones” without any problem these days. While initially more expensive than standard (POTS) phones, they offer significant – and often dramatic – call cost savings in the longer term. But what if you wanted to get into VoIP with a minimum 68  Silicon Chip of upfront cost? Wouldn’t it be nice if you could use just about any old (or new!) phone on your PC instead of buying something special. After all, most hobbyists and even significant numbers of the general populace must have a phone they are no longer using, gathering dust somewhere! Even a brand new phone can be found for less than ten dollars! Don’t look now . . . but you can! All it takes is a tiny bit of cheap circuitry to fool the phone into believing that it is plugged into a normal call – and it can then connect via the sound card in your computer to the internet and the rest of the world! We’re not going to make any claim to the originality of this circuit. We were alerted to a website containing just siliconchip.com.au such a project by a reader and it seemed to us that this would make a dandy little item for SILICON CHIP. You can see the original at www.grynx.com. All the information presented there is given here – with the exception of a rather long user forum which itself might answer some of the questions you have about this project. On that website it was called a “chat cord”. While that’s not a bad name, we prefer the slightly more prosaic but also more descriptive name we’ve given it: VoIP Analog Phone Adaptor – simply because it tells you what this does. By the way, the “grynx” website is one which we have a peek at quite regularly – they have some really neat ideas and products from time to time! Identical – but different! While the circuit is identical, we’ve made a couple of physical changes. The first thing we noticed was that the original project was constructed on Veroboard. Once again, regular readers may have noted that it is extremely unusual for SILICON CHIP to publish any project based on this stuff. For good reason, we detest using Veroboard – our experience is that readers find it far too easy to make a mistake, especially in the hole-cutting-out area. You only have to be one track across or one hole down and whoops – the smoke gets out! We’d much rather design a small PC board and minimise that possibility. Yes, it does add a little to the project cost – but in this case, the board has a minimal number of holes so a commercial board should be pretty cheap (the number of holes, more than the size, determines the cost to a large extent). And we know that many readers still like to make their own PC boards from the patterns we publish (you should hear the screams when one is left out!). So that is also an option if you really must save money. In fact, we made this PC board on the kitchen sink in about half an hour using only a reversed laser print of the pattern (on plain paper) – see “Making Your Own PC Boards At Home” in the March 2001 issue. Make your own board and all you are up for is the special transformer (around $12 from Altronics – more on that later), a phone socket (about $1), a 9V battery holder (80c) and a 150W resistor. Add a couple of 3.5mm plugs to connect to your sound card via short lengths of coax and, if you wish, a box to put it in. Really, that is all there is to it. Have a look at the circuit. Now do you believe us? 600 Ω/300 Ω+300 Ω ISOLATION TRANSFORMER MIC INPUT RJ11 PHONE SOCKET SC 2005 9V BATTERY 150Ω SPEAKER OUTPUT ON PC SOUND CARD VoIP ANALOG PHONE ADAPTOR As circuits go, you cannot get much simpler: one transformer, one resistor and one battery, plus connectors! (b) it fools the phone into believing that it is connected to a real exchange circuit. That’s the purpose of the 9V battery in series with the phone and transformer. Normally, an “on hook” telephone (ie, the handset is in the cradle) has about 48V DC across its terminals (which of course comes from the exchange). The phone ringing voltage is AC – perhaps 90-100V (which explains why you get a bit of a tingle if you’re across a phone line when it rings!). Off-hook (ie, taking a call), the voltage drops down significantly – usually to about 9V DC but can be a bit lower. So we simulate that 9V with a battery in series with the phone and transformer. We could have used a lower voltage – down to perhaps 6V and it would have worked just as well. That’s getting perilously close to the 5V available from a PC’s USB socket, which could have made the project self-contained – but unfortunately, 5V is just a little low – it sometimes works and sometimes doesn’t, depending on the phone. Besides, a 9V battery is a si mple, practical solution. As well as providing isolation between the phone and PC, the transformer ensures that the impedance which the phone “sees” is what the phone would expect if plugged into a phone line. If it doesn’t see this, the phone may not work properly or even work at all. The transformer is a special type with a 600W primary and two 300W secondaries. These are connected in series with the centre acting as a “ground” for both the input (mic) and output (speaker) circuits – connected via a 150W resistor to maintain the correct impedance. How it works This circuit performs two simple functions: (a) it couples the phone into the sound card at the right impedance, so losses are minimised – that’s the job of the transformer and resistor; and A view inside the box before we fitted the shielded cables which connect to the PC sound card. You can just see the ledge on which the board catches and sits, eliminating the need for screws to hold it in place. And it doesn’t matter if the battery is left in – when the phone is unplugged the battery is open-circuit anyway. siliconchip.com.au September 2005  69 Parts List – VoIP Analog Phone Adaptor 1 PC board, 60 x 124mm, code 03109031 1 UB3 Jiffy box, 130 x 68 x 43mm (Altronics H0153) 1 PC-mount 600W to 300W+300W isolation transformer (Altronics M1010 or M1005) 1 PC-mount 9V battery holder (Altronics S5048) 1 9V battery 1 PC-mount 4P4C (RJ12/RJ11) phone connector (Altronics P1422) 4 PC stakes 1 3.5mm stereo phone plug 1 3.5mm mono phone plug 2 lengths shielded cable, length to suit 1 telephone connection cable (RJ12-RJ12), length to suit 1 150W 0.25W resistor Code: brown-green-brown-brown (4 band) or brown-green-black-black-brown (5-band) 70  Silicon Chip 9V BATTERY HOLDER 600 Ω TO 300 Ω + 300 Ω TRANSFORMER SECONDARIES The transformer also prevents the 9V DC from the battery getting into your sound card, where it wouldn’t do any good at all. The phone, incidentally, can be just about any analog type – the garden-variety Telstra phone; RJ11 (4P2C) a two-dollar-special you picked PHONE SOCKET up from a flea market; a ten-dollar Chinese import special you found in the bargain store; even most cordless phones will work quite happily with this circuit. Hey, that would be pretty neat – talking via a cordless phone to the other side of the world for nothing – or next to nothing! (The old pushbutton Telecom phone photographed with our adaptor actually came from a council clean-up a couple of months ago. Rain threatened and it looked so lonely sitting there, I just had to stop the car and pick it up, take it home and see if it still worked. It did/does!) Input (from the phone) is via a standard RJ11 (or more correctly, 2P4C) socket. To connect the phone to this, you’re PRIMARY Here’s the completed PC board with matching component overlay underneath. No mounting holes are needed with the Jiffy Box we used. Our construction time was about one hour – and that included making and drilling the PC board. TO PC CARD MIC SOCKET (PINK) 150Ω TO PC CARD SPEAKER SOCKET (BLUE) going to need a standard RJ12 to RJ12 (ie, “US-style”) phone cable, the length to suit how far away you want the phone and box to be. Output is via a pair of 3.5mm plugs, one of which goes to the “mic” input of your sound card (or integrated motherboard sound) and the other to the “speaker” (or headphone) output of the card. We’ve labelled these in pink and green on the circuit because they are the colour codes of the 3.5mm sockets on most modern computers/sound cards. It doesn’t really matter which one goes to which one because the circuit is symmetrical. However, we’ve labelled them specifically because the speaker/headphone socket is invariably a stereo type, while the microphone is usually mono (unless it is designed to handle an electret mic). Inserting a mono plug into the stereo speaker output will more than likely short out one channel of your sound card – and you really don’t want to do that. Hence the labelling. Construction With the very limited number of components – and none of them polarised – this is the simplest part. Start with the four PC stakes and the 150W resistor, followed by the 9V battery holder. As well as the two soldered pins, it’s wise to add at least one nut and bolt to hold the the battery holder firmly on the PC board. 9V batteries do have a bit of weight to them and could quite easily break the solder connection to the PC board. Next is the transformer: the PC board has been designed siliconchip.com.au The front panel label can be photocopied and glued to the jiffy box lid. It doesn’t look too bad in B&W if you don’t have access to a colour photocopier. Of course, it – and the PC board pattern, shown below, can also be downloaded and printed in colour from the SILICON CHIP website: www.siliconchip.com.au SILICON CHIP www.siliconchip.com.au mic PC SOUND CARD TELEPHONE VoIP Analog Phone Adaptor to take either a standard size (as shown in the photographs) or a miniature version. Both these transformers are available from Altronics. It’s important to get the transformer the right way around. The mini one is easy – it only has six pins – two on one side and four on the other – so you know which is the primary (two pins) and the two secondaries. The larger transformer is not so simple because it has eight pins – two on the primary side are unused. Have a close look at the pins (maybe with a magnifying glass) and on the secondary side, you’ll see very fine wires soldered to each pin. On the primary side, only two of the pins have wires soldered to them. Make sure the transformer goes into the PC board with the primary closest to the battery holder and the secondary closest to the output stakes. The final component is the RJ11 (or 4P4C) socket. This must be very carefully placed because it has very fine pins which are easy to bend out of position. The PC board has been designed to allow 4P6C sockets to be used if necessary, so make sure your socket is placed according to the overlay diagram to connect the right pins! The PC board will also handle two of the commonest sizes of socket – the holes between the pins and the edge of the board are designed to hold the moulded plastic locating pins on the socket. Drill the appropriate ones out to 2.5mm to allow these pins to go through the board and hold the socket in place. Once again, relying on the soldered connections (especially the tiny ones here) is not wise because insertion and removal of the RJ12 plug could easily break the joins. We’d suggest a drop of super glue on each of the moulded pins to secure them to the PC board – once you are absolutely sure the socket is in the right spot! Finally, solder appropriate lengths of coax to the four PC stakes – the inner conductors go to the outside stakes and the braid to the inner stakes. Fit these lengths of coax with mono or stereo 3.5mm phono plugs, as discussed above (mono for mic, stereo for speaker) – and board construction is complete. Give it a thorough check-over to make sure there are no missed or poor solder joints and, most importantly, no siliconchip.com.au spkr solder bridges between the very tightly spaced terminals under the phone socket. Finishing off We mounted our PC board in a UB-3 Jiffy box. This box has moulded channels in the side, with a recess about 10mm up from the bottom of the box – just made to capture the PC board and hold it without screws. If you make your own PC board, you’ll have to cut the corners out as per the photo and drawings to accommodate the four pillars inside the box. The easiest way to do this is to use, say, a 12mm drill and then finish off with a fine file. You’ll also need to mark and drill holes in the box for the two shielded cables (OK, we shouldn’t have soldered them on beforehand!). We cheated a bit and used a length of Fig.8 cable and then split it at both ends – it meant only two holes in the box, not three. Of course, you also need to drill and file a rectangular hole for the RJ11 socket at the other end. And that’s it: your VoIP Analog Phone Adaptor is now finished. Plug in the phone, connect the box to your sound card, load up your VoIP software . . . and start talking to the world. Want to know where to get VoIP services? For a comprehensive, up-to-date listing which also has extensive provider information, including pricing, visit www.OzVoip.com September 2005  71 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ MUDL ARK A 205 a u d i o s y s t e m s A 20-watt/channel class A2 triode amplifier In last month’s issue, we described the innovative design of the Mudlark A205 stereo valve amplifier which is based on parallel single-ended triodes and a “parafeed” output transformer arrangement. This month, we give the construction details and the parts list. Pt.2: By DAVID WHITBY B EFORE WE GO ON to discuss the assembly of the Mudlark amplifier, we should mention some of the chassis hardware and componentry in the design. While the output transformer configuration is unusual and was described last month, the 100V line output transformers employed are not cheap or inexpensive by any means. They employ quality M6 grain-orientated silicon steel laminations and interleaved windings, as used in the best conventional output transformers. As WARNING! High and possibly lethal voltages are present in the external power supply, underneath the chassis on the PC board and on the choke board assembly. DO NOT touch any parts with power applied and exercise extreme caution at all times while testing the amplifier. 76  Silicon Chip well, the transformers are mounted with their cores at right-angles to each other and have been fitted with copper straps. Both these measures have the effect of cancelling or greatly reducing residual leakage flux from the transformers which could otherwise prejudice the amplifier’s operation. The extruded aluminium chassis gives several advantages apart from having an attractive appearance, with a fine-grooved finish on the top section. It is very rigid and strong, providing a stable platform for the large PC board which mounts underneath. One major change which has been made to the under-chassis arrangement of the PC board involves the octal socket and matching plug which connects all the wiring to the chokes and transformers. In last month’s issue, this was shown with a cable which threaded under the board and into the transformer compartment on top of the chassis. Now the wiring has been greatly simplified because the ceramic octal socket is mounted on the topside of the PC board, the same as the octal sockets for the output valves. Then, inside the transformer compartment, a short cable connects from the octal socket to the vertical PC board which accommodates the nine chokes. The main PC board is double-sided with plated-through holes and 4-ounce plated copper tracks. It measures 180 x 233mm. As noted last month, the kit is available in two versions. Version 1 is a complete set of components and contains everything you need to build the amplifier down to the last detail. There is no drilling or cutting required and all you will need are general electronic assembly tools such as soldering/desoldering tools, pliers, side-cutters, screw & nut drivers, Allen keys, etc. By contrast, version 2 comes with a fully built and tested main PC board which makes it much easier to get the amplifier up and running. Main board assembly Construction starts with the main PC board assembly (Fig.5). First, remove the small RCA connector-mounting siliconchip.com.au 3W resistors. The 1W and 2W resistors are fitted first and all lie flush with the board. The 1W 3W resistor is mounted vertically to aid cooling and the four 27kW 3W resistors are mounted horizontally but raised 20mm up off the board, again to aid cooling. If you discover a mistake after soldering, carefully remove any wrongly placed components using a “solder sucker” or “solder wick”. Component removal is more difficult on a double-sided PC board than on a single-sided board due to the plated-through holes; all the solder must be completely removed from the holes before the component leads will easily pull out. The main thing is to take your time and not rush the job! Polarised components board from the corner of the main PC board and then familiarise yourself with the front edge (switches and pot), the back edge (terminal block connector pads), the component side (which has the most printing) and the underside (with the least printing). Next, fit the seven 16mm hex spacers to the outer hex marked holes on the component side along the righthand and lefthand edges of the board. These are secured with the supplied M3 x 8mm screws and star washers, fitted from the underside of the board. That done, fit two of the 12mm hex spacers supplied to the two hex marked holes in the underside of the board on either side of the central octal (8pin) socket. The remaining 12mm hex mounting spacers are fitted later, to the underside of the chassis. Next, fit the five 8-pin and two 9-pin sockets on the underside of the board, taking care to observe their orientation as shown on Fig.5. Note that the central 8-pin socket is oriented differently from the four other octal sockets. It is most important that you orient each octal socket correctly. The central siliconchip.com.au keyway must line up with the keyway shown on the PC overlay. The smaller 9-pin sockets are polarised and will only fit into the PC board one way around. All the sockets must be pushed as far as they will go into the PC board and held level/parallel with the board surface while they are soldered. The resistors are divided up into three separate packs of 1W, 2W and All the electrolytic capacitors in the kit are separately packed according to value and are clearly marked with voltage polarity. Take great care to orientate them strictly according to the overlay diagram of Fig.5. Since the voltages are high, reversal of polarity will quickly destroy them at switch-on, so take every precaution to get the polarity right according to the component overlay. It is also most important to install the diodes and zener diodes correctly. Don’t get them mixed up. All are critical to polarity but the ones which can cause the most fireworks if reversed are the two main power doubler diodes (D1 & D2) near the relay – so take care to double-check all the diodes and zener diodes before soldering. A socket is supplied in the kit for Measured Performance Output power ....................................................20 watts per channel into 8W Frequency response .......................................... 12Hz to 57kHz within ±3dB; -1dB at 50kHz (at 1W/8W – see Fig.10) Input sensitivity ......................................................... 360mV for 10W into 8W Harmonic distortion ......................typically less than 1.5% at listening levels (see Figs 11, 12 & 13). Separation between channels .........................................................see Fig.9 Signal-to-noise ratio ................... -67dB unweighted (22Hz to 22kHz); -91dB A-weighted, both with respect to 20W into 8W Damping factor...................... >6 with feedback applied; >2 with feedback off September 2005  77 Above: inside the finished amplifier. The octal sockets mount on the rear of the PC board and protrude through matching holes in the chassis. the 555 timer IC and the overlay clearly indicates the mounting direction. Do not fit the 555 timer into the socket at this stage. Mount the BC337 as shown on the overlay diagram. The two BF469 transistors must be mounted so that the metallic side of each transistor body faces towards the back of the PC board (ie, away from the switches and potentiometer). Having mounted all the polarised components, you can then install all the non-polarised capacitors. Board hardware Next, fit the two pushbutton switches to the underside of the PC board, making sure they are pushed firmly into the board and are as parallel as possible, before they are soldered. That done, fit the potentiometer, the relay and the three 3-way terminal blocks which together make up the 9-way connector at the relay end of the board. Next, fit and solder the PC pins for 78  Silicon Chip the feedback wires (either side of the 220kW 1W resistors at the front righthand corner of the board) and to the pads marked “LEDS” near to centrefront of the board. Finally, fit and solder the RCA input connector block to the component side of the small PC board which you previously broke off the main board. You can then connect the 4-way flat shielded cable as shown in Fig.5. The other end of this cable will need to be terminated on the underside of the main PC board, at the PC pins near switch S1. Preparing the chassis Six 12mm-long tapped spacers need to be to the fitted to the underside of the chassis using M3 x 8mm-long countersunk screws through the countersunk holes on the top of the chassis. No star washers are fitted and the spacers need to be held by a nut driver and tightened firmly from above. The front and back panels are Fig.5 (facing page): this diagram shows the component layout on the main PC board as well as the wiring to the RCA input connector board at the top lefthand corner. Note that the two 10mF 400V capacitors should have a bead of silicone sealant under them to anchor them securely to the board. packed with brackets and screws for mounting to the chassis .The panel positions are obvious due to their shape and the printing. You need to attach the three small right-angle brackets for each panel using slotted countersunk screws and nuts, then use countersunk Allen screws and nuts to attach the panels to the chassis. At the same time as you mount the central right-angle brackets under the chassis ends, you can also attach the top cover mounting brackets, on the top of the chassis. Before tightening the screws, position each panel as symmetrically as possible over the end of the chassis. Fit the power switch to the left-hand siliconchip.com.au 10k 2W CON1 V5.21 D2 V52 25V (THIS BOARD MOUNTS UPSIDE DOWN ON BACK PANEL) 1000F/63V 1000F/63V SH D1 D4 NC C 220k 2W 10nF 250V 100F 25V 220k 2W 330k 2W 100F/400V FIT UNDERNEATH 10nF 100V 100 1W 100F/400V 100 1W 220uF/50V 100nF 100V 100 2W FIT UNDERNEATH SKT1 V3 IC1 LM555 180 2W Q3 BC337 330k 2W 27k 2W 56 2W 220F/50V ZD1 12V 1W NO 220k 1W 1000F/63V 1000F/63V RELAY1 270F/200V D7 D6 D5 220 2W D3 56 2W 270F/200V 270F/200V 1000F/63V 470k 1W 270F/200V 22k 1W SH 10k 2W 12.5V 47F 25V RBLL V6 1000F/63V FLAT 4-WAY SHIELDED CABLE UNDER PC BOARD FIT UNDERNEATH 47 1W 47 1W 10F/400V 10F/400V 47 1W 1 3W 47 1W 10k 2W 1N4007 VOLUME CONTROL siliconchip.com.au 220 1W 22nF/400V TO R&L SPEAKER TERMINALS 470k 1W ZD2 NFB (L) R47 PRE/DRIVER VALVE HEATER VOLTAGE WIRE (UNDER BOARD) 220k 1W + – BLUE LEDS UNDER BOARD (CONNECTED IN SERIES, PUSHED INTO HOLES PROVIDED) 220k 1W 1000F/63V NFB (R) 22k 2W V4 Q2 BF469 220k 1W 10k 1W 10k 1W 10k 1W 22k 1W 50k+50k 100k 1W MUDLARK A205 502A Rev1 KRALDLUM 10k 1W MULDLARK A205 S2 – FIT UNDERNEATH 100k 1W 470k 1W 470nF/630V 22nF/400V YEL WH SH RED BLK SH Q1 BF469 22k 1W 220 1W FIT UNDERNEATH 220k 1W 27k 3W 100k 1W 27k 3W 10F/450V KLINK NIL 27V/1W 27k 3W 470 2W 27k 3W 1000F/63V 10F/450V 22k 1W 47k 1W 10k 2W C17 S1 – FIT UNDERNEATH V5 470nF/630V 10k 2W 100k 1W 100k 2W 1000F/63V 22k 2W V1 1000F/63V 10k 2W 470nF/630V 220F 50V 1000F/63V 1000F/63V 10F/450V FIT UNDERNEATH 1N4007 1N4007 1000F/63V 47k 1W 10F/450V 220k 1W 680 1W 470nF 630V 10F/450V 4.7k 2W 220 1W V2 D10 1N4007 D8 FIT UNDERNEATH D11 D9 4.7k 2W FIT UNDERNEATH 10k 2W 100 2W 100 1W 220F/50V WARNING: LETHAL VOLTAGES ARE PRESENT ON THIS BOARD WHILE IT IS OPERATING! SHIELDED WIRE (UNDER PC BOARD) September 2005  79 TO PINS ON OCTAL PLUG 3 4 8 7 6 1 2 5 WARNING: LETHAL VOLTAGES ARE PRESENT ON THIS BOARD WHILE IT IS OPERATING! FROM PRIMARY OF LEFT CH. OUTPUT TRANSFORMER 3 4 7 6 1 2 5 OIDUA SSELG CON1 OUTPUT TRANS FROM PRIMARY OF RIGHT OUTPUT CH. TRANSFORMER LEFT CHANNEL PLATE CHOKE 1 RIGHT CHANNEL PLATE CHOKE 1 LEFT CHANNEL HT FILTER CHOKE LEFT CHANNEL PLATE CHOKE 2 RIGHT CHANNEL PLATE CHOKE 2 RIGHT CHANNEL HT FILTER CHOKE LEFT CHANNEL PLATE CHOKE 3 RIGHT CHANNEL PLATE CHOKE 3 8 502HC Fig.6: here’s how the eight chokes are installed on the PC board which sits on top of the chassis. The output leads go to an octal plug – see Fig.7. side of the front panel and the speaker terminals to the appropriate holes in the back panel. The terminals with the red rings mount close to the top of the chassis. Line up the lead holes so that they are horizontal before you tighten the nuts (this makes it easier to insert and attach the speaker leads when you finally listen to the amplifier). Two rubber grommets are also fitted to the two holes at the rear of the chas- sis to take the wires from the output transformers to the speaker terminals. Choke assembly We now move to the top of the chassis and proceed with the choke assembly which fits under the central cover. Fig.6 shows the wiring diagram for the choke board but you have to follow the strict assembly procedure set out below. This view shows the rear of the choke PC board before the protective plastic cover is fitted. This cover provides shock protection. 80  Silicon Chip Begin by fitting six stacked pairs of 30mm male/female spacers to the top of the chassis, at the rear (ie, away from the valve socket holes). Fasten these firmly with 3mm nuts and star washers from the underside of the chassis. Next, affix the longer of the two 27mm self-adhesive foam strips to the chassis, centrally between the two rows of spacers. The next step is to locate six of the eight EC9 chokes between the spacers as shown in the photo. They are stacked as three pairs of chokes. Fit the choke PC board over the terminal pins to make sure everything lines up, then secure the larger of the two supplied aluminium plates with four 30mm male/female spacers and two M3 x 8mm screws to the tops of the spacers. This clamps the six chokes into position as shown in the photos. Make sure that this aluminium plate is the right way around – the long edge of the plate with the holes further in goes towards the terminal pin side of the chokes. You should now affix the smaller 27mm self-adhesive foam strip to the top of larger aluminium plate, located siliconchip.com.au OUTPUT TRANSFORMERS ALUMINIUM PLATE 30MM SPACERS ALUMINIUM PLATE EC9 CHOKES This photo shows the top view of the chassis with the metal transformer cover removed. This reveals the stacked array of EC9 chokes and the two output transformers which have copper straps around their windings to reduce leakage flux. 3 centrally between the spacers just fitted. Once it’s in place, fit the remaining two EC9 chokes between the spacers on the larger aluminium plate. That done, check that the choke pins line up with the corresponding choke PC board holes, then attach the smaller aluminium plate with the M3 x 8mm screws and tighten firmly to clamp the chokes in place. You can now solder all the choke pins to the board and fit the 3-way terminal block, as shown in the photo, followed by the short preassembled 8-way cable and octal plug assembly. The eight leads are soldered to the choke PC board, as shown in the diagram of Fig.6. As a final step to the choke assembly, fit the small aluminium plate and the protective plastic over the exposed choke PC board, to avoid shock hazard. Four screws secure this aluminium plate and the cover. 2 4 Fig.7 (right): the pin numbering scheme for the octal plug (viewed from the top). This plug and its 8-way cable are supplied pre-assembled and is wired to the choke board. The plug then connects to the central octal socket on the chassis, as shown below. 1 5 8 6 7 TOP (REAR) VIEW OF OCTAL PLUG Output transformers Each output transformer is fitted siliconchip.com.au September 2005  81 RED BLK SH YEL WH SH (RIGHT SPEAKER TERMINALS) (LEFT SPEAKER TERMINALS) E E + + CABLE FROM POWER UNIT SHIELDED CABLE FROM FEEDBACK RESISTORS (REAR PANEL) TO POWER SWITCH FROM OUTPUT TRANSFORMERS (4-WAY SHIELDED CABLE FROM FRONT OF PC BOARD) 9 (MAIN BOARD) 8 7 6 5 4 3 2 1 25V 12.5V Fig.8: follow this wiring diagram to connect the main board to the rear of the chassis and to connect the power cable and power switch wiring. The wiring from the output transformers is also shown. to the chassis, using four M3 x 8mm screws from the top and secured with four 3mm nuts and star washers from underneath. Note the positions of the leads from the transformers and check that the orientations are as shown on the photos. The leads from the transformers are supplied at the correct length and all you need to do is to strip the ends Compare this view inside the finished unit with the wiring diagram above. 82  Silicon Chip for connection and soldering. Strip about 12mm of insulation from the transformer wire leads and terminate them as follows: (1). The Blue and Brown leads are the primary (high-impedance) windings and the Black and White leads are the secondary (low impedance) windings. Twist and solder the two blue primary leads together and then trim the end to about 6mm long and terminate it in the lower terminal of the 3-way terminal block on the choke board. (2). Twist, fold back and tin the ends of each brown wire to produce a 6mm thicker end and then terminate the left-channel brown lead (from the transformer nearest the front of the chassis) to the upper terminal of the 3-way terminal block. Follow this with the right-channel brown lead from the other transformer to the central terminal of the terminal block. (3). Run the black and white secondary leads along either side of the choke assembly, as shown in the photo. The secondary leads from the left transformer are run along the choke assembly behind the choke board and siliconchip.com.au The twisted brown & blue wires to the power switch are run through the inside channel of the chassis, as shown here. Note that the two yellow 10mF 400V polypropylene capacitors sit on a bed of silicone sealant to hold them in place. the leads from the right transformer are run along the other side and held in place with tape. Feed the ends of the secondary wires down through their associated rubber grommets at the rear of the choke assembly for later soldering to the speaker terminals. Perspex panels & blue LEDs. Now for the Perspex panels and the blue LEDs. First, secure the top central cover using its two Allen screws, then place the chassis upside down on a soft surface (to protect the paint) for this operation. The Perspex panels come with a protective coating and are predrilled with blind holes to match the holes on the top front of the chassis. The Perspex panels are located so that the ends with two holes are located near the chassis centre. Fit the panels to the chassis using the special screws for plastic fastening and tighten gently until the panels are firm. Take care not to over-tighten the screws and do not use ordinary selftapping screws, as they are likely to crack the Perspex. Two blue LEDs and a twisted pair of wires, with small connectors to mate with the PC pins on the main board, are provided. The LEDs are later connected in series after fitting them into the panels, so note that the longest lead is the positive (anode) terminal. Orientate the LEDs so that the positive lead of one LED faces the negative lead of the other at the chassis centre siliconchip.com.au and then push them firmly through the chassis holes and into the blind holes in the Perspex panels. Bend the two central LED leads towards each other until they are horizontal and no more than about 8mm from the chassis. Next, trim them so they just overlap and solder them together. Cut the remaining LED positive lead to 8mm and solder the red wire of the twisted pair to this lead and slide the sleeving from the red wire fully down over the soldered joint. Repeat this procedure for the remaining LED lead and the white wire of the twisted pair. Finally, push the sleeve-covered LED leads and the twisted pair down flush with the chassis, with the leads directed to the right (when facing the front of the upside-down chassis). Fitting the assembled board Before fitting the main board to the chassis, we suggest that you spend more time double-checking the component placement and soldering. Any errors are much easier to fix now than after the board is fitted to the chassis and connected to the wiring. To fit the main board to the chassis, first face the back of the upside-down chassis towards you. That done, begin to load the board in component side up and as close to the inside of the chassis as possible, but slightly to the right of centre at first. When the volume control shaft is near the inside of the front panel, move the PC board to the left while putting some downward pressure on the back area of the board near the 9-way connector block. Now push forward until the volume control and switch shafts go through their front panel holes and the ceramic valve sockets locate into their respective holes in the chassis Next, secure the board to the six 12mm spacers on the chassis using six M3 x 8mm screws. From the top of the chassis near the central ceramic octal socket, fit two M3 x 8mm screws into the two 12mm spacers previously mounted on the underside of the PC board. Now fasten the 16mm mounting spacers which are on the component Where To Buy A Kit The price for the full kit (including finished metalwork, panels and all components) is $870.00 (including GST) or with a fully assembled and tested PC board $970.00 (including GST). All metalwork and panels in the kit are fully finished and no drilling, cutting or punching is required. Note: this design is copyright to Gless Audio. Mudlark A205 kits, fully built amplifiers and other components including valves are available from: Gless Audio, 26 Park St, Seaford, Vic 3198. Phone (03) 9776 8703; Mobile 0403 055 374; email glesstron<at>msn.com September 2005  83 The power supply box houses the two large toroid transformers, which are connected back to back– see Fig.9. Be sure to sleeve all exposed connections on the fuseholder and the BP connector that terminates the mains Neutral lead using heatshrink insulation. side edges of the PC board to the inside flanges of the chassis with 12mm clearance spacers and M3 x 20mm countersunk head screws. You can then fit the knob to the potentiometer. Internal wiring to the board The RCA input connectors should already be wired to the main board via the supplied cable. Fit them to their holes in the back panel, using an M3 x 15mm countersunk head screw. Most of the underchassis wiring is shown in the diagram of Fig.8. The 6-way power cable is supplied with the octal plug fitted and the ends of the cable stripped and tinned ready to fit to the 9-way terminal block on the main board. Fit the end of the cable through the hole in the back panel using the supplied rubber boot and terminate the tinned ends into the terminal block as follows (terminal block numbered from outside edge of PC board): 2 brown; 4 blue; 5 orange; 6 white; 7 red and 8 black. Speaker terminal wiring The next step is to connect the two supplied 100mm black leads to termi84  Silicon Chip nals 8 & 9. Twist their bared ends with the existing wires at these terminals before securing them. That done, twist the other ends of these wires to the black leads from the output transformer secondaries (as shown in Fig.8), then place the supplied blue sleeving over the joined ends and solder them to the correct black-marked speaker terminals. Now carefully identify the right and left secondary (speaker) wires and separate out the white wires. Twist their bared ends to the supplied feedback cable leads – red wire to the right and the yellow wire to the left – and place the supplied red sleeving over each. Solder each to the appropriate right or left red-marked speaker terminal. Next, feed the connector end of the feedback cable back along the inside outer edge of the chassis (see photo) and connect the yellow wire to the pin nearest to the edge of the PC board (ie, adjacent to the 220kW 1W resistors) and the red wire to the other pin. Power wiring The first step here is to terminate the previously fitted blue wire from the link pad near valve socket V4 under This close-up view shows the wiring to the octal socket that’s inside the power supply – see Fig.9. the PC board to terminal block pin 3 (ie, with the blue power lead) for the 14GW8/PCL86 valves supplied with the kit. Alternatively, if you want to use 6GW8/ECL86 valves, terminate this lead to terminal block pin 5 (with the orange power lead). The wiring for the power switch is supplied as a blue and brown twisted pair fitted with spade connectors compatible with the power switch. Terminate the brown wire to terminal block pin 1 and the blue wire to terminal block pin 3. That done, feed the spade connector ends back through the inside channel of the chassis and siliconchip.com.au MOUNTING PLATE OCTAL SOCKET FOR AMPLIFIER POWER CORD T2 4 4 5 3 6 2 7 1 3 6 7 8 1 REAR VIEW (NC TO PINS 2 & 5) 8 INSULATED WIRE JOINERS ('BP' CONNECTORS) HOW TO ATTACH THE EARTH LUG STAR WASHERS LUG EARTH LUG T1 METAL BASEPLATE FIT HEATSHRINK INSULATION OVER REAR OF FUSEHOLDER M4 x 10mm SCREW, NUTS AND STAR WASHERS N UE BL GRN/YEL BR FUSE 1 CORDGRIP GROMMET Fig.9: here’s how to wire up the external power supply. With the exception of the primary leads for transformer T1, all the transformer leads are connected to the octal plug. siliconchip.com.au MAINS POWER CORD WARNING: THIS POWER SUPPLY CIRCUIT OPERATES AT LETHAL VOLTAGES September 2005  85 AUDIO PRECISION SCFREQRE AMPL(dBr) & AMPL(dBr) vs FREQ(Hz) 10.000 27 JUL 05 12:26:56 AUDIO PRECISION SCTHD-HZ THD+N(%) vs FREQ(Hz) 10 27 JUL 05 13:01:33 5.0000 0.0 -5.000 -10.00 1 -15.00 -20.00 -25.00 -30.00 0.1 10 100 1k 10k 100k Fig.10: this is the frequency response of the amplifier at a power level of 1W into an 8-ohm load. It has a peak of +5dB at 11Hz. connect them to the spade lugs on the power switch – see photo. External power supply The parts line-up for the external power supply comprises a drilled polycarbonate box, two 160VA toroidal transformers, a laser-cut transformer mounting plate, mains cord, fuse-holder and 2.5A fuse, ceramic Here’s another view of the chassis with the metal transformer cover removed. Don’t operate the amplifier without this cover – it’s necessary to protect against dangerous voltages. 86  Silicon Chip 20 100 1k 10k 20k Fig.11: this graph shows the total harmonic distortion versus frequency at a power level of 1W into an 8-ohm load. octal socket and all necessary screws and hardware. Fig.9 shows the assembly details. Take special care with the mains wiring and the pin connections to the octal socket. Make sure that the mains cord is tightly secured with the cordgrip grommet – you must not be able to pull it out. Check also that the earth lug is securely fastened to the baseplate (see Fig.9) and insulate all exposed mains connections – ie, on the fuseholder & BP connector. Testing the amplifier Caution! – the Mudlark A205 operates at high voltages and the utmost care must be exercised in checking the internal circuitry when it is powered up (see the warning panel p.76). It’s possible to get the A205 going without any test gear as long as no faults exist but it is preferable to have at least a reasonable quality multimeter with maximum voltage range of 500V or more, to determine if all is OK before you fully power up the amplifier. The first job is to test the external power supply, before it is connected to the amplifier. Make measurements at the octal socket with a multimeter on the AC voltage ranges. To do this, you will need to link pins 7 & 8 of the socket with a short length of wire – this takes the place of the power switch on the amplifier chassis. Next, insert a 2.5A fuse into the fuseholder and apply power. Check that the following nominal voltages are present: between pin 1 & pins 7 or 8, 25VAC; between pin 1 & pin 6, 12.5VAC; between pins 3 & 4, 160VAC (take care!). If all is OK, unplug the mains cable before proceeding. siliconchip.com.au AUDIO PRECISION SCTHD-W THD+N(%) vs measured LEVEL(W) 10 27 JUL 05 12:15:16 27 JUL 05 12:19:27 1 1 0.1 50m AUDIO PRECISION SCTHD-W THD+N(%) vs measured LEVEL(W) 10 0.1 1 10 50 Fig.12: this graph shows the total harmonic distortion versus power at 1kHz. It is less than 1.5% for listening levels (less than 2W) but rises rapidly above 14W as the circuit goes into fairly soft clipping. Before testing the main amplifier, make sure that the 555 timer IC is not in its socket. We DO NOT want the main HT voltage present while we are checking the other voltages. Next, install all the valves, making sure that the spigots on the output valves line up with the central keyways in the octal sockets. That done, rotate the volume control to minimum and stand the amplifier upside-down on a soft surface, ready for measurement. With the front panel switch off, plug the cable from the amplifier into the power supply and then plug in the mains cable and switch on the mains power. Switch on the front panel power switch and the blue LEDs should light up the Perspex panels. After a minute of so, check that the valve filaments are lighting up. You may have to peer closely to see the output tube filaments. Now connect the positive lead of your multimeter to one of the screw heads near the centre back of the PC board and measure the negative DC bias voltage on ZD2 which is up near the front of the board. This should be about 26V DC. If this is OK, it is now safe to apply HT voltages to the output valves. Without negative bias, the valves could be damaged when the HT is applied. Switch off the power and wait for a few minutes before inserting the 555 timer in its socket and then switch on again. If all looks OK after a few minutes reverse the multimeter polarity, ready to measure positive voltages. These should be reasonably close to the values shown on the circuit diagram of last month’s issue. The voltage across the 56W cathode resistor of the power valves is a good indicator of correct operation. This should be around +6V a few minutes after switch-on, rising to about +7V after about 20 minutes of operation at average mains voltages. If all seems well, you can fit the baseplate to the amplifier and it is ready to test with some audio input signals. Connect your speakers and a CD player and enjoy! Finally, note that the power supply box runs quite warm during normal operation (the case is a high-temperature type, so this isn’t a problem). And watch out for the valves SC – they get very hot, so don’t touch them. siliconchip.com.au 0.1 50m 0.1 1 10 50 Fig.13: this graph shows the same test as for Fig.7 but this time the feedback from the output transformer secondary is disconnected, giving rise to about the twice the distortion. AUDIO PRECISION SCCRSTK XTALK(dBr) & XTALK(dBr) vs FREQ(Hz) 0.0 27 JUL 05 12:31:07 -20.00 -40.00 -60.00 -80.00 -100.0 -120.0 20 100 1k 10k 20k Fig.14: this graph shows the separation between channels at a power level of 1W into 8W. Fig.15: the distortion from the A205 is predominantly second harmonic, as demonstrated by these scope waveforms. The lower trace shows a 1kHz sinewave at 10W into an 8-ohm load while the upper trace shows the distortion products which have a frequency of 2kHz. September 2005  87 PICAXE Part 4: Making Things Move By Clive Seager* In Part 3, we used our Schools Experimenter board to generate sound and measure temperature. This month in Part 4, we’ll show you how to control motors, solenoids and even R/C servos! IN THIS ARTICLE, you will learn: • how to interface a motor, solenoid and servo; • how to use PWM to control a motor’s speed; • how to reverse a motor; • how to control a servo. Before we begin, be aware that you must not connect a motor (or solenoid) directly to the PICAXE output pins. The motor will draw more current than the PICAXE can safely supply (20mA) and so will permanently damage it! The easiest way to interface a small DC motor or solenoid to a PICAXE is with the use of a Darlington transistor and diode (see Fig.1). As indicated by its circuit symbol, a Darlington * About the author: Clive Seager is the Technical Director of Revolution Education Ltd, the developers of the PICAXE system. 88  Silicon Chip transistor is actually two transistors in a single package. This configuration produces a very high gain, allowing control of a large collector current with a relatively small base current. Small 1.5V DC motors typically draw little current, so they can be driven with low-power Darlington transistors such as the BCX38C. Examples of this type of motor are the DSE P-8980 “solar” motor and the Jaycar YM-2705 “hobby” motor. For 3V DC motors, the mediumpower BD681 Darlington transistor is a better choice. In this application, the BD681 can pass up to about 300mA without a heatsink. For example, you could drive a low-speed, low-torque “toy” motor such as the DSE P-9000 3V DC motor without problems. For larger motors such as the DSE P-9002, you will need to fit a heatsink to the BD681 – otherwise, it is likely to overheat. A small “U” type heatsink would be sufficient for motor currents up to about 1A. Note that higher voltage motors or solenoids (eg, 12V models) will work with this system, given the appropriate power supply. Of course, the PICAXE chip must still be powered from a 4.5V battery or regulated 5V DC supply but more on that later. As shown in Fig.1, a 1N4001 (or 1N4004, etc.) diode must be connected across the motor to limit back-EMF generated voltage spikes. Without this protection diode, the spikes might damage Q1 and otherwise interfere with normal circuit operation. Another potential problem is with electrical noise, generated by the windings as the motor turns. A 220nF polyester capacitor soldered directly siliconchip.com.au across the motor’s terminals will effectively reduce this noise. In the example given in Fig.1, the motor circuit is connected to output 1 (PIN 1) of the PICAXE micro. The program in Listing 1 shows how to switch the motor on and off every five seconds. Task – connect a small DC motor to your experimenter board, using the breadboard wiring layout in Fig.2. Enter the simple program in Listing 1 to prove that it works. Motor speed control There are two ways of controlling the speed of a DC motor. The first is simply to vary the voltage applied to the motor. For example, if 2V were applied to a small DC motor it will rotate at a lower speed than if 3V were applied. Unfortunately, reducing the applied voltage also reduces the “turning power” (torque) of the motor considerably. In the second method, the full voltage is always applied to the motor but it is switched on and off rapidly. The time that the motor’s supply is switched on is called the mark time, and the time that it is switched off is called the space time, as illustrated in Fig.3. By varying the mark-space (on-off) ratio, the speed of the motor can be varied. This method of speed control is commonly called “PWM” because it is achieved by pulse-width modulation of the applied motor voltage. PWM is an efficient means of speed control and unlike the first (linear) method, torque remains proportionally high. In addition, PWM speed control is easily implemented with a PICAXE microcontroller. The program in Listing 2 demonstrates how it’s done. In this example, a mark-to-space ratio of 1-to-10 is used to turn the motor very slowly. Tip: a small propeller connected to the motor shaft makes it much easier to see the speed difference. Task – experiment with different markspace ratios and observe the variations in motor speed. What is the slowest speed you can achieve? This month, the Schools Experimenter is used to control a small DC motor with the aid of a very simple breadboard circuit. Fig.1: only a few common components are needed to interface a small DC motor or solenoid to a PICAXE. Although not shown here, a 220nF polyester capacitor must be soldered directly across the motor’s terminals. Reversing a DC motor To reverse the direction of rotation of a DC motor, it’s simply a matter of reversing the polarity of its power supply. Obviously, this cannot be achieved with our simple Darlington driver circuit, which provides only siliconchip.com.au Fig.2: here’s how to wire up the motor circuit shown in Fig.1. The BD681 Darlington transistor used here is suitable for switching all low-power 3V DC motors. Don’t forget that 220nF capacitor on the motor terminals. September 2005  89 states of the PICAXE outputs (PIN 1 & PIN 2). The program in Listing 3 demonstrates how to drive a motor, first in one direction and then in the other. Note that before reversing the motor, it is brought to a full stop by taking both outputs low for about 100ms. This is necessary to prevent placing excessive load on the motor and its power supply. Powering the driver Fig.3: by varying the ratio of the “on” to “off” time of the applied voltage, the speed of a DC motor can be varied. This is referred to as “pulse-width modulated” (PWM) speed control. “on-off” control. What we need is a circuit that can switch both supply leads to the motor. Such a circuit requires a minimum of four transistors in a “H-bridge” configuration, as illustrated in Fig.4. In this configuration, the transistors are driven as pairs. When all transistors are off, no current flows and so the motor is off. If Q1 and Q4 are switched on at the same time, current flows from left to right through the motor. If Q2 and Q3 are switched on at the same time, current flows the other way, hence reversing the motor. Note that the top and bottom transistors on one side must not be switched on together as this would result in a short circuit across the power supply rails and certain disaster! Fortunately, there’s no need to wire up a complex H-bridge circuit if you would like to experiment with twoway motor control. Instead, an L293D Driver IC is ideal for the job. It contains four complete “push-pull” drivers (channels), each channel with its own output transistor pair and protection diodes. Two channels are all that’s needed to form a complete H-bridge configuration, allowing two motors to be driven from a single IC. The L293D is available in a standard 16-pin DIL package and includes in-built over-temperature protection. Fig.5 shows a general scheme for controlling two motors, although only one motor is controlled by the PICAXE in this example. Two outputs from the PICAXE are connected to the control inputs of two channels of the L293D on pins 2 & 7. Table 1 shows the response of Motor A to the four possible logic Fig.4: a minimum of four transistors in a “H-bridge” configuration is required to be able to drive a DC motor in both directions. Note that this is not a complete working circuit – it just illustrates the concept. 90  Silicon Chip The L293D should be powered from the same supply as the PICAXE. The positive rail (shown here as +4.5V) connects to pin 16 of the L293D and the 0V rail to pins 4, 5, 12 & 13. A separate input (pin 8) is provided for motor power. If controlling a 3V motor, this input can be connected to the PICAXE +4.5V supply as well. However, for higher voltage motors, pin 8 should be wired to a separate supply of 4.5-36V, as appropriate for the motor. When a higher voltage supply is needed, you may find it more convenient to power your PICAXE circuits from that supply, rather than using a separate 4.5V battery pack. This can be achieved by adding a simple regulator circuit, like that shown in Fig.7. This circuit will accept an input range of 6-17V DC and provide a regulated 5V output for the experimenter board. Similar regulator circuits are available in kit form. For example, both Jaycar (cat. KA-1797) and DSE (cat. K-3594) stock the “Universal Voltage Adapter” kit published in “Electronics Australia”. Note that these kits support user-selectable output voltages that must be set for 5V during assembly. Note also that a heatsink may be required for the L293D when driving larger motors. To avoid this pitfall, we recommend the use of low-power 3V motors for the simple experiments presented here. For those interested in all the details, the L293D datasheet can be downloaded from www.st.com and www.ti.com Task – wire up a L293D circuit on your breadboard and connect it to output 1 and output 2 of the PICAXE, as shown in Fig.6. Write a program that reverses the direction of the motor every time the switch on input 3 is pushed. Fault-finding Is your motor circuit behaving erratically? Chances are, it’s caused by motor noise. Try removing the motor siliconchip.com.au Par t s Lis t 1 BD681 Darlington transistor 1 1N4001 (or 1N4004) diode 1 L293D motor driver IC 1 small 3V DC motor (see text) 1 1.5kW 0.25W 5% resistor 2 220nF 50V polyester (MKT) capacitors 1 3-pin header 1 R/C servo (e.g. Jaycar YM-2760) Where To Buy Parts Fig.5: the L293D driver IC makes it very easy to control one or two small DC motors. In this example, two PICAXE outputs are used to control the direction of a motor (Motor A). If speed control is required as well, then the enable input (pin 1) of the L293D could be connected to a third PICAXE output rather than to the +4.5V rail. Back-EMF protection diodes are included in the L293D, so you don’t need to add them when using this chip. The L293D driver IC can be ordered from MicroZed, see www.picaxe. com.au for more information or phone (02) 4351 0886. Suitable 3V DC motors are available from Dick Smith Electronics and Jaycar Electronics or can be salvaged from old toys. The BCX38C Darlington transistor mentioned in the text is available from Farnell (cat. 425497), phone 1300 361 005. Table 1 Pin 1 H Pin 2 L Function Turn Left L H Turn Right L H L H Fast Stop Fast Stop Fig.6: it’s easy to drive a small 3V DC motor using the L293D IC. The wiring diagram shown here closely follows the circuit in Fig.5, although only two of the ground (0V) pins of the IC are connected. A 220nF capacitor provides additional noise filtering for the motor power input on pin 8. and replacing it with a LED and a 1kW series resistor. If your program then runs as expected, the problem is definitely a result of noise. As a first step, check that a 220nF polyester capacitor is connected directly across the motor terminals as described earlier. Also, try connecting the power supply leads for the motor circuit directly to the battery or power supply output, rather than to the header (H1) on the experimenter board. Extra power supply filtering near the motor may also prove beneficial. Radio control servos Small servos, such as those found siliconchip.com.au The L293D driver chip is ideal for use in small robotic vehicles, such as the PICAXE micro-robot (Part No. AXE120). September 2005  91 Fig.7: advanced experimenters may wish to use a 6V (or 12V) battery or plugpack to power a higher voltage motor or solenoid. In this case, the experimenter board can be powered from the same source by adding a simple regulator circuit. You can either assemble one like that shown here on a small section of prototyping board or buy a kit of parts (see text). in radio control (R/C) models, contain a motor, gearbox and controller board (see Fig.8). A potentiometer (variable resistor) is connected to the output shaft to provide position feedback to the controller board. This allows the controller to accurately position the shaft according to instructions from its host. To control a servo, it is not necessary to interface directly to its motor. Instead, a simple digital connection is made to the integral controller board via the white/yellow signal wire. A servo can be connected directly to the 3-pin header (H2) on the experimenter board. Two pins provide power to the servo, while the third drives the servo’s signal line via output 0 of the PICAXE. If you haven’t installed this header yet, then you should do that next. When plugged into the on-board header, the servo is being powered from the same supply as the experimenter board, so it will be running at less than the 4.8-6V supply usually specified for these devices. If more torque is required, then you will need to connect the supply leads to a separate 6V supply. For a servo to operate, it must receive a pulsed signal every 20ms. The length of this pulse (0.75-2.25ms) determines the position of the output shaft. For example, a pulse length of 1.5ms moves the shaft to the central position. Servo software The Schools Experimenter Board can directly drive an RC-type servo motor. Just connect it to the 3-pin header (H2) on the board and use the demo code shown in Listings 4 & 5. 92  Silicon Chip In Listing 4, you will find a small program that moves the servo to two different positions using for…next loops (described in Part 3). The pulsout command is used to generate the short pulse, where pulsout 1,100 literally means: “output a pulse of length 1.0 ms on output 1”. One drawback with this system is that the coded pulse must be sent every 20ms; otherwise, the servo goes “loose” and moves out of position. This could be quite a problem when you are trying to do other things (eg, waiting for a switch press) in your PICAXE program. Fortunately, the PICAXE servo command is designed to address this very problem! Unlike most other BASIC commands, the servo command (once activated) operates continuously in the background, supplying the servo with its pulse every 20ms. A simple siliconchip.com.au Program Listings What’s Inside A Servo? Listing 1 main: high 1 pause 5000 low 1 pause 5000 goto main Listing 2 Fig.8: exploded view of a typical R/C servo, showing that there’s a lot more than just a motor inside the plastic case. example is given in Listing 5, where a servo arm is moved back and forth in response to the press of a switch on input 3. What’s coming? Can this little 8-pin chip really do more? You bet! Next month, we’ll show you how to control the experimenter’s board using an infrared remote. We’ll also record and playback sounds with an add-on speech module. SC main: high 1 pause 1 low 1 pause 10 goto main Listing 3 main: ' ensure motor is stopped low 1 low 2 pause 100 ' forward direction high 1 low 2 pause 3000 ' stop motor low 1 pause 100 ' reverse direction low 1 high 2 pause 3000 goto main Listing 4 main: for b1 = 1 to 200   pulsout 1,100   pause 20 next b1 for b1 = 1 to 200   pulsout 1,200   pause 20 next b1 goto main Listing 5 main1: servo 1, 100 pause 1000 loop1: if pin3 = 1 then main2 goto loop1 main2: servo 1, 200 pause 1000 loop2: if pin3 = 1 then main1 goto loop2 TAKE YOUR PIC Picaxe.com.au DISTRIBUTOR: MicroZed.com.au Developed for students, & professional performance makes PICAXE the most easy-to-use micro ever: PICAXE “programmer" is two resistors and a 4.5V battery! PHONE (02) 4351 0886 8.30-4.30 AEST Mon-Fri FAX (02) 4351 0889 24 Hours ALL PICAXE ITEMS ON OUR SHELVES! STOCKISTS siliconchip.com.au In AUSTRALIA: In NEW ZEALAND sicom.co.nz altronics.com.au (Retail and Mail Order) oatleyelectronics.com surplustronics.co.nz School Electronic Supplies (John - 03 8802 0628 – School orders only) September 2005  93 Salvage It! BY JULIAN EDGAR Scrounging & using shortwave radios This month, we’re going to make use of a discarded appliance that’s complete – no dismantling or salvaging of bits required! Welcome to the world of shortwave radio. Not quite sure what a shortwave radio is? Well, quite simply, it’s a radio that can tune in stations that operate at frequencies much higher than those on the familiar broadcast band. These stations also operate at shorter wavelengths than broadcast band stations (the higher the frequency, the shorter the wavelength), hence the term “shortwave stations”. With the ability of the web to run streaming audio from all around the world, listening to foreign stations via shortwave radio has dramatically declined in popularity. But take it from me, it’s a lot of fun exploring the shortwave radio bands and tuning in overseas stations. And best of all, it can cost next to nothing to obtain a shortwave radio and almost nothing to run it. That’s a lot different to paying for a PC and the bandwidth chewed up by streaming audio downloads! Shortwave radio stations are set up by countries primarily to present their political and cultural perspectives to the rest of the world. They’ve been doing that for well over 70 years but that doesn’t mean the program content is always dry – there’s music, news, talkshows and other program material, just like on a national broadcaster. What’s really interesting is the way This close-up view clearly shows the two shortwave radio bands (SW1 & SW2) on the dial of the old National Panasonic unit. in which world events are seen so differently by individual countries – it can be startling to hear the same news event described in terms that are completely different to what you are used to. In many cases, overseas broadcasts are nothing more than blatant propaganda but it’s still interesting to listen to other perspectives on world events. Buying a shortwave radio This old National Panasonic radio-cassette player was picked up at the local tip for just $5. In addition to AM/FM radio reception, it also boasts shortwave reception on two bands and has external aerial and earth connections. It also features a fine-tuning knob, making it perfect for listening to shortwave stations. 94  Silicon Chip Dedicated shortwave radios can be bought secondhand from about $30, or even less at a garage sale. Alternatively, you can buy low-cost units new for somewhere around $40. However, there are shortwave radios and there are shortwave radios – in my experience, the “cheapies” are terrible. In any case, $30 is outside our budget here. Instead, the trick is to find an old portable radio-cassette player – one that was once an expensive unit. In addition to FM and AM bands (and of course the cassette part as well), quite a few of these have shortwave reception. And they tend to be cheaper than dedicated radios – it seems no one wants cassette players these days! There are some key points to look for – the radio must have external aerial and earth connections and it must have siliconchip.com.au a fine-tuning knob. Let’s take a look at why each is required. Despite many shortwave radios using nothing more than a whip antenna, in most cases you really need a longwire antenna and an earth connection to get usable reception (they’re both easy to organise, so stay with us). Also, tuning a shortwave radio is a very different to tuning a conventional radio. In short, you need to be able to very precisely tune in a given station – hiccup and you’ll miss it. That’s where a fine-tuning knob is critical; without it, you’ll find that accurate tuning is quite difficult. Other features to look out for are those that you’d expect in any quality radio – things like a headphone socket, line-level outputs, and bass and treble controls. You’re not necessarily going to use any of these but their presence is evidence that you’ll got a quality piece of gear in front of you – one that is likely to give good shortwave reception. The radio-cassette player pictured here is a National Panasonic RX-5100 unit and was purchased from the shop at the local tip for a measly $5. It was in pretty good order but was missing its whip antenna and lacked a power cord. It also has some dents and scratches – the latter probably occurring when it was thrown on the tip. The volume controls (it uses dual controls) were also scratchy. But those quibbles aside, the unit works beautifully, with good sound and excellent shortwave reception. Aerial and earth After you’ve checked that the radio actually works (try it on the broadcast band), you’ll need to add an aerial and an earth. Connect the aerial first – some radios earth themselves through the mains power connection while in others, an earth connection seems to make little difference. The aerial can consist of any long piece of wire that’s supported as far above the ground as possible. That doesn’t mean you need to invest in tall masts and lots of high-quality wire – any wire that’s strong enough to support the span will do. You can string it between trees or from the roof of your house down to the ground, with insulators at the “tie-offs” at each end. The one I used is about 15 metres long and about five metres above the ground. What will work for you siliconchip.com.au An external aerial is a must for good shortwave listening but it doesn’t need to be anything fancy. Here, the aerial wire has been run from a short mast at left to the elevated house at right (ie, between the two arrows). depends a lot on the radio and your location – try different lengths and heights. Connect one end to the aerial terminal of the radio and try tuning carefully and slowly across the shortwave bands. You should now be able to hear shortwave stations that were previously buried in noise. Note that tuning a shortwave radio is not like twiddling an AM or FM dial: tuning slowly across the whole band might literally take you 10-15 minutes. When you hear a loud noise, fine-tune with the appropriate knob. Unless you’re very unlucky, you should be able to hear some stations – stations that your near-zero-dollar radio is pulling in from around the world! Once you’re hearing something, try adding an earth connection. This is literally a wire connecting the earth terminal to the ground outside – it’s best if you drive a copper stake into the ground or make a connection to a copper water pipe. If the earth connection improves reception, that’s great. If it doesn’t, leave it off. You’ll soon learn that analog radios tend to drift a little, so you will have to re-tune periodically to stay on-station. Note also that shortwave stations change the frequencies on which they broadcast at different times of the day. That’s done to counter changing reception conditions. So next time you see an old portable radio-cassette player going for a song, grab it and have a listen. Tuning in to the shortwave bands is lots of fun. SC Rat It Before You Chuck It! Whenever you throw away an old TV (or VCR or washing machine or dishwasher or printer) do you always think that surely there must be some good salvageable components inside? Well, this column is for you! (And it’s also for people without a lot of dough.) Each month we’ll use bits and pieces sourced from discards, sometimes in mini-projects and other times as an ideas smorgasbord. And you can contribute as well. If you have a use for specific parts which can easily be salvaged from goods commonly being thrown away, we’d love to hear from you. Perhaps you use the pressure switch from a washing machine to control a pump. Or maybe you have a use for the highquality bearings from VCR heads. Or perhaps you’ve found how the guts of a cassette player can be easily turned into a metal detector. (Well, we made the last one up but you get the idea . . .) If you have some practical ideas, write in and tell us! September 2005  95 ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST Silicon Chip Back Issues April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. September 1989: 2-Chip Portable AM Stereo Radio Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Active Antenna Kit; Designing UHF Transmitter Stages. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. March 1995: 2 x 50W Stereo Amplifier, Pt.1; Subcarrier Decoder For FM Receivers; Wide Range Electrostatic Loudspeakers, Pt.2; IR Illuminator For CCD Cameras; Remote Control System For Models, Pt.3. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. April 1995: FM Radio Trainer, Pt.1; Balanced Mic Preamp & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. March 1993: Solar Charger For 12V Batteries; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. May 1995: Guitar Headphone Amplifier; FM Radio Trainer, Pt.2; Transistor/Mosfet Tester For DMMs; A 16-Channel Decoder For Radio Remote Control; Introduction To Satellite TV. April 1993: Solar-Powered Electric Fence; Audio Power Meter; ThreeFunction Home Weather Station; 12VDC To 70VDC Converter. June 1995: Build A Satellite TV Receiver; Train Detector For Model Railways; 1W Audio Amplifier Trainer; Low-Cost Video Security System; Multi-Channel Radio Control Transmitter For Models, Pt.1. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars. July 1995: Electric Fence Controller; How To Run Two Trains On A Single Track (Incl. Lights & Sound); Setting Up A Satellite TV Ground Station; Build A Reliable Door Minder. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Antenna Tuners – Why They Are Useful. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; How To Identify IDE Hard Disk Drive Parameters. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; Satellites & Their Orbits. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; Jacob’s Ladder Display. October 1995: 3-Way Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Nicad Fast Charger. November 1995: Mixture Display For Fuel Injected Cars; CB Trans­verter For The 80M Amateur Band, Pt.1; PIR Movement Detector. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. December 1995: Engine Immobiliser; 5-Band Equaliser; CB Transverter For The 80M Amateur Band, Pt.2; Subwoofer Controller; Knock Sensing In Cars; Index To Volume 8. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. December 1993: Remote Controller For Garage Doors; LED Stroboscope; 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. May 1996: High Voltage Insulation Tester; Knightrider LED Chaser; Simple Intercom Uses Optical Cable; Cathode Ray Oscilloscopes, Pt.3. July 1990: Digital Sine/Square Generator, Pt.1 (0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; January 1994: 3A 40V Variable Power Supply; Solar Panel Switching Regulator; Printer Status Indicator; Mini Drill Speed Controller; Stepper Motor Controller; Active Filter Design; Engine Management, Pt.4. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter. August 1990: Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. September 1990: 3-Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band; Taking Care Of Nicad Battery Packs. October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. February 1994:90-Second Message Recorder; 12-240VAC 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. March 1994: Intelligent IR Remote Controller; 50W (LM3876) Audio Amplifier Module; Level Crossing Detector For Model Railways; Voice Activated Switch For FM Microphones; Engine Management, Pt.6. June 1996: Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. July 1996: VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser;. August 1996: Introduction to IGBTs; Electronic Starter For Fluores­cent Lamps; VGA Oscilloscope, Pt.2; 350W Amplifier Module; Masthead Amplifier For TV & FM; Cathode Ray Oscilloscopes, Pt.4. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. April 1994: Sound & Lights For Model Railway Level Crossings; Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. October 1996: Send Video Signals Over Twisted Pair Cable; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Multi-Channel Radio Control Transmitter, Pt.8. May 1994: Fast Charger For Nicad Batteries; Induction Balance Metal Locator; Multi-Channel Infrared Remote Control; Dual Electronic Dice; Simple Servo Driver Circuits; Engine Management, Pt.8. November 1996: 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; Repairing Domestic Light Dimmers; 600W DC-DC Converter For Car Hifi Systems, Pt.2. June 1994: A Coolant Level Alarm For Your Car; 80-Metre AM/CW Transmitter For Amateurs; Converting Phono Inputs To Line Inputs; PC-Based Nicad Battery Monitor; Engine Management, Pt.9. December 1996: Active Filter For CW Reception; Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Vol.9. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. January 1997: Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Thermometer (Monitors Eight Temperatures). August 1994: High-Power Dimmer For Incandescent Lights; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. February 1997: PC-Con­trolled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; Alert-A-Phone Loud Sounding Telephone Alarm; Control Panel For Multiple Smoke Alarms, Pt.2. September 1991: Digital Altimeter For Gliders & Ultralights; Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion. September 1994: Automatic Discharger For Nicad Batteries; MiniVox Voice Operated Relay; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Mics, Pt.2; Electronic Engine Management, Pt.12. March 1997: 175W PA Amplifier; Signalling & Lighting For Model Railways; Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. October 1991: A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. December 1991: TV Transmitter For VCRs With UHF Modulators; IR Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Vol.4. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-M DSB Amateur Transmitter; 2-Cell Nicad Discharger. May 1997: Neon Tube Modulator For Light Systems; Traffic Lights For A Model Intersection; The Spacewriter – It Writes Messages In Thin Air; A Look At Signal Tracing; Pt.2; Cathode Ray Oscilloscopes, Pt.9. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Aligning Vintage Radio Receivers, Pt.1. December 1994: Car Burglar Alarm; Three-Spot Low Distortion Sinewave Oscillator; Clifford – A Pesky Electronic Cricket; Remote Control System for Models, Pt.1; Index to Vol.7. June 1997: PC-Controlled Thermometer/Thermostat; TV Pattern Generator, Pt.1; Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For Stepper Motors. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dual Channel UHF Remote Control; Stereo Microphone Pre­amp­lifier. July 1997: Infrared Remote Volume Control; A Flexible Interface Card For PCs; Points Controller For Model Railways; Colour TV Pattern Generator, Pt.2; An In-Line Mixer For Radio Control Receivers. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. February 1991: A Practical Approach To Amplifier Design; Synthesised Stereo AM Tuner; Three Inverters For Fluorescent Lights; Low-Cost Sinewave Oscillator; Fast Charger For Nicad Batteries, Pt.2. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. July 1991: Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. ORDER FORM February 1995: 2 x 50W Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel LCD Thermometer; Wide Range Electrostatic Loudspeakers, Pt.1; Remote Control System For Models, Pt.2. April 1997: Simple Timer With No ICs; Digital Voltmeter For Cars; Loudspeaker Protector For Stereo Amplifiers; Model Train Controller; A Look At Signal Tracing; Pt.1; Cathode Ray Oscilloscopes, Pt.8. October 1997: 5-Digit Tachometer; Central Locking For Your Car; PCControlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3. Please send the following back issues:________________________________________ Enclosed is my cheque/money order for $­______or please debit my:  Bankcard  Visa Card  Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 98  Silicon Chip 10% OF SUBSCR F TO IB OR IF Y ERS OU 10 OR M BUY ORE Note: prices include postage & packing Australia ............................... $A8.80 (incl. GST) Overseas (airmail) ..................................... $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au siliconchip.com.au November 1997: Heavy Duty 10A 240VAC Motor Speed Controller; Easy-To-Use Cable & Wiring Tester; Build A Musical Doorbell; Replacing Foam Speaker Surrounds; Understanding Electric Lighting Pt.1. December 1997: Speed Alarm For Cars; 2-Axis Robot With Gripper; Stepper Motor Driver With Onboard Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2; Index To Vol.10. Preamplifier, Pt.1; Message Bank & Missed Call Alert; Protoboards – The Easy Way Into Electronics, Pt.3. December 2000: Home Networking For Shared Internet Access; White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Index To Vol.13. January 1998: 4-Channel 12VDC or 12VAC Lightshow, Pt.1; Command Control For Model Railways, Pt.1; Pan Controller For CCD Cameras. January 2001: How To Transfer LPs & Tapes To CD; The LP Doctor – Clean Up Clicks & Pops, Pt.1; Arbitrary Waveform Generator; 2-Channel Guitar Preamplifier, Pt.3; PIC Programmer & TestBed. February 1998: Telephone Exchange Simulator For Testing; Command Control For Model Railways, Pt.2; 4-Channel Lightshow, Pt.2. February 2001: An Easy Way To Make PC Boards; L’il Pulser Train Controller; A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Groundplane Antenna; LP Doctor – Clean Up Clicks & Pops, Pt.2. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Understanding Electric Lighting; Pt.6. May 1998: 3-LED Logic Probe; Garage Door Opener, Pt.2; Command Control System, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. June 1998: Troubleshooting Your PC, Pt.2; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. July 1998: Troubleshooting Your PC, Pt.3; 15W/Ch Class-A Audio Amplifier, Pt.1; Simple Charger For 6V & 12V SLA Batteries; Auto­ matic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. August 1998: Troubleshooting Your PC, Pt.4; I/O Card With Data Logging; Beat Triggered Strobe; 15W/Ch Class-A Stereo Amplifier, Pt.2. September 1998: Troubleshooting Your PC, Pt.5; A Blocked Air-Filter Alarm; Waa-Waa Pedal For Guitars; Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. October 1998: AC Millivoltmeter, Pt.1; PC-Controlled Stress-O-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. November 1998: The Christmas Star; A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Improving AM Radio Reception, Pt.1. December 1998: Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; Regulated 12V DC Plugpack; Build A Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Gliders. January 1999: High-Voltage Megohm Tester; A Look At The BASIC Stamp; Bargraph Ammeter For Cars; Keypad Engine Immobiliser. March 2001: Making Photo Resist PC Boards; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; A Simple MIDI Expansion Box. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger. May 2001: 12V Mini Stereo Amplifier; Two White-LED Torches To Build; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Tweaking Windows With TweakUI. March 2004: PC Board Design, Pt.2; Build The QuickBrake For Increased Driving Safety; 3V-9V (or more) DC-DC Converter; ESR Meter Mk.2, Pt.1; PICAXE-18X 4-Channel Datalogger, Pt.3. September 2001: Making MP3s; Build An MP3 Jukebox, Pt.1; PCControlled Mains Switch; Personal Noise Source For Tinnitus; Directional Microphone; Using Linux To Share An Internet Connection, Pt.4. April 2004: PC Board Design, Pt.3; Loudspeaker Level Meter For Home Theatre Systems; Dog Silencer; Mixture Display For Cars; ESR Meter Mk.2, Pt.2; PC/PICAXE Interface For UHF Remote Control. November 2001: Ultra-LD 100W/Channel Stereo Amplifier, Pt.1; Neon Tube Modulator For Cars; Audio/Video Distribution Amplifier; Build A Short Message Recorder Player; Useful Tips For Your PC. May 2004: Amplifier Testing Without High-Tech Gear; Component Video To RGB Converter; Starpower Switching Supply For Luxeon Star LEDs; Wireless Parallel Port; Poor Man’s Metal Locator. December 2001: IR Transceiver For PCs; 100W/Ch Stereo Amplifier, Pt.2; Pardy Lights Colour Display; PIC Fun – Learning About Micros. June 2004: Dr Video Mk.2 Video Stabiliser; Build An RFID Security Module; Fridge-Door Alarm; Courtesy Light Delay For Cars; Automating PC Power-Up; Upgraded Software For The EPROM Programmer. March 2002: Mighty Midget Audio Amplifier Module; 6-Channel IR Remote Volume Control, Pt.1; RIAA Pre­-­Amplifier For Magnetic Cartridges; 12/24V Intelligent Solar Power Battery Charger. November 1999: Setting Up An Email Server; Speed Alarm For Cars, Pt.1; LED Christmas Tree; Intercom Station Expander; Foldback Loudspeaker System; Railpower Model Train Controller, Pt.2. December 2003: How To Receive Weather Satellite Images; SelfDiagnostics Plug For Cars; PC Board Design, Pt.3; VHF Receiver For Weather Satellites; Linear Supply For Luxeon 1W Star LEDs; 5V Meter Calibration Standard; PIC-Based Car Battery Monitor; PICAXE Pt.10. August 2001: DI Box For Musicians; 200W Mosfet Amplifier Module; Headlight Reminder; 40MHz 6-Digit Frequency Counter Module; A PC To Die For, Pt.3; Using Linux To Share An Internet Connection, Pt.3. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Carbon Monoxide Alarm. October 1999: Build The Railpower Model Train Controller, Pt.1; Semiconductor Curve Tracer; Autonomouse The Robot, Pt.2; XYZ Table With Stepper Motor Control, Pt.6; Introducing Home Theatre. November 2003: PC Board Design, Pt.2; 12AX7 Valve Audio Preamplifier; Our Best Ever LED Torch; Smart Radio Modem For Microcontrollers; PICAXE Pt.9; Programmable PIC-Powered Timer. February 2004: PC Board Design, Pt.1; Supply Rail Monitor For PCs; Studio 350W Power Amplifier Module, Pt.2; Shorted Turns Tester For Line Output Transformers; PICAXE-18X 4-Channel Datalogger, Pt.2. February 2002: 10-Channel IR Remote Control Receiver; 2.4GHz High-Power Audio-Video Link; Touch And/Or Remote-Controlled Light Dimmer, Pt.2; Booting A PC Without A Keyboard; 4-Way Event Timer. September 1999: Autonomouse The Robot, Pt.1; Voice Direct Speech Recognition Module; Digital Electrolytic Capacitance Meter; XYZ Table With Stepper Motor Control, Pt.5; Peltier-Powered Can Cooler. October 2003: PC Board Design, Pt.1; JV80 Loudspeaker System; A Dirt Cheap, High-Current Power Supply; Low-Cost 50MHz Frequency Meter; Long-Range 16-Channel Remote Control System. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Tele­phone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; A PC To Die For, Pt.2; Backing Up Your Email. April 1999: Getting Started With Linux; Pt.2; High-Power Electric Fence Controller; Bass Cube Subwoofer; Programmable Thermostat/ Thermometer; Build An Infrared Sentry; Rev Limiter For Cars. August 1999: Remote Modem Controller; Daytime Running Lights For Cars; Build A PC Monitor Checker; Switching Temperature Controller; XYZ Table With Stepper Motor Control, Pt.4; Electric Lighting, Pt.14. September 2003: Robot Wars; Krypton Bike Light; PIC Programmer; Current Clamp Meter Adapter For DMMs; PICAXE Pt.8 – A Data Logger; Digital Instrument Display For Cars, Pt.2. January 2004: Studio 350W Power Amplifier Module, Pt.1; HighEfficiency Power Supply For 1W Star LEDs; Antenna & RF Preamp For Weather Satellites; Lapel Microphone Adaptor For PA Systems; PICAXE-18X 4-Channel Datalogger, Pt.1; 2.4GHZ Audio/Video Link. January 2002: Touch And/Or Remote-Controlled Light Dimmer, Pt.1; A Cheap ’n’Easy Motorbike Alarm; 100W /Channel Stereo Amplifier, Pt.3; Build A Raucous Alarm; FAQs On The MP3 Jukebox. July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. August 2003: PC Infrared Remote Receiver (Play DVDs & MP3s On Your PC Via Remote Control); Digital Instrument Display For Cars, Pt.1; Home-Brew Weatherproof 2.4GHz WiFi Antennas; PICAXE Pt.7. June 2001: Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; Low-Cost Automatic Camera Switcher; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For, Pt.1. March 1999: Build A Digital Anemometer; DIY PIC Programmer; Build An Audio Compressor; Low-Distortion Audio Signal Generator, Pt.2. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1. July 2003: Smart Card Reader & Programmer; Power-Up Auto Mains Switch; A “Smart” Slave Flash Trigger; Programmable Continuity Tester; PICAXE Pt.6 – Data Communications; Updating The PIC Programmer & Checkerboard; RFID Tags – How They Work. April 2002:Automatic Single-Channel Light Dimmer; Pt.1; Water Level Indicator; Multiple-Output Bench Power Supply; Versatile Multi-Mode Timer; 6-Channel IR Remote Volume Control, Pt.2. May 2002: 32-LED Knightrider; The Battery Guardian (Cuts Power When the Battery Voltage Drops); Stereo Headphone Amplifier; Automatic Single-Channel Light Dimmer; Pt.2; Stepper Motor Controller. July 2002: Telephone Headset Adaptor; Rolling Code 4-Channel UHF Remote Control; Remote Volume Control For The Ultra-LD Stereo Amplifier; Direct Conversion Receiver For Radio Amateurs, Pt.1. August 2002: Digital Instrumentation Software For PCs; Digital Storage Logic Probe; Digital Therm./Thermostat; Sound Card Interface For PC Test Instruments; Direct Conversion Receiver For Radio Amateurs. September 2002: 12V Fluorescent Lamp Inverter; 8-Channel Infrared Remote Control; 50-Watt DC Electronic Load; Spyware – An Update. October 2002: Speed Controller For Universal Motors; PC Parallel Port Wizard; Cable Tracer; AVR ISP Serial Programmer; 3D TV. July 2004: Silencing A Noisy PC; Versatile Battery Protector; Appliance Energy Meter, Pt.1; A Poor Man’s Q Meter; Regulated High-Voltage Supply For Valve Amplifiers; Remote Control For A Model Train Layout. August 2004: Video Formats: Why Bother?; VAF’s New DC-X Generation IV Loudspeakers; Video Enhancer & Y/C Separator; Balanced Microphone Preamp; Appliance Energy Meter, Pt.2; 3-State Logic Probe. September 2004: Voice Over IP (VoIP) For Beginners; WiFry – Cooking Up 2.4GHz Antennas; Bed Wetting Alert; Build a Programmable Robot; Another CFL Inverter. October 2004: The Humble “Trannie” Turns 50; SMS Controller, Pt.1; RGB To Component Video Converter; USB Power Injector; Remote Controller For Garage Doors & Gates. November 2004: 42V Car Electrical Systems; USB-Controlled Power Switch (Errata Dec. 2004); Charger For Deep-Cycle 12V Batteries, Pt.1; Driveway Sentry; SMS Controller, Pt.2; PICAXE IR Remote Control. December 2004: Build A Windmill Generator, Pt.1; 20W Amplifier Module; Charger For Deep-Cycle 12V Batteries, Pt.2; Solar-Powered Wireless Weather Station; Bidirectional Motor Speed Controller. January 2005: Windmill Generator, Pt.2; Build A V8 Doorbell; IR Remote Control Checker; 4-Minute Shower Timer; The Prawnlite; Sinom Says Game; VAF DC-7 Generation 4 Kit Speakers. February 2005: Windmill Generator, Pt.3; USB-Controlled Electrocardiograph; TwinTen Stereo Amplifier; Inductance & Q-Factor Meter, Pt.1; A Yagi Antenna For UHF CB; $2 Battery Charger. December 1999: Solar Panel Regulator; PC Powerhouse (gives +12V, +9V, +6V & +5V rails); Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Vol.12. November 2002: SuperCharger For NiCd/NiMH Batteries, Pt.1; Windows-Based EPROM Programmer, Pt.1; 4-Digit Crystal-Controlled Timing Module; Using Linux To Share An Optus Cable Modem, Pt.1. March 2005: Windmill Generator, Pt.4; Sports Scoreboard, Pt.1; Swimming Pool Lap Counter; Inductance & Q-Factor Meter, Pt.2; Shielded Loop Antenna For AM; Cheap UV EPROM Eraser; Sending Picaxe Data Over 477MHz UHF CB; $10 Lathe & Drill Press Tachometer. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Parallel Port Interface Card; Telephone Off-Hook Indicator. December 2002: Receiving TV From Satellites; Pt.1; The Micromitter Stereo FM Transmitter; Windows-Based EPROM Programmer, Pt.2; SuperCharger For NiCd/NiMH Batteries; Pt.2; Simple VHF FM/AM Radio; Using Linux To Share An Optus Cable Modem, Pt.2. April 2005: Install Your Own In-Car Video (Reversing Monitor, In-Car Navigation, etc); Build A MIDI Theremin, Pt.1; Bass Extender For Hifi Systems; Sports Scoreboard, Pt.2; SMS Controller Add-Ons; A $5 Variable Power Supply. March 2000: Resurrecting An Old Computer; 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver. January 2003: Receiving TV From Satellites, Pt 2; SC480 50W RMS Amplifier Module, Pt.1; Gear Indicator For Cars; Active 3-Way Crossover For Speakers; Using Linux To Share An Optus Cable Modem, Pt.3. May 2005: Getting Into Wi-Fi, Pt.1; Build A 45-Second Voice Recorder; Wireless Microphone/Audio Link; MIDI Theremin, Pt.2; Sports Scoreboard, Pt.3; Automatic Stopwatch Timer. May 2000: Ultra-LD Stereo Amplifier, Pt.2; LED Dice (With PIC Microcontroller); 50A Motor Speed Controller For Models. February 2003: PortaPal PA System, Pt.1; SC480 50W RMS Amplifier Module, Pt.2; Windows-Based EPROM Programmer, Pt.3; Using Linux To Share An Optus Cable Modem, Pt.4; Fun With The PICAXE, Pt.1. June 2005: Looking At Laptops; Getting Into Wi-Fi, Pt.2; The Mesmeriser LED Clock; Coolmaster Fridge/Freezer Temperature Controller; Alternative Power Regular; PICAXE Colour Recognition System; AVR200 Single Board Computer, Pt.1. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; Safety Switch Checker; Sine/Square Wave Oscillator. June 2000: Automatic Rain Gauge; Parallel Port VHF FM Receiver; Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor. July 2000: Moving Message Display; Compact Fluorescent Lamp Driver; Musicians’ Lead Tester; Switchmode Power Supply, Pt.2. March 2003: LED Lighting For Your Car; Peltier-Effect Tinnie Cooler; PortaPal PA System, Pt.2; 12V SLA Battery Float Charger; Little Dynamite Subwoofer; Fun With The PICAXE, Pt.2 (Shop Door Minder). August 2000: Theremin; Spinner (writes messages in “thin-air”); Proximity Switch; Structured Cabling For Computer Networks. April 2003: Video-Audio Booster For Home Theatre Systems; Telephone Dialler For Burglar Alarms; Three PIC Programmer Kits; PICAXE, Pt.3 (Heartbeat Simulator); Electric Shutter Release For Cameras. September 2000: Swimming Pool Alarm; 8-Channel PC Relay Board; Fuel Mixture Display For Cars, Pt.1; Protoboards – The Easy Way Into Electronics, Pt.1; Cybug The Solar Fly. May 2003: Widgybox Guitar Distortion Effects Unit; 10MHz Direct Digital Synthesis Generator; Big Blaster Subwoofer; Printer Port Simulator; PICAXE, Pt.4 (Motor Controller). October 2000: Guitar Jammer; Breath Tester; Wand-Mounted Inspection Camera; Subwoofer For Cars; Fuel Mixture Display, Pt.2. June 2003: PICAXE, Pt.5; PICAXE-Controlled Telephone Intercom; PICAXE-08 Port Expansion; Sunset Switch For Security & Garden Lighting; Digital Reaction Timer; Adjustable DC-DC Converter For Cars; Long-Range 4-Channel UHF Remote Control. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar siliconchip.com.au July 2005: Getting Into Wi-Fi, Pt.3; Remote-Controlled Automatic Lamp Dimmer; Lead-Acid Battery Zapper; Serial Stepper Motor Controller; AVR200 Single Board Computer, Pt.2; Salvaging & Using Thermostats; Unwired Modems & External Antennas; PICAXE in Schools, Pt.4. August 2005: The Mudlark A205 Valve Stereo Amplifier; Programmable Flexitimer; Carbon Monoxide Alert; Serial LCD Driver; Enhanced Sports Scoreboard; Salvaging Washing Maching Pressure Switches. PLEASE NOTE: issues not listed have sold out. All other issues are in stock. We can supply photostat copies from sold-out issues for $8.80 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date can be downloaded free from our web site: www.siliconchip.com.au September 2005  99 Vintage Radio By RODNEY CHAMPNESS, VK3UG The Sprague 500 multi-band receiver Ever wondered how interference to radio and TV reception is tracked down? In the 1960s, it was done used specialised multi-band receivers such as the Sprague 500. The Sprague Electric Company of America produced a wide range of electrical components and other apparatus. They also produced a number of specialised radio receivers, generically described as “Interference Locators”. These Sprague receivers nominally covered the frequency range from around 550kHz up to at least 220MHz. In practice, they were mainly used to trace sources of interference to radio and television reception (and occa- sionally to 2-way radios), although they were never originally intended to be used for this purpose. In order to successfully track down interference, it was necessary that the sets be fully portable. This meant that they could be powered from an inbuilt battery, as well as from 110/120V and 240V AC power. The internal wet-cell battery was automatically recharged whenever the unit was connected to the mains. In this case, “portability” is a relative term as the Sprague 500 weighs in at a hefty 12.5kg and measures 333mm high x 320mm long x 200mm wide. At the time of its manufacture (around 1960), portable equipment was still quite heavy and bulky. The Sprague 400 was the first in this line of receivers, followed by the model 500 in 1959 (the last of the “valved” units). This was then followed by the model 600, model 610 and finally, the model 700 in 1977. I understand that either Eddystone or Belling Lee (I’m not sure which) also made an interference tracing receiver but I’ve not seen one. I’ve personally used all the Sprague models at one time or another, with the exception of the 400. In my opinion, the 500 was the best – it gave minimal spurious responses and boasted good design and mechanical quality. Despite being well and truly obsolete by the late 1980s, the 500 soldiered Below: the front and back pages of the operating manual. The front panel of the Sprague 500 Interference Locator had a rather utilitarian appearance and carried a comprehensive array of controls. 100  Silicon Chip siliconchip.com.au RF AMP 6AN4 RF ATTEN MIXER 1/2 6CG8 Fig.1: block diagram of the Sprague 500 Interference Locator. A conventional BC/SW front-end based on a 6BJ6 RF amplifier and a 6BR8 oscillator/mixer covers the first five bands to 54MHz, while a second front-end based on a modified VHF TV tuner (6AN4 & 6CG8) covers the 54-220MHz band. S METER OSC 1/2 6CG8 SPEAKER 1ST IF AMP 6BJ6 RF AMP 6BJ6 2ND IF AMP 6BJ6 DETECTOR 1ST AF AMP 6AQ6 6AQ6 1/3 1/3 AF OUTPUT 6AK6 MIXER 1/2 6BR8 OSC 1/2 6BR8 AGC RECT B+ HT (B+) CONVERTER 6V 6-VOLT BATTERY 1/3 PHONE JACK 6AQ6 BATTERY CHARGER on well after many of the later models had been pensioned off. In some cases, they were even modified to suit the requirements of the government department that used them! But even the venerable 500 couldn’t keep going indefinitely. It was bulky, lacked the sensitivity of later equipment and didn’t have facilities to trace interference in the UHF band. It also lacked facilities for multi-mode reception and spectrum analyser operation. In the end, it was the Icom R7000 receiver that took over where the Sprague 500 left off. The Sprague 500 A quick glance at the Sprague 500 reveals that it’s not the sort of set you would set up in a lounge room. Unlike domestic radio receivers, it has a very utilitarian appearance, with a grey “crinkle-finish” aluminium case and a front panel style that resembles an item of test equipment. It also has a carrying handle and a fabric strap to aid portability. As previously stated, the receiver tunes from 550kHz to 220MHz over six bands. Its dial scale is located behind the meter case on the top left of the panel, while a second meter at right is “calibrated” for relative RF (radio frequency) signal level. The knob in the centre is the on-off control and is also used to switch on the inbuilt battery charger. The tuning control is at the bottom left of the panel, followed (from left to right) by the volume, band-change, meter zero and RF attenuator controls. siliconchip.com.au This view inside the Sprague 500 shows the top of the chassis. Note the large number of alignment adjustments. In use, the RF attenuator is adjusted so that the meter needle stays somewhere near the centre of the meter scale, even when the RF probe used with the set is quite close to the source of interference being traced. On the righthand side of the panel is a jack for a set of low-impedance headphones (the set has an inbuilt 100mm speaker as well), plus a BNC coaxial cable socket for the signal input. Finally, a neon indicator at the top left of the panel lights when the set is turned on. Antennas The specialised antennas used with the unit are generally mounted onto September 2005  101 The receiver case is hinged at the base and is opened by releasing four latches. That done, the unit can be separated into two halves by unplugging the 11-pin plug/socket connection and then sliding the hinge apart. a socket at the top of the front panel. These antennas and other accessories include a telescoping rod or dipole antenna (depending on how it is set up), a directional loop antenna for broadcast band reception, an RF probe, a roof mounting bracket for the antennas, two coaxial cables, a canvas carry case and a set of headphones. The cover that protects the frontpanel controls is missing on my unit, as it is on all the sets I have seen. That’s because it was invariably regarded as a nuisance by the operator and discarded. In addition, the headphones, the roof mounting bracket and most of the other accessories were rarely used. In practice, the sets were mostly used in cars and an antenna mounted permanently on the vehicle was connected to the set via a 50-ohm RG58 coaxial cable. Circuit details The circuit is quite conventional and uses eight valves. The first five bands cover to 54MHz using a conventional BC/SW front-end based on a 6BJ6 RF amplifier and a 6BR8 working as the oscillator and mixer. The Sprague 500 receiver was supplied with a range of accessories, including several antennas. 102  Silicon Chip The 54-220MHz band is covered using a second front end. This uses a modified incrementally-tuned VHF TV tuner, with a 6AN4 as a grounded grid RF stage and a 6CG8 oscillator and mixer stage. The rest of the receiver is common to both front ends. It consists of two 6BJ6 IF amplifier stages, a 6AQ6 detector/AGC and first audio amplifier stage, and finally, a 6AK6 as the audio output stage. AGC is applied to both IF stages and the signal strength meter is wired into the plate and screen circuit of the first IF amplifier. The IF amplifier is more complicated than the 455kHz IF stages found in domestic receivers. On the three bands up to 14MHz, the IF is 455kHz, but on the three bands above 14MHz, it’s 10.7MHz. The broader IF on the higher frequencies means that it is much easier to tune VHF signals, as there is no bandspread in the tuning system. The wave-change/tuner/IF selector is quite a complex switch, with no less than 14 sections! AGC is applied only to the two IF stages which means that, on strong signals, the unit is prone to overload. That’s where the attenuator comes into play – it’s situated between the antenna terminal and the RF amplifier and is used to reduce the signal strength. Note that, in some cases, the siliconchip.com.au signal strength can be quite high; eg, if the detection probe is just a few centimetres from the interference source. Power supply With the exception of the 6BR8 and 6CG8 oscillator/mixers, the valves are all low heater current types and also draw low HT (high tension) current. The HT is only 120V on the plates of the valves and this helps to reduce the set’s current drain – important for minimising the load on the internal lead-acid battery. The battery was a special 6V 20Ah type which is no longer available. To further reduce the current drain, the valve heaters in each front-end were powered only when that particular tuner was being used. This meant that if you switched from band A to band F (or vice versa, you had to wait for about 20 seconds for the selected tuner to become operational. In operation, the receiver is powered from the 6V battery at all times. This battery is continuously float-charged when the set is plugged into the AC mains, except when the power switch is set to one of the charge positions. In the latter case, the battery can be charged at a “slow” or “fast” rate. The battery also acts as a ripple filter for the power supply. The charging circuit isn’t regulated, so it was necessary to observe the hydrometer balls in the battery to determine its state of charge. This was quite easy to do, as each battery cell could be viewed through special holes in the back of the cabinet. It’s also interesting to note that the battery used was an early leak-proof design. It had several inches of rubber tubing going up from the filler on the battery. This meant that accidentally tipping the set over did not cause acid to spill (these sets were produced before fully sealed batteries were commonly available). As mentioned before, this battery is no longer available but a 6V sealed lead-acid battery of around 10Ah capacity will fit into the space available. Because the set operates from 6V, it was necessary to include a DC-DC converter to provide a 120V HT rail. This was achieved using a simple 2-transistor inverter circuit. Getting it going In Australia, these sets were used siliconchip.com.au This view shows the power supply, speaker and battery compartment after is has been separated from the rest of the case. extensively by the Radio Branch of the Postmaster General’s Department (PMG), for tracing interference to radio and TV reception. As a result, they led a fairly hard life, although most units generally survived quite well. However, the cases usually took a battering and the paint was chipped and worn away on many units. The front panel markings also tended to wear with extensive use. It all meant that these sets did look rather “beaten up” towards the end of their working life. Restoring the case In my case, I managed to obtain three of these sets and quite a few of the accessories, including an operating manual – that latter including a circuit diagram and a lot of other helpful information. I picked the one with the best cabinet and front panel and did a bit of swapping around of some the bits and pieces from the three units to get the very best set I could. The receiver case is hinged at the base and is opened by releasing four latches. That done, the unit can be separated into two halves by unplugging the 11-pin plug/socket connection and then sliding the hinge apart. The power supply can then be worked on without further dismantling the set. If necessary, the receiver chassis can be removed from the case by undoing the 11 screws that secure both it and the front panel in position. Once this is done, access to the underside of the receiver chassis is quite good. Unfortunately, various holes had been drilled into both the case and the front panel of each set. These were repaired by first gluing a small VALVES AUDIO HI-FI AMATEUR RADIO GUITAR AMPS INDUSTRIAL VINTAGE RADIO We can supply your valve needs, including high voltage capacitors, Hammond transformers, chassis, sockets and valve books. WE BUY, SELL and TRADE SSAE DL size for CATALOGUE ELECTRONIC VALVE & TUBE COMPANY PO Box 487 Drysdale, Vic 3222 76 Bluff Rd, St Leonards, 3223 Tel: (03) 5257 2297; Fax: (03) 5257 1773 Email: evatco<at>pacific.net.au www.evatco.com.au September 2005  103 Photo Gallery: Aristocrat Battery Console That done, I “colour-matched” the original paint and, using a spray pack, painted the whole of the outside of the case. I also spray-painted the cleaned area inside the case where the battery had been. The front panel is a slightly different colour to the rest of the case, so this too was “colour-matched” to retain an authentic appearance. This paint job also covered a Plasti-Bond repair to a hole in the front panel. It’s not perfect – the edge of the hole can still be seen if you look closely enough but it’s still quite good. The aluminium handle also has a wooden section attached to it and the paint on this had well and truly disappeared from most of its surface. I sanded the handle lightly, then handpainted it with black enamel so that it now looks like new. Circuit tweaks Manufactured by Electrical Specialty Manufacturing Company Ltd, Sydney, in 1935, this receiver was intended for use in areas not supplied with mains power. It was fitted into an Art-Deco style cabinet and required a 2V accumulator for the valve filaments and a 135V dry battery for the HT. The valve line-up was as follows: 34 RF amplifier, 15 autodyne mixer, 34 IF amplifier, 30 detector, 30 audio amplifier and 19 push-pull audio output stage. Photo: Historical Radio Society of Australia, Inc. The Sprague 500 receivers have always been reliable sets and restoration has usually been quite simple. The power supplies were trouble free and a sealed lead-acid battery is quite easy to fit in place of the original battery. Occasionally, a valve needs to be replaced but that’s quite rare as all the valves were run well below their maximum ratings. A full RF alignment is also sometimes required but the IF amplifier stages usually remained in tune. The passive components were also very reliable and seldom require replacement. The alignment points for the RF sections of the set are accessed when the case is split in two. That done, the two sections can be laid alongside each other and the 11-pin plug/ socket reconnected. Be careful when operating the set like this though, as the mains is exposed at one point in the power supply! Aligning the IF stages is a bit more complicated, as the chassis must be removed from its case section to gain access to half the adjustments. This takes a while to do but it’s not as hard as dismantling an AWA 617T. Summary piece of metal behind each hole (using Araldite), after which the holes were filled with Plasti-Bond and allowed to set. The Plasti-Bond was then carefully sanded down until it was level with the front of the panel, ready for painting. 104  Silicon Chip Another problem area was corrosion inside the case where the battery is mounted, no doubt due to acid leakage at some stage in the past. I scrubbed the affected area with soapy water and a scouring pad and it came up quite well. Due to its specialised nature, this is not a receiver that would appeal to a large number of restorers. In fact, I doubt that there are even a dozen such units in the hands of restorers in Australia, as it is now a relatively SC rare receiver. siliconchip.com.au ASK SILICON CHIP Got a technical problem? Can’t understand a piece of jargon or some technical principle? Drop us a line and we’ll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097; or send an email to silchip<at>siliconchip.com.au Line output adaptor for iPod player Here is an idea for a project: an audio adaptor from a 30-ohm headphone output to line input. There are so many iPods and stuff with headphone-only outputs in use now. It would be nice to connect it properly to bigger systems. (R. S., Tanunda, SA). • Such an interface would be only a resistor or two, no gain being required. You would just need a 33W resistor to simulate the headphone load and perhaps a 1kW resistor in series with the line output. Electrical problems in old Commodore I am trying to help my daughter who has advised me that the headlights on her 1986 Holden Commodore are very dull and she is finding it hard to see properly at night. Other than tell her to drive on high beam and see if other drivers react, can you advise what she could do? Much appreciated. (B. S., Penrith, NSW). • The first step would be to replace the lamps and then clean the reflectors. That done, check that all con- nections in the circuit are clean and low resistance – you might even have to replace the headlight relay if its contacts are worn. Check its socket contacts as well. Also check the battery and voltage regulator to see that they are putting out at least 13V when the engine is above idle. On any car that is almost 20 years old, the whole electrical system probably needs a thorough checkout. It might be a job for your local auto electrician. Possible error in table lamp dimmer I was having a close look at the remote-controlled table lamp dimmer in the July 2005 issue and believe that there is a serious error in the circuit. I am sure you would have already detected it as I can’t see how the project would work. On page 29 of the magazine, the circuit shows the top power line as being both +5V and 240VAC, in effect. I was wondering if the line should have a break between, say, the 2.2kW resistor on pin 4 of IC1 and the Triac. Perhaps I have missed something but it looks like there is no 5V rail, as this Viewing DVDs On A VGA Monitor I basically need to connect my DVD component video signals to the VGA connector of my PC monitor. I’ve found the article on “Component Video to RGB Converter” (SILICON CHIP, May 2004) interesting. However, this article is mainly for TVs with RGB and composite sync input. In the case of a PC monitor, the VGA connector is actually RGBHV, where the sync signals are separated. So I am wondering if I can modify the circuit like this: (1) use the LM1881 pin 1 (composite sync) as the horizontal sync output to the siliconchip.com.au VGA; and (2) use the LM1881 pin 3 (vertical sync) as the vertical sync output to the VGA. Do you expect there will be problem with this circuit? The problem I can think of is that the PC monitor is expecting a sync rate which is different from what is coming out of the DVD. I’m not quite sure about this and your help is appreciated. (Andy, by email). • It won’t work. VGA sweep speeds are radically different from PAL signals. The easiest way is to use a computer with a DVD player. line comes straight from the 240VAC mains. This would mean that pin 14 (Vdd) is at 240VAC potential. Have I missed something? I still enjoy the articles regardless; always learning something. (D. W., via email). • This is not an error. The 5V rail in the circuit floats from the incoming Active line of the 240VAC mains, as you suggest, and it is derived via the 220nF 250VAC capacitor, 1kW 1W resistor and zener diode ZD1. This is explained on page 31 of the article. Using the Coolmaster as a heater control Could the Coolmaster fridge controller from the June 2005 issue be used to switch a heater instead of a cooler, with minor changes? My understanding of electronics is limited but could it be as simple as swapping the inputs of pins 2 and 3 of the LM311 or is there a different chip which operates in the same way but with the output inverted? Alternatively, is there an equivalent to the LM335Z that has an inverse temperature response? (A. M., via email). • Your surmisal is correct. If you want to use the Coolmaster circuit to control a heater, this can be achieved by reversing the connections to input pins 2 and 3 of the LM311. This will be a bit tricky in practice though, as the PC board is quite small and congested, particularly in that area. Note that there are two tracks connecting to the pin 2 pad and both will have to be swapped over to the pin 3 pad. Coolmaster for motor protection application I would like to modify the Coolmaster temperature controller (June 2005) so that it will switch off the 240VAC power line when a temperature sense point of 65°C is reached. If this is possible, I will purchase the kit. September 2005  105 When Is The Battery Zapper Finished? I have found reading about the Lead-Acid Battery Zapper in the July 2005 issue interesting. One question though: how does one know when the battery is rejuvenated (after using the project)? (M. P., Christchurch, NZ). • Good question. It might take several days or more of zapping to get a result. Then you need to test whether the battery will accept a charge; ie, a charge of several amps or more, that takes a reasonable time for the battery voltage to come up to 14V or so. The battery should also begin to “gas” (ie, produce bubbles in The application is to protect the winding of a 240VAC single-phase sanitary pump motor. According to the supplier, on full load the current draw of the pump is 5A and at start up it is at least 15A. The existing “protection” of a small bimetallic switch on the active phase has failed to protect the winding. The contacts welded together, resulting in a cooked motor. Could I swap the inputs to pins 2 & 3 on the LM311 so that a rise in temperature would turn pin 9 low and ultimately, switch the Triac off? Would I need to uprate the Triac? Or should I leave the sensing circuit alone and use the MOC3021 output to switch the Triac off? When you investigate the price of commercial electronic motor protection relays which use a PTC thermistor I think there would be a ready market for such a kit. (T. J., via email). • We would not recommend modifying the Coolmaster to protect a motor winding. Instead, we would suggest the use of a 60° thermal circuit breaker, with a rated current of 10A. These are available from Altronics, Cat No S-5600. Their website is www.altronics.com.au More current for Luxeon driver circuit I recently obtained one of the new Luxeon III red LEDs for some optical communication experiments. To efficiently power it, I bought one of your 106  Silicon Chip the cells) if it is being charged at a reasonable rate. Ultimately, the only way to confirm that the zapping has worked is to put the battery through a number of charge and discharge cycles so that you can measure its actual capacity. In fact, you might find that it needs a series of zap/charge/ discharge cycles to bring the battery up to its maximum capacity. Of course, some batteries will be so far gone that the zapping process is unable to reverse the process of sulphation or it might be that the plates have shed material – a process that is irreversible. Starpower (April 2004) kits. However, I’ve discovered that the red, red/orange and amber Luxeon IIIs can take a lot more current than the older blue/green/white ones. 1.4A is the suggested operating level compared to 1A for the older ones. The Starpower is designed for a maximum current of 1A. Is there a way to modify it to provide 1.4A for the red Luxeon III? (D. S., via email). • The StarPower can drive a single red, red-orange or amber Luxeon III Star at maximum current (1.4A) with a few modifications, as follows: (1). Use a 0.068W (0.5W or higher) resistor for R1. A 0.1W resistor in parallel with a 0.22W resistor is suitable. (2). Use a 390pF ceramic disc for C1. (3). Replace the 0.15W 5W resistor with a value of 0.1W. (4). Use 1mm wire for the inductor (L1) and wind on only 16 turns, spaced evenly over the core area. Visual Basic for electrocardiograph In the February 2005 edition, you published an article on the “USBControlled Electrocardiograph”. On page 24 it said that the program was programmed with Visual Basic version 6. I have Microsoft Visual Basic and I was wondering if there is a difference. Secondly, no matter how many times I ask the Windows Office Assistant, I cannot find any code relating to the USB cable. If you could give me some advice, it would be greatly appreciated. (J. F., Bendigo, Vic). • There are quite a few versions of Visual Basic. There was the original version, for DOS-level programming (called VBDOS), and then six different versions of the Windows-based version: Visual Basic Versions 1-6, each of which was an upgraded version of the one before. More recently, they were all supposedly replaced with VisualBasic.NET, which is the only version sold nowadays. However, many of us prefer to keep using VB6, the one used to write the ECG program. To program communication with a device connected to the computer via a USB cable, you need to use what is known as a USB device driver – a small program written especially to communicate with the device concerned, via a USB port. With the ECG project, we used a USB interface on the ECG board which was based on a chip made by the Scottish firm FTDI, who made it easy because they make a matching driver program available free on their website. Actually, they make two different drivers available but we used the one which makes the USB port you connect to behave like another serial data port (ie, a virtual COM port). This allows you to communicate with the device in Visual Basic using VB’s plugin serial data control DCOM98. This doesn’t actually come with VB6 but you can download it from Microsoft’s Visual Basic website. Radio interference to Driveway Sentry I have successfully built the Driveway Sentry (November 2004), from a kit of parts supplied by Jaycar. The project has worked well, installed at the start of our 70m driveway on a 5-acre property; just the job for the situation where the main living area in the house is blind to the driveway. There is just one problem: every time I transit on the 2-metre amateur band, at even low power levels (<5W), the alarm goes off! Transmitting on HF frequencies, even at 100W, has no effect. I’ve tried various solutions like placing ferrite beads on all the wires leading into the control unit, bypassing the power and buzzer leads with various values of ceramic capacitors, etc, all with no effect. The 2-metre transmitter is a base siliconchip.com.au Notes & Errata Fig.1 (left): the parts shown in red (D4 & ZD2) are necessary to protect the IRF540N Mosfet from voltage spikes. Fig.2 (right): the extra parts can be added to the copper side of the PC board, as shown here. Lead-Acid Battery Zapper, July 2005: the parts list on page 43 states that Q2 is a 60V device, whereas its VDSS rating is actually 100V. Also, on the circuit diagram (Fig.2), the pinout diagram for Q2 is labelled “IRF640N” instead of “IRF540N”. In certain situations, the Mosfet (Q2) may fail due to excessive drainto-source voltage. To ensure that this cannot occur, a clamp circuit should be added to limit the peak voltage to a safe level. The clamp consists of a 75V, 1W zener diode (ZD2) in series with a UF4004 ultra-fast rectifier (D4), connected between the drain and source of Q2 (see Fig.1). A modified PC board design that Coolmaster Fridge/Freezer Temperature Controller, June 2005: a 2.2kW resistor was erroneously included in the parts list and is not required. Serial LCD Driver, August 2995: transistor Q2 on the overlay diagram unit located well away from the sensor, while the aerial is mounted well off the ground and properly matched. The odd passing taxi has also set it off. Any suggestions? I am toying with the idea of replacing the box with a metal one but that won’t have much effect if the RF is getting in along the leads. It takes the shine off what is otherwise a very reliable design. (N. D., Perth, WA). siliconchip.com.au accommodates these extra parts will be available in the future. For those that have the original published PC board design, the two components are easily added to the copper (underside) of the board, as shown in Fig.2. The anode lead of the UF4004 is soldered to drain pin of Q2, whereas the anode of the 75V zener is soldered to the source pin of Q2. Their cathode leads are then trimmed and Fig.3: the on-off switch can be mounted in the case next to the fuse. The 10nF capacitor across the switch reduces contact arcing. soldered together. Note that both components must be positioned flat against the PC board surface, with their leads shaped roughly as shown. Overall lead length should be kept to a minimum, and as a final step, the diodes can be glued to the PC board to ensure long-term reliability. Finally, we recommend that a switch be fitted in series with the positive battery lead to allow the unit to be isolated during connection and disconnection. This eliminates the possibility of arcing at the battery terminals. Any miniature mains-rated switch would be suitable, such as the Jaycar SK-0975 miniature toggle switch. A 10nF 100V polyester capacitor (Jaycar RG-5065) must be fitted directly across the switch terminals, as shown in Fig.3. (page 76) is shown reversed. The various photos and the silk screen on the PC board show the correct orientation. Carbon Monoxide Alert, August 2005: the 4-band colour code listed for the 470W 1% resistor is incor- rect. It should be yellow violet brown brown. Automatic Lamp Dimmer, September 2005: the 4-band colour code listed for the 470W 1% resistor is incorrect. It should be yellow violet brown brown. • We doubt that the 2-metre signals are getting into the Sentry via the sensor or sensor cable. It is more likely that it’s getting into the PC board either via the power supply or by direct radiation through the plastic box. So your idea of fitting the board in a metal shielding box is probably the right way to go. We expect this to stop the false triggering but if it doesn’t, you could try fitting ferrite beads on the sensor cable wires right next to the terminal block on the PC board. Digital audio adaptor for home theatre I have several pieces of equipment that have coax and/or optical audio outputs. My home theatre amplifier has only one coax and one optical input. At the moment, I have to unplug September 2005  107 How To Simplify The PowerUp In relation to the USB-activated power board (November 2004) and with cross-reference to the PowerUp circuit (July 2003), is it possible to create a simpler version of the PowerUp using the driver and Triac arrangement from the USB power board and a voltage sensor in the Neutral connection of one selected outlet “master” – the latter using a diode string, wirewound resistor, rectifier and smoothing to supply the optocoupler? I think even a power-point reversal would keep the same potential drop across the arrangement. Obviously, it is not an isolation device as 240VAC mains potential can still exist across the slave outlet/s. Using this arrangement, it would be one piece and replace it with another if I want digital sound. Is there a coax or optical adaptor available to build that would allow all pieces to be connected at the same time? I would only ever use one sound source at any one time so I am basically looking for a unit that saves the need to swap plugs. (R. T., via email). • You can buy an optical switcher from Jaycar, Cat AC-1675 for $19.95. Noise-cancelling in the home Have you ever had a project with regards to noise cancellation? I live near a very noisy highway and have heard that the noise can be nulled by recording the sound then playing it simple to install in a power board with three or four outlets, giving one master and one or two slave outlets. Making use of the original USB PC board is possible with the sensor in heatshrink sleeving. I am hoping it could be a simple, cheap energysaving device. My kids love to leave all the home theatre on when they turn off the TV. (J. P., via email). • We don’t think your suggested approach is workable, especially if it is to be built into a power board. It would not be sufficient to just sense Neutral current because you have to detect the difference between the current drawn by the TV (or whatever) on standby and normal operation. back through an amplifier in reverse. Any chance of such a project? (J. G., Perth, WA). • Such noise-cancelling techniques are practical in noise-cancelling headphones and in cars such as the latest Honda Legend but it is probably not practical in a larger environment such as a room. If it was to be done, it would involve having a microphone outside the window to pick up the noise which would be then amplified and reversed in phase to the noise in the room. Folding number plate controller I went to an electronics store with the question of how could I make number plates on my car fold down. I was told the best option would be to use a stepper motor. I would like the motor to turn the plates either through 90° or 180° but do not know how to construct the circuit for such a thing. Could you please help me find a solution? (E. J., via email). • It is probable that folding down the number plates of a registered vehicle is illegal. Having said that, if you wanted to do it (and had a legal reason), it would be easier using servos. Have a look at the tilt and pan control circuit in the January 1998 issue. Charging VRSLA batteries I read with interest some of your questions and answers on the topic of sealed lead acid batteries and the charging thereof. Are you able to point me in the right direction for a concise explanation of the different SLAs available, the best chargers for each and the don’ts associated with each? I work in a golf buggy shop and am continually confronted with questions on VRSLAs, AGM and gel cell SLAs and what charger suits what. I understand the charging requirements in particular for a gel SLA are different to that of a normal SLA. Often, customers come in with Arlec or Projecta type chargers and it is difficult to advise if they are suitable for their needs. Any ideas how I can determine if a customer’s charger is doing what it should and what the different SLAs require? (L. T., via email). • There are no easy answers. You need to see the battery maker’s specs to see the recommended charge rates and end voltages. Most simple car chargers are not really suitable for SLAs, as they will ultimately over-charge them. SC WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 108  Silicon Chip siliconchip.com.au MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $22.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $36.00 (incl. GST) per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Alternatively, fax the details to (02) 9979 6503 or send an email to silchip<at>siliconchip.com.au Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my  Bankcard    Visa Card    Master Card Card No. Signature­­­­­­­­­­­­__________________________ Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town ___________________________ Postcode______________ Phone:_____________ Fax:_____________ Email:__________________ siliconchip.com.au FOR SALE MORE CONTROL SOLUTIONS for you: Netiom Link – automatically transfer digital inputs and outputs between two cards over an Ethernet link Labjack USB Data Acquisition Module features 8 12-bit analog inputs, 20 digital I/O, 2 analog outputs and high speed counter. Free software DaqFactory Express, Labview driver and ActiveX component. Signal Conditioners non isolated and isolated – convert thermocouples, RTDs to 4-20mA or 0-10V. Fully programmable. Pixel Programmable Controller with 4 analog inputs, 8 digital inputs and 8 relay outputs. Uses a Picaxe 28X. Programmed in BASIC. Temperature and humidity sensors N1500 universal process indicator. Budget-priced displays thermocouple, RTD, 4-20mA and 0-5V readings. Fully programmable. Box of Connectors – choose BNC, UHF, N Type or RS232 gender changers and converters together. Serial and Parallel port relay controller cards. Pump and Trip Alarm Controller card. Duty-Standby operation. MicroProgrammers for Atmel and PIC chips. 2, 4 & 8 Relay Cards suitable for TTL and Open Collector Outputs DC, Stepper and Servo Motor controller kits. Switch-Mode, Battery Chargers and DC-DC converters. Full details and credit card ordering available at www.oceancontrols.com.au. Helping to put you in control. WEATHER STATIONS: windspeed & direction, inside temperature, outside temperature & windchill. Records highs & lows with time and date as they occur. Optional rainfall and PC interface. Used by government departments, farmers, pilots and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write September 2005  109 New New New Mark22-SM Slimline Mini FM R/C Receiver Wi-Fi 2.4GHz Antennas Directionals Omnis We also stock: • • • • • 6 Channels 10kHz frequency separation Size: 55 x 23 x 20mm Weight: 25gm Modular Construction Price: $A129.50 with crystal Electronics PO Box 580, Riverwood, NSW 2210. Ph/Fax (02) 9533 3517 email: youngbob<at>silvertone.com.au Website: www.silvertone.com.au Panel Antennas Ceiling Antennas Low-loss 50 Ω cable Connectors Pigtails Access Points Masts Amplifiers Power-over-Ethernet External Enclosures Everything you need for WiFi! FREENET-ANTENNAS Web: www.freenet-antennas.com Email: sales<at>freenet-antennas.com Tel: (08) 9319 3275 (int +618 9319 3275) Fax: (08) 9319 1720 (int +618 9319 1720) TAIG MACHINERY Micro Mini Lathes and Mills From $489.00 Stepper motors: 200 oz in $89.00, 330 oz in $110.00 Digital verniers: 150mm $55.00, 200mm $65.00 59 Gilmore Crescent (02) 6281 5660 Garran ACT 2605 0412269707      Foam surrounds,voice coils,cones and more Original parts for Dynaudio,Tannoy and others Expert speaker repairs – 20 years experience Australian agents for products Trade welcome – email for your user ID Phone (03) 9647 7000   speakerbits.com.au Select your microcontroller kit and get started... Fax a copy of From $295* RCM3400 this ad and receive a 5% discount on your order! Feature rich, compiler, editor & debugger with royalty free TCP/IP stack • Prices exclude GST and delivery charges. for our FREE catalog and price list. Eco Watch phone: (03) 9761 7040; fax: (03) 9761 7050; Unit 5, 17 Southfork Drive, Kilsyth, Vic. 3137. ABN 63 006 399 480. USB KITS: GPIB Interface, Thermostat Tester, LCD Module Interface, Stepper Motor Controller, PIO Interface, DTMF Transceiver, Thermometer, DDS HF Generator, Compass, 4 Channel Voltmeter, I/O Relay Card, USB via LabVIEW. Also available: Digital Oscilloscope, Temperature Loggers, VHF Receivers and USB ActiveX (and USBDOS.exe file) to control our kits from your own application. www.ar.com. au/~softmark SUPERBRIGHT LEDS from just 15 cents each, including new wide angle range! 12 volt LED lightbars, great for solar/camping. Nixie tubes and nixie 110  Silicon Chip clock kits. Lots of other stuff, and always more items being added. New webshop now online! www.ledsales.com.au RCS RADIO/DESIGN is at 41 Arlewis St, Chester Hill 2162, NSW Australia and has all the published PC boards from SC, EA, ETI, HE, AEM & others. Ph (02) 9738 0330. sales<at>rcsradio. com.au, www.rcsradio.com.au S-Video . . . Video . . . Audio . . . VGA distribution amps, splitters, standards converters, tbc’s, switchers, cables, etc, & price list: www.questronix.com.au ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC­08, 68HC11, 68HC12, 68HC16. from $330.00 Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in Tel: + 61 2 9906 6988 Fax: + 61 2 9906 7145 www.dominion.net.au 4007 both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $132.00, 14 pin $126.50, 8 pin $121.00. Full details on web-site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics. com.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 9593 1025. sesame<at>sesame.com.au www.sesame.com.au P-Tronics – Electronic Services & siliconchip.com.au Do You Eat, Breathe and Sleep TECHNOLOGY? Opportunities for full-time and part-time positions all over Australia & New Zealand Jaycar Electronics is a rapidly growing, Australian owned, international retailer with more than 39 stores in Australia and New Zealand. Our aggressive expansion programme has resulted in the need for dedicated individuals to join our team to assist us in achieving our goals. We pride ourselves on the technical knowledge of our staff. Do you think that the following statements describe you? Please put a tick in the boxes that do: Knowledge of electronics, particularly at component level. Assemble projects or kits yourself for car, computer, audio, etc. Have empathy with others who have the same interest as you. May have worked in some retail already (not obligatory). Have energy, enthusiasm and a personality that enjoys helping people. Appreciates an opportunity for future advancement. Have an eye for detail. Why not do something you love and get paid for it? Please write or email us with your details, along with your C.V. and any qualifications you may have. We pay a competitive salary, sales commissions and have great benefits like a liberal staff purchase policy. Send to: Retail Operations Manager - Jaycar Electronics Pty Ltd P.O. Box 6424 Silverwater NSW 1811 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Advertising Index 555 Electronics.............................51 Amateur Scientist CD ..................47 Altronics................................. 72-75 ATA...............................................49 Av-Comm...................................111 Delta Audio.....................................7 Dick Smith Electronics........... 16-21 Dominion Electronics............49,110 Eco Watch..................................109 Satellite TV Reception ELNEC IC PROGRAMMERS International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. Universal and specialised models High quality Realistic prices Large range of adaptors Free regular software updates Windows 95/98/Me/NT/2k/XP AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au GRANTRONICS PTY LTD PO Box 275, Wentworthville. 2145. Ph: 02 9896 7150 Repairs. Alarms/Immobilisers, TVs, Home Theatre Set-Ups. PIC Project Development & Designs. Ph: (08) 8277 7560 Fax: (08) 8276 7478 Adelaide S.A. Patrick<at>p-tronics.com.au Ortofon, SME, Western Electric, Altec, Marantz, McIntosh, Goodmans, Wharfedale, Tannoy, radio and wireless. Collector/Hobbyist will pay cash. (02) 9440 1267. johnmurt<at>highprofile. com.au Elexol...........................................51 Evatco........................................103 FreeNet Antennas......................110 Furzy Electronics........................110 Grantronics.................................110 Harbuch Electronics.....................62 Instant PCBs..............................110 www.grantronics.com.au Jaycar .................IFC, 53-60,65,111 JED Microprocessors................5,65 Microgram Computers....................3 MicroZed Computers....................93 Ocean Controls..........................109 CARBIDE PCB DRILL KITS:1/8in shaft, new or as new condition, 10 mixed sizes from 0.5-1.15mm. $25 inc p&p Australia. altectronics<at>bigpond.com WANTED WANTED: EARLY HIFIs, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, KIT ASSEMBLY H Heavy board covers with mottled dark green vinyl covering H Each binder holds up to 12 issues H SILICON CHIP logo printed on spine & cover. Price: $A12.95 plus $A7 per order (Australia only; not available elsewhere). Buy five and get them postage free. Just fill in & mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. siliconchip.com.au Prime Electronics.........................64 Quest Electronics..................65,110 Radiometrix..............................OBC RCS Radio.................................110 RF Probes......................................7 NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au Silicon Chip Binders Ozitronics..................................7,49 REAL VALUE AT $12.95 PLUS P & P SC Perf Elect. For Cars.......112,IBC SC Projects For Cars, Vol.2..........25 Silicon Chip Binders...................111 Silicon Chip Bookshop........... 96-97 Silicon Chip Subscriptions...........61 Silvertone Electronics................110 Siomar Batteries..........................25 Speakerbits................................110 Taig Machinery...........................110 Telelink.........................................65 ____________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. September 2005  111 From the publishers of The Lat SILICON s t n e t n o C UND TECH BACKGRO Intelligent turbo timer I SBN 095852294 - 4 TURBO BOOST & nitrous fuel controllers 9 780958 522946 $19.80 (inc GST) NZ $22.00 (inc GST) How engine management works We’ll let the contents speak for themselves: Not a reprint – new projects and articles not published before Learn how engine management works Build projects to control nitrous, fuel injection and turbo boost systems Switch devices on and off on the basis of signal frequency, temperature and voltage Build test instruments to check fuel injector duty cycle, fuel mixture and brake and coolant temperatures P L U S L O T S MORE 112  Silicon Chip t Managemen ng Engine stems work di an st er R 1: Und engine sy 6 CHAPTEhandle on how the various Getting a ement ine Manag anced Eng r ECU functions dv A : 2 R TE he 14 CHAP yond spark and fuel – ot Going be c Systems lled systems in a car er Electroni th O : 3 nically-contro R tro TE 20 CHAP rundown on the other elec A quick Systems pensive as Electronic ex odifying Carstems is not as difficult or M : 4 R TE electronic sy 26 CHAP Understa Systems ur car’s Modifying yo ink you might th n Modificatio Electronic right wires IY D : 5 R TE e 30 CHAP multimeter and finding th Using a ject Kits nic circuits ctronic Pro uilding Ele to successfully build electro B : 6 R TE P 36 CHA w basic skills You only need a fe , voltage er A Multimet – here’s how to measure eter TER 7: Using 40 CHAP make do without a multim can’t You resistance current and INSTRUMENTS Meter modes art Mixtureal time, see the operating TER 8: Sm 42 CHAP ur car’s fuel mixtures in re -load “lean-out” occurs if a high Track yo d be warned of the ECU an er h devices o y Cycle Met Injector Dut ty cycles or use it to switc : 9 R TE P A du or ct je in 50 CH el fu itor Digitally mon engine loads nt ometer off at differe igital Therm perature D to an incredible 1200°C m Te h ig H : re su TER 10 out, can mea mperature 58 CHAP or LED read D et te It uses an LC off at a pres vices on or can switch de SWITCHES AND TIMERS g rnal triggerin Auto Timer : Versatile er with lots of uses and exte 1 1 R TE P A le tim 66 CH se adjustab A multipurpo lots h ltage Switcalready under the bonnet – 2: Simple Vo 1 nsors ng R hi se e itc TE th P sw g A e in H id 72 C on and off us l to nitrous ox es ro Switch devic and fan cont water-spray of uses from y up to ture Switch rk all the wa 3: Temperajustable design that can wo 1 R TE P A H pose ad 77 C p general-pur A chea 245°C 4 RS ICS FOR CA E ELECTRON PERFORMANC siliconchip.com.au S M test From CHIP off witch equency Syou switch devices on and TER 14: Fr 82 CHAP eap adjustable design lets This ch speed according to Timer ta Throttle on and off, based on how es TER 15: Del 86 CHAP tricky way of turning devic A really iving ally you’re dr enthusiastic ne anding Engi s – p.6 ONTROLLERS MODIFIERS & C Controller LCD Hand – p.105 r rrecto Speedo Co – p.129 r se Adjuste to reduce t : Digital Pul noids in your car – use it extra fuel in 6 1 R TE P A le an l d so ro lse nt 92 CH pu co e or th control of g assistance t Managemen Take eerin ge power st boost, chan r d Controlle Adjuster, Dig 7: LCD Hanprogram the Digital Pulse rcuits 1 R TE P A H r ci r to lle lle ro ro nt nt 105 C Co co t nic Boos is plug-in Use th t Electro Independen Adjuster and daptor d Injector A u need this 8: Peak-Hold fuel injectors? – if so, yolse Adjuster 1 R TE P A H Pu -hol l ak ta gi pe Di 108 C ve , er ha your car Cycle Met Does e Duty tor to use th roller simple adap c Boost Cont ni tro ec El t en nd pe de In or el Adjustered to adjust air/fuel rat 9: Digital Fu 1 be us R -loop TE P A th H r to at can ange closed 112 C ltage intercep and even ch A brilliant vo eter or injector swaps m allow air-flow acteristics running char t oject will ge o Corrector tio? – this pr R 20: Speedission or altered the diff ra TE P A H C 129 t the transm tely again Swapped ou speedo reading accura r nic st Controlle your electro ctronic Booost maps at the flick of le E t en nd depe rbo bo tween two tu PTER 21: In 134 CHAine being able to change be just that do u yo Imag ts is project le a switch – th troller even just to s Fuel Con el supply or R 22: Nitrouinjector for the nitrous fu TE P A H C 149 ntrol an extra Use it to co fan speeds vary pump or Timer rd you’ve gent Turbo atch how ha R 23: Intelliengine idle-down time to m TE P A H C 154 er set the This turbo tim been driving Engine Advanced t – p.14 Managemen ture Smart Mix Meter – p.42 Capacitor : Resistor & ENDUM 160 ADD Codes om Jaycar The Kits available fr and. See Ze Where To Buyoject described in this Abousoktralariae an d New al ery pr l over details. Kits for ev d dealers al for further s stores an ck covers ba e id Electronic ts ou front and the inside p.50 cle Meter – or Duty Cy Fuel Inject om.au siliconchip.c r t Controlle Turbo Boos – p.134 Turbo Intelligent 4 Timer – p.15 om.au siliconchip.c Order direct from SILICON CHIP Publications Price: Aust. $A22.50 (inc. GST & p&p); Overseas $A26.00 (inc. p&p via airmail). Silicon Chip Publications Pty Ltd, PO Box 139 Collaroy, NSW, Australia 2097. Phone (02) 9939 3295; Fax (02) 9939 2649. Email silchip<at>siliconchip.com.au siliconchip.com.au September 2005  113