June 2008 - Silicon Chip Online

Outer Front Cover
Contents
Publisher's Letter: New Zealanders can legally do their own wiring - why can't Australians?
Feature: DIY Electrical Work: Are Aussies Dumber Than Kiwis? by Ross Tester
Feature: A Look At Crash Test Dummies by Peter Holtham
Project: DSP Musicolour Light Show by Mauro Grassi
Project: PIC-Based Flexitimer Mk.4 by Jim Rowe
Project: USB Power Injector For External Hard Drives by Greg Swain
Project: Balanced/Unbalanced Converter For Audio Signals by John Clarke
Review: Altitude 3500-SS Stereo Valve Amplifier by Leo Simpson
Project: A Quick’n’Easy Digital Slide Scanner by Brian Coulson
Vintage Radio: The Pye TRP-1 portable HF transceiver by Rodney Champness
Book Store
Advertising Index
Outer Back Cover

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SILICON SILICON CHIP C HIP AT L AT LAST AST . . . JUNE 2008 PRINT POST APPROVED - PP255003/01272 8 $ 50* NZ $ 9 90 INC GST INC GST The all-new DSP MUSICOLOUR The world’s best-ever lightshow? We review: Wagner’s ALTITUDE 3500-SS VALVE AMP: Just how good is it? siliconchip.com.au DOING YOUR O ELECTR WN WIRINGICAL ... THE NZ WAY! June 2008 1 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings.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 Vol.21, No.6; June 2008 SILICON CHIP www.siliconchip.com.au Features 12 DIY Electrical Work: Are Aussies Dumber Than Kiwis? Kiwis are legally entitled to do all sorts of electrical work in their own homes but are Aussies too dumb? Yes, say our state governments – by Ross Tester DSP Musicolour Light Show – Page 30. 24 A Look At Crash Test Dummies They’re really not dumb but instead carry lots of smart electronics to record their “pain” – by Peter Holtham 73 Review: Altitude 3500-SS Stereo Valve Amplifier How good are modern valve stereo amplifiers? We check out the impressive Altitude 3500-SS – by Leo Simpson Pr ojects To Build PIC-Based Flexitimer Mk.4 – Page 40. 30 DSP Musicolour Light Show It drives coloured lights to the beat of the music and has a dot matrix display menu that doubles as a spectrum analyser or VU meter – by Mauro Grassi 40 PIC-Based Flexitimer Mk.4 It’s easily programmed, offers time periods ranging from 1s to 90 hours and can be set for one-shot timing or continuous on/off cycling – by Jim Rowe 58 USB Power Injector For External Hard Drives USB hard drives are usually powered direct from your PC’s USB ports but what if they’re not up to it? This project is the answer – by Greg Swain 68 Balanced/Unbalanced Converter For Audio Signals USB Power Injector For External Hard Drives – Page 58. Easy-to-build unit can convert an unbalanced audio signal input to balanced outputs and vice versa. It’s just the shot for long cable runs – by John Clarke 84 A Quick’n’Easy Digital Slide Scanner Want to copy your slide collection to your PC before it’s too late? This method is quick, simple and doesn’t require any electronics – by Brian Coulson Special Columns 44 Serviceman’s Log Honey, I wrecked the iMac! – by the TV Serviceman 63 Circuit Notebook Balanced/Unbalanced Converter For Audio Signals – Page 68. (1) Synchronous AM Detector For Improved Shortwave Reception; (2) PhotoInterrupter Bias Circuit For Electronic Ignition Systems; (3) Infrared Close Object Detector; (4) Meteoric LED Display; (5) 6-Digit Demonstration Counter; (6) Simplified Headphone Adaptor 86 Vintage Radio The Pye TRP-1 portable HF transceiver – by Rodney Champness Departments 2 4 57 78 Publisher’s Letter Mailbag Order Form Products Showcase siliconchip.com.au 93 Ask Silicon Chip 97 Notes & Errata 102 Market Centre Altitude 3500-SS Stereo Valve Amplifier Reviewed – Page 73. June 2008 1 SILICON SILIC CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Mauro Grassi, B.Sc.(Hons.) Photography Ross Tester Reader Services Ann Morris Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG 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: $89.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. Fax (02) 9939 2648. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2 Silicon Chip Publisher’s Letter New Zealanders can legally do their own wiring – why can’t Australians? Long-time readers of SILICON CHIP may remember that we conducted a campaign some years ago so that Australians could legally do their own house wiring. We pointed to New Zealand and many other countries where this was permitted and concluded that it was safer to make it legal and promulgate the necessary information on how to do it, rather than ban it and effectively dry up any information on how it can be done. Partly as a result of readers’ apathy in not signing a petition we wanted to present to the various State governments, the campaign was completely unsuccessful. Nothing happened. It is still illegal for anyone other than a licensed electrician to do anything to house wiring. You cannot even legally remove a light switch from the wall in order to paint around it! Nor can you legally replace any faulty light switch, light dimmer, power point or even remove and replace a faulty light fitting, much less install a new one. At the rate we are going, it may eventually be illegal to replace a light bulb! Don’t laugh. In our nanny state (all of Australia), people are prevented from doing anything mildly dangerous and changing a light bulb can be dangerous – you might fall off a chair or ladder, the light bulb may shatter in your hands or you might even get a shock if you attempt to change an Edison screw bulb if the light circuit is still powered on. On the other hand, it is demonstrably far more dangerous to walk down stairs – lots of people are injured this way. As far as we know though, there has not been any move to ban stairs. Recently, we decided to take a different approach. Rather than rant on about how stupid the state governments are to ban domestic electrical work, we decided to point readers to websites in New Zealand where the information on such work is freely available. New Zealanders can do it you see, while we can’t. Australia and New Zealand use exactly the same wiring standard (AS:NZS3000), the same mains voltage and the same range of electrical fittings. So are Australians dumber than Kiwis? Clearly our state politicians and regulators must think so. But we think we might have found out why the authorities might be even more concerned about the hazards than we thought. In one of the New Zealand brochures we feature in this issue (pages 14 & 15) there is even, perish the thought, a picture of a woman removing a light switch from a wall! Good grief! So even New Zealand women are smarter than typical Aussie blokes! Earthshattering consequences. Seriously, there is no good reason why Australians should not be able to do their own wiring and nor is there any reason why the information on how to do it should not be available from Australian authorities. Well, it doesn’t matter anyway because the New Zealanders, sensible people that they are, have made the information freely available to their citizens for more than a decade. And guess what: in that same period, the number of electrocutions per head of population in New Zealand has been less than in Australia. Clearly, doing your own electrical wiring need not be dangerous. For anyone who has internet access, there is no longer any reason for anyone to remain ignorant about how to do their own wiring. The internet crosses all borders, so governments can do little to stop the flow of information. So it is just silly that it is illegal to do home wiring in Australia. Large numbers of people do it anyway, as already recognised by state governments. Now that people can access the necessary info via the ’net, doing your own wiring can be quite safe, even though it might remain forever illegal in Australia. Or do we live in hope that common sense might ultimately prevail? Leo Simpson siliconchip.com.au Digital LCR Meter with Transistor Tester Output Voltage: 11-16V adjustable Current Rating: 13.5A continous (15A max.) Regulation: 0.2% – Ripple: 17mV Dimension (mm): 155W x 55H x 165D $89.50 Weight: 1.2kg Size: 25 x 35mm. Induct.: 2mH, 20mH, 200mH, 2H, 20H, 200H Cap.: 2nF, 20nF, 200nF, 2µF, $57.80 20µF, 200µF, 600µF Res.: 20W, 200W, 2kW, 20kW, 200kW, 2MW, 20MW, 2000MW #36220 Trans. test: hFE (PNP and NPN) Display: 3.5-digit, 1999 count Protect: 315mA M205 fused on L/C inp #33250 12VDC Car Notebook Multi-Volt. P/Supply A compact switchmode power adaptor designed specifically for powering laptops from a car cigarette lighter. Set. O/P Volt.:15,16,18,19,20,22 & 24VDC up to 3.5A (regulated) Inc. 6 adaptors to suit most labtops 1.5-inch Digital Photo Key Ring * Resol: 128 x 128 pixels * NORFLASH: 8MB(Mbit,MByte * Lithium battery with 8-10 hrs * Format: BMP, JPEG,GIF, PNG, * 3.7V lithium battery or USB 5V Supply * Win 2000 / XP $19.20 #35396 USB All in 1 Card Reader * Compliant to USB 2.0 * Hot Swappable * Supports: CF/MD,SD/MMC,MS/ MS PRO/MD DUO/ MS ROM & xD/SMC. * Win,98Se, ME, 2000, XP, MAC $8.60 $19.60 #36742 $19.60 #36075 $13.90 #36081 5m High Res.Monitor Lead (with filter) Cycles through 7 colours; red, green, blue, light blue, pink, white & yellow. in 35 seconds #34753 All are 2-pin configuration Forward voltage (typ.): 4.2V Forward voltage (max.): 4.5V Forward current (typ.): 90mA #36679 $1.50 MR16 Type 12V DC Multi LED Lamp * Contains 20 Super Bright LEDS #36711 * Long life 100,000 hours * Beam angle: 35 degrees. $13.80 * Current draw: 125mA <at> 12VDC * Direct replament for MR16 Lamp Types $19.50 Laser Pointer / Mini Torch Keychain 12V 50W Halogen Spot Light (Pk-10) $4.50 #36736 40mm (Dia) 3X Eye Magnifier * With Glass Cover * 60 Deg. 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Batteries #36670 ROCKBY ICS ELECTRON 11-16 VDC 15A Regulated Power Supply #36742 ROCKBY ICS ELECTRON ROCKBY ICS ELECTRON Showroom & Pick-up Orders: 56 Renver Rd, Clayton Victoria 3168 Ph: (03) 9562-8559 Fax: (03) 9562-8772 * Indicator Lamp * Safety Overload Protection $12.90 * Rating: 10A 2400W * 1-metre Mains Cord #36664 Manuf.: SANSAI Mail Orders To: PO Box 1189 Huntingdale Victoria 3166 Internet: ROCKBY ICS ELECTRON ROCKBY ICS ELECTRON ROCKBY ICS ELECTRON Web Address: www.rockby.com.au Email: salesdept<at>rockby.com.au * Stock is subject to prior sale Y BY KBOrdering On-Line And Other Products See Website: C CKwww.rockby.com.au O ROFor ROur S IC N O R RONICS T T C C E E EL EL MAILBAG Letters and emails should contain complete name, address and daytime phone number. Letters to the Editor are submitted on the condition that Silicon Chip Publications Pty Ltd may edit and has the right to reproduce in electronic form and communicate these letters. This also applies to submissions to “Ask SILICON CHIP” and “Circuit Notebook”. What do you do if a PIC fails? In response to your February 2008 editorial, microprocessors have been a part of projects from the 1970s, including some ambitious computer circuits. Microcontrollers are easy to deal with and they let the builder put something together that’s more sexy than a Morse code buzzer without being blindingly complex. One thing that concerns me with pre-programmed PICs is what do you do if the PIC fails? Perhaps there’s a third party role there, like supplying PC boards, where a company holds the software and can program a replacement PIC. Educationally, your PIC-based articles have a good history of setting out the explanation of both the role of the PIC and the role of the interfacing circuitry. If you wanted to reinforce this training you could set out a circuit with optional PIC or discrete sections, eg, an analog-driven alarm for the tank level kit. I see this as a training exercise. From a trade/industrial perspective, Confusion over SD & HDTV broadcasts Your editorial in the March 2008 issue left me a little confused. It seemed to suggest that not only analog transmissions but SD (DVD quality) digital will be phased out, requiring every Australian to purchase a new high-resolution display device. I was under the impression that only analog will be stopped and SD (standard definition) will continue on digital. Could you please clarify this? Also, it is my experience that unless a very large screen is used, there is very little noticeable difference in picture quality between SD (720 x 576) and higher resolutions (HDTV), ie, the higher the resolution the more 4 Silicon Chip these projects don’t expose the builder to some of the standards used in such environments. Industrial microcontrollers are expensive but you have advertisers who market more modestlypriced modules. Perhaps SILICON CHIP could showcase either real applications of these or some tertiary skills training using such boards? Some of your other projects using simple discrete designs, butchering consumer electronics or using surplus parts round off your electronic skills environment. Well done, S ILICON CHIP! Kevin Shackleton, Dandaragan, WA. Comment: it is possible to obtain programmed micros from www.rcsradio. com.au who also supply PC boards for our projects. Boolean algebra in logic circuits I read with interest the question posed by Leo Simpson on microcontrollers and I agree that many projects would be too complex without the use of a micro in the design. Anyway, in physical pixels needed. There seems to be an awful lot of hype surrounding digital TV, with the term HDTV applying to all digital TV transmissions. D. Dorling, Buderim, Qld. Comment: at the moment, the real reason for going to an HD STB is that some programs are only available on HDTV broadcasts. Depending on your eyesight and the screen size, there is a significant improvement over SD when watching a true HDTV program. However, most programs are still only in SD. Ultimately though, we believe that most broadcasts will be HDTV and Blu-Ray players will get a lot cheaper in the next few years. response to the question of whether to use micros or use a more complex circuit with conventional logic ICs, my thought is that the younger generation should be aware of the application of Boolean algebra as it applies to logic circuits in order to understand what is going on. So there should be a good mix of logic circuits and micro circuits so as not to lose the fundamental understanding of logic design. Rob Zanchetta, Forest Lake, Qld. Microcontroller projects could be much more complex Microcontrollers have become the only way to go and as such, should feature prominently in all but the simplest designs. Some designs (eg, RF projects) should remain analog with lots of components, of course. It is interesting to note, however, that even the RF bits in the projects in this very issue (February 2008) incorporate RF modules which appear to the remainder of the circuit as digital devices. It is very important to continue to provide, as you do in the download area of your web site, both the “hex” file (to load into the microcontroller) and the corresponding source code “asm” file. Without the source code, the microcontroller is just a “black box” from which the constructor learns nothing. Failing to provide the microcontroller’s source code would be like not printing the circuit diagram for a project. If there are projects from outside sources you might have to negotiate some copyright issues to ensure that the source code is available. Things were easy when there were only a handful of relatively simple devices. Now the manufacturers have 8-bit, 16-bit and 32-bit devices, many including sophisticated features like ADCs, USB and RF interfaces, among many others. Some even have microcontrollers incorporated into FPGAs, siliconchip.com.au Micros now used in kettles After reading the editorial in the February 2008 issue, I would like to add my two bytes’ worth. When talking of component counts in electronic units/systems, I doubt that there would be a circuit ever designed that had a higher component count because a microprocessor was used. This alone makes the micro a better choice, especially given the low cost of micros these days. It was once said that they would even replace the humble 555 timer chip. This is now true. What function can a 555 do that most 8-pin micros cannot? Add to this the fact that the 555 needs external components whereas the micro does not. This moves the cost differences much closer between the two. Circuit boards are expensive to design and manufacture when the project is in prototype form. How many non-micro designs have been finished with only one design of circuit board? Normally many changes are made to the design, each one requiring a new PC board. In the case of an equivalent microcontrolled design, changes can usually be done in software, resulting in great cost savings. I believe that the micro is, and has been since its inception, the way of future electronics. There will no doubt always be a requirement for small designs without micros but these are becoming rarer and rarer. My less than 3-month old kettle has a micro looking after things. Recently I took a screwdriver to the base of the unit. Why would I do that? Well, the instructions said “Intelligent Water Monitoring System” and I was curious. Sure enough, a PIC12C508 looks at the water level pushing closer to the ultimate “single chip” design solution for some projects. The designs in the magazine are not too complex; indeed, they could often be said to be too simple given the power of the microcontrollers available. More complex designs require more complex software, however, so a big project quickly becomes as siliconchip.com.au and uses some form of steam/temperature sensor; no doubt to know when to switch off the power via a Triac. Who would have thought that a simple kettle could be computercontrolled? The mind boggles at what the future holds. The down side of publishing microprocessor controlled projects in SILICON CHIP is that explaining how the circuit works becomes more difficult, as software explanations can take a lot of time and magazine space. I think one of the strengths of SILICON CHIP is the amount, variety and quality of the projects described. Being the only magazine of its type, you have little competition but that has not stopped the staff at SILICON CHIP from aiming high in the project department. I and I’ll bet hundreds, even thousands, of other people have learned much about electronics from the projects published in SILICON CHIP. When the project is “microprocessorised”, the software is usually available for free download. My programming skills have improved a great deal by studying and analysing these programs. My special thanks to John Clarke; his programming skills have taught me much over the years. Proof of the project quality is in other magazines. How many SILICON CHIP projects have been published in overseas magazines? Quite a few that I know of. Please keep the magazine content as it is because your balance of projects, reviews, articles and other related features is, I believe, one of if not the best in the world. Jeff Monegal, CTOAN Electronics, Jimboomba, Qld. much a software project as a hardware project. It would be difficult to capture in a series of articles the intricate trade-offs between the hardware and software components of a given design. Consider the many digital storage oscilloscopes with USB capability advertised or described in this issue. Imagine what their design involved, with analog and 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 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 June 2008 5 Mailbag: continued digital sections all under the supervision of a microcontroller. As for suggested projects, I would like to see designs that incorporate programmable logic devices, including FPGAs. The trick will be to find legitimate real-world applications, not ones that just use the technology for its own sake. With the growing importance of monitoring and controlling energy and water usage, there should be a wide range of projects, from the simple to the very complex, to satisfy all levels of interest. I look forward to receiving the magazine every month and I always find many things of interest inside. Bill Hanna, Alice Springs, NT. RF projects wanted for amateur radio In the Publisher’s Letter for the February 2008 issue, Leo Simpson asks what do the readers want in SILICON CHIP magazine. Well, there are too many articles on microprocessors. Filling up the magazine with a series on how to use the PICAXE VSM Circuit Simulator is too much. Information on how to use the simulator is provided by the PICAXE people and can be obtained online at their website. It’s a pity that SILICON CHIP is now also being filled up with equipment marketing reviews on equipment like the Atten ADS7062CA Storage Oscilloscope (February 2008, p16). There was even an article on how you used a digital camera in your publishing office. If I wanted and article on cameras I would have gone to a camera magazine, not an electronics magazine. What I would like to see is more amateur radio articles like SoftwareDefined Radios (SDR), Digital Signal Processing (DSP), I/Q signals with regard to SSB, AM and FM signals, Softrock SDR, a HF transceiver like the Pic’a’Star HF transceiver that is a Yahoo group (also in the RSGB Handbook), QRP transmitters and receivers, and HF/VHF/UHF antennas for amateur radio. Electronics Australia magazine used to have lots of articles on amateur radio. I believe SILICON CHIP should cover a wide range of electronic subjects and keep clear of the marketing reviews; these are only a copy of the manufacturers’ marketing documentation. Place them in the Product Showcase section but not as a full article. Roderick Wall, via email. Comment: your request for more RF articles is duly noted. However, we will continue to have detailed reviews on the latest digital scopes because this is an area of interest to many readers. By the way, we do not simply rehash manufacturers marketing documentation. We spend quite a lot of time using the scopes and putting them through their paces. We also take screen grabs to demonstrate their performance. As far as we know, we are the only magazine in the world that does this type of comprehensive product review. Keep those circuits coming Guys, please do not EVER stop publishing circuits, kits and projects. My kids are becoming so specialised in their work and study streams that few bother to stop and think how things work. This just encourages the “throw away” mentality. I got started in electronics in a rural family in Queensland where there was next to no help and support. There was, however, a magazine called Electronics Australia. I was about 10 and I read a project article called “A Probe Type Capacitance Meter”. My eyes opened wide. I didn’t know this stuff existed and the careers advisors at school were next to useless as they didn’t know about it either and I must say from my children’s experience the careers advisors are still out of date. This is a big country. There is unlimited need for electronic expertise “I’ll GO THE RIGOL ... UNBEATABLE FOR PRICE AND PERFORMANCE” Rigol DS5062MA 60MHz Rigol DS5102MA 100MHz Rigol DS1202CA 200MHz Rigol DS1302CA 300MHz 60MHz Bandwidth, 2 Ch 1GS/s Real Time Sampling 4k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 100MHz Bandwidth, 2 Ch 1GS/s Real Time Sampling 4k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 200MHz Bandwidth, 2 Ch 2GS/s Real Time Sampling 10k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 300MHz Bandwidth, 2 Ch 2GS/s Real Time Sampling 10k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty ONLY $799 Sydney ex GST Melbourne Tel 02 9519 3933 Tel 03 9889 0427 Fax 02 9550 1378 Fax 03 9889 0715 email testinst<at>emona.com.au 6 Silicon Chip ONLY $1,099 Brisbane ex GST Tel 07 3275 2183 Fax 07 3275 2196 ONLY $2,036 Adelaide Tel 08 8363 5733 Fax 08 83635799 ex GST Perth Tel 08 9361 4200 Fax 08 9361 4300 web www.emona.com.au ONLY $2,620 ex GST EMONA siliconchip.com.au 3 IN 1 SHEETMETAL MACHINE SCHEPPACH $ 277 WET STONE (W860) GRINDER Bender Rolls Guillotine 300 x 1mm 760 x 1mm 1000 x 1mm 97 (W861) $ HOUSE HOLD - SHARPENING KIT Jig 40 Jig 120 Jig 60 97 (W862) $ $ $ $ HAND SHEARS $ Jig 25 ARBOR PRESSES Jig 55 Grinding s. 110 Stone Grader BS-5 BANDSAW 1 TON $87 (P118) 2 TON (P119) 87 (S186) 6.5mm Shear, $ 300mm Blade 147 (S188) HOLE ENLARGING DRILL SET • For drilling holes in thin material • 4-12mm, 6-20mm, 6-30mm 3-piece Set 57 (D107) 90º ANGLE CLAMP 167 HSS DRILL SETS Precision ground 25pce Metric 1-13mm $ (D127) $ 327 (B009) 29pce Imperial 1/16 - 1/2" $ (D128) 247 (P020) Dies: 22, 27.5, 34.3, 43, 49, 60.8mm • Vertical table • 115 x 205mm capacity • 3-Speed 1/3HP motor • Cast iron construction HM-10 MINI MILL DRILL ROLLER STANDS 450-720mm $ 27 • 350W, 240V Motor, • Electronic Variable speed • 2 speed gearbox • Head tilts ±45º 47 $ 57 (W343A) 710-1125mm $ 37 797 (W343) (M150) COUNTERSINK SETS 207(B043) PUNCH CHASSIS HYDRAULIC SET $ $ 3 TON $217 (P120) 4mm Shear, $ 150mm Blade $ COLD BENDING FLAT: 100 x 5mm SQUARE: 16 x 16mm ROUND: 18mm dia. 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Specifications and prices are subject to change without notice & are valid until 30-06-08. 2_SC_JUNE_08 siliconchip.com.au METRIC SLOT DRILL END MILL SIZE SHANK CODE CODE PRICE $ 3mm 6mm M3201 M3230 14 $ 4mm 6mm M3202 M3231 14 $ 5mm 6mm M3203 M3232 14 $ 6mm 6mm M3204 M3234 16 $ 7mm 10mm M3205 M3235 16 $ 8mm 10mm M3206 M3236 16 $ 10mm 10mm M3210 M3237 20 KEYED KEYLESS 43 (C289) 57 (C290) 97 (C292) 117 (C294) $ 13mm Keyed JT6 $ 16mm Keyed JT3 4-Pce 2-20mm 6-Pce 6.3-20mm $ 13mm Keyless JT6 Hole Type 3 Flute Type $ $ $ 16mm Keyless JT3 (D105) (D106) 57 57 RUBBER MAT - Anti Fatigue • 1530 x 920mm (12mm thick) • Tapered edge to reduce tripping BENCH DRILL • 3/4HP 240Volt • 16-speed with 16mm chuck • 1m High PRECISION GROUND M244 57 (M242) 77 (M243) $ 200x150x125mm 137 (M244) AL-30 BENCH LATHE 112x88x75mm 150x125x112mm $ $ • 250W 240V Motor $ • 300mm BC (L194) • Includes accessories 777 $ $ 37 (M800) 217 (D138) 257 (D140) FLOOR MODEL $ PRICES INCLUDE G.S.T. June 2008 7 Mailbag: continued in so much of Australia. In water management alone there is a huge vacuum. I know that your magazine sustains a special readership that must have access to this kind of journal even if parts are sometimes hard to get. This actually could be a great time for Aussie electronics. Component prices for more complex devices such as accelerometers have never been better thanks to the strength of the Aussie dollar. Please, for the kids out there who still want to know how things work, keep going. Jason Walters, Donvale, Vic. TV screen size now measured in inches “Who in Australia still uses ‘oldfashioned’ Imperial units?” asks T. Robinson (Mailbag, March 2008). It would seem the answer is every manufacturer, sales outlet, advertising agency, salesperson and consumer associated with the sale or purchase of any new large-screen TV set. Who is prepared to accept this “old-fashioned” measurement? Most probably all Australians and it would appear, without protest. Do we refuse to purchase these items or boycott the offending stores using this “unit of measurement no 8 Silicon Chip longer applicable in Australia”? I do not think so and as an aside, it appears that intending purchasers are able to convert inches to parts of a metre without much mental difficulty. Leslie McDonald, Yeppoon, Qld. No conspiracy against electric cars Why do you publish nonsense like the letter from Jacob Westerhoff, (Mailbag, April 2008) claiming that there’s some sort of conspiracy against electric cars? The Reva wasn’t refused registration in Australia. The rules require all new vehicles to pass crash safety tests. The Reva’s importers chose not to submit it because they knew it would fail. If there had been a conspiracy against it, the Australian authorities would have left it at that but in fact at taxpayers’ expense, they organised to have one purchased in Britain and crash-tested by the Vehicle Certification Agency there. It failed so catastrophically that Britain’s Transport Minister sought an urgent review of the EU regulations that allow them to be registered there. There is nothing, not in the law or registration authorities’ attitudes, stopping a safe electric car being registered in this country. Many have been that are electric conversions of cars that met safety regulations in their original petrol-powered form. Gordon Drennan, Burton, SA. Misconception about capacitors in series I have a query regarding the article on ultracapacitors in the April 2008 issue. In the article it states that as capacitors are connected in series, the capacitance decreases. This statement is not correct; while the overall capacitance is limited to the capacitor with the smallest value, a bank of series capacitors of the same value will only increase the voltage rating. For example, two 1mF 10V capacitors in series will become a 1mF 20V capacitor. However, if two capacitors of dissimilar values were used, you would have following: 1mF 10V and 0.47mF 10V in series will give a capacitor of 0.47mF 20V. For parallel capacitors the capacitance is added up but the voltage is limited to the capacitor with the lowest value. Ray Jones, via email. Comment: you are wrong. If you put two equal-sized capacitors in series, you end up with a capacitor with half the value. For example, two 1mF caps in series is 0.5mF. If you don’t believe us, you can do the test with a digital multimeter, provided it has a capacitance range. siliconchip.com.au Another way of thinking about it is to regard each capacitor as having a finite impedance. If you connect capacitors in series, the resulting impedance will be sum of the capacitor impedances; the same as if you connect resistors in series. So if you connect 10 equal-sized capacitors in series, the resultant capacitance will be one-tenth of the single capacitor (or 10 times the impedance). However, it is approximately true that if you connect a very large capacitor in series with a small capacitor, the effective capacitance will be almost the same as the small capacitor. B batteries did exist I would just like to make a comment on Rodney Champness’ article on battery types (SILICON CHIP, March 2008). Rodney’s list of general-purpose batteries listed A, C, D & F but omitted B. There was indeed a B battery and I have an old torch which took the B-size cells. Needless to say, this torch has not been used for many years because of the lack of cells to suit as I think they were discontinued about the late 1940s. The cell length was shorter than the present day AA type. Reg Hynes, Parkfield, WA. Banning lasers is stupid It is without doubt that we have some unbelievably brainless individuals in our midst but the stupidity of our politicians and authorities is amazing. Once again these idiots bring out the “ban and make it illegal” solution, instead of applying any common sense or intelligence to the situation. It apparently has not passed through the minds of these imbeciles that there are many legitimate reasons why peo- siliconchip.com.au Metal detectors may find gold The letter and your response regarding gold detector projects (SILICON CHIP, April 2008) reminds me of an experience with ETI magazine. It was, I think, in late 1979 when I (as then managing editor) received a phone call from a newly-founded electronics supply store in Melbourne to the effect that it was being sued by an ETI reader who claimed that the ETI metal detector project he had bought did not work. The store owner said the unit seemed to do that claimed for it but asked if we could assist, as losing the case could bankrupt his recently started business. The claimant was claiming the airfares, the price of the kit, plus the value of the gold he had expected to find which he put (from memory) at $150,000. He also sought damages. Our then editor, Roger Harrison suggested a few checks and these confirmed that the unit appeared to meet the realistically modest claims made for it in the ETI article. It sounded intriguing and with the store owner clearly needing help, I suggested that Roger and I act as expert witnesses in court. We flew to Melbourne accordingly. The claimant was a somewhat curious man who claimed that he had bought the kit specifically to find gold in South America. His argument was that the shop had ple own lasers, be they pointers or just for experimentation. The irony of this stupidity is that it will do absolutely nothing to stop idiots from aiming them at planes or anyone else. The idiots already have lasers and if the authorities think they are going told him that it would find gold. On that basis he bought the kit and had then booked a flight to South America for a couple of months later. He told the court he had found that the device did not find gold. He had accordingly cancelled his trip but he claimed that the airline would not refund his money. My questioning elicited that he had tried the unit in his backyard in Carlton. He admitted it detected metal much as described in the ETI article. A further question showed that he had not however tried it on a planted gold sample. He then told the judge: “Why would I do that. I bought it find gold, not just detect it”. The judge suggested this seemed an improbable location in which to seek gold. Not surprisingly the case was thrown out of court (as it had no merit). My time with ETI confirms the comment appended to your reader’s letter that few metal detectors reliably detect metal below 100mm or so. I had long suspected that ETI attracted a tiny subset of readers possibly even zanier than a few of the staff. One (reader) claimed to be picking up Radio Moscow on his pubic hair – but the metal detector was the only $150,000 claim! Collyn Rivers, Founder Editor – ETI, Broome, NT. to stop because they are made illegal, they are dumber than anyone can imagine. Once again the only people that will be affected are those who are using them responsibly. I have a couple of solid-state laser modules which I use for optical experiments. So now I am June 2008 9 Mailbag: continued Helping to put you in Control Data Acquisition Measure voltages, currents, temperatures and more with your PC Labjack U12 USB DAQ device with 8 12-bit analog inputs, 2 analog outputs, 20 digital I/O, and a 32-bit counter. From $195+GST Labjack U3 USB DAQ device with up to 16 12-bit analog inputs, up to 20 digital I/O, 2 10bit analog outputs, up to 2 counters, and up to 2 timers. $159+GST Labjack UE9 High Speed USB/ Ethernet DAQ device with 14 analog inputs (12- to 16-bit), 2 analog outputs (12-bit), 23 digital I/O, 2 counters, and 6 timers. $599+GST MyPCLab USB DAQ device monitors two universal analogue inputs, accepts thermocouples, Pt100, Voltages and 4-20mA current loops along with one digital input. With easy-to-use Windows software . $129+GST iUSBDaq USB DAQ device with 8 12-bit analog inputs, 16 digital I/O lines, 2 programmable pulsewidth output channels, and 1 16-bit counter channel. $155.00+GST Digirail Modbus I/O DIN Rail I/O modules with Modbus RTU comunication 3 models, a 2-channel universal analogue I/P, a 2channel relay O/P and a 4channel digital input/ counter unit. $149+GST Contact Ocean Controls Ph: 03 9782 5882 www.oceancontrols.com.au 10 Silicon Chip going to be a criminal, along with people in boardrooms. What about DVD players, CD players, lighting displays etc? Are we now all criminals? The only thing more terrifying than morons who aim lasers at planes are idiots who make decisions with “no” knowledge of what they are doing. Tony Joyce, Macquarie Fields, NSW. How to get into digital TV I am an antenna installer servicing the northern and surrounding districts of Brisbane and I wish to comment on the article “How To Get Into Digital TV, Pt.2”. Most people and even some “professional” installers forget or just don’t know that each component from the antenna right through to the TV forms part of the system and needs to be of the right specification, fitted correctly and in good condition for the best results. A single loose strand or a poorly made connection can render one or all channels unstable and result in varying degrees of signal breakup. I would also like to point out that in anything less than a good signal strength area, it can be very difficult for a novice to achieve a satisfactory result. A Digital Field Strength meter is often the only way to ensure that the correct antenna is used and mounted in the best possible location. Also, the quality of the tuner in the STB (or TV) is important. In a poor area or indeed, a poor installation, a cheap box may not work well. As an aside, in many cases I have achieved great results using a good quality box with signals as low as 26dBmV at the antenna. This signal must lock as digital and must be amplified with no less than a 34dB masthead amplifier. This would just not be possible if any of the components were sub-standard. Wayne Mathie, Brisbane, Qld. Signal strength and quality is critical with digital TV I read with interest the recent Alan Hughes’ articles on digital TV, especially the second one on antennas. Only a couple of months before, I discovered the problem of too much signal the hard way. We went digital in late 2006 and had no problems with picture breakup until the second half of 2007 when I suspect the TV stations increased transmitter power as they started to crank up HD transmissions. Initially, I suspected the TV and/or STB/HDD/ DVD unit problems (both Panasonic, standard definition only) but the warranty service agent found no problems. Eventually, after discussions with Panasonic Technical Support and visits to the Topfield DVD Forum, I became aware of the possibility of too much signal and this proved to be the case. We live in an area historically rated as very difficult for TV reception. We are about 43km from the transmitters and could probably see them from the top of the roof (with binoculars), as we are on top of a small hill. Consequently, when we moved to our present house in 2001, I installed not only a high-quality, digital-ready antenna (Matchmaster 01MM-DC23A) but also a distribution amplifier. I had the builder install six outlets in the house and quad-shielded cable from the antenna to the main TV outlet. With analog TV this worked extremely well, giving an excellent picture and sound on all channels (including SBS and Access 31) on all TVs. I did not require the full gain of the Matchmaster 10MM-MA32 amplifier which could overload one of the older TVs. I used “F” connector devices throughout, with a proper tap for the main TV and an FM splitter for the audio system. All devices, except the MA32, are in well-shielded metal boxes (Matchmaster devices). To solve the digital “overload” problem, I moved the distribution amplifier so that the antenna signal went straight to the “Tap” for the main TV, while the amplifier fed the 6-way splitter for the other TV points. This has eliminated the overload problem, with signal quality now 100% on all channels and signal strength 100% on SBS and 80-90% on all others. Note that the “Tap”, FM splitter and a 2-way splitter (to separately feed a Topfield STB and the siliconchip.com.au How to solder surface mount devices Thanks for the interesting article on SMD soldering by Jim Rowe in the March issue. I have found that solder masks are essential for applying paste for very small chips. I recently had that problem and it nearly drove me to abandon the design. The chip in question is a MiniCircuits DAT-31 digital attenuator. I don’t know if the footprint for this device actually has a designation but there are five pads on each of the four sides spaced 0.5mm apart and 0.25mm wide. The chip measures 4 x 4mm. The 0603 resistors look like fence posts by comparison. Even using a sharpened toothpick and a 30X microscope did not enable me to place an approximately useable amount of solder paste. I really tried! After some research, I found a process known as “Chemical Milling”, used to produce small model railway parts. So using the process described in SILICON CHIP for the toner transfer method to make PC boards, I decided to try to make a solder mask. I used 3-thou brass shim instead of a PC board and etched it the normal way (I did remember to cover the back with Scotch tape after the first try). After several attempts, I managed to produce a solder mask I could use. After that it was straightforward – apply the solder paste, place the chip with tweezers and then “cook” it in the toaster oven described by Jim Rowe. The attenuator now works in a Vector Network Analyser using the AD8302 chip. The brass shim is sturdy enough so that the mask can be re-used many HDD recorder) have a total attenuation of 16dB at the main TV. If I insert an extra 10dB attenuator at the main TV, I still get 100% quality, even though signal strength drops to about 50-60%. It would seem that we are not really in a poor signal area, in spite of the general reputation for the suburb. It is very important to note that the crucial measurement is the signal quality, rather than strength. With siliconchip.com.au A solder mask for SMDs can be made by etching the device “footprint” out of 3-thou brass shim. After the solder paste is applied, the device is placed in position and cook ed in an oven toaster. times. I also thought of using plotter/ cutters which theoretically have the resolution to produce these tiny slots in vinyl which again, theoretically, could be used as solder masks. I wonder if any of your readers have experimented with this idea? The number of interesting projects that can be produced with throughhole technology is rapidly dwindling and as hobbyists or professionals, we need to learn to handle the incredibly small devices. I am old enough to remember the 70W soldering irons from the valve era and the transition to PC boards and those “tiny” transistors. Over the years we learned to handle that – now we have a new ballgame with microscopes and tweezers. Change is what keeps us alive! Frank Winter, Buderim, Qld. the original setup (with the amplifier, at minimum, feeding the main TV as well), signal strength was essentially the same but signal quality was about 70-90% when there was no picture breakup, with breakup occurring when quality dropped to 50-60%. I hope this information is of interest to other readers. Ron Rosich, SC Ocean Reef, WA. FRONT PANELS & ENCLOSURES Customized front panels can be easily designed with our free software Front Panel Designer • Cost-effective prototypes and production runs • Wide range of materials or customization of provided material • Automatic price calculation • Fabrication in 1, 3 or 7 days Sample price: USD 43.78 plus S&H www.frontpanelexpress.com June 2008 11 When it comes to doing your own electrical work. . . Are Aussies DUMBER than Kiwis? By Ross Tester Did you know that it if you want to paint a wall and need to unscrew a power outlet or light switch, you cannot do it legally in any Australian state? Nor can you replace a light switch or power outlet, install a dimmer or ceiling fan. Nor anything else which involves any form of electrical installation, repair or modification. But you can in New Zealand! I n fact, in NSW (and probably other states), at the very moment there are radio commercials saying how dangerous it is to attempt your own electrical repairs. It was these commercials which in part prompted this feature. The same commercials, incidentally, state that one in five “handymen” do exactly that. Naughty, naughty. Like all other states, Queensland law says that you have to call a licenced electrical contractor to do any electrical 12 Silicon Chip work involving fixed wiring. Unlike most other states, in Queensland you cannot even repair plug-in appliances (such as jug elements, etc). But we are getting ahead of ourselves. Now let’s suppose that a handyman, unlicensed, does some electrical work. It may be absolutely exemplary but by definition (and law!) such work is declared “dangerous” and cannot even be tested and certified after the event by siliconchip.com.au Non-contact mains voltage detectors: an essential item in every toolbox! an electrical contractor! There have been prosecutions, for example in the Northern Territory where a contractor did certify work done by an unlicensed person. The contractor was fined and lost his own licence. It doesn’t matter that work may have been done to a higher standard than the electrical contractor would have done it. At the risk of earning the wrath of every sparkie in the land, they are normally working at the maximum speed to the minimum acceptable standards, simply so they can earn a buck. But even the very best quality unlicenced work can never be “legal”. Now, if you were across the pond in New Zealand, such actions are quite legal. In fact, in New Zealand you can not only change a power outlet or light fitting, you can add additional power outlets, even rewire your entire home if you want to right back to (but not including) the switchboard. The NZ power authorities actually publish information to help the do-it-yourselfer do it him (or her) self. If you don’t believe us, have a look at www.consum- eraffairs.govt.nz/mediacentre/wordofadvice/2004/ ECP5051.html or www.energysafety.govt.nz/templates/ Page____17682.aspx They’re just a couple from a number of sites setting out what is completely legal. But the Kiwis go even further than that – they actually publish instructions to show home owners how to do it – safely! Again, have a look at www.energysafety.govt.nz/upload/33458/ecp51v18.pdf and www.energysafety.govt.nz/upload/33456/ECP50v18. pdf Why the difference? Maybe the Kiwis have different equipment to that in siliconchip.com.au Unlike neon test screwdrivers, non-contact tester s, as their name implies, do not require any contact with live circuits. This is very important for safety – it’s easy to see if the circuit is dangerous simply by bringing the tester tip close to it (ie, within a centimetre or so). If you are doing any sort of electrical work, one of these devices is absolutely essential. They’re rated to detect AC voltages from 110 to 1000V. Two models are shown above: at top is a Digite ch QP-2271 “Voltfinder” from Jaycar Electronics. It not only glows bright red when it senses a live circuit but also has a relatively loud beeper to warn you. In addition, there is a handy bright LED torch built in. It retails for $17.95 at all Jaycar Electronics stores and webstore. The lower model is a Fluke VoltAlert 1AC-II. It is small er than the Digitech and also appears to be slightly more sensi tive. It too features a warning beeper but no torch and retails for $48.00 from electrical wholesalers and some hardware stores . Both of these will easily identify a live power outlet from the front (ie, while it’s still in the wall); they’ll also detec t live wiring from outside its plastic outer sheath. In fact, they’l l also yell their heads off if they’re next to your mobile phone when it rings! Australia, perhaps easier to use and understand? No, it’s absolutely identical. Same voltage, same fittings, same hardware. . . same! Do the Kiwis operate to a different set of electrical standards? No, in fact the standard is called AS/NZS:3000 – that’s Australian Standard/New Zealand Standard number 3000. (It used to be called SAA Wiring Rules). Why then are the regulations in the two countries so different? June 2008 13 Are Aussies that much dumber than Kiwis? Absolutely, if we are talking about the bureaucrats and politicians. And quite possibly the general public as well, because we have allowed the bureaucrats and politicians to force their demonstrably false regulation on us. What the Kiwis obviously have is a much more enlightened, sensible and informed Government and bureaucracy (well, certainly in this regard!). It’s all about safety No it’s not. That’s the line that Australian electricity authorities trot out whenever the subject is raised – and they are supported by electrical unions, by electrical contractors, etc, who want to ensure that they keep the work to themselves. And they are supported by mainstream media and tabloid TV shows who are convinced (conned?) that having handymen doing their own wiring will cause corns and callouses, rot wooden legs and bring plague and pestilence to the land. We mentioned New Zealand a moment ago. Compare the statistics between Australia and New Zealand: they ably demonstrate that electrocutions are at least as rare in New Zealand as they are in Australia. Table 1 shows the comparison between the Australian states and NZ for the years 2005-2006 (the last year currently available). Notice something? With the exception of the Northern Territory (whose figures are skewed by the low population), most Australian states and New Zealand have pretty similar electrical 14 Silicon Chip STATE NSW VIC QLD WA SA TAS ACT NT Population (millions)# 6.8 5.1 4.1 2.0 1.6 .49 .34 .2 NZ 4.1 # Australian Bureau of Statistics, 2006 Electrical Fatalities* 6 6 3 3 0 0 0 3 Fatalities per Million Population 0.88 1.17 0.8 1.5 15 3 0.7 * Electrical Incident Data 2005-2006, ERAC Table 1: wouldn’t you expect New Zealand to have significantly higher electrical fatalities than all Australian states, if doing your own electrical work is so dangerous? It is clearly not so! fatality figures (note that we are not breaking these down into types nor locations, though if you are interested, those breakdowns can be found on the Electrical Regulatory Authorities Council website: www.erac.gov.au). And there is certainly no suggestion that these fatalities occurred due to unlicensed people doing their own electrical work. It would appear from our reading that the majority are either workers in the electrical industry (complacency, perhaps?) or, far too often, accidents such as allowing crane siliconchip.com.au jibs or boat masts to contact high-voltage overhead lines. Leaving the Northern Territory and the three states which had no fatalities at all in the 2005-6 year out of the equation, Australian states experienced between 0.8 and 1.6 deaths per million people. But the one thing that stands out, more than anything else, is New Zealand, with little in the way of restrictions, has less fatalities than any Australian states which had them. Now if the Australian authorities are correct – that it is dangerous to do your own electrical work – wouldn’t you expect that to show up in the stats? Wouldn’t you expect New Zealand to have significantly higher fatalities, because doing your own electrical work is so dangerous? As the song says, “it ain’t necessarily so”! Let’s look at another set of statistics – the United Nations Fire Statistics Study (www.genevaassociation. org/FIRE%20N%C2%B0%2014%20-%20September%20 1998%20.pdf) Certainly, these statistics are for more than house fires. And no-one is saying that all fires are electrical in origin (although just about every time you hear about a house fire on the news, an “electrical fault” is blamed). If it was so dangerous to do your own electrical work it’s not too long a bow to stretch to assume that more fires would be caused by that electrical work being done by unlicenced people. Woops. New Zealand has a lower cost of fires per population than Australia. Scratch that theory! Again we have to ask, are Aussies that much dumber than Kiwis? In this regard, the authorities seem to answer YES! siliconchip.com.au What is the Australian Supply Voltage? Ask most Australians what the supply voltage is and (if they know!) they’ll say 240. Indeed, most electrical equip ment made in Australia is labelled 240V, 50Hz. But they’d be wrong! That’s what it used to be . . . In 1983, the International Electrotechnical Comm ission initiated a program to standardise the 50Hz internationa l voltage at 230/400V. On 23rd February 2000, a new Australian Standard, AS600382000 came into force which replaced the original standard. In a nutshell, it stated that in normal circumstances, the nominal supply voltage should be 230/400V, +10%, -6%. Another Australian standard, AS/NZS3000, states that the voltage drop (caused by load) at the customer’s prem ises should not vary by more than 5%. Therefore, the supply voltage must be 230/400V +10, -11%, or between 205-253V/3 56-440V. Supply authorities recognise that a lot of electrical equipment would struggle with the lower figure so endeavour to keep the single phase supply at 230V, +10, -2% (225-253V ). Perhaps not quite coincidentally, this range confo rms to the previous 240V standard! Reproduced below is the New Zealand government’s “Guide to Doing your own Electrical Work safely and legally” – what you can and cannot do. This enlightened approach has not resulted in more electrical accident fatalities, pro-rata, over the Tasman. The guide is a little small here to read the fine print – but you can download a copy yourself on www. energysafety.govt.nz/upload/31994/brochure.pdf June 2008 15 In this regard, the authorities seem to answer YES! Not only are New Zealanders allowed to do their own electrical work, the NZ government publishes a number of guides to tell them exactly how to do it, with safety paramount. They are savvy enough to realise that people ARE going to attempt their own electrical repairs and installations, so go out of their way to make sure that those people are given the information they need to do those repairs and installations responsibly and, most importantly, safely. No amount of radio advertising is going to stop people in Australia doing the same thing. It’s simply a fact of life. And prosecutions for doing so are so rare that we couldn’t find very much data at all. There were related prosecutions – and we’re sure there would be some prosecutions out there. But not that we could track down. A little knowledge is a dangerous thing . . . So the proverb goes. But no knowledge is much worse. The following example is not exactly doing your own “electrical work” but it’s close enough – and it serves to illustrate the point. I once had a next-door neighbour who owned an electric Flymo. One day, the inevitable happened and she ran over the power lead, cutting it. So she went down to the local hardware store and bought a 240V cord-top plug and socket. So far, so good. There were pretty pictures on the back of the packs showing which wires connected to which pins, how long to cut and strip each wire, etc, which she managed to achieve without drama. The only problem was that she fitted the female socket to the lead attached to the mower and the male plug to the lead from the power outlet – that is, male at both ends of the power lead – so that when it was plugged in she had live, exposed pins ready to do their worst. I was aghast – but at first she couldn’t understand the problem. It took a while, then she said “why didn’t they explain that to me?” The reason, quite simply, is that authorities here are not explaining anything – for safety reasons, of course. But withholding the information is not going to stop people, like my next door neighbour (who by her own admission knew nothing!) – they’re going to do it anyway and make the mistakes that kill people. This is one of the “modern” style outlets (switches are the same) with a removable face plate so that (theoretically!) it doesn’t get painted. However, it has been painted over – but even more importantly, it has a faulty switch mechanism (left side) so the whole outlet will need to be replaced. 16 Silicon Chip Closer to home, (literally!) when I moved into my home many years ago, there was a bare 240V globe in a socket hanging off a branch in a tree near the entrance. A length of perished figure-8 cable ran back through various tree branches until it disappeared through a ventilation grate under the house. I asked the previous owners about it and they told me that it was there when they bought the house but it had never worked. Talk about Jerry-built! I decided to remove this forthwith – only to find the circuit was live (the globe was blown!); it was wired in parallel to the oyster light at the front door. So it was live whenever the front door light was on! Of course the authorities would point to this example and say “See, we told you so. People should not be allowed to do their own wiring.” We say that if whoever (Jerry!) had put this flawed light circuit in had the correct information given them, they would have put in a proper light circuit using the correct cable, conduit, switching and so on. It’s precisely because they didn’t know how to do it properly that they did it incorrectly – and fraught with danger. In New Zealand, this information is supplied by the government in order to prevent those very mistakes. They make the rather strange assumption that it’s better to have live people with appropriate knowledge than dead people with none. Repairing appliances Again in New Zealand, D-I-Yers are allowed to repair their own electrical appliances, such as jugs, heaters, toasters, etc – especially those with such things as elements and the like which can and do fail. Already in some states of Australia, such is forbidden by law, despite the fact that you can buy replacement jug and heater elements (and other parts) over the counter. From the mumblings we’ve heard, it probably won’t be too long before all states follow suit. Could this account for the number of electric heaters etc put out in council cleanups and taken to landfill tips? It’s too expensive to call an electrician to replace a heater element but it’s so easy to yourself – if you were allowed. Even if you’ve been doing it for a lifetime, even if you have a PhD in electrical engineering, unless you have an Woops! We said theoretically . . . the sloppy painters missed the wall – but got the switch plate! It is precisely situations like this which call for the switch to be replaced if the owner is at all house-proud. But it would probably cost you at least $100 (or more!) to get an electrician to do the job! siliconchip.com.au electrician’s ticket, you can’t touch anything powered by mains. In fact, it gets worse. You won’t be allowed to build any mains-operated device if you follow the letter of the law. No more amplifiers, radios, lighting displays – in fact, no thing powered by more than a battery or a plug-pack! Needless to say, most hobbyists will continue to treat this with the contempt it deserves. Wasn’t it Thomas Jefferson who once said (and we paraphrase somewhat) if a law is stupid it is every citizen’s right to ignore or disobey that law? And the reason the bureaucrats and politicians give for this stupidity? Why, safety, of course! Of course, that’s utter rubbish. One wonders how all the brilliant electrical inventions over the years would have come about if this craziness had been on the statute books since, say, Marconi’s time. And what of all the trades people, technicians and professionals who cut their teeth on simple projects, moving up to (perish the thought!) mains-powered devices before embarking on their careers in the industry? Where would they be today? Where would we be today? Buying the bits OK, so we’re going to assume that someone (no, not you, of course!) is going to want to, say, change a power outlet from a single to a double. Maybe put in a dimmer or electric fan. Or even replace that old ceiling rose that’s so old it’s dangerous. Where do you (oops, sorry, they!) get the bits to do it? Not so long ago, you could buy power outlets, light switches, dimmers and a host of other electrical hardware at virtually any supermarket. Not any more: today you have to buy from either an electrical “wholesaler” or, more likely, from a large hardware store. You’ll almost certainly save money buying retail from a hardware store than buying wholesale because unless you have an account with one of the wholesalers, the prices they will ask are often ridiculous. Most wholesalers work on the system of charging a certain price on the “invoice” or sales docket (the one the electrical contractor gives the customer to claim back purchases) but when the wholesaler’s account is sent out to the contractor, there is an often-quite-substantial discount applied. That way, it “appears” that the contractor is supplying the goods to the customer “at cost”, where in fact he ends up making a substantial profit. We’re not saying that is wrong or right – it’s another fact of life. Or you could go to electronics retailers such as Jaycar and Altronics, both of whom stock a range of common D-I-Y equipment such as power outlets, light switches and mains cables – at very good prices. However, for such things as conduit and the myriad of electrical fittings, the hardware store is still the best bet. Keeping it up-to-scratch As we said before, it is (legally) impossible for an unlicensed person to do any electrical work and get it signed off by an electrical contractor. But if you are doing any work, you might as well do it “by the book”, if for no other reason than, you guessed it, safety. Here we have no argument with the regulations which all electrical contractors have to abide by. For the most part, they make perfect sense siliconchip.com.au Press Release Electrical contractors and electricians will effectively be banned from working on equipment operating at normal mains voltage under a new guideline Code of Practice issued by EnergySafety. The Code applies to electrical contractors and all electricians working in general industry. It also places obligations on contractors’ clients and all employers of electricians who request that live work be performed,” Director of Energy Safety Albert Koenig has said. “Working on live electrical circuits and equipment or in very close proximity to live parts is potentially dangerous and mostly places the lives of electricians at risk needlessly,” Koenig said. Loss of production, increased costs and operational inconvenience will not be regarded as justifying live work. Under the Code, live work will be justified only if there is a greater risk of danger to lives of people using, or affected by, an electrical installation, compared with risks incurred by electrical workers asked to perform live work. In such circumstances, a live work justification case, backed by a formal risk assessment under the Code, must be made out by the licensed electrical contractor’s client, requesting that live work be carried out. In respect of residential type installations, the Code never allows live work. If the electrical employer is satisfied that live work is justified and it can be carried out safely, a strict safety plan must be followed, comprising: • The contractor must prepare a detailed work plan and set of procedures, complying with the Code, to cover the work; • All electrical workers involved in performing the work must agree it can be done safely; • A competent and independent safety assessor must approve plans and procedures if the prospective fault current exceeds 10,000 amperes at the site in question; • An experienced safety observer must be present at all times while the live work is under way and must have no other duties while carrying out the observer role. Koenig said the Code provided for routine activities which generally need to be conducted while circuits are live, including testing, commissioning and location of faults. “With this Code, we are addressing a large number and variety of situations where electrical contractors and electricians are placed under commercial pressure by their clients to perform risky live work, merely to hold costs down, keep production going and avoid inconvenience,” he said. He also noted that the guideline Code does not apply to the electricity transmission and distribution related activities within the electricity supply industry, as this sector has its own guidelines for safe work practices. EnergySafety is currently conducting a series of industry presentations around the State at regional centres, to outline recent electrical industry legislation and technical standards changes, and this new Code. June 2008 17 This old-style fuse box, circa 1950, has most of its plug-in fuses replaced with circuit breakers. The main switch (highlighted) clearly shows whether it is in the on or off position. Contrast this with the modern DIN rail box below: its “master isolator” (top left) switches two phases. This box has combined RCDs and circuit breakers. or plasterboard, creating an unsightly mess. It’s simple to avoid this if you know how. We said this is in a grey area because you aren’t actually doing any wiring installation or modifications. But we have seen, time and again, warnings from electricity authorities that you must not do this because, they say, it is (a) dangerous and (b) illegal. To (a) we say, with proper guidance , poppycock. To (b) we will agree to disagree. Anyway, temporarily loosening the switch or outlet is less dangerous than replacing a light globe (they have exposed mains pins, the bulbs break etc etc) – just as long as you follow a few simple steps. Here are those steps: specifying the number of outlets on a circuit means less chance of an overload and fire, for example. So if you plan to do some electrical work, get yourself a copy of the SAA Wiring rules which explain in detail what you can and cannot do. You’re more likely to find them described as “AS/NZS3000” You can get an on-line (PDF) version for just under a hundred dollars – expensive, yes; but at least you’ll know what is required (see www. SaiGlobal.com/wiringrules). You may also be able to find a copy at a major library. (1) Turn the power off at the main switch (or, if you can positively identify which circuit the outlet/switch is on, by flipping the circuit breaker or removing the fuse). (2) Test that you have indeed turned the power off using a non-contact voltage indicator. One of these devices should be in every handyman’s toolbox. They’re not expensive and are much better than the old neon test screwdriver, which does require contact with the live circuit (see panel on P13). Only if you are absolutely sure that the power is cut off, proceed to step 3. (3) Many modern outlets and full-size switches (such as HPM’s “Excel” range and Clipsal’s “2000” series) have a clip-on cover plate over the actual outlet/switch. This is very easily removed by sliding a sharp knife under the edge and prising the cover plate off. Older power points and switches simply have two screws Let’s get down to it In this first instalment, we’re going to describe how to do something that, legally, is arguably in a “grey” area: temporarily pulling a light switch or power outlet out from the wall or architrave so that you can paint behind it. “Too easy”, you say. Oh yeah? How then do you account for the millions of light switches and power outlets in homes and offices with paint around the edges! And, just as importantly, the number of damaged walls around outlets (or switches/architraves) where the offending device has pulled away paint or even the outer layer (skin) of Gyprock 18 Silicon Chip It’s an all-too common sight: someone has removed the light switch and taken a chunk of paint with it. It’s easy to avoid this problem . . . but is it legal? Incidentally, whoever removed this light switch obviously didn’t bother to insert the plastic “pips” to cover the screws. siliconchip.com.au This light switch is certainly not “dead” – the non-contact tester is glowing red and singing its head off! As you can see, these devices work quite happily from the front of the outlet/switch so you can test them before you do anything! Having turned off the main switch, turned off the appropriate circuit breaker (or removed the fuse) and then checked again that it is dead, cut a thin line right around the outlet/switch to make sure you don’t remove any paint. holding them in, usually covered by two small flushmounting plastic “pips” which have to be removed before you can access the screws. It is possible to lever them out without damage, so they can be re-used, by using a sharp knife or tiny screwdriver. However, they are replaceable (hardware stores usually have them) so most times they are simply dug out with a screwdriver and discarded. (4) Whether you have an outlet/switch with a cover plate or without, before you undo any screws, use a very sharp knife (a craft knife is best, a box-cutter will do at a pinch) to score around the outlet or switch, using the outlet or switch as a template. The idea is to cut a very thin line through the paintwork underneath so that when you do remove the outlet/switch, it doesn’t adhere to the paint and pull some away. (5) Undo the screws holding the switch/outlet in place moving back and forth between the screws, a little at a time. You should find that if your cut (in 1 above) is deep enough, the outlet will be able to be prised off the paintwork without damaging it. It’s quite possible, indeed likely, that the paintwork underneath the switch/outlet will be damaged but if you replace the switch/outlet in exactly the same position, you won’t see it. You may not even need to remove the outlet/switch completely – just as far as necessary to reach behind it to paint. If you do remove the screws completely, don’t pull it out any further than you need to and don’t place any strain on the cabling (especially if it is old!). (6) With the outlet/switch out of the wall/architrave, temporarily run a couple of layers of electrical insulation tape (or Gaffer tape, which sticks better to dusty surfaces) around ALL of the back of the outlet/switch, making sure that you cover any connection points and screws and the wires going into them. Having said that, try to avoid moving the outlet/switch any more than you have to. Wiring, particularly old wiring, is often brittle. (7) With the tape in place, you can restore power if necessary and start painting. Remember that water-based (acrylic) paint is conductive so avoid getting too close to the switch parts, even if the power is turned off and even if you have covered it in tape. Replacement is simply the reverse of these steps, with restoring power the very last thing! SC This step – wrapping the back of the switch or outlet in insulation tape of masking tape – really is a “belt and braces” approach but is one which ensures your safety. Wet paint is conductive, so you want to be sure, to be sure! Finally, screw the switch/outlet back in just far enough to ensure that you can paint behind it without getting paint on the plate (as numerous painters have obviously done here!) When touch dry, screw it all the way back in. siliconchip.com.au June 2008 19 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 They go through the pain – so we can survive Photo courtesy Denton ATD Inc. Crash Test Dummies By Peter Holtham Ever seen those video clips of car crash tests where the dummies are thrown about like rag dolls? The dummies are highly engineered to simulate the effect of crashes on human bodies and they carry lots of instrumentation to record the pain (forces & deflections) they suffer. 24 Silicon Chip siliconchip.com.au W orldwide, car accidents kill about 400,000 people and injure 12 million more every year. Despite these grim statistics our roads are much safer than they were 50 years ago. The reason is simple. New cars are repeatedly crashtested by their makers, until they are safe as can be made for the price. Inside almost every doomed car sits one or more very expensive and very life-like anthropomorphic test devices. You and I call them crash test dummies. Packed inside each dummy are sensors that record the accelerations, forces and movements felt by its head and body throughout the crash. This data allows engineers to see what happens to the driver and passengers millisecond by millisecond. It enables them to pinpoint how particular injuries occur. Such complex capability did not appear overnight. Sixty years of development has taken crash test dummies from simple mannequins to today’s complex biomechanical marvels. Sierra Engineering built the first test dummy, for the United States Air Force, in 1949. Christened ‘Sierra Sam’, he tested ejection seats in jet aircraft. Weighing over 90kg, Sam was not very life-like and so the air force also used human volunteers. Strapped into seats on a rocket-powered sled, the volunteers experienced up to 45Gs of deceleration while testing harness designs and seating positions. In the mid 1950s, General Motors got to hear about the air force work. Shortly afterwards, GM started to use mannequin-like dummies in a simple crash test program. They soon discovered that their dummies were not able to survive repeated crashes. Nor would apparently similar dummies behave in the same way in similar crashes. By the 1960s, road safety was becoming a big issue for US politicians. In 1966 the United States Congress passed an Act setting minimum safety standards for new cars. To help GM meet the standards, the company started serious development Hybrid III head and neck (photo courtesy Denton ATD Inc.) siliconchip.com.au of a new crash dummy. They took components from two crude dummies then commercially available and combined them to create Hybrid I. Hybrid I was a 50th percentile male dummy, meaning its body (1.75m tall) and mass (77kg) represented an average US adult male. Although much improved compared with the early mannequins, Hybrid I was still not particularly life-like. GM kept up the research and development effort. In 1972 they introduced Hybrid II, with improved shoulders, spine and knees. By careful calibration they standardised its design and performance. Then, rather than keeping the knowledge locked away inside the company, GM made the drawings and calibration data freely available to anyone. GM introduced a third generation, the Hybrid III, in 1976. Now for the first time crash test dummies had a scientific foundation. Hybrid III’s builders used biomechanics, the study of how a human body responds mechanically to impact, to guide their design. Foot accelerometer and X-axis potentiometer wiring (source THOR documentation). The dummy family Hybrid III formed the basis for a whole family of dummies. Next came a petite 5th percentile female, followed by her ten, six and three-year old children. Reflecting the super-sizing of America, there is also a 1.88m tall, 101kg 95th percentile male. As with Hybrid II, GM made the plans and calibration data for Hybrid III publicly available. Several companies worldwide now manufacture Hybrid IIIs to the GM specification. In 1991 the International Standards Organisation (ISO) adopted Hybrid III as the standard crash test dummy for frontal impact testing. Whatever their size, all Hybrid III dummies are built in the same way. Each consists of over 300 component parts. The skin for the head, arms, and legs is made from pink coloured vinyl plastic while the flesh is made from urethane foam. The vertebrae of the neck are made up of rubber and plastic disks sand- Wire routing and strain relief, THOR main bundle of instrumentation wires (source THOR documentation) June 2008 25 Table 1: Hybrid III Sensors Location Type Amplitude Channels Head Accelerometer 250G 3 Neck Load cell Rotation 14kN 290Nm 3 3 Chest Accelerometer Deflection 150G 100mm 3 1 Pelvis Accelerometer 150G 3 Thigh (L & R) Load cell 20kN 2 Knee (L & R) Deflection 19mm 2 Lower leg top (L & R) Load cell Rotation 12kN 400Nm 4 4 Lower leg bottom (L & R) Load cell Rotation 12kN 400Nm 4 4 wiched between steel rings. The consistency of the disks is carefully controlled so that the structure mimics the rotation, stretching and bending movements of the human neck. The upper body has six high-strength steel ribs with polymer-based damping material. This arrangement simu- lates how a human chest responds to the crushing forces of an impact. The lower body has a curved cylindrical rubber spine; typical of a person slouched in their seat. The pelvis is an aluminium casting fixed in a sitting position. A ball-jointed thigh bone mimics human hip to upper leg movement and rotation. Knee, lower leg and ankle movements are all reproduced. Feeling the pain If you have any empathy at all you will shudder when you see the impacts that crash test dummies are exposed to. And they do the feel the pain. Or at least they have electronic sensors which register the forces which would cause extreme pain if the dummy was alive. Dummy manufacturers supply little or no instrumentation themselves, just the spaces where it can be fitted. Sensors are supplied by specialist instrument companies and are selected and fitted for a particular crash test. Hybrid III dummies have four different types of sensor built in, as shown in Table 1. Load sensors record the forces on different body parts during a crash, while rotation sensors measure twisting moments. Load and rotation sensors are built into the thigh and shin bones, for example. Accelerometers are fitted all over the body to measure acceleration in a particular direction. The head has accelerometers for three directions: front to back, side to side and up and down. Female Hybrid III with her two children on the back seat (photo courtesy Denton ATD Inc.) 26 Silicon Chip siliconchip.com.au Movement sensors record deflections during a crash. A linear potentiometer is fitted inside the chest to measure the amount of compression caused by a seat belt for example. Another, called a ‘knee-slider’, is used to measure forces transmitted through the dummy’s knees, particularly if they hit the lower facia. No instrumentation is built into the arms. In a head-on crash the arms flail around uncontrollably but serious injuries are rare and worthwhile protection is difficult to achieve. Table 2: THOR Sensors Location Type Channels Head Accelerometer Tilt sensor 9 1 Face Load cell 5 Upper neck Load cell 6 Lower neck Load cell 6 Front neck Load cell 1 Recording the data Rear neck Load cell 1 Data from the sensors is of no value if it cannot be recorded for later analysis. In the early days of crash testing, data logging systems were too bulky to fit in the car. Umbilical cables connected the few instruments in the test car and the dummy to a remote data recording system. Data was stored as analog signals on tape for later playback and analysis. Carmakers do not want to fill up test cars with bulky or heavy instrumentation as it might affect the outcome of the crash. Yet they want all the data they can possibly get from the crash test dummies, as well as any other sensors mounted on the car. Companies specialising in crash test data loggers now produce on-board units with as many as 96 data channels. Mass per channel is less than 150g and sampling rates reach as high as 22000 samples per second. These rugged, battery-powered on-board data loggers amplify, filter, digitise and store in flash memory all the signals from the dummy’s sensors. Multiple data acquisition units can be daisy-chained together when the test car is carrying a family of dummies. The whole data logging system is cabled to a laptop Head rotation Potentiometer 1 Chest Accelerometer Deflection 1 12 Upper abdomen Accelerometer Deflection 1 1 Lower abdomen Deflection 6 Spine Accelerometer Load cell Tilt sensor 2 1 4 Pelvis Accelerometer Load cell 1 8 Thigh (L & R) Load cell 2 Knee (L & R) Deflection Rotation 2 2 Load cell Accelerometer 8 2 Load cell Ankle rotation Leg accelerometer Foot accelerometer 12 6 2 6 Lower leg top (L & R) Lower leg bottom, ankle and foot (L & R) Location of sensors in THOR 50th percentile male dummy (source THOR documentation). siliconchip.com.au June 2008 27 computer while it is programmed for a specific test. Once the test is set up, the cable is removed and the car is ready to be crashed. Data from the sensors is recorded from the moment the car starts moving until it comes to rest after the crash. Not content with this level of miniaturisation, data loggers are now moving from on-board to in-dummy. The loggers can be connected together by Ethernet through a central hub. There is a single cable from the dummy for network communication, trigger, and off board power if necessary. In-dummy batteries allow the dummy to run completely cable-free during a test. Each sensor is cabled through the dummy in small channels in the flesh and spine. What of the future? Hybrid III is now over 30 years old and is beginning to show its age. It does not measure injuries to the abdomen, there is only a single chest deflection measurement, and its leg bones are rigid. It is just not sensitive enough to crash test modern cars fitted with seatbelt pre-tensioners, seatbelt load limiters and multistage airbags. The latest dummy Development of a new front impact test dummy called THOR (Test device for Human Occupant Restraint) started in the late 1990s. Designing THOR involves the efforts of carmakers, research groups and governments worldwide. The current version of THOR was released in late 2001. A spine and pelvis that allows it to sit in different poBelow right: the WorldSID 50th percentile male. By contrast, the CAD image opposite is WorldSID 5th percetile dummy (images courtesy of WorldSID Task Group). 28 Silicon Chip sitions is just one of THOR’s many improvements. Its face has five load sensors to measure facial injuries while its rib cage measures deflections in four places compared with Hybrid III’s one. Three deflection sensors are fitted inside the abdomen to assess soft tissue damage. The legs have bushings to simulate the elasticity of real bone. Up to 21 sensors on the leg bones measure loads, accelerations and ankle rotation. These additional sensors require THOR to have as many as 134 data channels, four times as many as Hybrid III (Table 2). Despite the millions spent on its d e s i g n , T H O R ’s drawings and operating manual can be downloaded by anyone from the US Department of Transportation website. See www-nrd. nhtsa.dot.gov/departments/nrd-51/thornt/ THORNT.htm Different dummies Not all crashes are siliconchip.com.au THOR head components (source THOR documentation). frontal impact. Many are side impacts (T-bones!) caused by drivers running red lights. Because the injuries are different, the requirements of dummies for side impact tests are different. Carmakers need to measure the risk of injury to the ribs, spine and internal organs such as the liver. Head and neck injuries are also common and carmakers need crash test data for head airbag development. Hundreds of scientists and engineers from over 45 organisations worldwide have just spent eight years and US$14 million designing WorldSID (World Side Impact Dummy). Companies from the Netherlands, France and Britain designed WorldSID’s head, neck and pelvis while companies from the USA developed the rib cage, spine, arms and legs, as well as the sensors and data loggers. The result is the most life-like crash test dummy ever created. WorldSID’s 212 built-in sensors record accelerations of the head, upper and lower spine, shoulder, ribs, pelvis and arms. It also logs compression of the shoulders and individual ribs, as well as rotation of the head, torso, pelvis and ankles. But whether it’s one of the Hybrid III family, a THOR or a WorldSID, the procedure for using a dummy remains identical. International standard test protocols are followed exactly. Technicians first assemble the dummy, carefully testing and calibrating each individual ‘body part’. They dress the dummy in shorts, a short-sleeved shirt and shoes, and precisely position it in the car. They stick yellow and black adhesive targets to the sides of the head to serve as reference points for the crash films. The eyebrows, nose, chin, knees and lower legs are painted with patches of different colours. Any contacts with the car during the crash will then show up as coloured smears. Once the instrumentation in the dummy and the car has been checked, the test can start. The test bay is flooded with light and high-speed film cameras start up. A tow cable pulls the car towards the crash barrier at 64km/h (40 mph). Just before impact the cable is released and the car smashes into the barrier. In just 10 seconds the test is over, although the megabytes of data recording the dummy’s ‘injuries‘ will take weeks to SC analyse. Ultimately, the result is safer cars for us all. Radio, Television & Hobbies: ONLY the COMPLETE 00 $ 62 archive on DVD &P +$7 P • Every issue individually archived, by month and year • Complete with index for each year • A must-have for everyone interested in electronics This remarkable collection of PDFs covers every issue of R & H, as it was known from the beginning (April 1939 – price sixpence!) right through to the final edition of R, TV & H in March 1965, before it disappeared forever with the change of name to Electronics Australia. For the first time ever, complete and in one handy DVD, every article and every issue is covered. If you're an old timer (or even young timer!) into vintage radio, it doesn't get much more vintage than this. If you're a student of history, this archive gives an extraordinary insight into the amazing breakthroughs made in radio and electronics technology following the war years. And speaking of the war years, R & H had some of the best propaganda imaginable! Even if you're just an electronics dabbler, there's something here to interest you. NB: Requires a computer with DVD reader to view – will not work on a standard audio/video DVD player the handy handy order order form form Use the on page 57 of this issue on page 81 of this issue. siliconchip.com.au June 2008 29 Run your own disco light show with the PT.1: By MAURO GRASSI DSP Musicolour This DSP Musicolour accepts audio input signals and drives coloured lights “in tune” with the music. Its four output channels respond to different audio frequency bands and the brightness of the lights is in direct proportion to the amplitude of the frequency components. A dot-matrix LED menu display is featured on the front panel and this also functions as a spectrum analyser or VU meter. I N PRESENTING THIS brand new project, we are reviving a name which became synonymous with party light shows in the 1970s and 1980s. Long time readers will be familiar with the “Musicolour” light shows which were presented in “Electronics Australia”, the last one being the Musicolour IV in the August 1981 issue. SILICON CHIP magazine followed the same theme with the Discolight project in the July & August 1988 issues and produced a 12V version called the 30 Silicon Chip “Lightshow” in the January & February 1998 issues. All of these projects were analog designs based on op amps and logic ICs. The audio was passed through different pass-band filters for each channel and the filtered outputs were used to drive either phase-controlled Triacs in the Musicolour and Discolight circuits or power Mosfets in switchmode in the case of the 12V Lightshow. The logic ICs were used in the Discolight and 12V Lightshow to produce the chaser modes, which were alternating patterns controlling the output channels in the absence of an audio input. These chaser modes meant that you could have pleasing lighting effects without any music. Two decades on from the Discolight we now present the brand new DSP Musicolour, a full digital design using DSP (digital signal processing). It is based on a single DSP microcontroller to produce a comprehensive list of features that were simply not possible siliconchip.com.au This photo and the photo on the facing page show the completed DSP Musicolour boards fitted to the case. The displays have been lit by temporarily powering the Display Board using an external DC supply. with previous analog designs. The DSP Musicolour operates from 230-240VAC or 115-120VAC mains (detecting the 50Hz or 60Hz mains frequency automatically) and drives four channels of incandescent lights. The total power output rating is 2400W for the 230-240VAC 10A version and 1600W for the 115-120VAC 15A version. For the 240VAC version, each channel is rated at 800W maximum (as long as total power is less than 2400W). For the 120V version, each channel is rated at 400W. By making the design suitable for both 230-240VAC and 115-120VAC 50/60Hz mains supplies, we are ensuring that the DSP Musicolour can be built in any part of the world without modifications, apart from changing the power transformer’s primary connections. Incidentally, since February 23rd 2000, Australia’s mains supply has been nominally 230VAC, with a normal range from -6% to +10%, ie, 216-253V (AS60038-2000). In practice though, supply authorities try to maintain the range at between 225V and 253V. Operating features Pictured in this article is the prototype DSP Musicolour without its front or rear panels. The photos show the quite complex vertical PC board which accommodates a 7x15 (rows siliconchip.com.au x columns) dot-matrix LED display, an array of illuminated pushbuttons and three potentiometers. By contrast, the main PC board is larger but not as packed with components. It carries the microcontroller and the 240VAC Triac circuitry. The pushbuttons are used to navigate through the menus which are displayed on the dot-matrix display. This display can also be switched to function as a spectrum analyser or as a VU meter, or can be used to display “screen saver” patterns. One potentiometer on the front panel is used to vary the screen brightness, screen refresh rate, the frequency band, the gain and the quiescent current of each output channel, among other settings. Another two potentiometers are used to independently control the input sensitivity of each channel. It is then possible to mix the two channels in software before processing the audio data or to select either channel independently as the audio input. The back panel carries an IEC male mains socket (with an inbuilt mains switch and fuse) plus four 3-pin 240VAC sockets for the four output channels (these are used to connect the lights). It also carries a 4-way speaker terminal block to accept two audio input channels, an optional connector for an external microphone and an optional 10-way IDC connector that can be used to update the firmware (more on this in a later article). Block diagram The block diagram of the DSP Musicolour is shown in Fig.1. As can be seen, there are three audio input channels. Two audio channels come from the 4-way speaker terminal block on the back panel while the third channel is for an onboard electret microphone or an optional external microphone. The two audio channels pass through the front panel potentiometers and are then fed into independent AC-coupled inverting amplifiers. The output of each amplifier is then fed to a dsPIC microcontroller at inputs AN1 & AN2 and are converted to digital signals by onboard ADCs (analog-todigital converters). Similarly, the microphone signal is fed to an AC-coupled inverting amplifier and the output again connected to the microcontroller, this time at AN3. Note that the optional third audio input for connecting an external microphone is mixed with the output of the onboard electret microphone. The two audio channels are independent and as mentioned earlier, have separate sensitivity controls. They can be optionally mixed in software in different proportions (selectable balance). So there are three distinct audio channels: the two audio channels and the microphone channel. June 2008 31 MAINS OUTLETS POTENTIOMETERS OPTO COUPLED PHASE CONTROL TRIAC 15 x 7 DOT MATRIX DISPLAY OP AMP AUDIO CHANNEL INPUTS AN1 OP AMP MIC INPUT AN2 AN3 ADC INPUTS dsPIC 30F4011 DSP MICRO CONTROLLER OP AMP OC1 OPTO COUPLED PHASE CONTROL TRIAC OC2 OC3 OC4 OPTO COUPLED PHASE CONTROL TRIAC INT0 ZERO CROSSING DETECTOR FROM TRANSFORMER SECONDARY OPTO COUPLED PHASE CONTROL TRIAC 7 x USER INPUT SWITCHES AND POTENTIOMETER ACTIVE NEUTRAL Fig.1: the block diagram of the DSP Musicolour. The audio inputs are digitised and processed using a dsPIC micro controller to produce control signals for four frequency bands. The dsPIC then phase controls four optocoupled Triac output stages to power the mains outlets. As stated previously, the audio channels are converted to digital format by onboard ADCs in the dsPIC microcontroller. These are each sampled at around 48kHz (slightly higher than double the highest audible frequency) in order to avoid aliasing. Next, the resulting digital time domain data is transformed to the frequency domain using an FFT (Fast Fourier Transform) algorithm. The result is a list of amplitudes for the frequency components of the audio input signal. The computed frequency amplitudes are then used to drive the four output channels via phase-controlled Triacs in the output stages. These Triacs are driven via optocouplers which ensure full mains isolation for the low voltage sections of the circuit. As may be apparent from the description so far, there are no op amp filters so the frequency bands for each channel are user-selectable. Furthermore, different arithmetic operations can be applied to the digitised audio data to amplify or attenuate it. This means that each input channel is effectively post-amplified in software. Moreover, the various input channels can be selected and mixed in software with different weighting. In previous designs, the switching was 32 Silicon Chip accomplished using a toggle switch. Providing the chaser modes is also much easier with a digital design. Again, it’s all done in the software and no extra circuitry is involved. Circuit operation Let’s now look in more detail at the circuit operation of the DSP Musicolour. Figs.2-4 show the full circuit details. It’s based on microcontroller IC1, a dsPIC30F4011 from Microchip. This combines most of the common peripherals of a PIC with a high-performance RISC (reduced instruction set computer) processing core that has instructions optimised for digital signal processing (DSP). The Microchip dsPIC series of microcontrollers incorporate DSP features like MAC (multiply accumulate), variable bit shifting, bit reversed addressing modes, dual data fetching (multiple operands), high-precision arithmetic operations (including fractional hardware divide and multiply) and multiple 40-bit accumulators. All DSP instructions are single cycle, meaning the dsPIC series is surprisingly powerful, with throughputs in the tens of MIPS (millions of instructions per second). In this design, IC1 runs off an internal system clock operating at about 29MHz. Among other things, it’s responsible for digitising the audio inputs, processing the audio inputs (including computing the FFT), synchronising with the mains frequency and implementing real-time phase control, driving the multiplexed LED display and responding to key presses. The operation of the software is explained in greater detail later in this article. The output stages of the DSP Musicolour are virtually identical to those in the Discolight but have been uprated using heavy-duty BTA41-600B Triacs. These are isolated-tab Triacs rated at 600V, with continuous current ratings of up to 40A and a surge current rating of close to 400A. This high surge-current rating is necessary in order for the Triacs to withstand the large fault currents which can occur if a 150W floodlight blows its filament. This is a particular problem if the floodlight is facing upwards. In that case, the broken filament can flail around and short to the adjacent filament support. The resulting arc continues until the stem fuse inside the lamp blows. In addition, the software programm siliconchip.com.au ed into the dsPIC has a facility to set the filament preheat current of each output channel. This helps minimise surge currents to protect the lamps. Note that the four Triacs, which are housed in TOP3 packages, are mounted in pairs on the main board and each pair share a heatsink. These heatsinks are necessary, as the Triacs will get hot during normal operation, even if each channel is only rated at 800W. Each Triac is triggered by the dsPIC via a MOC3021 optocoupler (OPTO1OPTO4), to ensure full mains isolation from the low voltage part of the circuit. As shown, IC1’s “output compare” pins (OC1-OC4) are used to drive the internal LEDs of the optocouplers which then switch on the Triacs until the next zero crossing of the mains waveform. Following the Triacs, each channel output has a filter network consisting of a 100mH inductor (rated at 5A) and a 0.1mF 250VAC capacitor, to reduce EMI. As can be seen, the mains Active is connected to the A2 terminal of each Triac and is switched through to the mains output sockets via the 100mH inductors – see Fig.3. The outputs are then fed to screw terminal blocks CON4 & CON5 on the main board. Audio inputs As shown in Figs.2 & 4, the two audio channels are fed in via pins 2 & 4 of CON2 and are attenuated by two 270W resistors. These resistors ensure proper attenuation of the incoming signals, which are derived from the loudspeaker outputs of an amplifier. From there, the signals are fed to pins 5 & 6 of connector CON1 and then to pins 5 & 6 of CON7 on the display board (CON1 & CON7 are connected via a 26-way flat-ribbon cable). The audio signals are then further attenuated using potentiometers VR1 & VR3 on the display board and fed back to pins 4 & 3 of CON1 on the main board. These pots set the input sensitivity for the audio channels. Link LK4 is optional and allows the two audio channels to be mixed together via the 270W input resistors. It’s normally left out of circuit. The outputs of VR1 & VR2 (at pins 3 & 4 of CON1) are AC-coupled to op amps IC2a & IC2d via 68nF capacitors and 33kW series resistors. These two op amps are wired in inverting mode and operate with a gain of 0.3 as set siliconchip.com.au Main Features • • Full digital design using a DSP microcontroller (dsPIC) • • Four phase-controlled output channels (8-bit resolution) • • • Zero voltage switching of Triacs for minimum RF interference • • • • • • • • Selectable filament preheat current for each output channel • • • Software-controlled input selection with software mixing Powered from 230-240VAC or 115-120VAC mains with auto-detection of mains frequency Optocoupled Triac triggering for complete isolation of control circuitry from output circuitry Four mains outputs rated at 800W each (240VAC) or 400W (120VAC) Selectable gain plus selectable minimum and maximum frequencies for each output channel Persistent software settings Self-diagnostics Chaser modes Direct stereo inputs for audio modulation of lights Microphone input/third channel input for audio modulation of lights 7x15 pixel dot-matrix LED display for menus Dot-matrix display can function as a spectrum analyser, screen saver or VU meter Adaptive potentiometer control for software settings Optional provision for ICSP (in-circuit serial programming) by their 10kW feedback resistors and 33kW input resistors (ie, 10kW/33kW = 0.3). Because the circuit operates from a single +5V supply rail, the noninverting inputs of IC2a, IC2d and IC2c (pins 3, 12 & 10 respectively) must all be biased to half supply (Vcc/2). This is achieved using op amp IC2b. Two 10kW resistors are wired as a voltage divider to derive a 2.5V reference and this is fed to pin 5 of IC2b which is connected as a voltage follower. IC2b’s pin 7 output then provides the Vcc/2 (ie, 2.5V) rail to bias the remaining op amps. IC2c is used to amplify the signal coming from the on-board electret microphone. It’s also wired as an inverting amplifier but operates with a gain of 30. As before, the signal is fed to the op amp via a 68nF capacitor and 3.3kW resistor. Power for the electret microphone is derived from the +5V rail via 1kW and 4.7kW resistors, while a 47mF capacitor filters this supply. In addition, the signal from an external microphone can be fed to IC2c via pin 3 of CON2. In that case, the signals from the two microphones will be mixed and applied to IC2c. The outputs of op amps IC2a, IC2d & IC2c are connected to the ADC inputs of microcontroller IC1 (AN1, AN2 & AN3). Another ADC channel (AN0) is used to read the value of potentiometer VR3 which is also on the display board. This 10kW linear potentiometer is used to change settings. Resetting the micro Each time power is applied to the circuit, the MCLR-bar (reset) input of IC1 is pulled high (ie, towards the +5V rail) via diode D8 and a 1kW resistor. This releases the reset on the dsPIC30F4011 so that it can start operating. Note that pulling the MCLR-bar input low resets the microcontroller but this is not used in this circuit. Instead, an internal POR (power on reset) circuit resets the microcontroller when power is first applied. Diode D8 is included because the MCLR-bar line connects to 10-way IDC connector CON3. This connector is optional and is included to allow ICSP (in circuit serial programming). June 2008 33 CON1 +5V 11 13 100nF 14 40 100nF AVdd 15 16 CN 28 17 SER 38 19 CK2 21 G 23 CK1 26 S7 24 S6 22 S5 20 S4 18 S3 10 S1 8 S2 12 AN0 V12 3 V22 6 V13 5 V23 68nF 3 1k MCLR RF6 PGC PGD RF0 RF1 270 1W 26 25 30 29 12 IC2a 5 1 AN3 OC3 4 OC1 AN2 OC2 RE4 IC2d RE5 14 22 19 23 18 34 33 A LED8 4 R AUDIO 68nF 3 MIC 5 K 1k 1 3.3k 47 F 16V 4.7k 100k 3 470 AN1 9 68nF ELECTRET MIC LK6* 1k 13 2 L AUDIO 24 IC1 dsPIC30F4011 10k 33k 270 1W 1 LK5* OC4 68nF 1 D8 K 10k 33k LK4* 2 A 32 Vdd CN17 2 25 CON2 21 Vdd SFR 37 RE1 36 RE2 35 RE3 15 RC13 14 RC15 10 RB8 9 RB7 8 RB6 6 RB4 7 RB5 2 AN0 9 4 11 Vdd 10 IC2c INT0 8 AVss 39 + Vss 12 Vss 17 1k Vss 20 31 +5V 100nF 10k 5 10k 47 F 16V 6 * NOTE: IN THE DEFAULT CONFIGURATION, LK4 AND LK6 ARE OMITTED AND LK5 IS INSTALLED 4 IC2b 7 +2.5V D8 -D10: 1N4148 11 A K D11-D14: 1N4004 SC 2008 DSP MUSICOLOUR MAIN BOARD A LM317T K OUT ADJ OUT IN Fig.2: the Main Board circuit. Microcontroller IC1 accepts audio inputs from op amps IC2a, IC2d & IC2c, processes the signal and drives the four Triac output stages via optocouplers OPTO1-OPTO4. It also drives the Display Board via CON1 and processes the inputs from the various controls on this board. Since the MCLR-bar pin is multiplexed with the programming voltage (Vpp) for ICSP and because the typical level used is around +13V (much higher than +5V), D8 is reverse biased during 34 Silicon Chip ICSP and thus protects the circuit from over-voltage. LED8 is used as a “normal function” indicator for the microcontroller and is normally lit. It may also be used by future software versions to indicate runtime errors in the program. The 470W resistor limits the LED current to about 10mA. Note that this LED is mounted on the main board and is not siliconchip.com.au 680 6 1 OPTO2 MOC3021 +5V 2 CON3 5 A2 G 4 A1 TRIAC3 BTA41-600B 100nF 250VAC CON4 220 100 H 1 9 680 2 10 6 1 6 OPTO4 MOC3021 7 8 2 3 A2 TRIAC4 BTA41-600B G 4 100nF 250VAC A1 220 4 100 H 680 6 1 OPTO1 MOC3021 A2 TRIAC1 BTA41-600B 2 G 4 100nF 250VAC A1 CON5 220 100 H 680 6 1 OPTO3 MOC3021 A2 TRIAC2 BTA41-600B 2 G 4 100nF 250VAC A1 220 100 H 270 1W NOTE: ALL WIRING AND PARTS IN THIS SHADED AREA OPERATE AT MAINS POTENTIAL. CONTACT COULD BE FATAL! K D10 A 5.6nF D11– D14 A D9 A K OUT K IN ADJ 100 470 F 120V 7.5V REG1 LM317T +5V T1 K 4700 F 16V A K A A K 0V 0V LK1 LK2 LK3 FOR 240V, FIT LK2 ONLY FOR 120V FIT LK1 AND LK3 ONLY 120V 7.5V 0V 0V 100 1 F 16V LED8 30VA CON6 100 N BTA41-600B 100 FUSED MALE IEC SOCKET WITH SWITCH K A A1 visible with the case lid on. LK5 & LK6 are used to set IC1 so that it operates according to the audio input mode set using LK4 (more on this in a future article). The default siliconchip.com.au A A2 G * FUSE F1 RATING: 10A FOR 240V, 15A FOR 120V configuration is to omit LK4 & LK6 and install LK5. Display board circuit Now let’s take a look at the display F1* MAINS IN E board circuit (Fig.5). It’s based on three 74HC595 shift registers (IC3-IC5) which are used to drive the 7x15 dotmatrix LED display in multiplexed fashion. This display is actually made June 2008 35 CON4 MAINS OUTPUT SOCKETS A N E N A E CON5 N A E N A E MAINS EARTH MAINS NEUTRAL Fig.3: the switched Active lines from CON4 & CON5 are connected to the mains outlet sockets as shown here. up using three separate 7x5 dot-matrix red LED modules (Kingbright TA1211EWA, distributed by Tenrod). IC3 & IC4 are cascaded to form a combined 16-bit shift register. This is controlled by the CK2 (clock), G-bar (enable) and SER (data) lines coming from microcontroller IC1. By using these three lines, any 16-bit value can be loaded into the shift register. In operation, the 16-bit shift register drives the 15 columns (ie, the anodes) of the 7x15 dot matrix display. The remaining column output, at pin 7 of IC4, is used to drive transistors Q16-Q22. These in turn drive LEDs1-7 which are inside the tactile switches (S1-S7). In greater detail, the first 15 bits of the combined shift register drive PNP transistors Q1-Q15 (all BC327s) via 470W resistors. These transistors are necessary to provide the high currents required to obtain a display that is bright enough. Because the display LEFT AMPLIFIER OUTPUT RIGHT AMPLIFIER OUTPUT + – is multiplexed, each LED is only switched on very briefly and therefore must be driven quite hard. Note that there are no series resistors to limit the current. That’s because the switching occurs very briefly and this limits the currents and protects the display modules. In addition, the cathodes are driven by a ULN2003 Darlington array (IC6) and this also limits the total peak currents. The Darlington transistors inside IC6 are driven by the remaining shift register (IC5). This is controlled in a similar way to the 16-bit register and is clocked using the CK1 (clock) line from the microcontroller. The G-bar (enable) and SER (data) lines are shared with the other two shift register ICs. Using a separate clock ensures that IC5 can be controlled independently of the two cascaded shift registers. IC5 thus functions as an independent 8-bit shift register and is used to drive the seven rows (R0-R6) of the dot matrix display via IC6. The extra bit is not used. The seven rows of the display are all cathodes and the ULN2003 (IC6) is necessary to provide the required current drive. In operation, this device can sink up to 500mA for each of its seven outputs. It’s also used to drive the “extra” row formed by the seven LEDs inside the tactile switches (LED1-LED7) – ie, IC6 drives the cathodes of LEDs1-7, while pin 7 of IC4 switches their anodes. During the display update period, the microcontroller sends the G-bar (enable) line high and this forces all the shift register outputs to also go high. This effectively blanks the display but this blanking interval is so short that it is imperceptible. The SER (data) line feeds the data from the microcontroller into the shift registers during this blanking period. Note that because the display is multiplexed, the microcontroller can control the 7x15 dot-matrix display CON2 2 + 4 – 3 OPTIONAL EXTERNAL MIC INPUT 36 Silicon Chip 5 1 Fig.4: the left & right audio input signals are derived from the speaker terminals of an amplifier and fed in via connector CON2. The external microphone input is optional. and LEDs1-7 using just four digital outputs, ie, CK1, CK2, G-bar & SER. Switches S1-S7 are all pushbutton momentary-contact types. These switches are used to change the operating modes and drive the menus (more on this next month). In practice, each switch is connected to a separate microcontroller input (via CON1 & CON7) and these seven inputs are all normally pulled high (ie, to +5V) by 1kW resistors. The other side of each switch is connected to ground and the switch contacts are debounced by the software. Diodes D1-D7 and their associated 1kW pull-up resistor form a 7-input AND gate. Its output (at the anodes) connects to the CN17 (pin 28) input of the microcontroller. This input is used to trigger an interrupt when it changes state and is used by the software to respond to switch presses. Power supply Now let’s go back to Fig.2 and describe the power supply. As shown, power for the low-voltage side of the circuit is derived using a 30VA mains transformer with dual primary and secondary windings. The two primary windings are either connected in series or in parallel, depending on the mains voltage (either 240VAC or 120VAC, respectively). For a 240V AC supply, LK2 is fitted to connect the primary windings in series. Alternatively, for a 120VAC mains supply, LK1 & LK3 are fitted to connect the windings in parallel. The selected links are soldered to the main PC board, before the transformer is installed. The incoming mains voltage is fed in by a fused male IEC socket. For 230-240VAC mains, this fuse should be rated at 10A while for 115-120V mains, it should be rated at 15A. The two 7.5VAC secondary windings are connected in parallel and feed a bridge rectifier comprised of diodes D11-D14 which are standard 1N4004 types. The rectified output of the bridge is then filtered using a 4700mF capacitor and fed to an LM317T variable-voltage regulator (REG1) to derive a regulated +5V rail. This +5V rail is used to power the low-voltage section of the circuit, including the op amps, the microcontroller and all the display circuitry. An LM317T was used instead of the common 7805 +5V fixed regulator siliconchip.com.au CON7 Q1 +5V 11,13,14 9,12 AN0 100nF VR3 10 16 Vdd Q0 Q1 Q2 Q3 MR 1F 16V 17 SER 14 19 CK2 12 Sin 47F 16V 100nF B B B C Q9 +5V E Q15 E B C E B C C 1 2 3 4 IC3 Q4 74HC595 5 10 12 11 G 13 1k 7 x 470 R6 R5 R4 R3 R2 R1 R0 +5V 9 100nF 16 Vdd Q0 Q1 Q2 Q3 MR 14 12 11 13 Sin 16 1 10 15 1 2 3 3 IC5 Q4 4 74HC595 5 4 Q5 6 Q6 7 Q7 9 So LCK SRCK OE 15 2 LED ARRAY 1 VR1 LED ARRAY 3 +5V 470 13 12 5 B B IC6: ULN2003 B B B LED4 K Q22 E B C A E B C A LED3 K 470 Q21 E C A 470 Q20 E C A LED2 K 470 Q19 E C A LED1 K 470 Q18 E C A 10 7 470 Q17 E 11 6 470 Q16 6 V13 4 V12 LED ARRAY 2 14 Vss 8 C14 14 21 16 Vdd 15 Q0 1 Q1 2 Q2 3 Q3 Sin IC4 Q4 4 74HC595 5 Q5 6 LCK Q6 7 Q7 SRCK 9 So OE Vss 8 MR 8 C7 Vss C8 SRCK OE C1 11 C0 Q5 6 Q6 7 Q7 9 So LCK 13 23 CK1 Q8 E C 8 x 470 15 Q2 E LED5 K C A LED6 K LED7 K 8 2 V11 5 V23 3 V22 1 V21 15,16 10 8 18 20 22 24 26 1k VR2 LED1 INSIDE S1, ETC CN A A D1 K S1 S2 S3 A A K K A D4 D3 D2 K A K A K K S4 S5 S6 S7 7 x 1k 25 D1 – D7: 1N4148 A SC 2008 D7 D6 D5 DSP MUSICOLOUR S1 S2 S3 S4 S5 S6 S7 K B DISPLAY BOARD E C Q1 – Q22: BC327 Fig.5: the Display Board circuit uses three 74HC595 shift registers (IC3-IC5) to drive the dot-matrix LED displays and the LEDs inside the switches in multiplexed fashion. These shift registers are driven by the dsPIC microcontroller via CON7 using just four digital outputs. Switches S1-S7 select the various operating and display modes. siliconchip.com.au June 2008 37 Note: all the parts on the heatsink side of the Main Board operate at mains potential (ie, 240VAC). Contact could be lethal – see Fig.2 & warning panel! because it can supply greater current (up to 1.5A). The four 100W resistors set the output voltage from the regulator according to the formula: VOUT = 1.25 x (1 + R2/R1) where R1 is the resistance between the OUT & ADJ terminals and R2 is the resistance between the ADJ terminal and ground. In this case, R1 = 100W and R2 = 300W, so VOUT = 1.25 x (1 + 300/100) = 5V In practice, slight manufacturing variations mean that the 1.25 factor How The Software Works The software is responsible for most of the Musicolour’s functions and uses various interrupts to accomplish time critical tasks. For example, the multiplexed LED display is driven by the microcontroller using a periodic interrupt based on an internal timer. This allows the display refresh rate to be set by the software. Each time the timer expires, an interrupt occurs and display data is sent to the display driving hardware. The display is “multiplexed”, meaning that only one column of seven LEDs is lit at any one time. The seven LEDs inside the tactile switches effectively form the 16th column of the display. The “dead 38 Silicon Chip time” between screen refreshes can also be programmed and this effectively controls the perceived brightness of the display. Pressing any of the seven tactile switches (S1-S7) also triggers an interrupt. The software then debounces the switch and adds the key press to an internal queue implemented as a FIFO (first in, first out). This ensures that there are no missed key presses due to software latencies. Digitising the audio The microcontroller is also responsible for digitising the four analog input channels. Three of these are audio inputs can be anywhere between 1.2 and 1.3. Because of this, the PC board has been designed so that there are three resistors in series between ADJ and GND terminals. This allows REG1’s output to be fine-tuned by changing one or more resistor values, to obtain a supply rail that’s very close to +5V. Note, however, that this fine-tuning will not be necessary unless you plan to use the optional 10-way header (CON3) for in-circuit programming coming from the op amp circuits, while the fourth is used to read the setting of potentiometer VR3. This latter value is used to change various settings, according to the menu selected. Note that when changing a value with this potentiometer, the value will only begin to change when the potentio meter’s setting matches the current value of the setting that’s being changed. This gives the potentiometer a kind of “memory”. The analog-to-digital conversion of the four input channels is automatically handled by the ADC subsystem within the microcontroller (IC1). Each channel is sampled at around 48kHz. Most of the data produced is ignored and only one audio stream (or a mixed stream) is actually stored in an internal buffer. An interrupt is generated when- siliconchip.com.au These photos show the assembled Main Board and Display Board modules. The construction details are in next month’s issue (note: boards are shown slightly smaller than actual size). (and then only if the output voltage isn’t close to +5V). Zero-crossing detection As well as driving the bridge rectifier, one side of the transformer’s secondary winding is also fed to pin 17 of IC1 via 270W and 1kW resistors. Diodes D9 & D10 clip the positive and negative excursions of this AC signal to +5.6V and -0.6V respectively, to prevent damage to the microcontroller’s INT0 input. In addition, the signal is bypassed using a 5.6nF capacitor to filter any noise on the line. This capacitor changes the phase of the signal slightly but this effect is corrected by the software. ever the internal ADC system buffer (16 bytes) is full. The firmware then stores only the relevant channel data in an internal buffer. This happens after any mixing, amplifying or averaging is performed on the audio data. The FFT (Fast Fourier Transform) is computed in real time without loss of samples. This is accomplished by the software using double buffering. While the FFT is being computed on the data stored in an internal buffer, another internal buffer is being filled by the interrupt servicing the ADC subsystem. When the FFT is finished on the active buffer, it is then computed on the other buffer. In this manner, the two buffers are alternately filled and then processed by the FFT. Note that the microcontroller runs at close to 30MIPs using its internal clock siliconchip.com.au In operation, the microcontroller uses the clipped AC signal to detect the zero crossings of the mains waveform. This is necessary in order to correctly drive the Triacs using phase control and to minimise the interference caused by the Triacs switching the mains. Basically, the INT0 (pin 17) input of the microcontroller functions as an edge-triggered external interrupt source. This is used by the software to phase control the four output channels. That’s all we have space for this month. Next month, we’ll describe the assembly of the PC boards and the SC internal wiring. source. This is fast enough to compute the FFT on the audio channels without loss of samples. Phase control The frequency domain data output by the FFT is used to drive the Triacs using phase control. For each output channel, an 8-bit brightness level is computed from the frequency domain data, depending on the settings for its frequency band. An interrupt is used to detect the zero crossings of the mains waveform. When the zero crossing is detected, the microcontroller sets the triggering period for each of the four “output compare” (OC1-OC4) channels. When each period expires, the microcontroller emits a short pulse at each output compare pin. These OC pulses turn on their cor- Warning! All the parts in the red shaded area on the Main Board circuit diagram (Fig.2) operate at mains potential (ie, 240VAC) and contact with any of these parts could be FATAL. These parts include the PC tracks, the optocouplers (OPTO1-4), the Triacs, the 100m 100mH inductors, the 680W 680 W resistors, the 100nF 250VAC capacitors, screw terminal blocks CON4-CON6, the transformer primary and the wiring to the mains input and output sockets. DO NOT TOUCH any of these parts unless the power cord is unplugged from the mains supply. DO NOT CONNECT this device to the mains unless it is fully enclosed in the specified case. This project is not for the inexperienced. Do not build it unless you know exactly what you are doing and are completely familiar with mains wiring practices and construction techniques. responding Triacs until the next zero crossing of the mains waveform. The earlier in the half-cycle that each Triac is triggered, the greater the power delivered to its load. The effective power varies according to the area under the mains waveform from the trigger point in each half cycle. This relationship is not linear and so an internal correction factor is calculated by the microcontroller to make the channel responses linear. The microcontroller also adjusts the triggering periods of the output channels according to their quiescent current settings (ie, the user can set the “off” level for each output channel). Most lamps will respond better with a small current flowing through them at all times, so that they glow faintly in the “off” state. This will also increase lamp life. June 2008 39 A new PIC-based Flexitimer Mk.4 Uses jumpers to set the timing periods H One-shot or continuous on/ off cycling H Independent on/off periods ranging from 1s to over three days. H By JIM ROWE Here’s a new and enhanced version of a very popular project: an easily-programmed lowcost electronic timer module. It’s compact, easy to build and offers a choice of either a single on period or continuous on/off cycling with independently programmable periods. I N THE MARCH 1991 issue of “Electronics Australia”, Rob Evans presented the design for a “cheap and cheerful” electronic timer module called the “Flexitimer”. It could be programmed using a set of wire links and also by changing the value of the timing oscillator components, over a range from a few seconds to approximately one day. It could also be set for either one-shot or continuous on-off cycling, although the on and off times were always the same. This simple, low-cost circuit offered a great deal of timing flexibility and as a result, it became extremely popular. An updated design was published a few years later and the parts retailers sold kits of both this and the original version for many years. It was partly because of the popular40 Silicon Chip ity of the original Flexitimer that we subsequently developed the Programmable Flexitimer, described in the August 2005 issue of SILICON CHIP. It was based on a PIC16F84A micro controller and was programmed rather like a microwave oven, using a set of pushbuttons and a small LCD screen. It worked well but in many ways it was “overkill”. It was rather expensive and as a result, it hasn’t been anywhere near as popular as the original Flexitimer. Despite that, it’s clear that many people still want a timer module that’s low in cost and just as easy to program as the original Flexitimer but which offers even more flexibility. For example, many people want independently programmable on and off times, as well as a considerably wider range of programmable times for each. This new Flexitimer Mk.4 fills the bill. Like the original, it’s cheap and easy to build but this new unit offers 54 independently programmable on and off time periods. These periods range from one second up to to 90 hours (or 3.75 days!) and are easily programmed using jumper links. In addition, the unit can operate in either of two timing modes – one-shot or continuous on/off cycling. Circuit details Fig.1 shows the circuit details of the Flexitimer Mk.4. As you can see, the hardware is very simple. That’s because all the timing “work” is done by a firmware program running inside IC1, a low-cost PIC16F628A microcontroller. The on and off timing periods are set by jumper shunts fitted to headers LK1-LK6, while the timing mode (one-shot or continuous on/off cycling) is set via another jumper shunt that’s either fitted to or left off LK7. The firmware in IC1 reads the status of all of these links when it starts following power-up (or is reset after switch S1 is pressed). It then uses these settings to determine the timing. siliconchip.com.au LK4: ON TIME x1/x10 LK6: OFF TIME x1/x10 LK3 A K 8 h 9 6 s 11 5 LK4 m 3 s 2 LK5 8 4 h OFF TIME s/m/h 12 D3 13 6 LK1 ON TIME D5 K A A K D4 A 1 18 K A D2 A K 14 Vdd RA4 K 17 K IN GND 100nF A + 12V DC INPUT – 470 F 16V 2.2k 22k LED RB4 K RA7 RB3 16 A 1-SHOT /CONT RB5 LED1 LK7 RB6 MCLR K RB2 A RLY1 K D7 A 1k 4 IC1 7 RB1 PIC16F628A 1 LK6 3 10 7 m OUT D6 OFF TIME LK2 ON TIME s/m/h D8 REG1 78L05 2.2k NC1 COM1 NO1 NC2 RESET 10nF S1 RB7 COM2 NO2 RB0 RA3 RA2 CLK 15 OUT RA1 10k 2 C B E TP1 Q1 PN100 B TPG RA0 C Vss 5 D1 PN100 E 78L05 SC 2008 D7,D8: 1N4004 D1–D6: 1N4148 FLEXITIMER MK4 A K A K COM IN OUT Fig.1: the circuit is based on PIC microcontroller IC1 and this drives relay RLY1 via transistor Q1. Links LK1-LK6 program the on and off times, while link LK7 sets the timing mode (either continuous or one-shot). In operation, the PIC16F628A runs from an on-chip clock oscillator which is calibrated at the factory to have a frequency of 4MHz ±1%. As a result, this is also the timing accuracy of the Flexitimer Mk.4 (ie, ±1%), which should be close enough for the vast majority of timing applications. During its “on” timing periods, IC1 provides a logic high signal at pin 2 (RA3) which is used to turn on transistor Q1. Q1 in turn activates relay RLY1, to switch the control outputs. At the same time, LED1 turns on to indicate that the timer is currently in a “relay ON” period. Diode D7 protects Q1 from damage due to inductive transients when RLY1 is switched off, while D1-D6 are used to allow the firmware in IC1 to read links LK1-LK6 via a multiplexing routine. Relay RLY1 and LED1 operate directly from the 12V DC input to the module, via polarity protection diode D8. By contrast, IC1 requires a supply voltage of +5V and this is derived from the +12V line via a 78L05 regulator (REG1). The incoming supply to REG1 siliconchip.com.au is filtered using a 470mF electrolytic capacitor, while a 100nF capacitor filters any noise on the +5V rail. Construction All the parts used in the Flexitimer Mk.4 module fit on a small doublesided PC board coded EC8284 and measuring 42 x 102mm. Fig.2 shows the parts layout. As you can see, the timing circuitry and programming links are on the lower half of the board while the relay and its driver transistor (Q1) are on the upper half, along with REG1, the DC input connector and the output terminal blocks for the relay contacts. The assembly is straightforward but here’s a suggested order of assembly: (1) Fit the five resistors, followed by the three capacitors. Note that the 10nF MKT capacitor goes at lower Main Features & Specifications • Operates from nominal 12V DC, with low current drain: <50mA when relay is on, <5mA when relay is off. Relay status indicated via a red LED. • Outputs via the contacts of a DPDT relay (ie, 2x normally closed, 2x normally open), with 5A contact rating. • Jumper link selection for either a single ON timing period or continuous ON/OFF cycling. • Relay ON and OFF times separately programmed via jumper links for any of 54 different time periods; ie, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90 seconds, minutes or hours. • • • Timing accuracy is ±1% at all settings. Timer may be restarted at any time by pressing a reset pushbutton. Module fits inside a standard UB3 utility box. June 2008 41 (8) Install pushbutton switch S1 and relay RLY1. Take care with the orientation of the switch – it must be installed with its flat side to the left, as shown in Fig.2. (9) Complete the assembly by plugging microcontroller IC1 into its socket. Be sure to align its notched end with the notch in the socket – see Fig.2. Setting the jumpers With the board assembly completed, you now have to set the various jumpers to program the timer. As explained previously, these jumpers set the timing mode and the timing period (or periods) you want. The easiest way to do this is by referring to the Jumper Settings Table. The first jumper to set is LK7, which controls the timer’s operating mode. If you fit a jumper shunt across LK7, the timer will operate in continuous on/off mode, ie, it will activate the relay for whatever ON time you program, then turn it off for whatever OFF time you program, then turn it on again for the programmed ON time and so on. In other words, the relay will continuously toggle according to the programmed ON and OFF times. Conversely, if you leave LK7 without a jumper shunt, the Flexitimer will operate in one-shot mode. This means that the relay will be turned on for the Fig.2: install the parts on the PC board as shown in this overlay diagram and the accompanying photos. Table 2 shows how to set the various links, to program the timing periods and select the operating mode. right, while the 100nF multilayer monolithic goes on the left just below IC1. The 470mF electrolytic is at upper left, with its positive lead towards the bottom edge of the board. (2) Fit diodes D1-D6, followed by D7 and D8. Be sure to orientate each diode correctly. (3). Install an 18-pin DIL socket for IC1, taking care to orientate it with its “notch” end towards the bottom edge of the board. (4) Fit the three 8x2 DIL header strips to the board (for LK1, LK2 & LK3-LK6). These may need to be cut from longer strips using a sharp hobby knife. Then install the remaining 1x2 header at lower left for LK7. (5) Fit two PC board terminal pins to the board in the positions marked TP1 and TPG. (6) Install REG1, Q1 and LED1, again taking care with their orientation. Note that the boards supplied with the Jaycar kits will have multi-way pad “footprints” for REG1 and Q1, allowing you to mount these devices with their leads unsplayed if that’s how they are supplied. However, take care to avoid solder bridges when soldering the leads, as some of these pads are very close together (splay the device leads if you prefer). (7) Fit the DC input connector (CON1) to the upper left of the board, then clip the two 3-way screw terminal blocks together and fit them in the adjacent position. Table 1: Resistor Colour Codes o o o o o No. 1 1 2 1 42 Silicon Chip Value 22kW 10kW 2.2kW 1kW 4-Band Code (1%) red red orange brown brown black orange brown red red red brown brown black red brown 5-Band Code (1%) red red black red brown brown black black red brown red red black brown brown brown black black brown brown siliconchip.com.au Parts List Table 2: Flexitimer Jumper Settings Table RELAY OFF PERIOD RELAY ON PERIOD Time LK1 jumper positions 1 2 3 4 5 6 7 8 1 2 1 1 3 5 8 9 8 7 7 6 7 6 5 6 5 4 4 3 4 2 2 3 LK2 jumper positions Time 8 9 On Time Units & Mult LK4 & LK3 jumper positions LK4 (x10) Seconds Seconds x 10 LK3a (s) Seconds x 10 Minutes Minutes x 10 Timer Operating Mode (LK7) programmed ON time and will then be turned off again and remain off. Having set LK7, you then set LK1, LK3 & LK4 for the required relay ON time. As shown in Table 2, the basic ON timing period is set by a jumper for LK1, while the units (seconds, minutes or hours) are set by a jumper for LK3 and the multiplier (x1/x10) by a jumper for LK4. It’s all quite intuitive but note that to program LK1 for a time period of nine units, no jumper is fitted to any of the eight possible positions. To illustrate this by an example, the timer is programmed for an ON period of 90 seconds as follows: no jumper on any of the LK1 positions, a jumper on the first LK3 position (LK3a = seconds) and a jumper on LK4 (= x10). Get the idea? If no jumper shunt is fitted to LK7 to select the one-shot operating mode, there’s no need to fit jumpers for LK2, LK5 or LK6 because the OFF timing period won’t be used. Conversely, if a jumper is fitted across LK7 for continuous mode timing, you will have to set the LK2, LK5 & LK6 jumpers for the desired relay OFF period. siliconchip.com.au Off Time Units & Mult Seconds Hours Hours x 10 LK3c (h) Minutes Minutes x 10 LK3b (m) LK6 & LK5 jumper positions LK6 (x10) LK5a (s) LK5c (h) Hours Hours x 10 LK5b (m) Jumper In: Continuous On/Off Timing Jumper Out: One Timing Period (Relay On) These are set the same way as LK1, LK3 & LK4. So for a relay OFF period of, for example, 40 minutes, you’d fit a jumper in the ‘4’ position for LK2, and also jumpers in the LK5b (minutes) and LK6 (x10) positions. Checkout time To check out your Flexitimer Mk.4 for the first time, try setting it up with the jumpers for one-shot mode (ie, no jumper for LK7) and 60 seconds of ON time, ie, jumpers on the ‘6’ position of LK1, on the LK3a position and on LK4. That done, apply 12V DC to the Flexitimer. LED1 and the relay should immediately turn on and remain on for very close to 60 seconds. They should then turn off and stay off indefinitely, unless you press the RESET pushbutton (S1). If the RESET button is pressed, they should immediately be turned on for another 60 seconds before they go off again. If this all works as expected, your Flexitimer is very likely to be working correctly and should now be ready for use. However, just to make sure, try setting it up for continuous mode by 1 PC board, code EC8284, 42 x 102mm 1 DPDT 12V relay (Jaycar SY4052) 1 PC-mount SPST pushbutton switch, red, (Jaycar SP-0720) 2 3-way PC-mount screw terminal blocks, 5.08mm or 5mm pitch 2 20x2 DIL jumper strips 7 jumper shunts 1 2.5mm PC-mount DC socket 1 18-pin DIL IC socket 2 PC board terminal pins Semiconductors 1 PIC16F628A microcontroller programmed with Flextime4. hex 1 78L05 regulator (REG1) 1 PN100 NPN transistor (Q1) 1 5mm LED (LED1) 6 1N4148 diodes (D1-D6) 2 1N4004 diodes (D7-D8) Capacitors 1 470mF 16V RB electrolytic 1 100nF multilayer ceramic (code 100n or 104) 1 10nF MKT polyester (code 10n or 103) Resistors (0.25W 1%) 1 22kW 2 2.2kW 1 10kW 1 1kW Where To Buy A Kit This project was developed by Jaycar Electronics and they own the copyright on the PC board. Kits will be available exclusively from Jaycar retail outlets and dealers (Cat. KC-5464). fitting LK7 with a jumper shunt and programming in an OFF period of, say, two minutes, ie, a jumper in the “2” position of LK2, a jumper across LK5b and no jumper on LK6. Now press S1 again. This should initiate a continuous sequence whereby LED1 and the relay are ON for 60 seconds, OFF for two minutes, ON for another 60 seconds, OFF for another two minutes, and so on. If it doesn’t work, check the frequency at TP1 using a scope or frequency meter. You should get a reading that’s very close to 1MHz. If not, check the soldered joints on the microconSC troller’s socket. June 2008 43 SERVICEMAN'S LOG Honey, I wrecked the iMac Despite doing my best to avoid computers, I recently became involved with a couple of Apple iMacs. The first was a friend’s iMac G5 which had quite a nasty accident, apparently due to his impatient clumsiness. A friend of mine had a “little” accident with his newish 20-inch iMac G5. As well as the G5, his computer room had a 20-inch Sony monitor precariously propped up on his desk and while he was reaching over and plugging in a lead at the back, it slowly tumbled forward. As it did so, it nudged the iMac G5 so that, like a chain of dominos, it too tumbled over onto its front. It came to rest with its LCD screen hitting the edge of the keyboard and the heavy Sony monitor then landing on top of it. The Sony monitor then continued on its way, all the way to the floor. By all accounts, my friend’s initial reaction was a stunned silence. The rest is best left to your imagination. Let’s just say that those in the immediate vicinity were made well aware of his profound unhappiness. The iMac was off at the time and an initial quick survey of the damage revealed nothing wrong. Unfortunately, it was quite a different story when it booted up, the LCD screen displaying a conglomeration of crazy lines and black blobs from where the crystalline structure had broken underneath. Well, there was nothing for it – the LCD panel was beyond repair and so it had to be replaced. However, my friend didn’t want to spend the necessary money (about $1000 plus fitting) at an accredited Mac Service Centre and so I was asked to investigate to see what could be done. The first thing I had to do was find out what the part number was for this panel but first I had to establish which iMac G5 we had here. There are heaps of numbers all over the base of the computer and in the “About This Computer” box. In fact, there are about seven 20-inch iMac G5 models but with the aid of the serial number, I determined from the internet that this was a fourth generation “early 2006 2.0GHz Intel Core Duo with iSight”, Model No. MA200LL EMC2105 M9845X/ A A1174. Fig.1: despite the fall, the computer inside the damaged iMac G5 still worked normally, as this video grab of the signal going to the LCD panel reveals. 44 Silicon Chip Items Covered This Month • iMac G5 MA200LL EMC2105 M9845X/A computer • iMac G3 M5521 CRT com puter • Philips 26PF9956/75 LCD TV set (LC 4.2A chassis) • LG Flatron LCD TV (Model L173SAB) • Philips 29PT2162/79R TV (L01.1A chassis) • TCL Electronic Icemaker TIF15S. • Menumaster UC14E industrial microwave oven Unfortunately, I couldn’t find any information on the part number of the display panel. That meant that it had to be removed so that I could see what was written on it. You may recall that I wrote about my son’s 20-inch iMac some months ago. His was an M9250X/A EMC2008 1.8GHz first-generation (A1076) machine, so I thought I would pretty much be an expert on these. Well, I was wrong. Both computers look almost identical but when it came to disas- Fig.2: it was a different matter with the LCD panel itself, though. This picture, taken with a digital camera, clearly shows the cracks in the panel’s crystalline structure. siliconchip.com.au sembling my friend’s machine, it was an entirely different ballgame. The cabinet has six screws holding it together along the underneath edge, four Torx and two Phillips. On the original iMac, the back and stand come off from the rear. However, this model is the opposite and opens up from the front. This must be done with great caution, so as not to snare the two plastic arms of the memory case. You also have to be sure to release the two metal hooks on the top inside lefthand and righthand sides, as well as the leads going to the camera and microphone. Once the front mask has been removed, you have access to the display which is taped into the case. You have to first pull back the metal foil and tape at the bottom to reveal the computer motherboard and the plug that connects the display to it. This has to have two miniature Torx screws removed before being unplugged. Next, you have to remove four Torx screws from the corners of the panel. These are difficult to find in amongst the dark recesses, with the tape and case needing to be held back with the third hand you’ve grown especially for the occasion. Hopefully, you’ve also grown a fourth hand because this is necessary to hold a torch so that you can see what you are doing. Once the LCD panel is “loose” (actually it isn’t loose, as the cabinet is so tight), you have to prise it out from the righthand side. This requires a great deal of caution because the back lights are still attached via four plugs to the inverter power supply. Finally, with it all unplugged and on its back, I discovered that the panel was a 20.1-inch Samsung TFT LTM201M1-L01. However, there appeared to be no part number. I trawled the web and eventually found four Mac part numbers but couldn’t tie them directly to this display. It wasn’t until I spoke to a friendly Mac technician that I discovered that the significant set of numbers of the nine I found written on the display was UJ6061JPU0XA which in turn equates to Apple Part Number 661-3895. Further research revealed that this panel could be had for $US899.25 or £595 (British pounds), plus freight and tax – not far off the Australian price of about $1000 plus fitting. There had to be another way and I found other siliconchip.com.au manufacturer’s displays were available from $129.99. The only problem was, every time we placed an order, they were out of stock and the price subsequently doubled. Still, we are hanging in there and hoping to find a secondhand one sooner or later. We are not sure whether an LG, Philips or Toshiba LTM201M1-L01 panel are directly interchangeable but are prepared to give it a try. In addition, the Samsung 20.1-inch display must be used in a lot of different computers and TVs, so we’re hoping one will pop up soon. In the meantime, my mate is using his spare iMac via a mini-DVI lead to the Sony monitor – the same one that fell 1.5 metres to the floor. Amazingly, it still worked. It crushed the corner of his computer desk on the way down but the only damage was a scuff mark on its cabinet which has since been removed. Sony sure made a tough monitor. The no-start iMac My next iMac was a 2000 iMac G3 M5521 CRT computer which is really past its use-by date. The unit was trying to turn on but just not quite making it. You could hear the static of the EHT but there was no light on the front panel, nor could you hear the familiar “dong” of an Apple booting up. The big problem in this set is the Chinese puzzle that makes up its cabinet. In fact, if I hadn’t downloaded an instruction sheet from the web I would June 2008 45 Serr v ice Se ceman’s man’s Log – continued tures. It declined to take OS10.4 as the hardware was too old. Philips LCD TV set still be working out the sequence. Suffice to say, you start the disassembly from the front and end with the back, peeling it off in shells like an onion. I am sure it is all very contemporary and clever but frankly I was close to using a chainsaw to get in (I could always superglue it back together afterwards!). To get to the power supply, the computer and CRT have to be removed first and then the question is how do you test it and measure voltages? The answer is that you don’t fully disassemble it until you have good idea what the cause is. I measured the 12V rail to be OK on the plug to the hard drive but there was no 5V rail. I then found that by freezing an LM7805 regulator that was tucked deep inside under the tube, I could actually get the set to start. At that point, I disassembled the set further and removed the motherboard. I replaced the 5V regulator and also the 1000mF 25V and 100mF 63V electros preceding and following it. I then spent hours reassembling it and had a few screws left over when I had finished (bit of a worry that) but the set doesn’t look as though it’s going to fall to bits anytime soon. Now that the supply was working, I watched it boot until after its Disk Utility when the computer would hang with a Finder error type 41. I went back to my PC and searched for “Mac OS Error Type 41” on the net, only to find that this error required a system reinstallation. This set came with OS9.03 which I subsequently upgraded to OS9.21. This fixed the problem plus added a lot more fea46 Silicon Chip The main advantage when it comes to repairing LCD TV sets these days is that they are much lighter and less bulky than their old CRT counterparts. My first story this month concerns a 2004 Philips 26PF9956/75 LCD TV (LC 4.2A chassis) which was brought in with a number of weird problems. It had no “focus”, a dark picture and poor colour. I tested it by going to each different input source and noted that the OSD menus and computer input were all perfectly OK. After enabling the Service Alignment Mode (SAM) by dialling 062596OSD, I could see that there were no error codes in the buffer (interestingly, the Customer Service Mode, or CSM, is now accessed by dialling 123645 instead of the old volume/mute method and this too gives the error codes in a read only mode). ComPair (Computer Aided Repair) is now much more sophisticated, giving very precise detail of all the data on the TV’s I2C rails. However, this is still very expensive and only for Philips Agencies. Anyway, I spoke to the Philips agents and they suggested that the problem might be due to the Pixel Plus Panel (PPP) containing the Electronic Programmable Logic Device (EPLD) and the Low-Voltage Differential Signalling (LVDS). So, acting on this advice, I ordered another board, even though this set is designed to be repaired to component level. All the boards, regardless as to their size or complexity, are available for exchange at a trade price of $387 each plus GST and freight. Unfortunately, the new board made no difference and although they do not normally allow refunds, they did so when I returned it. It was time for some real troubleshooting, so I attacked the problem by connecting a signal generator to AV1 and then tracing the signal using an oscilloscope. I followed the CVBS (composite video) signal all the way from the input to pin 48 on the 128pin Hercules microprocessor (IC7011, TDA12029H). I then followed the Luminance Y OUT from pin 74 to pin 6 of the “Histogram Picture Improvement” IC (IC7560, TDA9178T/N1). It was meant to then come out on pin 19 and go back to pin 72 of the Hercules processor but there was no signal at this point. I couldn’t find any short circuits and as I had already swapped the PP Panel, it had to be IC7560. The bad news was that this is a 24-pin surface-mount IC on the bottom side of the TV and Scaler Board (A3). The good news was that it is fairly large with reasonable pin spacing, which meant that I could replace it without too much difficulty. In the event, I was on the money. Replacing this IC restored the luminance and fixed all the other symptoms at the same time. Storm damage A 2005 LG Flatron LCD TV (Model No L173SAB) came in DOA (dead on arrival) after a storm. When its back had been removed, along with all the metal screening, it was obvious that the 5V/15V 2A switchmode power supply had blown up, probably due to a lightning strike. The TOP246YN FET switcher (U101) had had a large chunk blown out of it and had taken out fuse F101 (3.15A) with it. C130, a 10mF 50V electrolytic, had also exploded, leaving bits all over the board. It is hard to be precise as to the full extent of the damage but for the sake of a few dollars, I erred on the side of caution and also replaced optocoupler PC201, 15V zener ZD111, C132 (47mF 25V) and the bridge rectifier. I also cleaned any residue left by this catastrophe off the PC board. That fixed the power supply but I found out later that the cost of a replacement board would have been cheaper than the sum of the faulty parts. I guess I should remember to only repair plasma and LCD TVs to board level but old habits die hard. I r o n i c a l l y, a 2 0 0 4 P h i l i p s 29PT2162/79R (L01.1A chassis) also arrived DOA, thanks to the same storm. Its power supply is an integral part of the main board and it too was blown in a similar way. Power FET Q7521 had a hole blown in it and this had taken out fuse F1500. Collateral damage included the controller chip (IC7520, TEA1507) and a variety of other parts, including Q7522, D6523, D6525, C2508 and R5323. siliconchip.com.au While I was at it, I also replaced C2455 (47mF) as it is notorious for failing, which results in no sound and no picture through lack of horizontal drive. Unlike the LG set, this CRT set had to be fixed to component level as there was no low-cost alternative. The icemaker cometh I was recently asked to repair a TCL Electronic Icemaker, model TIF-15S. Now my closest association with ice before seeing this machine was with the ice tray in my fridge. It’s really simple – put water into a plastic thingy, put it in the freezer, wait for an hour or so and you’ve got ice. However, this was different – I had no idea how to even use this machine, let alone repair it. Fortunately, the client was sensible enough to provide the instruction book. To make ice, you first fill the unit’s reservoir with water up to a predetermined level. You then select one of three sizes of ice cube on the control panel and switch it on. When you do that, the machine pumps the water in its lower reservoir into an upper water box which contains a set of freezer nipples. Any excess water overflows back into the lower reservoir. After a few minutes, ice forms around the nipples, the size being determined by the time allowed. At the end of the preset time, the machine reverse cycles the coolant and the heat causes the ice balls to fall off the nipples. An ice shovel then pushes the ice balls over the edge and siliconchip.com.au This view inside the TCL Electronic Icemaker shows how the ice forms around the freezer nipples in the upper water box. At the end of the preset time, the machine reverse cycles the coolant and the resulting heat causes the ice to fall of the nipples. They are then pushed into the ice bucket. into an ice bucket. Any excess water drains through the ice bucket and falls back into the reservoir and so the cycle continues. The problem with this machine was that it was intermittently stopping and leaving the red warning LEDs blinking. Unfortunately, it took a long time for my tired old brain to work out what was causing this problem – especially as it was intermittent. Gradually, however, it became obvious that the ice shovel was sometimes unable to dump the ice over the edge and into the bucket, resulting in the microswitch connected to it not being able to close as part of a sequence. As a result, I decided to disassemble the water box/ice shovel assembly to see if I could spot the problem. Sure enough, when I removed the motor on the righthand side, I found that the plastic coupling had broken around the shaft, which would account for the symptoms. I ordered a new water box and shovel assembly and in the meantime re-glued the old pieces together to see what happened. The machine now worked flawlessly for a few days. However, eventually, when using the smallest setting for the ice balls, the shaft broke again. This was probably due to the small ice balls getting underneath the ice shovel and jam- June 2008 47 Serr v ice Se ceman’s man’s Log – continued ming the mechanism until it broke the coupling. Unfortunately, at the time of writing, the parts are still on back order, so I cannot confirm whether they will completely solve the problem or whether there is a problem elsewhere which causes the timing to get out of sequence and cause the whole thing to jam. I will keep you posted. Yamaha amplifier A large Yamaha surround sound amplifier came in with the complaint that it was intermittently cutting off. This one should be easy I thought, so I connected a speaker to the centre channel and started taking voltage measurements. However, after taking these measurements and then spending some time swapping parts between the left and right channel amplifiers and comparing voltages, I came to the conclusion that there was nothing wrong with it. In fact, it turned out that it was actually the rear channel amplifier that was closing the protection circuit down due to an intermittent short on the output. However, the exact location of this short continued to elude me until I found that I could bring on the fault by tapping the set. With more patience than I am usually able to muster, I subsequently discovered that the fault was caused by a solder dag that was intermittently shorting the output to ground. Removing this solder dag fixed the problem. Incidentally, I was given a little trick when checking surround amplifiers out. If you connect one loudspeaker between any two +ve channel speaker outputs, you can very quickly assess whether there is a problem because there will be no sound at all if either channel is faulty. This is quicker than having to listen to each loudspeaker in 48 Silicon Chip turn and hence reduces the amount of smoke and flames when something is wrong. Editor’s note: this troubleshooting technique relies on the difference signal between the two channels when a signal is fed in and is similar in concept to the old Hafler surround sound system. However, it won’t work if one of the amplifiers has a shorted output. Industrial microwave I have repaired lots of microwave ovens over the years. Recently, the demand has dropped in line with the price of new ovens, although the introduction of inverter power supplies in more recent models might redress this trend as the supplies fail. However, I was recently begged by a restaurant to fix an industrial microwave oven as no-one else was interested in repairing it. This turned out to be an American-made Menumaster UC14E which is a stainless-steel dual 1400W magnetron oven. The actual oven space is quite small and doesn’t have a carousel but the rest of the unit is large and heavy. Anyway, the unit kept turning itself off, so I unplugged it, removed the covers and checked the transformer voltages. There was mains voltage on the transformer’s primary but nothing on the secondary which indicated a short somewhere. I then unplugged the unit and after checking that the high-voltage capacitors had discharged (most important if you want to live), began making some continuity checks using an ohmmeter. This quickly revealed that there was a dead short from each magnetron to ground. After carefully unplugging various leads, I honed in on the diodes on the high-voltage capacitors as the likely culprits. These were located underneath on the other side of the microwave, well away from the magnetrons and capacitors. In fact, there were four identical HVR-1X3 9kV diodes – two in parallel for each magnetron. When I removed them, I found that only two diodes were short circuit, each in parallel with an identical good diode. So why did only one of the parallel diodes fail in each magnetron/capacitor combination? I have no idea but I refitted four new ones just to make sure and replaced the oven lamp. And that did the trick. I tested it with a cup of water and it worked as expected. It also tested it using a fluorescent lamp without the metal end caps. It lit up incredibly SC brightly. siliconchip.com.au TOOLS These are excellent screwdrivers and are insulated right down to the tip. The blades are chrome-vanadium, and they are VDE tested and approved to 1,000V. The range includes Phillips, slotted and Pozidrive. TD-2200 TD-2202 TD-2204 TD-2205 TD-2206 TD-2207 TD-2208 TD-2210 2.4 x 75mm Flat Blade 5.5 x 125mm Flat Blade 8.0 x 175mm Flat Blade #0 x 60mm Phillips #1 x 80mm Phillips #2 x 100mm Phillips #3 x 150mm Phillips #2 x 100mm Posidrive $1.95 $2.45 $3.25 $1.95 $2.45 $2.95 $3.25 $2.95 This is an economical unit that can charge Ni-MH batteries as well as Ni-Cd batteries (Yes, even 9V Ni-MH). • Discharge function • Recharges AAA, AA, C, D, & 9V cells in singles or in groups • Includes battery tester for 1.2V to 1.5V cells • Accepts various combinations of batteries • Operates from 240V mains socket • Energy Authority approved • 200(W) x 50(H) x 95(D)mm Was $28.95 $5 23 95 SMD Soldering Iron These surface mount soldering tweezers will allow easy soldering and desoldering of all surface mount components from small resistors to large 'flat pack' ICs. The iron is mains powered and features rapid heat recovery. It is supplied with 2 x 2mm tips and a metal stand with sponge. Fully Electrically Safety Approved. Larger tips to 20mm are available. Cat: TS-1700 Was $99.95 $20 $ 44 95 Cat: TD-2452 79 KITS FOR KIDS Five great experiments to choose from: KJ-8840 The Wind Machine KJ-8842 Flashing UFO KJ-8844 Solar Energy KJ-8846 Fruit-Powered Watch KJ-8848 Fingerprint Kit Were $9.95ea All models (ea) $ TOOLS The drill has a powerful motor and is speed adjustable from 8,000 to 18,000 RPM. Suitable for model-making or other precision cutting and shaping tasks. Includes loads of attachments see instore or website for details. Was $59.95 This high quality engine immobilising car alarm surpasses the AS/NZS 4601:1999 standard and boasts a range of features including: • Micro- processor controlled technology • 2 button 2 channel code hopping remotes • External relay output for the third immobilisation point • Panic button personal safety feature $ • Horn or siren output • Remote central locking (if car fitted Cat: LA-8970 $10 with central locking) • Heavy duty 2 x 40 amp immobiliser relay circuits Was $119 These educational DIY kits are an ideal way of demonstrating basic scientific theory . They assist in promoting manual dexterity and stimulate young creative minds. Each kit contains everything you need to construct the project and are supplied with comprehensive instructions. Cat: MB-3505 $ SHADOW 3-Point Engine Immobilising Car AlarA Kit Experiments for Kids Universal Battery Charger with Tester & Discharger $ CAR SECURITY 109 POWER 60 Piece 12 Volt Variable Speed Grinder Kit 50% OFF EACH 95 $15 7 95ea $2ea NEW KITS LIGHTING 50% OFF EACH Professional Grade Outdoor Garden Lighting Quality Die Cast low voltage outdoor garden lighting range. Each fitting is die cast, powder coated and moisture sealed with neoprene gaskets. The spectacular range can be powered by 12 volt halogen lamps or a professional 24V for large installations where voltage drops would normally be a problem. Garden Flood Light • Size (length including spike) 310mm • Dia. at globe 75mm Cat. SL-2770 Was $14.95 Now $7.45 Focal Spotlight/Highlighter • Length: 320mm approx • Dia at globe: 65mm Cat. SL-2772 Was $14.95 Now $7.45 General Purpose Spotlight / Highlighter • Size 100(H) x 96(dia)mm excluding bracket and spike. Cat. SL-2774 Was $14.95 Now $7.45 Wall Mount Step Light This light will mount on a wall, and is ideal for lighting a path, or steps. • Size 100(dia) x 50(D)mm Cat. SL-2778 Was $9.95 Now $4.95 Pathway Illuminator A stylish contemporary design used to reveal a pathway at night. • Size 170(H)mm excluding spike which is 160(L)mm • Dia 60mm Cat. SL-2780 Was $16.95 Now $8.45 Flexitimer/Interval Timer Ref: Silicon Chip Magazine June 2008 Here's a new and completely updated version of the very popular low cost 12VDC electronic timer. It is link programmed for either a single ON, or continuous ON/OFF cycling for up to 48 on/off time periods. Selectable periods are from 1 to 80 seconds, minutes, or hours and it can be restarted at any time. Kit includes PCB and all specified electronic components. $ 29 95 Cat: KC-5464 Improved Low Voltage Adaptor Ref Silicon Chip Magazine May 2008 This handy regulator will let you run a variety of devices such as CD or MP3 players from your car cigarette lighter sockets or even powered speakers from the power supply inside your PC. It will supply either 3V, 5V, 6V, 9V, 12V or 15V and (when used with an appropriate input voltage and heat sink) deliver up to four amps at the selected output voltage. Kit includes screen printed PCB and all specified components. Heatsink not included. Flushmount Illumination This lamp is designed to be embedded into a path or walkway. It can actually be walked on. • Size 100(H) x 96(Dia)mm Cat. SL-2776 Was $14.95 Now $7.45 $ 1495 Cat: KC-5463 Pagoda Light • Size 300(H)mm excluding spike • Dia 140mm Cat. SL-2784 Was $19.95 Now $9.95 Limited stock on some items. Pricing whilst stocks last - no rainchecks. Free Call: 1800 022 888 for orders! www.jaycar.com.au 1 $30 These speakers sound every bit as good as sets two and three times their price! Qms: 3.464 Qes: 1.040 Qts: 0.800 BL: 4.492 TM Power Handling: 60WRMS Impedance: 4 Ohms Voice Coil Resistance: 3.3 Ohm Sensitivity: 87.8dB/Wm Vas: 6.155 Was $149.95 $ 119 95 Cat: CS-2329 VEHICLE GLOBES Ideal replacements for your vehicles incandescent lamps. • Suitable for off road use only. • Voltage: 12V • 19 LEDs White Stop / Tail Light Cat. ZD-0311 Cat. ZD-0317 Unit allows connection of an audio source from a CD, DVD, MP3 player and etc to your car stereo via the FM radio antenna. Input connectivity is through a pair of RCA sockets and output is $7 tuned to one of four selectable frequencies in the FM band. A rocker switch is provided for on/off control. Output level $ is also adjustable. 95 Was $69.95 Cat: QM-3780 62 3 Channel Video Distribution Amplifier for Cars This one-to-three video amplifier is ideal for automotive use and will let you share the video signal from your in-car video or DVD system with back seat passengers or other screens in the car. • Composite video input and output • One input to three outputs • Lead length: 200mm • Works with all in-car video screens • 12 volt powered $ • Female RCA I/O connectors 95 • 63(L) x 32(W) x 30(H)mm Cat: QC-3436 Was $29.95 Red Stop / Tail Light $5 Perfect for use in a good quality bookshelf speaker system. Features a 6" driver and a massive 10oz magnet. • 8 ohm impedance • 30 watts RMS 50 • 20Hz to 4kHz response Was $24.95 $12 Cat. ZD-0319 Cat. ZD-0318 Pins Cat Was Now Save White 2 ZD-0311 $19.95 $15.95 $4 Red 2 ZD-0316 $14.95 $11.95 $3 Yellow 1 ZD-0317 $14.95 $11.95 $3 White 1 ZD-0319 $19.95 $15.95 $4 Red 1 ZD-0318 $9.95 $7.95 $2 7" TFT Monitor with VGA & Touch Screen $50 Bursting with value, this 7" 12V monitor has superb picture resolution and exceptional audio clarity. $ 12 45 Cat: CW-2108 Auto Current Tester This handy test unit makes it so easy to measure currents on individual circuits. Simply plugs into any standard blade type fuseholder and provides an easy-to-read LCD of the circuit's performance. Measures up to 20A. Was $29.95 $5 $ 449 Cat: QM-3749 149 Cat: LR-8869 Features a waterproof control unit, siren, and remote controls, so it can handle the weather extremes. The alarm is triggered by a shock sensor, which is mounted inside the control unit, as is the immobiliser relay. A flashing LED also acts as a deterrent. Great features at a great price, backed with a 12 month warranty. • Anti burglary • Anti hijacking • Car park locator function $ 95 • Selectable mute arm/disarm • Panic alarm Cat: LA-9020 Was $69.95 $10 59 Microwave Sensor for Car Alarms 2 Way Paging Car Alarm with Rechargeable Remote $ 24 95 Cat: QP-2251 This handy unit will automatically wind up your car windows as you arm the alarm or activate your immobiliser. Two models are available: 2 door and 4 door. Each can trigger either positive or negative activated power windows. It's also the only unit we $10ea know of that has an adjustment so you can set it to leave the window partially open and avoid suffocating Fido. Of course your car will need power windows already fitted. Wiring loom and wiring diagrams included. • Voltage: 9-15V • Current: 15A max • Static Current: <10mA $ 95 LR-8851 - 2 Door Power Window Closer Cat: LR-8851 Was $49.95 39 LR-8853 - 4 Door Power Window Closer Was $59.95 $ 24 Power Window Closers Featuring touch screen capabilities, which enables use with laptops/PCs or other VGA operated peripherals. Ideal for those who want to complete their in car entertainment system with a top of the line viewing device. Was $499 Not only does this excellent reversing sensor alert you to objects or people behind your vehicle, it will also give you an estimated distance to them and indicate their approximate location via the dash-board mounted display. Was $169 Microwave sensors send out ultra high frequency sound waves, and detect the reflections. If someone $5 walks near your car, they will start to reflect the microwaves. The receiver detects the change in reflections, and if the object remains within the microwave field for a length of time (depending on the alarm it is used with), it will trigger the alarm. It has an effective range of 3m. It also has a sensitivity adjustment to avoid false $ 95 alarms. Was $29.95 Cat: LA-9030 50% OFF Red for Car Tail (bayonette) Lamp Reversing Sensor with Dashboard Display Motorcycle Alarm 24 White - Car Indicators CAR SECURITY $20 6" Polycone Woofer Cat. ZD-0316 Yellow - Car Indicators AUTOMOTIVE Stereo FM Modulator 6.5" Kevlar Splits $ 49 95 $60 Utilises FSK technology and will relay the status of your vehicle to the key fob of up to 3 kilometres (direct line of sight). An adjustable shock sensor is supplied in the system and can also accommodate a microwave sensor (LA-9030) to help protect your valuable assets. Comes with a battery back up siren to give continuous sound output even if the wires are tampered or cut off and can only be turned off with the security keys (supplied). • Massive distance transmitting range of up to 3km • Two way remote controls with colour LCD screen • Visual and audible and vibrating indication of alarm status • Remote control arm and disarm • Silent arming mode • Remote boot release (with optional solenoid) • Car park locator function • Auto rearming • Anti-burglary and anti-hijacking Was $299 $ 239 Cat: LA-9018 Cat: LR-8853 Limited stock on some items. Pricing whilst stocks last - no rainchecks. 2 Free Call: 1800 022 888 for orders! www.jaycar.com.au CAMERAS ExView HAD Colour CCD Camera ExView CCD-equipped camera todramatically improve low-light performance. • Sony ExView HAD CCD Sensor • Extremely high performance in low light levels • Flickerless • Auto iris control • Automatic white balance • Back light compensation • 2 stage automatic gain control • High speed electronic shutter $ • Min lux .05 Cat: QC-3298 Was $249 $20 229 Day/Night Colour CCD Camera Day/night camera with Sony sensor, colour by day, black and white by night. • Perfect for use with infrared illuminator • Extremely high performance in low light levels • Flickerless • Auto iris control • Automatic white balance • Back light compensation • 2 stage automatic gain control • High speed electronic shutter • Min lux .01 Was $199 $10 $ SURVEILLANCE Dual Beam Infrared Barrier 189 Dual beam detector for enhanced security. Housed in a strong aluminum housing and suitable for protected outdoor environments (IP55). Was $149 $30 $ 119 Cat: LA-5186 2 Zone Alarm for Caravans Ideal as a caravan, motor home or boat alarm. It is activated by one of 2 x IR remote controls (supplied). It has exit and entry delay, standard 3 minute cut-out siren driver, and built-in door chime and panic switch. You can even wire a doorbell button to it for an entry chime. It has 2 zone capacity so $10 you can wire a passive infrared detector to one zone and reed switches to the other. It will drive an 8 ohm horn speaker, such as our AS-3180 horn or better - trigger our LA-5305 unit which is an attractive strobe as well as a siren. Unit comes with comprehensive instructions. • Measures 120(W) x 80(H) x 32(D)mm $ 95 • Simply screws to a wall Was $69.95 Cat: LA-5210 RFID RFID Access Control System The Radio Frequency Identification Device (RFID) technology means that no actual contact or card swiping is required as the lock will recognise an RFID card within a range of 100mm. This unit can be administrated via a PC using the RS232 interface or standalone using the included programming cards. The data is encrypted before transmission and can't be intercepted. 12 volt operation means that the system can be used in remote locations to provided unattended access security. The reader is splash-proof and can be used in a sheltered outdoor environment. Was $199 $ $20 59 179 Cat: LA-5120 Cat: QC-3300 Stor-A-Key Safe Colour CCD Camera - Pro Style • Flickerless • Audio • Auto Iris control • Automatic white balance • Back light compensation • 2 stage automatic gain control • High speed electronic shutter • Min lux 0.03 $ Was $149 $15 134 MONITOR Mounts directly onto a wall or flat surface and holds up to 5 keys. Allows you to provide access to family, friends or tradespeople to any building when you're not there. Simply change the combination after their visit and the keys are once again secure. Was $99.95 14" B&W 4 Channel Quad Surveillance Monitor $100 $ $40 59 95 Cat: LA-5356 Cat: QC-3309 B&W CCD Camera - Pro Style This versatile B&W CCD camera utilises a 1/3" Samsung image sensor chip and can accommodate either a fixed or Auto Iris lens of both C and CS type. The camera can be mounted on a wall or ceiling bracket or fitted inside our protective outdoor housing. • Extremely high performance in low light situations • Audio • Auto iris control • Automatic gain control • High speed electronic shutter • Min lux 0.05 $ Was $69 CCTV Camera Extension Cable with DC A range or extension cables for composite video with DC power cable included. WQ-7275: CCTV Camera Extension Cable BNC to RCA 5m WQ-7277: CCTV Camera Extension Cable BNC to RCA 15m WQ-7278: CCTV Camera Extension Cable BNC to RCA 20m 10% OFF EACH $5 64 $ 17 DOOR BELLS This excellent doorbell has 32 melodies and is completely wireless. Just mount the transmitter near your door and the receiver in a convenient location. Suitable for homes and offices. • 100 metres operating range Was $12.95 $3 $ 9 95 Cat: LA-5018 95 From Cat: QC-3310 Wireless Doorbell with 32 Melodies $ 299 Visitor Door Chime Alarm with Counter V8 Wireless Doorbell If you love cars you'll love this fantastic wireless doorbell. Choose between a thumping V8, a Formula-1 racer, or motor bike and get your heart pumping every time the doorbell rings. If that gets too exciting you can switch to a sedate ding-dong while you recover. • 30m range • Requires 3 x AAA batteries $ (Use SB-2413) Was $29.95 This 14" B&W monitor accepts up to 4 cameras and will automatically display each camera's picture on the monitor screen or display all four images at once. The video input is via BNC or mini-DIN connectors while the output is via RCA connectors. The video out is in quad format and can be displayed on a remote monitor or record it on a VCR/DVR etc. Advance features include: • Video loss detection • Freeze frame • Image zoom • Picture-in-picture (PIP) • Front panel controls • 2 way sound system Cat: QM-3418 • Mains operated Was $399 $5 24 95 This handy little unit is perfect for shop, office or home use. When passed it gives a pleasant 'Ding-Dong' chime which alerts you to the entry, and records the customer in its digital tally count. Effective for up to 5 metres, this door chime/alarm comes with a convenient clip-in wall mount bracket or it can simply be hung on a door knob. $ Was $19.95 Cat: LA-5000 $5 14 95 Cat: LA-5009 Limited stock on some items. Pricing whilst stocks last - no rainchecks. Free Call: 1800 022 888 for orders! www.jaycar.com.au 3 OUTDOORS BBQ ACCESSORIES Stainless Steel BBQ Tongs with LED Light Use your BBQ in any lighting conditions with complete confidence. These stainless steel BBQ tongs with in-built LED light allows you to see all your cooking delights even in the complete dark. A must-have item for any camping enthusiast or BBQ master chef. • 400mm long • Requires 2 x AAA batteries $3 (Use SB-2426) $ 95 Was $14.95 Cat: GG-2309 BBQ Fan This three blade BBQ fan is equipped with a radio to help pass the time and an LED torch to keep your environment illuminated while cooking your meals. It also features a timer and clock with an alarm to help you cook your food to perfection. The fan connects to a long flexible goose-neck that can be clamped to almost anything. 11 7-14X Zoom Monocular • Requires 4 x C batteries: SB-2416 • Count-down timer • Clamp opening - 60mm • Fan diameter - 120mm Was $49.95 $ 44 95 Cat: GG-2308 $5 Ultra compact and lightweight, the monocular only weighs 84 grams. Featuring 7-14x zoom, it has a 21mm coated optic lens and easily fits into your pocket or purse. Includes hand strap. Was $19.95 $ Solar Mobile Charger with Detachable Solar Panels $5 14 95 Cat: GG-2128 Truly portable power that allows you to charge your phone or other digital devices wherever you are! Can be topped up by solar power, USB port, or mains adaptor. Was $69.95 $15 $ 54 95 Cat: MB-3588 $10 $ 29 90 Cat: AR-1773 Wireless Weather Station with Computer Interface Set up your own weather channel or connect to your computer for storage and analysis. The indoor receiver measures the indoor temperature, humidity, atmospheric pressure and receives weather data from the outdoor thermometer-transmitter sensor, wind sensor, and rain gauge. The receiver unit has USB interface output allowing data to be uploaded to a PC or laptop and an AV output so you can view the weather data on your TV. Was $299 $50 $ 249 Cat: XC-0332 $ 19 95 Cat: GH-1116 Cat: ZM-9018 $ 129 Cat: XC-4895 $ This compact LED clip-on light utilises a Nichia 5mm white LED to produce an output power of 1.8 lumens and weighs only 28g (without batteries). Use it while camping, fishing, any activity where you need your hands free but need a bright light. Just clip the unit onto your belt. • Batteries included • Burn time: 60 Hours (Maximum output: 2.5hrs) • Output power: 1.8 lumens $ 95 • Product size: 30 x 30 x 42mm Cat: ST-3319 Was $19.95 14 Dynamo Solar Torch with Radio & Siren 89 Cat: ST-3128 Ideal for charging sealed lead acid batteries, this 12 volt 4.5 watt solar panel is tough enough to be walked on and can be mounted on a flat surface or on its brackets so it can be moved to follow the sun. Great for use on a yacht or boat or in a car. Voltage (max): 18V Current (max): Up to 250mA Panel Size: 187 x 255 x 17mm Was $99.95 89 95 This high performance 20 channel receiver sends location data to your Bluetooth enabled PDA, notebook computer or mobile phone. Works with TomTom Navigator, Destinator and other free and commercial software including Google Maps. Position accurate to approximately 5m. Was $149 $5 12 Volt 4.5 Watt Solar Battery Charger $ Bluetooth GPS Receiver with SIRF III Chipset Clip-On LED Head Torch A super bright white LED lamp with an integrated compass. The internal rechargeable batteries and external devices, such as mobile phones, can be charged via mains power, car charger or by he unit's solar panel. • Mains and car chargers supplied •4xD rechargeable batteries included • Lamp measures 250(H) x 108(Dia.)mm Was $99 $10 $5 TORCHES Light Lantern LED with Solar Charger PSU Adaptor $10 24 $5 Dynamo Weatherproof Radio Take this self-powered AM/FM radio with LED torch fishing, boating, camping or bushwalking or use it as an emergency light - it's weatherproof! Was $39.95 Drink your wine at the optimum temperature. Celsius, Fahrenheit and preset with 16 popular varieties. • Requires 2 x AAA batteries $ 95 (Use SB-2426) Cat: GH-1920 • 245mm long Was $29.95 $20 Pocket UV Meter Protect yourself from harmful UV rays with this excellent detector. It reads UV index, mW per cubic metre or a bargraph meter of low to very high UV radiation. Battery, lanyard and belt clip included. Dimensions: 60(L) x 40(W) x 9(D)mm Was $24.95 LCD Wine Thermometer The perfect companion for camping and other outdoor activities. This weatherproof torch and AM/FM radio can be powered by the dynamo hand crank, solar cell, batteries, or external mains power. The torch has 3 high intensity LEDs that can be diffused for use as an reading lamp & a siren and strobe function to attract attention in case of emergencies. Was $49.95 $10 $ 39 95 Cat: ST-3354 45 LED Torch Durable and compact, this torch packs the punch of 45 superbright LEDs. It has 3 settings of 9, 16 or 45 LEDs for variable brightness and a knurled grip. • Requires 4 x AAA batteries (Use SB-2413) • Dimensions: 150(L) x 32(dia)mm Was $29.95 $ 95 $5 24 Cat: ST-3395 Limited stock on some items. Pricing whilst stocks last - no rainchecks. 4 Free Call: 1800 022 888 for orders! www.jaycar.com.au Automatic Pet Dish The lid automatically opens as your pet gets within 30cm of the sensor then closes when your pet has had their fill and walks away. • Stainless steel dish • Measures 80(H) x 150(dia)mm • 4 x AA batteries required (Use SB-2425) Was $29.95 $ $5 RC Horse Racing Game GADGETS Motorised Tie Rack 24 95 Holds 30 ties, forward and reverse and a two-level LED light for dark closets. • Requires 4 x C batteries (Use SB-2416) • Dimensions: 290(L) x 140(W) x 70(H)mm Was $39.95 $ Cat: GG-2319 SHOCKINGLY GOOD Shocking Trivia Game 34 95 $5 Cat: GH-1406 $20 GIDDY UP! Run your own Melbourne Cup with this terrific horse racing set. Playing cash is also included. Pick a horse and try to win. • Track measures 1200(L) x 600(W)mm • Spare horses available • Horses & remotes require 2 x AA batteries each (Use SB-2333) Was $99.95 $ 79 95 Cat: GT-3240 V8 Alarm Clock Anti-Fog Shaving Mirror with MP3 Speaker & Radio $ 19 95 Cat: AR-1769 $5 Designed for use in the shower, this mirror won't ever steam up. The unit has twin LEDs to assist when shaving, stereo speakers and an AM/FM radio. It has a water resistant compartment with a 3.5mm stereo jack, so you can listen to your iPod® or other MP3 player through the unit's speakers. • Total size: 195(W) 245(H) x 40(D)mm • Requires 4 x AA batteries (Use SB-2425) Was $29.95 This ozone sanitiser emits highcontent ozone to rapidly kill bacteria and neutralise odours. It can eliminate over 90% of breeding escherichia coli and pseudomonas aeruginosa in minutes. • Absolutely safe and pollution free, this ozone sanitiser uses no chemicals or cover-up sprays • Require 6 x AA alkaline batteries (SB-2424) or a 7.5VAC/DC adaptor from our range Was $39.95 $ $ 24 95 Cat: GH-1063 The easy and humane way to catch creepy-crawlies. Vacuum them up into the chamber and release them into the outdoors safely. It's fully recharged in 14-16 hours, comes with power supply and runs up to 20 minutes on one charge. Was $39.95 29 95 Cat: GH-1192 Perpetual Spinning Top with LEDs This spinning top transfixes all ages with the duration of just a single spin! Electromagnetic fields keep the top spinning and the LED lights on the top give a stunning visual display! Family and friends will love this amazing little device. Comes with its own power pack or can run on 2 x 9 Volt batteries. Was $24.95 $5 $ $ 34 95 Cat: GH-1392 $5 Hot Price $5 Was $24.95 $ 19 95 Cat: GT-3135 $ 24 95 Cat: GH-1106 Shocking Autopsy Game Remove the various weapons from the body without touching the injury area. Make a slip and you get a mild shock. Turn the shock function off and he'll just scream instead. Requires 3 x AAA batteries. • 1 - 4 players • 14yrs+ • Requires 3 x AAA batteries (SB-2413) Hot Price Belt as many rodents on the head as you can. The game gets faster and faster and they squeal and squeak as you hit them. • Requires 3 x AAA batteries (Use SB-2413) • 240mm wide • 6yrs+ Cat: GH-1822 Cat: GH-1134 Lock temptation away in your Shockolate Vault and set the timer. If you try to open the vault too early you will cop a mild electric shock. Makes a great diet incentive. • Measures 190(H) x 110(Dia.)mm • Batteries included • 14yrs+ Whack-a-Mouse Game 19 95 19 Shockolate Vault Rechargeable Long Reach Bug Relocator $10 Shocking Number Guessing Game $5 $5 Personal Ozone Sanitiser 49 With two separate games of number guessing and Simon Says you're guaranteed hours of fun. Have as many people as you like play along but beware! The person who eventually guesses the secret number or gets the Simon Says sequence incorrect will cop a mild electric shock. Requires 3 x AAA batteries (Use SB-2413) • Base measures 120mm Dia. • 14 yrs+ $ 95 Was $24.95 $20 Wake up to the realistic V8 engine-sounding alarm. Easy to use and attractive in design, it is sure to be a hit with any motoring enthusiast young or old. • Realistic pedals for demo and clock controls • Spinning brake disc when the alarm is activated • Clock 120mm dia. • Requires 3 x AA batteries (Use SB-2425) Was $24.95 Makes sure you have your thinking cap on. Each player gets a hand piece to select the answers with. The Quizmaster picks the right answer and if yours doesn't match, you get a mild electric shock. Questions are multiple choice, question cards, scorecard and erasable marker included. • Base measures 180mm across • 14yrs+ • 1-4 players $ 95 • Requires 3 x AAA batteries (Use SB-2413) Cat: GH-1091 Was $69.95 $ 19 95 Cat: GH-1108 Pocket Shock Are you a shock-a-holic who can't be without their shocking game fix? Take this one on holidays, on the train or to the pub. Two games - Lighting Reaction and Shock Roulette. • 2-4 players • 14yrs+ • Batteries included Was $24.95 $ 19 95 Cat: GH-1128 $5 Limited stock on some items. Pricing whilst stocks last - no rainchecks. Free Call: 1800 022 888 for orders! www.jaycar.com.au 5 KITS AUDIO KITS Theremin Synthesiser Kit Studio 350 - High Power Amplifier Ref: Silicon Chip August 2000. Ref: Silicon Chip Jan / Feb 2004. STUDIO QUALITY, LOW NOISE, LOW DISTORTION. The Studio 350 power amplifier will deliver a whopping 350WRMS into 4 ohms, or 200WRMS into 8 ohms. It offers some real grunt without any compromise, using 8 (yes, EIGHT!) 250V 200W plastic power transistors - four MJL21193/4 complementary pairs to be precise. It is super quiet, with a signal to noise ratio of -125dB(A) at full 8 ohm power. Harmonic distortion is fantastic - just 0.002%, and frequency response is almost flat (less than -1dB) between 15Hz and 60kHz!. We have mentioned the power, but we forgot to give you the music power figures of 240W* into 8 ohms and 480W* into 4 ohms Kit supplied in short form with PCB and electronic components. Kit requires heatsink and +/- 70V power supply (a suitable supply is described in the instructions). * Power figures applicable when described power supply is used. Cat: KC-5372 $ 12-24V High Current Motor Speed Controller Kit AUTO KITS Ref: Silicon Chip Magazine March 2008 Want to control a really big DC motor? This design will control 12 or 24VDC motors at up to 40A continuous. The speed regulation is maintained under load, so the motor speed is maintained even under heavy load. It also features automatic soft-start, fast switch-off, a 4-digit LED 7-segment display to show settings, an overload warning buzzer and a low battery alarm. All control tasks are monitored by a microcontroller, so the functionality is extensive. Kit contains PCB and all $ specified electronic components. Fuel Cut Defeat Kit Ref: Silicon Chip February 2007 This cheap and simple kit enables you to eliminate this factory fuel cut and go beyond the typical 15-17PSI factory boost limit. The kit simply intercepts the MAP sensor signal, and trims the signal voltage above 3.9V to avoid the ECU cutting the fuel supply to the engine. Kit includes PCB with overlay & all specified electronic components. $ AVR ISP Serial Programmer Kit Ref: Silicon Chip Magazine October 2002 Program, erase and rewrite the program and data memory in your AVR microprocessor without even removing it from the application circuit. This kit connects to the computer serial port, uses royalty-free software available on the Internet and allows you to program a multitude of micros in the AVR 8-bit RISC family (see website for full $ listing). Kit supplied with PCB, Jiffy box with silk-screened lid and all electronic Cat: KC-5340 components. 45 POWER & TEST KITS Improved Low Voltage Adaptor Ref Silicon Chip Magazine May 2008 This handy regulator will let you run a variety if devices such as CD, DVD or MP3 players from your car cigarette lighter sockets or even a digital camera or powered speakers from the power supply inside your PC. This unit can will supply either 3V, 5V, 6V, 9V, 12V or 15V) from a higher input voltage at up to four amps (with suitable heatsink). Kit includes screen printed PCB and all specified components. 95 • Heatsink not included. $ 14 Cat: KC-5463 Cat: KV-3590 Low Voltage Battery Warning This circuit monitors any battery voltage between 3-15 volts once set. Whenever the voltage falls below a predetermined value a Red LED lamp lights up. It does not, however, automatically disconnect the battery. Uses a tiny amount of power from the battery being monitored. Could save you embarrassment or a fortune by avoiding battery damage. $ 9 95 Cat: KG-9000 BOOKS 30 Electronic Musical Projects Was $6.50 Now $4.55 Save $1.95 Semiconductor Equivalents Book - Volume 2 BM-4582 Automate your house, switch on garden lighting, turn on sprinklers or even control your household heating with this terrific kit. Each SPDT relay can handle 10 amps and has an LED to show whether it is on or off. Software is provided on a 3.5 disk. Kit includes PCB, relays, software, and all electronic components. 8-12VDC power $ 95 required. 59 Was $39.95 Now $27.95 Save $12.00 30% OFF Cat: KC-5295 We have improved and refined this kit since it was published and it is now even more stable and accurate. If you're into any kind of racing like cars, bikes boats or even the horses, this kit is for you. Kit includes all specified components.. $ 99 95 Cat: KC-5441 Front End Pre-Amp For PC Sound Cards PC Link for Automatic Control 59 95 Ref: Silicon Chip Nov-Dec 2006 Cat: KC-5465 Cat: KC-5439 $ Radar Speed Gun Mk2 99 95 19 95 COMPUTER KITS BM-2450 175 This modern Theremin synthesiser produces eerie science fiction movie sounds when you move your hand between a metal plate and antenna. Features a built-in loudspeaker for practice sessions and line output. Kit includes case, silk screened front panel, metal plate, antenna, speaker and all electronic components. 9-12VDC plugpack required - use MP-3146 $ Refer: Electronics Australia August 1998 29 95 Cat: KA-1811 Turn your computer into an oscilloscope, audio monitor or spectrum analyser! Plug the kit into your computer's soundcard and by using software available over the Internet, measure or monitor just about any audio signal. Most PC sound card inputs have a limited dynamic range, relatively low input impedance and poor overload protection -this kit will eliminate these limitations and allow tiny signals, like those from op-amps, to be measured without degradation. Power is derived from the soundcard's D15 Joystick output socket. • Kit includes case, silk-screened front panel, PCB, and all electronic components • Optional CRO probe to suit - use our QC1902 • Or use it for amplifying a high quality microphone for sampling Filed Intensity Meter 3V to 9V DC to DC Converter Kit Refer: Silicon Chip March 2004. 14 $ 95 9V batteries are a great source of portable power, but let's face Cat: KC-5391 it - they don't last long if you want more than a few milliamps, and they are not real cheap either. This great little converter allows you to use regular Ni-Cd or Ni-MH 1.2V cells, or Alkaline 1.5V cells for 9V applications. Using low cost, high capacity rechargeable cells, the kit will pay for itself in no-time! You can use any 1.2-1.5V cells you desire. Imagine the extra capacity you would have using two 9000mAh D cells in replacement of a low capacity 9V cell. Kit supplied with PCB, and all electronic components. This low cost project will confirm the operation of a transmitter such as a garage door opener or CB radio within the range of 10100MHz. Connects to the transmitter's antenna and lights a LED to indicate transmission. • Generates no interference • Operates from 9V DC $ 8.50 Cat: KG-9084 TOOL Budget 150mm Digital Vernier Calipers This carbon composite digital caliper is ideal for use where the cost of our precision stainless steel tool is not justified. Excellent value for money and tradesman tough. Was $19.95 $10 The Best of Silicon Chip's Test Equipment Kits BS-5070 Was $10.95 Now $7.65 Save $3.30 Electronic Projects For Cars Vol. II BS-5075 Was $12.95 Now $9.05 Save $3.90 $ 9 95 Cat: TD-2081 Limited stock on some items. Pricing whilst stocks last - no rainchecks. 6 Free Call: 1800 022 888 for orders! www.jaycar.com.au COMPONENTS Mini Blade Fuses with Failure Lamp Integrated lamp which illuminates the moment the $0.25ea fuse blows. • Ideal for circuits up to 32VDC • Measure: 19(H) x 10.8(L) x 4(W)mm approx. SF-5050 3A Pink SF-5052 5A Orange SF-5074 7.5A Brown SF-5076 10A Red SF-5078 15A Blue SF-5080 20A Yellow SF-5082 25A Clear SF-5064 30A Green $ Were $1.25 ea All Models (ea) Projects the time and the temperature on your wall or ceiling ! The LCD constantly displays time, temperature, day and date while the alarm and snooze option finish off this neat little unit. • 12 or 24 hr time display • C° or F° digital temperature display $ 95 • Measures 140(L) x 34(W) x 90(H)mm Cat: XC-0219 • Requires 2 x AA batteries (Use SB-2424) or 3V DC adaptor (Use MP-3130) Was $19.95 14 1 Super Bright 3 Watt LED Star Modules Blindingly bright Service life of 100,000 hours • 25 lumens per watt. ZD-0520 - Red ZD-0522 - Amber ZD-0524 - Green ZD-0526 - Blue ZD-0528 - White $ ZD-0530 - Warm white Were $19.95 ea $5ea $5 12" Toolbox with Storage Lid Includes two detachable containers and a removable tray. Excellent for home storage or travelling! • Measure 320(W) x 165(D) x 137(H)mm Was $9.95 $ 14 95 Contain all of the amplifier's electronics and require only a simple power supply to get them up and running. • Low distortion • Suitable for 4 or 8 ohm operation. • Power supply & some external components required. Cat No. $5ea $ 9 24W 60W 80A Normally Open Thermostat Switch - 50° 6021 9699 9709 9678 9369 9905 4620 4365 9439 9476 4965 9683 4721 8831 6788 4699 2822 9669 3899 4130 7155 3433 4799 6221 3799 3377 8337 3151 Wireless Colour LCD Weather Station Cat: HB-6327 18W Soldering Iron This iron is perfect for precise soldering of more delicate components. It offers rapid heat up, instant recovery, a stainless steel barrel and iron clad chrome plated long life interchangeable tip. Fully SAA approved. Was $34.95 $ 95 24 Cat: TS-1551 Wireless outdoor temperature and hygrometer sensors transmit data to the LCD receiver which displays temperature, humidity, heat index & dew point levels, the time, barometric pressure and comfort index, and forecasts the weather through 5 weather icons. Outdoor sensors require AAA batteries. Not supplied. Plugpack for main unit included. Dimensions: 170(L) x 95(H) x 50(D)mm (including stand) $30 Was $149.95 $ 119 95 Cat: XC-0342 Now Commercial Contractor Grade Clamp Meter Spark Plug Tester Check your spark plugs before you replace them. Ideal for the mechanic, auto electrician, auto club member or just the average guy (or girl). Was $5.95 $ Non Contact Voltage Detector This model features adjustable sensitivity so you can find live wires from more than 1 meter away, then gradually reduce the sensitivity to isolate individual wires in a bundle. Was $19.95 Sydney City Taren Point Tweed Heads Wollongong VICTORIA Coburg Frankston Geelong Melbourne Ringwood Springvale Sunshine Thomastown QUEENSLAND Aspley Cairns Ipswich Maroochydore $3 50% OFF 2 95 Cat: QP-2264 3 NEW SOUTH WALES Albury Ph (02) Alexandria Ph (02) Bankstown Ph (02) Blacktown Ph (02) Bondi Junction Ph (02) Brookvale Ph (02) Campbelltown Ph (02) Erina Ph (02) Gore Hill Ph (02) Hornsby Ph (02) Newcastle Ph (02) Parramatta Ph (02) Penrith Ph (02) Rydalmere Ph (02) Cat: XC-0336 $10 These thermostat switches have normally open contacts, it short circuits once the temperature reaches a 25% specified limit and automatically resets to its original normally open state once the temperature off ea drops below the rated temperature. These are suitable for power amplifier applications and other temperature sensitive devices where a cooling fan needs to be integrated to cool the device down. Mounting holes are provided, ideal for attachment to a heatsink or any metallic surface. They are UL and CSA approved. ST-3831 - Thermostat 50°C N.O ST-3833 - Thermostat 70°C N.O $ 35 ST-3836 - Thermostat 100°C N.O Were $4.45 ea All models (ea) YOUR LOCAL JAYCAR STORE $10 The system consists of two wireless outdoor sensors, a wireless doorbell and an indoor receiver. The device will measure indoor and two outdoor temperatures, humidity, barometric change as well as the respective maximum/minimum temperatures and humidity. The indoor receiver has a large LCD which shows full clock and calendar functions, humidity, temperature readings, barometric change as well as an audio and visual annunciation when the doorbell is pressed. It also can be either desk (stand supplied) or wall mounted. See website for specifications. $ 95 Was $99.95 From $14.95 $9.95 $19.95 $14.95 $23.95 $18.95 Australia Freecall Orders: Ph 1800 022 888 4 Wireless Weather Station with Doorbell 89 95 95 Power Power Output Power Output Required 8 Ohms 4 Ohms Was ZL-3760 +/- 22V 20W ZL-3762 +/- 35V 50W ZL-3764 +/- 42V 70W $5 All Models (ea) Audio Power Amplifier IC Modules WHILE STOCKS LAST Multi-Function Clock with Dual Projector 50% OFF $ $10 • 200A AC Current Capability • Non-contact voltage 40 to 600VAC • Capacitance • True RMS • Backlight • Vibration mode to verify AC Voltage • Harmonics Indicator • Max Hold • CAT III 1000V • Low Battery Indication • Overload protection on all ranges • Integral Lead Storage • Audible Dangerous Voltage Warning • Auto Power Off • Compact Clamp Head Was $299 $30 9 95 $ Cat: QP-2276 Ph Ph Ph Ph (02) (02) (07) (02) 9267 9531 5524 4226 1614 7033 6566 7089 Ph Ph Ph Ph Ph Ph Ph Ph (03) (03) (03) (03) (03) (03) (03) (03) 9384 9781 5221 9663 9870 9547 9310 9465 1811 4100 5800 2030 9053 1022 8066 3333 Ph Ph Ph Ph (07) (07) (07) (07) 3863 4041 3282 5479 0099 6747 5800 3511 Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 Woolloongabba Ph (07) 3393 0777 AUSTRALIAN CAPITAL TERRITORY Belconnen Ph (02) 6253 5700 Fyshwick Ph (02) 6239 1801 TASMANIA Hobart Ph (03) 6272 9955 SOUTH AUSTRALIA Adelaide Ph (08) 8231 7355 Clovelly Park Ph (08) 8276 6901 Gepps Cross Ph (08) 8262 3200 WESTERN AUSTRALIA Maddington Ph (08) 9493 4300 Midland Ph (08) 9328 8252 Northbridge Ph (08) 9328 8252 269 Cat: QM-1628 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Christchurch Ph (03) 379 1662 Dunedin Ph (03) 471 7934 Glenfield Ph (09) 444 4628 Hamilton Ph (07) 846 0177 Manukau Ph (09) 263 6241 Newmarket Ph (09) 377 6421 Palmerston Nth Ph (06) 353 8246 Wellington Ph (04) 801 9005 Freecall Orders Ph 0800 452 9227 Limited stock on some items. Pricing whilst stocks last - no rainchecks. 8 Free Call: 1800 022 888 for orders! www.jaycar.com.au SILICON SILIC 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. 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Card expiry date: Signature_____________________________ 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) 9939 3295 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9939 2648 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, AustraliaJune 20972008 57 06/08 By Greg Swain USB power injector for external hard drives A portable USB hard drive is a great way to back up data but what if your USB ports are unable to supply enough “juice” to power the drive? A modified version of the SILICON CHIP USB Power Injector is the answer. F OR SOME TIME NOW, the author has used a portable USB hard drive to back up data at work. As with most such drives, it is powered directly from the USB port, so it doesn’t require an external plugpack supply. POWER ONLY DATA + POWER An external USB hard drive is usually powered by plugging two connectors at one end of a special USB cable into adjacent USB ports on the computer. This allows power to be sourced from both ports. 58 Silicon Chip In fact, the device is powered from two USB ports, since one port is incapable of supplying sufficient current. That’s done using a special USB cable that’s supplied with the drive. It has two connectors fitted to one end, forming what is basically a “Y” configuration (see photo). One connector is wired for both power and data while the other connector has just the power supply connections. In use, the two connectors are plugged into adjacent USB ports, so that power for the drive is simultaneously sourced from both ports. According to the USB specification, USB ports are rated to supply up to 500mA at 5V DC, so two connected in parallel should be quite capable of powering a portable USB hard drive – at least in theory. Unfortunately, in my case, it didn’t quite work out that way. Although the USB drive worked fine with several work computers, it was a “no-go” on my home machine. Instead, when it was plugged into the front-panel USB ports, the drive repeatedly emitted a distinctive chirping sound as it unsuccessfully tried to spin up. During this process, Windows XP did recognise that a device had been plugged in but that’s as far as it went – it couldn’t identify the device and certainly didn’t recognise the drive. Plugging the drive into the rearpanel ports gave exactly the same result. The problem wasn’t just confined to this particular drive either. A newly-acquired Maxtor OneTouch4 Mini drive also failed to power up correctly on my home computer, despite working perfectly on several work computers. That clearly indicated that the fault lay in my home computer. However, the USB ports on this machine worked fine with my WiFi transmitter, a printer and various flash drives, so what was the problem? From the symptoms, it was apparent that the USB ports on my home machine were incapable of supplying sufficient current to power USB hard drives, even though the computer is siliconchip.com.au D5 1N4004 K Q2 IRF9540 D2 1N5819 CON3 A 6V DC INPUT K S 1000 µF 16V REG1 LM2940CT-5 D OUT IN LED GND G 10k A K 22 µF 16V 10 µF A 820Ω 22k CON1 USB SKT TYPE B 10k 1 Vbus 4 GND USB IN FROM PC SC 2004 B 2 D– 3 D+ C A Q1 PN100 λ E K LED1 USB POWER CON2 USB SKT TYPE A 2 3 LM2940CT-5 USB POWER INJECTOR REV USB OUT TO PERIPHERAL 4 D 1N5819 IN GND IRF9540 1 G OUT D S A K Fig.1: the revised USB Power Injector is essentially a switch and a 5V regulator. The Vbus supply from USB socket CON1 turns on transistor Q1 which then turns on power Mosfet Q2. This then feeds a 6V DC regulated supply from an external plugpack to regulator REG1 which in turn supplies 5V to USB socket CON2. only about three years old and uses a well-known brand of motherboard. For some reason, its USB ports were below specification, so it was necessary to find another way to power my USB hard drives. USB power injector A powered USB hub would be one way of tackling this problem. However, without knowing the hub’s output current specifications, there was no guarantee that this would work. Another option was to use the “USB Power Injector” described by Jim Rowe in the October 2004 issue of SILICON CHIP. This device is powered from an external plugpack and is designed to connect in series between the PC’s USB port and the peripheral. In practice, the device is connected via two onboard USB sockets. When it detects 5V DC coming from the PC’s USB port (or from a hub), it switches power from the plugpack through to a 5V regulator which then powers the peripheral. So the peripheral is no longer powered directly from the PC’s USB port but by the injector instead. Conversely, the data (D+ & D-) and ground connections are run straight though from the input USB socket siliconchip.com.au to the output socket. Only the Vbus line is broken to switch the regulator on and off, with the regulator providing the new 5V Vbus line. This seemed to be the way to go so a USB Power Injector kit was obtained from Altronics and assembled. This was teamed with a 9V AC 1A plugpack and it worked. Once connected, the injector could successfully power either USB drive and they could now be used with my home computer. Note that only the USB plug with both the power and data connections at the “Y-connector” end of the cable is connected to the USB Power Injector. The connector with just the supply connections is left disconnected. How do you know which connector is which? Well, sometimes, the connectors are labelled. If not, then the straight-through connector is invariably the one with both the power and data connections. Alternatively, you can dispense with the “Y-cable” and use a conventional single-ended cable to connect the drive to the USB Power Injector. It gets too hot Unfortunately, that wasn’t the end USB hard drives like this Maxtor OneTouch4 Mini typically draw between 350mA and 750mA. Used with a 6V regulated DC plugpack, the modified USB Power Injector is ideal for powering this type of drive if your PC’s USB ports aren’t up to the task. of the story. Although, this arrangement worked, the 5V regulator on the USB Power Injector board quickly became much too hot for comfort whenever power was applied. In fact, it was getting so hot that there was a June 2008 59 REGULATED 6V DC INPUT 1N5819 CON3 LINK 1000 µF 16V R E W OP B S U R OT CEJ NI 4 1 – REG1 LM2940 CT-5 10k 22k CON1 USB IN 2 D2 + 3 CON2 10k USB OUT 1 + D5 4002 © Q1 PN100 3 2 22 µF 14001170 Q2 IRF9540 4 820Ω 1N4004 LED1 A + 10 µF Fig.2: follow this parts layout diagram and the photo at right to assemble the PC board. Don’t get Q2 and REG1 mixed up – they look the same! danger that its inbuilt thermal overload protection circuitry would shut the device down. It’s not hard to figure out why. After rectification and filtering, a 9V AC plugpack delivers about 13V DC to the input of the regulator (REG1) which means that there is about 8V across it. In addition, a quick check of the Maxtor drive revealed that it draws between about 350mA and 750mA or more, depending on the amount of disk activity. In fact, these figures were measured on a DMM, so the peak current draw is probably in excess of 800mA (eg, when the disk is copying large files). Assuming an average current of 500mA (0.5A), this meant that the regulator was dissipating around 4W (ie, 8V x 0.5A = 4W). No wonder it was getting hot! Substituting a regulated 9V DC plugpack is not the answer either. Although this drops the voltage on the regulator’s input to about 7.7V (after allowing for the two diode drops in the bridge rectifier), the regulator still dissipates 2.7V x 0.5A = 1.35W. That’s much better than 4W of course but the regulator isn’t fitted with a heatsink and still gets much too hot. So, as it stood, the USB Power Injector was not really up to the job of powering an external USB drive over any length of time – especially as these drives can draw 750mA or more. In fact, the original project was not designed to supply that sort of current and so was never intended for this particular task. Keeping it cool OK, that’s the bad news. The good news is that it’s easy to make a few simple changes to the USB Power Injector so that it can supply the extra current while keeping its cool. The trick is to get the dissipation in the regulator right down. We did that by making the following changes: (1) Using a 6V DC 2.2A regulated plugpack instead of a 9V plugpack (we used a switchmode design from Jaycar, Cat. MP-3482); (2) Removing the bridge rectifier and substituting a 1N5819 Schottky diode (a 1N4004 would drop too much voltage); and Choosing A Regulated Plugpack Supply To keep the dissipation in the regulator to a minimum, it’s important to use a 6V DC regulated plugpack. If you intend powering a USB hard drive, then we recommend the Jaycar MP-3482 plugpack which is rated at 2.2A, although any other 6V DC regulated plugpack rated at 1A or more would also be suitable. For devices which draw less than say 600mA maximum, then the Jaycar MP-3145 which is rated at 800mA could be used. However, it will be marginal at best for use with USB hard drives which have peak currents of 800mA or more. 60 Silicon Chip (3) Replacing the 7805 with an LM2940CT-5 low-dropout regulator and increasing the 100nF ouput capacitor to 22mF to ensure stability. In practice, the 6V plugpack we used has an output of about 6.1V. The Schottky diode drops this by about 0.4V, while the drop across the switching Mosfet in series with the regulator is negligible at about 0.05V (for 500mA). That leaves about 5.65V at the input to the regulator which now dissipates just 0.65 x 0.5 = 0.325W (or 325mW). That’s easily handled by the regulator’s metal tab and by the earth pattern at the back of the PC board which provides a modest amount of heatsinking. In practice, the regulator now runs only slightly warm to the touch when powering a USB hard drive. Circuit details Fig.1 shows the revised circuit of the USB Power Injector. As can be seen, power from the 6V regulated DC plugpack is applied via Schottky diode D2. This diode serves two purposes: (1) it provides reverse polarity protection; and (2) as indicated above, it drops the plugpack voltage by 400mV to reduce the dissipation in the regulator (REG1). A 1000mF electrolytic capacitor is used to filter the resulting 5.6V supply rail which is then applied to the source of power Mosfet Q2. CON1 is a USB “Type B” socket and this is used as the input port on the injector. This is connected to a USB port on the PC (or a hub) via a standard “Type A” to “Type B” USB cable. As shown, its two data lines (D+ & D-) are fed straight through to CON2, a “Type A” USB socket which is used as the siliconchip.com.au The PC board is mounted inside the case on four M3 x 9mm tapped spacers and secured using machine screws. Note how the 1000µF electrolytic capacitor is mounted. output port. Similarly, CON1’s ground pin (pin 4) is connected straight through to CON2’s ground pin. CON2 connects to the USB peripheral (eg, a hard drive) via another standard USB cable. As a result, USB data can pass straight through the injector (ie, between the PC and the peripheral) in either direction. The +5V (Vbus) line from CON1 is not fed through to CON2, however. Instead, it’s used to control transistor Q1. As shown, the Vbus line drives Q1’s base via a 22kW resistor. When the input cable is disconnected, Q1’s base is held low via a 10kW resistor. As a result, Q1 is off and so Mosfet Q2 is also off and no power flows through to regulator REG1. Conversely, when the input cable is connected (and the PC is on), +5V appears on pin 1 of CON1 and this turns transistor Q1 on. This pulls Q2’s gate low and so Q2 now switches on and feeds the voltage at the output of D2 through to low-dropout voltage regulator REG1. REG1 is turn provides a nominal +5V output to pin 1 of CON2 to power the external USB device. Note that when Q2 turns on, it becomes a very low resistance – somewhere around 0.1W. As a result, the voltage across it for a current drain of 500mA is just .05V. In addition, when Q2 turns on, LED1 also turns on to indicate that power is present at USB output socket (CON2). An 820W resistor is series with LED1 limits the LED’s current to around 7mA. Diode D5 protects regulator REG1 siliconchip.com.au from reverse voltage damage when the power is turned off (it’s probably not needed with the LM2940CT-5 but was included in the original circuit). The 10mF and 22mF capacitors provide additional filtering to ensure stable operation of REG1. Construction The PC board used is the same as for the previous version. It is coded 07110041 and measures 76 x 41mm. Fig.2 shows the parts layout. Note that the 1N5819 Schottky diode is fitted to the D2 position (instead of the 1N4004 previously used there), while diode D3 is replaced by a wire link. The other two diodes previously used in the bridge rectifier, D1 & D4, are left out of circuit. Begin the assembly by installing the resistors and diodes (D2 & D5). Check the value of each resistor using a DMM before soldering it into place and take care to ensure that the 1N5819 diode goes in the D2 position. Take care also with the diode polarity. Next, install the three capacitors. Note that the 1000mF electrolytic is mounted on its side, with its leads bent down through 90° to go through the board holes. All capacitors must be fitted with the correct polarity. Transistors Q1 & Q2 can go in next. Q1 is straightforward – just push it down onto the board as far as it will comfortably go and check its orientation before soldering its leads. Q2 is mounted with its metal tab flat against the board. First, bend its leads down by 90° about 5mm from its body, then fit it to the board and secure its Parts List 1 PC board, code 07110041, 76 x 46mm 1 UB-5 plastic utility box, 83 x 54 x 31mm 1 PC-mount type B USB socket, (CON1) 1 PC-mount type A USB socket, (CON2) 1 PC-mount 2.5mm DC socket (CON3) 4 M3 x 9mm tapped spacers 6 M3 x 6mm machine screws 4 M3 x 6mm machine screws, countersink head 2 M3 lock washers 1 50mm-length 0.7mm tinned copper wire (for link) Semiconductors 1 LM2940CT-5 5V regulator (REG1) 1 PN100 NPN transistor (Q1) 1 IRF9540 P-channel Mosfet (Q2) 1 3mm green LED (LED1) 1 1N5819 Schottky diode (D2) 1 1N4004 diode (D5) Capacitors 1 1000µF 16V PC electrolytic 1 22µF 16V PC electrolytic 1 10µF 25V tantalum Resistors (0.25W 1%) 1 22kΩ 1 820Ω 2 10kΩ tab using an M3 x 6mm machine screw, nut and washer. Q2’s leads can then be soldered and trimmed. Note: don’t solder Q2’s leads before June 2008 61 at right angles about 4mm above the board. This is done so that it will later protrude through the end of the case. The PC board assembly can now be completed by fitting connectors CON1-CON3. Make sure that these all sit flush against the PC board before soldering their leads. Final assembly The assembly is housed in a standard UB5-size plastic utility box. This box requires rectangular cutouts at either end to provide access to the two USB connectors (CON1 & CON2), plus a 3mm hole in the end next to CON2 to allow LED1 to protrude. A 9mm hole must also be drilled in one side of the box to provide access to the DC power socket (CON3). And finally, four holes are drilled in the base to mount the PC board. These holes are countersunk from the outside of the case, to accept countersink-head machine screws. Fig.3 shows the drilling details. Note that the sections in this diagram are all full-scale and can be used as drilling templates. Once the holes have been drilled, attach four M3 x 9mm tapped spacers to the PC board, then secure the assembly inside the box using four M3 x 6mm countersink screws. Checkout time Fig.3: this full-size diagram shows the drilling and cutout details for the plastic case that’s used to house the board assembly. USB OUT SILICON CHIP USB +Vbus PC USB PORT 6V DC INPUT Fig.4: this front panel label can be cut out and attached to the lid of the case. It can be protected using wide strips of clear adhesive tape. USB POWER INJECTOR securing its tab. If you do, you risk cracking the PC board tracks as the mounting screw is tightened. Regulator REG1 is mounted in exactly the same manner as Q2. As 62 Silicon Chip before, be sure to secure its metal tab before soldering the leads. LED1 is next on the list. It’s soldered in place with its body about 11mm above the PC board, after which it is bent down The unit can now be checked for correct operation. To do this, apply power from a 6V DC regulated plugpack and check that LED1 lights when you connect CON1 to your PC’s USB port. The LED should go off again if the cable to CON1 is disconnected. Next, check the voltage on the OUT pin of the regulator. This will probably be around 5.2-5.3V unloaded but should be very close to 5V if a load (eg, a USB hard drive) is connected. The USB specification is for a voltage in the range of 4.75-5.25V, so make sure it is in this range. The unit is now ready to power your USB hard drive or other peripheral. All that remains is to fit the lid and attach the front-panel label (Fig.4). Full-size artworks for the label and the PC board can be downloaded from the SILICON CHIP website. Finally, be sure to leave the poweronly connector on the cable to the hard drive disconnected when using the USB Power Injector. Do not plug it into a USB port on your comSC puter. siliconchip.com.au 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. IF INPUT 100k 10nF B 10nF C Q1 BC547 E +9–15V 1k 100nF 220 220pF 100k IFT1 4.7k 220 K A K C 470k D2 10nF B C AF 100nF OUT K A 10k D4 A Q2 BC547 E IF INPUT A D3 D1 10nF K IFT1: 10.7MHz IFT WITH C = 50pF ADDED, TO TUNE 9MHz IF's, OR 455kHz IFT WITH INTERNAL C FOR NORMAL INTERMEDIATE FREQUENCIES AF OUT BC547 D1–D4: OA90,1N34 ETC (REMOVE EXISTING AM DETECTOR) A K B E C Synchronous AM detector for improved shortwave reception This simple add-on synchronous AM detector will significantly ease the reception of difficult shortwave AM signals by reducing background noise, holding the signal and noise at a more constant level, and reducing selective fading and distortion. The wanted signal will always be above the atmospheric noise level and artefacts such as heterodyne whistles and added noise are not introduced. Transistor Q1 functions as a buffer, to eliminate any loading on the host receiver’s circuitry. Q2 is an amplifier/limiter which, because it is driven hard into clipping, strips any AM modulation from the received carrier. The phase of this signal is shifted by the required 90° by inductor IFT1 and the signal then used in a balanced diode ring mixer (D1-D4) to demodulate the original carrier which is injected via the two 220W resistors. The diodes are switched at the intermediate frequency (IF), thereby synchronously demodulating the wanted signal. The circuit is designed to replace the existing diode detector in the host receiver. This is done by removing the diode and its filter circuit and then connecting the input and output of the synchronous detector Photo-interrupter bias circuit for ignition systems Those people who want to use a Crane Cams optoelectronic ignition or experiment with a photointerrupter from a printer (or Jaycar’s ZD-1901) can use this simple biasing circuit. The 470W resistor from the 12V siliconchip.com.au rail feeds about 20mA through the infrared LED while the 2.2kW collector resistor ensures a clean 12V switching signal as a vane in the interrupter gap turns the phototransistor on and off. SILICON CHIP. module in its place (see diagram). You will need to check the circuit of the host receiver to make sure the AGC is supplied by a separate detector diode. If this is not the case, then the input of the module can be connected in parallel with the existing detector circuit, with the original diode being left in-situ. The output of the module is then taken to the appropriate input of the audio section; usually the top of the volume control, the mode switch or even to a separate amplifier. The input connection to the detector will need to be very short and shielded cable will be required to prevent oscillation and feedback problems. IFT1 is chosen to suit the IF, either 455kHz or as with most Icom equipment, 9MHz. In the latter case, a 10.7MHz IF coil can be used, with a 50pF capacitor across the tuned winding to allow it to resonate at the lower frequency. No other changes to the circuit are required. To set up, tune the receiver to a weak, noisy signal and adjust IFT1 for maximum signal and least noise. The rough “frying egg” sound of background noise will be reduced to a soft hiss, making the received signal easier to listen to. Lightning crashes and other “pops” will be reduced to the same level. The IF coils used can be obtained from a defunct radio-tape player and the circuit can be made small enough to be easily installed in almost any receiver. Dayle Edwards, Taylorville, NZ. ($80) +12V 470 0.5W 2.2k INTERRUPTER A DISC SPINDLE K C TO SIGNAL INPUT OF HIGH ENERGY IGNITION E June 2008 63 Circuit Notebook – Continued Infrared close object detector The circuit can be used on a line follower robot or a close object detec- tor. While shown with a 5V supply, it could be used at battery voltages from 6-9V without alteration. This circuit uses a forward facing LED to illuminate a short path and a phototransistor to detect the light reflected from obstacles. When an obstacle is detected the circuit turns on a piezo sounder and lights LED1 for a few seconds. IC1, a 555 timer, is wired as a free-running multivibrator (astable) with adjustable pulse width ranging from 100ms-1s, as determined by the components connected to pins 2, 6 & 7. Trimpot VR1 sets the output pulse width. The output pulses from IC1 drive a standard infrared sender diode (eg, LD271) via transistor Q1. While the internal infrared LED does not need to flash, this is done to conserve battery power. When reflected IR light falls on the phototransistor, it conducts to provide bias current to Q2 which also turns on Q3. At the same time, Q2 charges the 220mF capacitor at its emitter which ensures that Q3 remains on for a short time after the obstacle is detected. The infrared LED and phototransistor can be obtained from a standard photo-interrupter (eg, Jaycar ZD-1901). This is cut in half and the pieces mounted as shown in the diagram but oriented so as optimise detection of obstacles. The detection range of the circuit is about 15cm and this depends mainly on the reflective properties of obstacles. Trimpot VR2 should be adjusted to optimise sensitivity while minimising false triggering. T. K. Hareendran, Kerala, India ($40) 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 contri- 64 Silicon Chip bution 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, 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. siliconchip.com.au E C Q9 B D8 E Q8 C K A B D7 E Q7 C K A B D6 E Q6 C K A B D5 E Q5 C K A B D4 E Q4 C K A B D3 E Q3 C K A B D2 E Q2 C K A E Q1 C K B D1 A B 12 3 CP1 Vss 8 O0 O5-9 2 O1 13 4 15 5 K A. Lo is this m we on winner th’s Peak At of a las Instrum Test ent Here is a moving LED display that looks like a meteor. The leading LED is bright and the three LEDs behind it are decreasingly bright. Thus the display looks like a meteor streak rather than a moving dot, if the LEDs are set in a reasonably large circle. The circuit is a standard 4017 decade counter driven by a 555 timer in astable mode, to provide the clock signal. The speed is adjustable by potentiometer VR1 and pushbutton switch S1 provides a stop function, if required. The difference between this circuit and a standard LED chaser is that each LED is connected to those before it via a dimming resistor and a diode. For example, when LED6 is on, LED5 is also partially alight due to the current via diode D5 and the associated 560W and 220W resistors. LED4 will be dimmer still, as it is supplied with lesser current due to D4, D5, two 560W and two 220W resistors. There is even less current through LED3, fed via D3, D4, D5 and the six associated resistors. LED2 & LED1 would have negligible current and would not be lit at all. Note that the LED10 drive circuit provides dimming current to LED1 via diode D10. As the counter advances, the partially lit LEDs behind the leading LED follow along. The circuit shows only one LED for each counter output but this could be increased to three LEDs, say, per output, to show three rings. In that case, you would put three LEDs in series and reduce the 560W resistors to 220W and leave the dimming resistors at the same value. A. Lowe, Bardon, Qld. siliconchip.com.au 1 IC1 555 STOP S1 Circuit Ideas Wanted 0V 100nF 2 6 100k 100 F +9V 330k 7 8 4 3 1k 1k VR1 10k 14 MR O2 7 CP0 O3 O5 1 IC2 4017B O4 10 5 O6 6 O7 O8 11 Vdd 16 O9 E 9 10 x 10k C B Q1–Q10: BC547 K A A E D1–D10: 1N4148 Q10 B C K D10 K A D9 220 220 220 220 220 220 220 220 220 560 560 A 220 560 560 560 560 560 560 560 K K K K K K K K 560 A K K LED10 A LED9 A LED8 A LED7 A LED6 A LED5 A LED4 A LED3 A LED2 A LED1 LEDS Meteoric LED display Do you have a good circuit idea? If so, sketch it out, write a brief description of its operation & send it to us. Provided your idea is workable & original, we’ll publish it in Circuit Notebook & you’ll make some money. We pay up to $100 for a good circuit idea or you could win some test gear. Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. June 2008 65 Circuit Notebook – Continued ON/OFF RESET S1 IN S2 9V BATTERY REG1 7805 +5V OUT GND 4 10 F DEo 16 Vdd S8 100nF 1 2 3 14 15 Co Og Of CLK CKI DEi 5 7 6 f 11 e IC8 Oe 9 4026B Od Oc UCo Ob R Oa Vss DISP6 g d 13 c 12 b 10 a a f g e b c k k d 560 8 IC5, IC6, IC7, DISP3–4–5, S5–6–7 ETC (ALL WIRED AS IC4, DISP2 & S4 BELOW) +5V 100k 7 6 100k 8 4 4 3 IC2 555 1 2 1 3 1nF 10 F 16 Vdd S4 5 2 DEo 14 15 Co Og Of CLK CKI DEi 7 Od Ob UCo Vss Oa DISP2 g 6 f 11 e IC4 Oe 9 4026B Oc R 5 d 13 c 12 b 10 a a f g e b c k k d 560 8 +5V 100k 7 6 100k 7805 8 1 3 IC1 555 2 GND 10k 4 2 5 3 GND DEo 16 Vdd 1nF 1 F 14 15 Co Og Of CLK CKI DEi Od Oc Ob UCo R 5 7 Vss Oa DISP1 g 6 f 11 e IC3 Oe 9 4026B S3 1 IN 4 d 13 c 12 b 10 a a f g e b c k k d 560 8 OUT 6-digit demonstration counter This circuit uses CMOS 4026B counters which are binary coded decimal (BCD) types, meaning that they count from 0-9 rather than from 0-15 as for a binary counter. The counters are cascaded so that the carry output from one counter (eg, pin 5 of IC3) connects to the clock input of the next counter (eg, pin 1 66 Silicon Chip of IC4). Each counter counts from 0-9 and a carry-out signal is produced at the time the count returns to zero. Each counter directly drives a common cathode 7-segment display via a common 560W current limiting resistor. This economical approach will result in varying display brightness, depending on the number of segments that are lit. (Editor’s note: a more conventional approach is to use separate 560W limiting resistors for each segment and tie the cathode directly to ground). Counters IC4-IC8 can be preset with a count by pressing the associated switch that connects to the clock input. So, for example, switch siliconchip.com.au Simplified headphone adaptor Some readers who are interested in the Headphone Adaptor featured in the April 2008 issue may want to build a simplified version which does not require any logic circuitry, relays and a plugpack supply. If so, this circuit is the answer. It uses the same audio circuitry but uses two 2-pole 2-position switches in place of the two relays and associated logic. Only the right channel of a stereo headphone adaptor is shown in the circuit. Switch S1a switches the amplifier drive signal between the 22W 10W dummy load resistor and the right channel loudspeaker. Switch S2a switches the headphones on or off. There is just one drawback to this passive circuit in comparison to the relay-switched circuit in the April 2008 issue; the specified relays have 10A contacts whereas typical miniature toggle or rotary switches S4 normally connects the pin 1 clock input of IC4 to the carry out at pin 5 of IC3. When S4 is pressed, it connects the pin 1 clock input of IC4 to the pin 3 output of IC2 which is wired as a free-running oscillator. This counter will then increase in value at the clock rate. If the counter reaches 9 and returns to zero, then counter IC5 will be increased by 1 because of the carry out to clock cascading. Counters IC5, IC6, IC7 & IC8 can also be preloaded using S5-S8 respectively. These switches also connect IC2’s clock signal to the selected counter’s clock input. The first counter, IC3, is clocked using another 555 oscillator (IC1). The clocking can be inhibited by pressing switch S3. This causes the pin 2 inhibit input to go to +5V via the 10kW resistor and so clocking ceases until the switch is released. Note that while this 6-digit counter counts up at a rate set IC1, it can be clocked from an external 0-5V signal if required. 555 timers IC1 and IC2 are both connected as astable oscillators with siliconchip.com.au + SPEAKER S1a OFF 22 5W DUMMY LOAD ON AMPLIFIER RIGHT CHANNEL OUTPUT + RIGHT SPEAKER – – PHONES S2a OFF ON 270 270 VR2a 1k VOLUME PHONES 2 PHONES 1 VR1a 1k VOLUME PHONES 1 PHONES 2 AMPLIFIER CHASSIS (ONLY RIGHT CHANNEL WIRING SHOWN; LEFT CHANNEL USES S1b, S2b, VR1b & VR2b) will have contacts with much lower ratings. That will not be important if you are using this adaptor with a valve or solid-state amplifier which the capacitor at pins 2 & 6 of each device charged via two series 100kW resistors. When the capacitor voltage reaches the 2/3rds supply threshold voltage of pin 6, the pin 7 output discharges it via the associated 100kW resistor. The charge period, during which the pin 3 output is high, is 0.693 x the capacitor value x (100kW + 100kW), or 138.6ms for IC1. The discharge period (pin 3 low) is 0.693 x the capacitor value x 100kW or VR1b VR2b is rated up to about 40 watts per channel. Hugh Paton, Tallangatta, Vic. ($35) 69.3ms. The period is thus 207.9ms, giving a frequency of 4.8Hz. (Editor’s note: ideally, the pin 15 Reset inputs to IC3-IC8 should be tied to ground via a normally closed Reset switch (removed from in series with REG1) and pulled high to 5V via a 10kW resistor. That way, briefly pressing the Reset switch will momentarily pull the pin 15 Reset inputs high). Joshua Beck. ($40) Bordertown SA. Issues Getting Dog-Eared? Keep your copies safe with these handy binders Available Aust. only. Price: $A13.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. REAL VALUE AT $13.95 PLUS P&P Buy five and get them postage free! June 2008 67 Balanced/unbalanced converter for audio work By JOHN CLARKE If you work in the professional audio field, you need to use balanced lines for long signal runs to prevent hum and noise pickup. This Balanced/Unbalanced Converter is really two projects in one. It can convert an unbalanced input to balanced outputs and vice versa. P ROFESSIONAL AUDIO GEAR invariably has balanced inputs and outputs. However, what if you want to connect standard audio equipment that has unbalanced outputs to equipment that has balanced inputs? Alternatively, what if you want to connect a balanced output signal to an unbalanced input? Either way this Balanced/Unbalanced Converter project can do the job. The reason professional audio equipment utilises balanced inputs and outputs is quite simple. It’s done so that audio connections can be made over quite long distances without add68 Silicon Chip ing extra noise to the signal. These balanced connections use 3-pin XLR plugs and sockets and screened twincore cable. Fig.1 shows the basic arrangement. Basically, the audio output signal is coupled to two separate amplifiers and these drive the two signal leads in the cable in anti-phase (ie, the signals have opposite phases). In this case, Amplifier 1 has an output signal that’s in phase with the input, while Amplifier 2 has an output that’s opposite in phase with the input. The output impedance of each amplifier is the same and the twin-core cable carries the signal to the equipment at the other end. However, in some cheaper balanced line drivers, one core does not carry any signal but is grounded instead. So in this case, Amplifier 2 is left out and the lefthand side of resistor R2 is grounded. In operation, there will be some noise and hum pickup over the length of the cable even though the cable is shielded. However, because the cores in the cable are close together, any signal that is picked up will be common to both. At the receiving end, the signal in each of the two cores is subtracted to produce the original audio signal. At the same time, this also removes most of the noise and hum that was picked up in the leads, since the same noise signal is present in both. If one of the cores is grounded, as in the cheaper type of balanced driver, then the signal level after subtraction will be the same as the signal in the main core. Alternatively, if anti-phase signals are applied to both cores, the subtraction process produces an audio signal level that’s twice the level in the individual cores. As well as the increased signal level at the receiving end, using two antiphase signals gives a better result than using a balanced line driver with an earthed line. There are several reasons for this. First, when using two anti-phase signals, the two amplifiers that drive them are similar and basically follow the same impedance variations over siliconchip.com.au BALANCED OUTPUTS AMPLIFIER 1 A = +1 R1 BALANCED INPUT 2 TWIN CORE SHIELDED CABLE 2 1 SIGNAL INPUT 3 AMPLIFIER 2 (UNBALANCED) A = –1 R2 3 SHIELD Fig.1: the basic arrangement for converting an unbalanced audio input signal to a balanced signal and back again. the audio frequency range. Second, with the full anti-phase (or differential) lines, the electromagnetic field due to the signal in each is theoretically zero and so crosstalk into adjacent cables is minimised. And third, the cable will still supply signal should one of the cores be shorted due to a wiring fault (or damage). How it works Refer now to Fig.2 for the circuit details. As can be seen, it’s based on three LM833 op amps (IC1-IC3). IC1a, IC1b & IC2a make up the “Balanced Input To Unbalanced Output Converter” section. As shown, the balanced input signal is fed in via pins 3 & 2 of the XLR socket. These inputs are each tied to ground using a 100kW resistor to prevent the signal lines from “floating” with no input connected. From there, the audio signals are coupled via 10mF non-polarised (NP) electrolytic capacitors to pins 3 & 5 of op amps IC1a & IC1b respectively. The 220pF capacitor between the two inputs and the 100pF capacitors at pins 3 & 5 are included to filter RF (radio frequency) signals. In addition, pins 3 & 5 are each tied to ground via a 10kW resistor to set the DC bias for IC1a and IC1b. These 10kW resistors either connect to the signal ground or to a half-supply ground, depending on the power supply configuration used. IC1a & IC1b both operate as noninverting amplifiers with a gain of 1, as set by their 10kW feedback resistors and resistor R1 (20kW). A 100pF capacitor across each 10kW feedback resistor rolls off high-frequency signals above about 160kHz. The outputs from IC1a and IC1b apsiliconchip.com.au SIGNAL OUTPUT (UNBALANCED) 1 pear at pins 1 & 7 respectively and are summed in differential amplifier stage IC2a. For signals from IC1a, IC2a functions as an inverting amplifier – ie, it operates with a gain of -1. Conversely, for signals on its pin 3 input, it operates as a non-inverting amplifier with a gain of 2. Because of this, the signals from IC1b are divided by two using a 10kW resistive divider before being fed to IC2a. This means that each signal path has overall unity gain through IC2a. However, IC2a inverts the signals from IC1a so that they are now in-phase with the signals from IC1b. as a result, both signals add to provide an overall gain of 2. The resulting unbalanced signal appears at pin 1 of IC2a and is AC-coupled to the output via a 22mF NP capacitor and a 150W resistor. The 100kW resistor from the 22mF capacitor to ground ensures that the output signal swings above and below ground with no DC bias. Unbalanced to balanced stage A single LM833 dual op amp (IC3) is used for the “Unbalanced Input To Balanced Output” stage. As shown, the audio input signal is AC-coupled via a 10mF NP capacitor to the noninverting input (pin 3) of IC3a. A 100pF capacitor shunts any RF signal Parts List 1 PC board, code 01106081, 103 x 85mm 1 2.5mm PC-mount DC socket 2 3-way screw terminal blocks (5.08mm or 5mm spacing) 4 2-way screw terminal blocks (5.08mm or 5mm spacing) 4 M3 x 6.3mm tapped standoffs 4 M3 x 6mm screws 2 2-way pin headers (2.54mm spacing) 1 3-way pin header (2.54mm spacing) 3 jumper shunts 1 60mm length of 0.8mm tinned copper wire Semiconductors 3 LM833 dual op amps (IC1-IC3) 2 15V 1W zener diodes (ZD1,ZD2) 2 IN4004 1A diodes (D1,D2) Capacitors 2 470mF 25V PC electrolytic 1 100mF 25V PC electrolytic 3 22mF NP electrolytic 1 10mF 16V PC electrolytic 3 10mF NP electrolytic 3 100nF MKT polyester 1 220pF ceramic 7 100pF ceramic Resistors (0.25W, 1%) 6 100kW 1 4.7kW 1 20kW 4 150W 13 10kW 2 33W Specifications • • • Signal to noise ratio: -100dB with respect to 1V output, 4.7kW input load. • Signal handling: supply dependent; requires 30VDC or ±15V for 9V RMS signal handling. Frequency response: -3dB at 2Hz and 200kHz. Total harmonic distortion: less than .001% from 20Hz to 20kHz with a 1V input. June 2008 69 Table 1: Link Configurations SUPPLY LK1 ±9-15V DC OUT IN LK2 LK3 OUT OUT + 0V – 7-12V AC OUT IN OUT IN 9-30V DC IN OUT IN LK4 POWER INPUT + 0V OUT + 0V Note: install LK4 for an AC supply only Fig.2: the circuit can be split into three sections: (1) a balanced input to unbalanced output converter (top); (2) an unbalanced input to balanced output converter (centre); and (3) the power supply circuitry (bottom). to ground, while the associated 10kW resistor sets the DC bias for IC3a. Note that this 10kW resistor either 70 Silicon Chip connects to the signal ground or to a half-supply ground, depending on the power supply configuration used (this is the reason for the different earth symbol at the bottom of this resistor). The 100kW resistor at the input ties the siliconchip.com.au Power supply Power for the circuit can come from a 9-30V DC source, a ±9-15V DC source or a 7-20VAC source. The current requirements are quite modest at just 30mA. The simplest supply arrangement is to use a ±9-15V DC source (this type of supply can often be found in existing equipment). The positive rail is simply connected to the “+” supply input, the negative rail to the “–“ input and the ground to 0V. Diodes D1 & D2 provide reverse polarity protection, while two 470mF capacitors filter the supply rails. Zener diodes ZD1 & ZD2 protect the op amps by conducting if the input voltage rails exceed ±15V. A 33W resistor in series with each supply line limits the current through ZD1 and ZD2 when they conduct but note that voltages above ±18V may destroy these zener diodes. With this supply arrangement, the two different grounds on the circuit are tied together using link LK2 (see siliconchip.com.au + SIG 100nF LK3 NP 22 F 0V LK1 150 150 100k 10k NP 0V 100pF 0V 33 33 ZD2 470 F 10 F 10k 10 F NP NP – – 100k 10k IC3 LM833 100 F 220pF 100pF 100pF D2 LK4 4.7k 100k 10k 10k D1 ZD1 10k 100nF 20k 22 F 100pF 100k 10k 150 10k 10k IC1 LM833 10k 22 F NP 100nF NP 100pF 10 F 10k IC2 LM833 10k 10k + 150 100pF 100k 0V LK2 100pF 10 F – POWER INPUT 0V DC SOCKET BALANCED OUT UNBALANCED OUT 100k input line to ground when no signal is connected. IC3a is wired as a unity gain buffer stage and so its pin 1 output follows the signal input. The non-inverting (+) component for the balanced signal is then AC-coupled via a 22mF NP capacitor and a 150W resistor to pin 2 of the XLR output socket. The 150W resistor isolates IC3a’s output from external capacitive loads, to ensure stability. The 100kW resistor on the output side of the 22mF capacitor ensures that the signal swings symmetrically above and below ground. The out-of-phase signal is derived using IC3b. This stage is also fed from pin 1 of IC3a and functions as an inverting amplifier with a gain of -1 as set by its 10kW feedback resistor. As before, a 100pF capacitor across the feedback resistor shunts any frequencies above 160kHz to prevent amplifier oscillation. IC3b’s output at pin 7 is inverted compared to IC3a’s output. It drives pin 3 of the XLR socket via another 22mF capacitor and 150W resistor combination. Note that the pin assignments on the XLR socket follow standard practice. Pin 1 is the ground, while pin 2 is for the “hot” or non-inverted (+) signal and pin 3 is for the “cold” or inverted signal. + BALANCED IN 470 F /DE C NALA B DE C NALA B NU RETREV N O C 18060110 SIG 0V UNBALANCED IN Fig.3: install the parts on the PC board as shown in this parts layout diagram. Table 1 (facing page) shows how to install links LK1-LK4 to suit the selected power supply. Table 1). This biases the op amp inputs at 0V so that the signal swings above and below ground. AC supply A 7-12V AC supply can also be used to derive positive and negative supply rails. In this case, the “+” and “-” inputs are connected together using link LK4 and the supply is connected between either of these two inputs and the 0V (ground) terminal. With this supply configuration, diodes D1 & D2 function as half-wave rectifiers, with filtering provided by two 470mF capacitors. D1 conducts on the positive half-cycles to derive the positive rail, while D2 conducts on the negative half-cycles to derive the negative rail. As before, the two grounds are connected using link LK2. 9-30V DC supply The circuit is a little more complicated for a 9-30V DC supply. That’s because the signal can no longer swing below the 0V rail, since there’s no negative supply. As a result, the op amps must be biased to a mid-supply voltage, so that the signal can swing symmetrically about this voltage. This mid-supply voltage is produced using a voltage divider consist- ing of two 10kW resistors between the V+ rail and ground. A 100mF capacitor filters this half-supply rail which is then fed to IC2b. IC2b is wired as a unity gain buffer stage. Its pin 7 output drives a 10mF capacitor via a 150W decoupling resistor to produce the Vcc/2 half-supply rail to bias the op amps in the converter stages. In this case, links LK1 & LK3 are installed. Link LK1 connects the Vcc/2 rail to the junction of the 10kW bias resistors on the pin 3 & pin 5 inputs of IC1a & IC1b. It also connects the Vcc/2 rail to the pin 3 input of IC3b via another 10kW resistor. Link LK3 connects the negative supply pins for the op amps to ground. Finally, the AC coupling capacitors at the inputs and outputs of the various op amps remove any DC component from the signal. Building it The assembly is straightforward with all the parts installed on a PC board coded 01106081. This board also carries screw terminal blocks for the audio input and output connections, plus a DC socket for the power supply connections (depending on the supply used). Fig.3 shows the parts layout. Begin June 2008 71 Table 3: Capacitor Codes Value 100nF 220pF 100pF A 9-30V DC supply can be connected either via the DC socket or via the “+” and 0V terminals on the “Power Input” screw terminal block. An AC supply is connected in exactly the same manner (ie, via the DC socket or between the “+” and 0V terminals). For the ±9-15V DC supply option, connect the positive lead to the “+” terminal, the negative lead to the “-” terminal and the 0V lead to the 0V terminal. Again, make sure the links are correct – see Table 1. Apply power and check that close to the supply voltage appears between pins 8 & 4 the ICs. If the supply is 12V DC, for example, then the pin 8 to pin 4 voltage should be close to 10.3V (after allowing for a 1.7V drop across D1 and its series 33W resistor). The Vcc/2 supply, as measured at pin 6 of IC2b and at the pin 1 & pin 7 outputs of the other op amps, should be close to 10.3V/2 or 5.15V. For an AC supply, the pin 8 voltage should be positive with respect to ground and the pin 4 voltage negative. The actual voltages should be about 1.414 times the AC voltage minus about 1.7V for the diode and resistor drop. Thus, for a 9VAC supply, the voltage should be about 12.7V - 1.7V = 11V DC. This means that there should be +11V with respect to ground on pin 8 of each IC and -11V on pin 4 of each IC. Finally, for a ±9-15V DC supply, the pin 8 and pin 4 voltages should be about 1.7V less than the input voltages. For example, if the supply is ±12V DC, there should be about +10.3V on pin 8 of each IC and -10.3V on pin 4 SC of each IC. This view shows the fully-assembled PC board. Take care to ensure that the semiconductors and electrolytic capacitors are correctly installed. by checking the board for any defects such as shorted tracks or breaks in the tracks. Check also that the hole sizes for the DC socket and screw terminal blocks are correct by test fitting these parts and check that the four corner holes are drilled to 3mm. Install the links first, followed by the resistors. Table 2 shows the resistor colour codes but you should also check each resistor using a DMM before soldering it in place, as some colours can be difficult to decipher. The diodes and zener diodes can go in next, followed by the three ICs. Take care to ensure that these parts are all oriented correctly and be sure to use the correct diode at each location. We used IC sockets on the prototype but this is not really necessary and you can simply solder the ICs straight in. The capacitors are next on the list. Take care with the electrolytic types, as they must all be fitted with the correct polarity. The two 470mF capaci- mF Code IEC Code EIA Code 0.1mF 100n 104 NA 220p 221 NA 100p 101 tors are mounted on their sides, with their leads bent down through 90° so that they pass through the holes in the board. Finally, install the pin headers (for the links), the DC socket and the screw terminal blocks. The 4-way screw terminal blocks are made by sliding two 2-way terminals together, using the dovetail mouldings on either side. Installation As mentioned earlier, there are several supply options for the Balanced/ Unbalanced Converter. The current requirements are quite low at 30mA maximum when each output is driving a 1V signal into 600W. Installation is basically a matter of deciding which type of supply you want to use and then choosing the linking options – see Table 1. Note that link LK4 is installed only for an AC supply. Table 2: Resistor Colour Codes o o o o o o o No. 6 1 13 1 4 2 72 Silicon Chip Value 100kW 20kW 10kW 4.7kW 150W 33W 4-Band Code (1%) brown black yellow brown red black orange brown brown black orange brown yellow violet red brown brown green brown brown orange orange black brown 5-Band Code (1%) brown black black orange brown red black black red brown brown black black red brown yellow violet black brown brown brown green black black brown orange orange black gold brown siliconchip.com.au Review by LEO SIMPSON ALTITUDE 3500-SS Stereo Valve Amplifier Amplifier Some readers may be annoyed by the sight of a review of a valve amplifier in SILICON CHIP – but we often get requests to publish a modern design. So we thought it would be useful to put this model through our usual performance testing. L et’s get one thing straight: we are biased! Most readers will already know that as we have always stated our preference for solid-state amplifier designs, even though quite a few people are interested in valve amplifiers. Having noted our bias, let’s try to set it aside while we check out the impressive Altitude 3500-SS amplifier. This very well presented amplifier is siliconchip.com.au made by Fountek Electronics Co Ltd, in China but has been carefully tweaked for our market by the noted Australian designer, Russell Storey, on behalf of WES Australia. It is fairly conventional in layout, with the valves on top of and toward the front of the chassis while the very large power and output transformers are at the back. These transformers have cylindrical housings but they are unlikely to be based on toroids – they are too tall for that. We think they probably have conventional E-I laminated cores. The chassis itself is especially impressive, being made from interlocking aluminium extrusions 7mm thick while the top and bottom plates are 3mm thick aluminium secured with multiple stainless steel countersunk screws. Everything has been precision June 2008 73 Underneath, the Altitude 3500-SS is very neat, just like the top side. The only real giveaway that it is a valve amplifier are the sockets on the PC board (and possibly the absence of ICs and transistors!). This shot also gives a good idea of the rear panel input/output layout with its gold-plated sockets. machined for close fit of all sections. The valve sockets are recessed into the top of the chassis and they sit on a large PC board underneath. The front panel knobs also fit into machined recesses on the panel. The valve line-up is two 12AX7 and two 12AT7, both twin triodes, and four EL34 pentodes, used as matched pairs in each channel. The valves are branded ElectroHarmonix, a US-based company but they are labelled “Made in Russia”, as are most valves these days. By the way, that is not a back-handed comment on quality – Russian-made valves are equal to the best that were made in the past. 74 Silicon Chip As far as we can tell, each channel uses the 12AX7 as a direct-coupled cascode preamplifier stage and the two triodes in the 12AT7 are used for the phase-splitter driver to the push-pull pentode output stages. The pentodes appear to be connected in simple push-pull and not ultra-linear, which implies transformer primary connections to the pentode screens. The output transformers have secondary taps for 4W and 8W connections so there are three gold-plated binding post terminals for each channel on the back panel. Also on the back panel are four pairs of gold-plated RCA sockets which are intended for line level signals and are labeled CD, Tuner, Aux1 & Aux2. The mains power connection is made via a 3-pin IEC socket, the same as used on computers and a lot of consumer electronics equipment these days. The front panel is very clean and simple, with two large knobs, Selector and Volume, flanking the centrally mounted push-on push-off power switch and the four LEDs which indicate the selected source. An interesting feature on top of the chassis is the inclusion of two stainless steel vertical plates which deflect heat from the valves away from the transformers. This is one of the modifications for the Australian market. siliconchip.com.au We asked Russell Storey for some details about the modifications for the local market. Apparently the stainless steel plates have two advantages. First, they greatly reduce the heat rise of the power transformer (“by at least 22°C”) and second, they reduce the induction of 50Hz hum into the output pentodes which has resulted in less output hum and intermodulation. Another significant difference in the Australian version (referred to as Altitude 3500-SS) includes a change to the power transformer primary voltage from 230V to 240V which has the effect of reducing filament voltages to the correct range for longer valve life and also reduces overall power consumption by about 9%. Other changes to the circuit include improved amplifier slew rate, matched EL34 valves and factory selection of the 12AX7 and 12AT7s for low noise and optimum gain. By the way, for those not familiar with valve amplifiers, they do get stinking hot. This will be quite obvious for old-timers familiar with valves but newcomers will be astonished. The output pentodes get hot enough to give you a serious burn if you are not careful. As the owner’s manual states: “Keep out of reach of children. Valves get hot!” Under the chassis Most of the circuitry under the chassis is mounted on a large doublesided PC board, as mentioned above. Audio Precision The only components mounted on the topside of the PC board are the ceramic valve sockets and the board is mounted so that the tops of the pentode valve sockets just sit flush with the top surface of the chassis. The smaller ceramic triode sockets sit lower so that the valves end up being slightly recessed into the chassis. There is a small vertical PC board associated with the RCA input sockets and this carries four double-pole relays and the associated transistors which are switched by the front panel rotary switch. All the power supply components are on the mains PC board, apart from the iron-cored choke which is mounted underneath the chassis. There are also small PC boards associated with the rotary selector switch, the dual ganged volume control and the four front panel LEDs which indicate which source is selected (1-4). Good quality components are used throughout and the overall standard of workmanship is excellent. The Altitude 3500-SS sits on three large feet, two at the back and one in the front, more or less corresponding to the heavyweight transformers. As an aside, we found that the feet are too hard and as a result, the amplifier will slide quite easily on hard surfaces. In fact, at one stage we almost had the amplifier slide off a small coffee table. We hate to think of the consequences. . . Apart from that little drawback, the Altitude 3500-SS ticks the boxes for Frequency Response 8 Ohm (1W) 04/18/08 10:38:25 The frequency response is very flat, less than –1dB down at 50kHz and ruler flat at the low end to below 10Hz. Those output transformers must be exceptionally good. siliconchip.com.au Audio Precision all the right features; it really is most impressive in its presentation. Specifications The Altitude 3500-SS is rated at 32 watts per channel into 8 or 4-ohm loads, for a rated total harmonic distortion of 0.63% at 1kHz. Its frequency response is 15Hz to 50kHz ±0.5dB (1W), while its power bandwidth is 10Hz to 90kHz at the -3dB points. Its signal-to-noise ratio is -76.2dB unweighted, with respect to full power (32W). Input sensitivity is quoted as 375mV RMS for full power. These are very respectable specifications for a valve amplifier, particularly with regard to signal-to-noise ratio. This is one of the quietest valve amplifiers we have ever come across and there is certainly no hum evident from the speakers – the noise is just a faint hiss. Significantly, there does not appear to be any sign of microphony either. To explain, microphony is a problem in high gain audio valve circuits and is an audible ringing heard through the loudspeakers, when any of the valves, particularly those in the small signal stages (ie, 12AX& etc) are tapped. Performance The six graphs included in this article give a pretty good picture of the amplifier’s performance. In general, we would have to state that it has come very close to meeting all of its specifications. We have also included a number of Cross Talk vs Freq 8 Ohm (1W) 04/18/08 10:35:40 The separation between channels. This demonstrates commendably low crosstalk in the small signal stages and very little crosstalk via the power supply rails. June 2008 75 The amplifier operating in the mid-power range with a 1kHz sinewave: the yellow and green traces show both outputs while the purple trace is the residual harmonic distortion from one channel, at around 0.5% THD. digital scope waveform grabs to illustrate the amplifier’s typical distortion performance. For example, the scope grab immediately above shows the amplifier driven with a 1kHz sinewave at 25W into an 8-ohm load. The top two traces (yellow and green) show the outputs from both channels while the blue trace shows the harmonic distortion waveform which consists of mainly lower order harmonics (about 0.6% THD). Other scope waveforms are included to show the performance with square waves at 1kHz and 10kHz (at 5W into 8-ohm loads), with and without a 2mF capacitor shunting the load. The 2mF capacitor is a severe test of amplifier stability and while it causes noticeable Audio Precision The square wave response of the amplifier at 1kHz. The yellow trace is the input signal while the green trace is the amplifier output. As you can see, the wave shape is pretty good with only modest overshoot and minimal ringing. ringing on the waveform the amplifier’s performance is commendably stable. No problems there. We should also note our measurement for signal-to-noise ratio. This was measured with respect to 32W into 8-ohm loads and gave a result of -76dB unweighted, with a measurement bandwidth of 22Hz to 22kHz. That’s a very good figure for a valve power amplifier. As always when we test an amplifier, we check its damping factor, particularly at low frequencies. Damping factor is the ratio of the nominal loudspeaker impedance to the output impedance of the amplifier and is an indication of how well the amplifier “controls” the loudspeaker’s cone THD+N vs FREQ 4 Ohm (25W) 04/18/08 10:42:43 Audio Precision excursions, particularly within the “piston” range below about 500Hz. Solid-state amplifiers generally come up with very high figures for damping factor and this is partly due to the fact they employ high orders of negative feedback and partly due to the fact that they are inherently low impedance sources which can provide lots of drive current. By contrast, valve amplifiers employ output transformers and these limit the amount of negative feedback which can be applied before instability becomes a problem. The Altitude 3500-SS evidently uses very high quality output transformers but they still have the same limitation. THD+N vs FREQ 8 Ohm (25W) 04/18/08 10:43:30 These two graphs show the distortion versus frequency at a power level of 25W into 4 and 8-ohm loads. Interestingly, one channel (red trace) was significantly better than the other, although both were within specifications. 76 Silicon Chip siliconchip.com.au This scope grab shows the square wave response of the amplifier at 10kHz. The upper trace (yellow) is the input signal while the lower trace is the amplifier output. This is very good for 10kHz and any ringing is very well damped. We measured damping factor at a power level of 1W into an 8-ohm load and the result is 1.68 at 1kHz and 1.64 at 100Hz. These figures are equivalent to an output impedance of about 4.7W (using the 8W connection). If the 4W connection is used, this output impedance should be halved. Power consumption We measured the power consumption of the amplifier at around 135W with no signal present, rising to around 230W with both channels driven to full power (32W; ie, a total of 64W). This level of power consumption is about what you would expect from an amplifier of this power rating. As an aside, we were pleased to Audio Precision Finally, this shows the amplifier driven with a 10kHz square wave with the output shunted by a 2mF capacitor. This is a stiff test for any amplifier and demonstrates a high level of stability with any ringing still well damped. note that the owner’s manual recommends against leaving the amplifier permanently switched on. This would not only waste electricity but greatly reduce the operating life of the valves. Also noted in the manual is the fact that the valves will need replacing after several years, depending on how much use they get – this applies particularly to the output pentodes which should all be replaced at the same time, as matched pairs. Sound quality We spent quite a lot of time listening to this amplifier with a range of CDs and feeding a pair of very good loudspeakers. And while this was never going to change our overall opinions about THD+N vs Power 4 Ohm 04/18/08 10:46:28 Audio Precision valve versus solid-state amplifiers, we have to state that this particular valve amplifier performs very well. As already noted, it is particularly quiet and it gives a good account of itself on a wide range of musical programs. If you are attracted to the sound of valve amplifiers, you will really like this one. Recommended retail price of the Altitude 3500-SS is $1899.00 including GST. It is available direct from Wagner Electronic Services Australasia, 138 Liverpool Road, Ashfield, NSW 2131. Phone (02) 9798 9233. www.wagner. net.au The amplifier can also be purchased from Stones Sound Studios www. stonessoundstudio.com.au SC THD+N vs Power 8 Ohm 04/18/08 10:48:44 Here is the distortion versus power for both 4 and 8-ohm loads, at a frequency of 1kHz from 50mW up to the level of clipping (where the THD values rise rapidly). Again, one channel is significantly better than the other siliconchip.com.au June 2008 77 PRODUCT SHOWCASE Mobile 4-Channel DVR with 250GB Hard Disk Security DVRs (Digital Video Recorders) are not new... but but this one from Jaycar is! It’s mobile – that is, works from 12-24V and is intended for mobile security and surveillance applications. With four channels, it provides real-time monitoring and digital recording from up to four cameras and will accept up to four alarm trigger inputs and an audio input. Video is recorded in high-quality MPEG4 format at a resolution of 720 x 576 at 50fps or 360 x 288 at 100 fps. Video monitoring can be via composite video or VGA monitor output. The system supports motion detection recording, scheduled recording, OSD setup, event logging and file search. A regulated 12VDC output is available that can be used to power the cameras or other low powered 12V equipment. The system includes software to enhance and correct video images and reduce unstable image movement caused by Contact: Jaycar Electronics (all stores) camera vibration etc. The recorder comes with a 250GB PO Box 107, Rydalmere NSW 2116 hard drive already installed, and will Order Tel: 1800 022 888 Fax: (02) 8832 3188 accept a drive over 400GB if required. Website: www.jaycar.com.au New LED colour range Cree, Inc. repesented by Cutter Electronics and a market leader in LED lighting, has expanded its family of XLamp® XR-C highpower LEDs to include royal blue, blue, green, amber, red-orange and red. These LEDs are available in production quantities. Standard flux order codes at 350mA are available up to: • 350mW in royal blue, • 23.5 lm in blue, • 67.2 lm in green, • 51.7 lm in amber, red/orange and red. The XR-C color LEDs feature the same isolated thermal path, low thermal resistance and high reliability as the white LEDs in the XR-C family. They also offer a smooth upgrade path for customers looking to use the same footprint as the XR products. Contact: Cutter Electronics 5 Highgate Way, Rowville, Vic 3178 Tel: (03) 9753 9911 Fax: (03) 9753 9455 Website: www.cutter.com.au ANTRIM Aussie’s own Ots Labs releases OtsAV DJ, Radio and TV International software success story Ots Labs, based on Queensland’s Gold Coast, has released a powerful new OtsAV DJ, OtsAV Radio and OtsAV TV version, providing powerful MIDI Hardware Control, world-first Zorphing and more! This is a free upgrade for all licensed OtsAV DJ, OtsAV Radio and OtsAV TV users (including former Pro-licensed users). The NEW OtsAV 1.85.064 release delivers: • MIDI Hardware Control supporting all MIDI-compatible hardware via flexible and user-editable OHML (Ots Hardware Mapping Language), including 2-way MIDI control for LEDs and supported screens. (OtsAV DJ Pro/Classic, OtsAV Radio Broadcaster, OtsAV TV Broadcaster only). • Native MIDI support (OHML) • Old School mode. Route Deck A through to your External Mixer Channel 1 and Deck B to Channel 2, for hands-on mixing, while still benefiting from the Ots Labs Dynamics Processor, Automated Beat Mixing and Automated Fade Mixing as desired. • ASIO cue/secondary channel support. • World-first Zorphing (scratching with tempo). • New low-pass filtered high quality scratching. • Support for additional information sent via Shoutcast streams for copyright compliance (Album Title and Item Copyright). Users with an OtsDJ 1.15 Silver or Boombox Contact: licence can benefit from the many more features Ots Labs Pty Ltd added. The new 1.85.064 licensed version can PO Box 1177 Surfers Paradise, Qld, 4217 be downloaded from http://www.otsav.com/ Tel: (07) 5570 3333 Fax: (07) 5570 3999 Website: www.otslabs.com.au download/relnotes.html 78 Silicon Chip TRANSFORMERS manufactured in Australia by Harbuch Electronics Pty Ltd harbuch<at>optusnet.com.au Toroidal – Conventional Transformers Power – Audio – Valve – ‘Specials’ Medical – Isolated – Stepup/down Encased Power Supplies Toroidal General Construction OUTER INSULATION OUTER WINDING WINDING INSULATION INNER WINDING CORE CORE INSULATION Comprehensive data available: www.harbuch.com.au Harbuch Electronics Pty Ltd 9/40 Leighton Pl, HORNSBY 2077 Ph (02) 9476 5854 Fax (02) 9476 3231 siliconchip.com.au Grandad’s Crystal Calibrator in 21st Century! Grandad’s Electronics (a registered tradename of Novatech Instruments, Inc.) has introduced the Model XTAL1, a 100kHz crystal calibrator kit. This is a small (67mm by 45mm) circuit which contains a 100kHz crystal controlled Pierce oscillator, rich in harmonics past 30MHz. On board is a Hartley modulation oscillator which can be switched on for producing tones on AM-only radio receivers. Power is supplied by two AAA (LR03) alkaline batteries mounted on the back of the board. The crystal oscillator is capable of being tuned to within ±30ppm of true zero-beat. The low power and small size allow the XTAL1 to be carried to ham conventions to make quick test of radios that you are thinking of purchasing. You can easily custom modify this board to fit with your Contact: Boat Anchor radio. The XTAL1 list price is $17.95 (USD). Novatech Instruments Inc Delivery is via US Postal Service First PO Box 55997, Seattle, WA 98155 USA Class Mail ($2.00 USA, $4.50 ROW). Website: www.novatech-instr.com/grandadselectronics.html PayPal accepted. Microgram’s wireless trackball keyboard This streamlined, full-featured RF keyboard with built-in track ball goes where you go thanks to its 2.4Ghz radio link with a 15m effective working range. With notebook keyboard module, it enables handheld operation and effortless typing. It offers 360° navigation in a sleek and elegant design. It also sports a USB port. Like Henry’s Ford, you can have any colour you like, as long as its black! Contact: Microgram Computers PO Box 8202, Tumbi Umbi, NSW 2261 Tel: (02) 1800 625 777 Fax: (02) 4389 0234 Website: www.mgram.com.au Matrix Multimedia’s new ARM Flowcode Matrix have recently launched a new version of their popular graphical programming language for microcontrollers – ‘Flowcode for ARM microcontrollers’. 32-bit ARM microcontrollers are now available for the same price as 8-bit micros but offer massive advantages to developers: low power, more I/O lines, several times more ROM and RAM than a typical 8-bit micro, full floating point and maths libraries and a massive increase in processing speed and power. This new version of Flowcode provides engineers and developers access to all of these features of the ARM based on Atmel’s popular range of AT91 microcontroller range. Flowcode for ARM is also backwards compatible with Flowcode for PICmicro siliconchip.com.au microcontrollers and Flowcode for AVR microcontrollers which provides an easy migration route to 32-bit power. ARM hardware development tools, based on the Matrix’s Eblocks range, are also available. A fully functional demonstration version is available on the Matrix web site. Ozitronics Tel: (03) 9896 1823 Fax: (03) 9011 6220 Email: sales2008<at>ozitronics.com K146. 40 Second Message Recorder Multiple message recorder up to 40 seconds. Non-volatile memory using ISD2540 chip. Message looping switch to repeatedly play the first message. Hurry while stocks last! $33.00 More kits & documentation available on website: www.ozitronics.com Verbatim’s colourful LightScribe DVDs Verbatim Australia has started shipping the world’s first colourbackground LightScribe 16x DVD+R media. The 25-disc spindles of 4.7GB LightScribe DVD+Rs are available in vibrant shades of red, orange, yellow, blue and green in addition to the original gold colour and include five discs of each colour. With a rainbow of background colours to choose from, consumers and businesses can burn customised LightScribe labels for their videos and multimedia presentations that will give them a professional look. Verbatim’s new coloured LightScribe DVD+Rs were specifically designed for LightScribe-compatible drives and the latest software licensed by Hewlett-Packard Company (HP). According to HP, approximately 50 million LightScribe-enabled drives are currently installed and that number is growing at 4-5 million per month. Coloured LightScribe DVDR discs are label-compatible with all LightScribe-enabled drives. For optimised labelling, Verbatim recommends that users always upgrade their LightScribe system software to the latest version. Software and label gallery downloads are available at www.lightscribe.com. To ensure that the discs LightScribe users produce can be played by the broadest number of CD/DVD playback devices, Verbatim’s complete family of LightScribe media is fully compatible with all current CD-R, DVD-R and DVD+R standards. SC Contact: Contact: The Factory, Emscote Street South, Halifax, W. Yorks, HX1 3AN, England Website: www.matrixmultimedia.com 6 Weir St, Glen Iris VIC 3146 Tel: (03) 9823 0999 Fax: (03) 9824 7011 Website: www.verbatim.com.au Matrix Multimedia : Verbatim Australia June 2008 79 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/ A simple way to copy slides onto your computer’s hard drive A Quick’n’Easy Digital Slide “Scanner” Design by BRIAN COULSON Do you have a large collection of slides which are deteriorating by the day? Are they growing mouldy or becoming discoloured? Then there is no time to waste. Get them onto your computer’s hard drive before it is too late. This method is very quick, simple and does not require any electronics. W e’re sure a lot of readers would be familiar with this problem, because many people have large collections of slides (transparencies) which they have collected over the years, or boxes inherited as older generations pass on. They’re often of too much sentimental value to throw out, so they sit in the back of a cupboard somewhere, perhaps not seeing the light of day for perhaps decades. But if you have looked at any of them recently, you may well be horrified at their deterioration. Slides suffer from two main problems – they discolour or they grow mouldy. So how do you preserve your priceless family history? If you don’t do something soon, it may well be too late to recover any image at all. Once an image starts to deteriorate, it keeps on deteriorating. And some slide films of yesterday are well known for deteriorating virtually from day 1! Perhaps you even have a scanner – but have been putting it off for a rainy day when you will get down to it. But most flat-bed scanners are not suitable for scanning slides because their light source is reflective, not transmissive. Even flat-bed scanners with transparency adaptors are seldom ideal, being a compromise. To scan a transparency properly, you need a scanner designed for the 84 Silicon Chip purpose. And they don’t come all that cheap (unless you can pick one up on eBay – and if you want one, there are quite a few to choose from!). But there is a method available to anyone with a reasonable digital camera (say 5-megapixel or better with a macro lens). With that, you already have most of the solution. With the simple set-up described here, you can rapidly scan a lot of slides – much more quickly than if you used a specialised scanner. It’s cheap, not-so-nasty – and it works reasonably well! We must point out that the method described here can never achieve as good a result as you would get from a dedicated slide scanner. In fact, we did an A:B comparison with our Canon slide scanner and found that while the method works, and is fast, the comparison of quality of A light source (40W bulb mounted in a tin can!), a slide holder with an ice-cream carton lid “neutral-density” filter and a digital camera with macro lens – that’s all there is to this you-beaut digital slide scanner! siliconchip.com.au Here’s the result we achieved using the set-up described here. It’s not too bad, considering the simplicity – but you would not be able to enlarge it much beyond postcard size. The other BIG advantage is that this took about 10 seconds to set up and capture. resultant picture is chalk and cheese, especially if you want to enlarge the image beyond postcard size. We’ve reproduced a couple of images from our experiments to show the difference. We used both a 5MP Fuji “happy snap” (albeit with macro function) and a 6MP Nikon DSLR fitted with a quality macro lens. There wasn’t much difference. We found that we could print both to postcard size; any larger and the quick method resulted in quite markedly inferior results. Having said that we know that, by far, the lion’s share of prints made from digital images are no bigger than postcard size, so this limitation may not even be of concern. It’s certainly good enough for the pics to share amongst family members. If you have a digital camera, give it a go: you have nothing to lose except a bit of time! The set-up The complete set-up consists of a digital camera, a slide holder which doubles as a glare shield and a light source. The camera shown in these photos is a Ricoh 3MP with macro. Its minimum focus distance (macro) is 12mm. It was used in the macro mode; the distance from the lens (extended) to the slide was about 25mm. But as already noted, we think you should use a 5-megapixel camera as a minimum (and these are becoming remarkably cheap these days). The method is very simple. A slide is placed in the holder which is backlit siliconchip.com.au For comparison, this is from our dedicated Canon 4000AS Slide Scanner. Overall, the definition is quite a lot better – but this took about ten minutes to set up, scan and save! Limitations of the offset printing process may not show the resolution but this could be enlarged to A3+ without problems. by a standard 230/240VAC 40W incandescent globe. A neutral density filter placed behind the slide stops it getting too hot, while at the same time ensures that the light is evenly distributed. The camera is focussed onto the slide, you press the button and you are done. You only have to focus the camera once, as it remains in position for each shot. Once you get into the swing of things, removing and replacing slides and pressing the shutter button, you can scan slides at the rate of one every few seconds. You can certainly get through a batch of a few hundred in under an hour. Take it from us; this is very much faster than you could do it with a specialised slide scanner. After you have done a batch, you can download the shots into your computer for further processing with Photoshop or similar photo-processing software. You could then print them on your own colour inkjet or laser, or simply take a CD or flash memory stick to the local digital processor to get them printed. The slide holder is very basic and we are sure that readers will be able to come up with more refined versions, if they wish. As you can see from the photo, it consists of a piece of timber with a block at one end to place it on a slope. The slide holder was made from two pieces of 3-ply with appropriate cutouts, glued together. Note that the holder is open on the camera side which makes for faster loading of the slide. Having the unit on a slope helps hold the slide in position, as well as making it easier to view the camera’s rear fixed screen. Although the featured camera only has auto focus in the macro mode, this did not prove a problem, as it focuses in about one second. The overall dimensions of the slide holder may seem larger than necessary but it also functions as a light shield when you are working at the camera end. The light source is a standard clear 40W Crompton Fancy Round incandescent lamp mounted in a standard cordgrip lamp holder and fitted inside an 825ml fruit tin. The clear lamp was found to give better lighting than a 40W frosted lamp. The fruit tin protects the light from physical damage and prevents contact with the very hot globe. The tin itself gets quite hot but not nearly as hot as the naked globe and it prevents local glare and light flare. The neutral density diffuser on the slide holder is a piece of white plastic cut from an ice-cream container. So there you are: a crude and simple jig for scanning all those slides. It does not need to be anything fancy although we would be inclined to make a better mounting arrangement for the camera so that if it is set up for fixed focus, it will not move around while you shoot each slide. Our thanks to Brian Coulson for coming up with this very simple set-up. SC June 2008 85 Vintage Radio By RODNEY CHAMPNESS, VK3UG The Pye TRP-1 Portable HF Transceiver Despite government opposition, radio communications spread rapidly in Australia following the end of WW2. Released in 1949, the Pye TRP1 was one of the new breed of HF portable transceivers designed to meet the growing demand for suitable equipment. This view shows the fully restored transceiver. The original brown cabinet was resprayed a hammertone green colour and looks new again. 86 Silicon Chip F OLLOWING THE END of World War 1, many groups pushed for the widespread adoption of radio communications despite strong government resistance. In Australia, these groups initially included people who were remote from telephones and the tele graph systems of the day. One pioneer, the Rev. John Flynn oversaw the development of radio communications for what was to become the Royal Flying Doctor Service. The first of his innovative pedal-powered radios came into use in 1929 and used several shortwave frequencies. Fishing trawlers also started using radio communications at about this time. Early radio transceivers were quite bulky but as World War II approached, a number of “compact” transceivers were developed for the Flying Doctor Service, rural fire brigades, small aircraft, fishing vessels, forestry and farming groups, and surveyors and government departments. However, the number of sets produced during this period was not large as the government was still reluctant to licence radio communications services and placed many obstacles in the way of those wishing to use this medium. In addition, suitable radio transceivers were expensive to produce, were still relatively bulky and were nowhere near as effective as communications equipment is today. After being exposed to HF radio communications during WWII, many returned servicemen could see the value of HF communications in peacetime. As a result, radio communications began to rapidly expand in the civilian sector and a number of companies produced suitable equipment to meet the demand. One such company was Pye-Electronics Pty Ltd, which included Electronic Industries Ltd and Radio Corporation (Astor). The TRP1 transceiver Just prior to WWII, Radio Corporasiliconchip.com.au tion designed and built the RC-16B HF transceiver (and the ATR4A/B military version). This covered the 3-7MHz band and had a transmitter output of around 1.5-2W. It was quite effective for its time but its battery drain was quite high, the set consuming around 4W of power on receive and 12W on transmit. It was hardly a lightweight either, with the equipment packs adding up to around 19kg. With the availability of lowcurrent miniature valves after the war, Pye decided to design and build a replacement for the RC-16B. It would have similar performance to its predecessor but would be considerably lighter and use less power. In addition, its tuning range would be 2.7-7MHz, which is slightly wider than the tuning range of the RC-16B. The result was a portable HF amplitude modulated (AM) transceiver designated the TRP-1 and released in 1949. This set used a conventional chassis made from “Duralium” (a lightweight aluminium alloy) and this in turn was housed in an aluminium case to keep the weight down. Designed for use either as a semifixed portable or as a true portable transceiver, the TRP-1 consumes around 2.6W on receive and around 9W on transmit (considerably less than the RC-16B). Configured as a “Walkie-Talkie” station, it weighs just 9.5kg and the receiver draws 350mA at 1.5V, 14mA at 150V and 0.06mA at -10.5V. As expected, the transmitter draws considerably more, with 540mA at 1.5V, 50mA at 150V and 100-200mA at -10.5V. The portable battery weighs 3.6kg while the larger “camp” battery weighed in at a massive 16.7kg. Circuit details Fig.1 shows the circuit details. The receiver is a conventional superhet with a 1T4 RF stage, a 1R5 converter, a 2-stage IF amplifier using 1T4 valves, a 1S5 detector/AGC/audio amplifier and a 3V4 audio output stage. A bias of -4V is used for the 3V4 and this is obtained directly from a tapping on the -10.5V bias battery. The RF, converter and the first IF stages all have simple AGC applied siliconchip.com.au Above: the top of the chassis is neatly laid out, with good access to all parts. to them. The converter can either be manually tuned across the 2.77MHz band or accurately tuned to a spot frequency using a crystal oscillator. The high tension (HT) for the receiver is supplied by a 150V battery via two parallel 10kW resistors. These drop the voltage to around 75V when the receiver is operating. Now let’s take a look at the transmitter section. As shown, it uses a 3S4 as a crystal oscillator and driver for the output stage. This stage has -4V of bias applied to protect the valve in the event that crystals are not fitted to all three possible positions (ie, if a vacant position is selected by the frequency switch). The oscillator plate circuit is tuned by C31, C32 or C33 to suit the particular crystal selected by switch S2. The RF output stage consists of two double-triode 3A5 valves, with all sections in parallel. Each plate is fitted with a 50W “parasitic stopper” resistor to prevent spurious signals from being transmitted. With four triodes in parallel, it is mandatory to include a neutralising The cabinet had been knocked about during its life and had quite a few dents and flaking paint. The dents were knocked out and the cabinet resprayed green to match an earlier production run (see facing page). circuit. In this case, neutralisation is achieved by feeding back energy in anti-phase via the tapped secondaries of driver coils L5 and L6. The resulting anti-phase signal is applied via neutralising capacitors C27 & C28 to June 2008 87 88 Silicon Chip siliconchip.com.au Fig.1: the receiver section is a conventional 6-valve superhet based on V1-V6. The transmitter circuit is also conventional and uses a a 3S4 as a crystal oscillator and two 3A5s in parallel for the RF output stage. switches the antenna from the receiver to the transmitter, disconnects the receiver filaments and applies 1.5V to the transmitter filaments. Note that the HT is left on at all times in both the transmitter and the receiver. This means that no work should be done on either the transmitter or receiver sections with the set turned on. Restoration Although neat, the wiring under the chassis is quite crowded, making some parts difficult to access. The paper capacitors all required replacement. null out the grid-to-plate capacitance in the valves (this circuit is similar to that used in the early triode-tuned radio frequency (TRF) receivers). Note that the output circuit is manually tuned and the circuit loaded for best output on each transmission frequency selected. The modulator is the essence of simplicity. It consists of a carbon microphone, a -10.5V supply to power the microphone and provide bias for the RF output stage, plus a microphone transformer (T5). In operation, speech signals are picked by the microphone and fed to transformer T5. This then modulates the transmitter by applying the audio signal directly to the grids of the 3A5 valves which operate with the full -10.5V of bias. The changeover from receive to transmit is accomplished by pressing the press-to-talk (PTT) button on the microphone. This grounds one side of the changeover relay which then siliconchip.com.au As can be seen from the photographs, the cabinet of the unit featured here had been knocked around quite a bit. In fact, the paint was flaking off and the cabinet had a few dents in it but this is understandable considering the type of work the set did. I knocked out the dents in the case using a small hammer and a heavy flat piece of metal which was placed behind the surface being worked on. That done, the case was cleaned with a turpentine-soaked rag to get rid of any grease and then sanded to remove any loose paint. Next, I covered the rubber grommets and the labels on the cabinet with masking tape and gave the worst areas a coat of spray primer. The first production run of these sets was painted a green hammertone colour but this one, part of a later run, was painted a salmon colour. However, I repainted this unit hammertone green like the Taken from the handbook, this photo shows the TRP-1 transceiver (centre) complete with all its accessories, including batteries, antennas and the microphone. The large “camp” battery at top left was optional June 2008 89 Photo Gallery: AWA 7-Transistor Radiola the plug and to the set. The wire colours are different to those in the original cable so I had to be careful that I didn’t wire the 150V HT lead to the 1.5V filament line. However, just to make sure I hadn’t made any errors, I removed all the valves and applied power from my power supply. A quick check with a DMM then confirmed that everything was correct. While the valves were out, I sprayed each valve socket with Inox to clean any corrosion off the socket pins. Fortunately, the chassis was relatively clean on both sides and only needed a light dust out with a small paint brush. An air compressor can also be used (with care) for this job. Overhauling the receiver MANUFACTURED BY AWA in the 1960s, the Radiola Transistor Seven came in quite a few model numbers, each based on a small upgrade. These model numbers included the B19, B19Y, B19Z B24, B24Z & the B52. The transistor line-up was as follows: 2N1639 converter; 2N1638 first IF amplifier; 2N406 overload; 2N1638 second IF amplifier; 2N408 audio driver; and 2 x 2N408 push-pull audio output stage. The diode detector was a 1N87A. The audio output was just 150mW before noticeable distortion and although this doesn’t sound much, it was still very acceptable. Photo supplied by the Historical Radio Society of Australia Inc (HRSA), PO Box 2283, Mt Waverley, Vic 3149. www.hrsa.net.au first production run, as I had almost a full can of this relatively expensive paint. In fact, I had previously used it to repaint another communications transceiver (ie, the Harbros 12/54B featured in October 2005). With the painting completed, I removed all the knobs and cleaned them with warm, soapy water and a nail brush. They were then thoroughly rinsed and allowed to dry before being put back on the set. I also had to remove the receiver’s tuning-dial for service and this is done by loosening two screws on the gang shaft. The dial is then slid forward along with the tuning knob and the edge-drive mechanism slipped off the edge of the dial. I cleaned the dial-drive system and then proceeded to carefully reassemble it. The two pressure washers, which grip on opposite sides of the dial scale, are under quite some pressure from a coil spring. They took some separating but with perseverance I succeeded in getting them to once 90 Silicon Chip again grip the edge of the dial. That done, I reassembled the drive. All of the control shafts were then lightly oiled so that they operated smoothly, although none was stiff due to congealed oil or grease. Perished battery cable The battery cable had perished rubber leads, which could have caused shorts in the set or placed 150V onto the valve filaments with disastrous results. The safest thing to do was to replace this lead entirely. I removed the 4-core cable from the set, along with its plug. The plug cover was a bit rusty so it was cleaned up and spray-painted matt black. Originally, I intended making up a lead using four strands of heavy hookup wire but then I remembered that I had some 5-core automotive trailer cable. This looks much the same as the original except that it has plastic covered wires inside the sheath. It has five wires so I just ignored the spare and went ahead and wired the lead to Now that the set and its cabinet had been cleaned up, it was time to overhaul the electronic circuitry. Unfortunately, the parts are difficult to access in some areas, particularly around the transmitter section, but I was eventually able to replace all the paper capacitors. They were all quite leaky, even though it was obvious that they had been replaced about 40 years ago. Some of the sub-miniature metallised paper capacitors were smaller than my polyester capacitors, so fitting new ones wasn’t all that easy. One or two resistors had drifted in value and were also replaced. At this stage, with no shorts or other circuit faults evident, I applied power to the receiver. It came on immediately with a rush of noise from the speaker. I connected it to an antenna and although I couldn’t hear many stations (at least not during daylight hours), it appeared to be working just like it had nearly 60 years ago. Next, I decided to check the alignment of the various coils. The oscillator coil was slightly out of adjustment at the low-frequency end of the dial and adjusting it brought both the low and high ends of the tuning range back in line with the dial markings. However, the performance dropped off for frequencies above 6MHz so I checked the alignment of the RF and antenna coils. At the low-frequency end, they were slightly out of adjustment and I corrected them by adjusting the core slugs at around 2.8MHz. Conversely, at the high-frequency end of the dial, I found that the persiliconchip.com.au ew See revi onth’s m s i h in t HIP SILICON C ALTITUDE 3500-SS Valve Stereo HiFi Amplifier 32W/Channel, 4 or 8Ω This close-up view shows the front panel controls on the fully-restored unit. It tunes the frequency range from 2.7-7MHz and has a transmitter power output of between 1.5W and 2.3W. formance improved if I placed a piece of insulated rod near the RF coil. Unfortunately, I couldn’t adjust the wire trimmer due its awkward position in the set so I soldered an adjustable trimmer across it and adjusted this for best performance instead. The receiver’s performance was now quite good, with a fairly even noise level from the speaker across the whole 2.7-7MHz band. The set was also working well in the “Pack” frequency position. In this position, a crystal is switched into the converter circuit and the set will only tune to the frequency of the crystal minus the IF frequency (455kHz). However, the manual tuning control is quite critical to set in this mode. Note that the set can also be tuned quite easily to an image frequency, ie, to a frequency 910kHz higher than the desired frequency. I fitted a 3247kHz crystal into the holder and the set now tunes on crystal control to 2792kHz (3247kHz - 455kHz), or to the image at 3702kHz (3247kHz + 455kHz). I selected this particular crystal frequency because the set came equipped with a 2792kHz crystal in the transmitter. Overhauling the transmitter There was only one paper capacitor fitted to the transmitter section and this was replaced with a polyester type. The remaining capacitors are siliconchip.com.au all mica types and were in good condition. I examined the wiring carefully and could see no signs of any short circuits or other problems. However, it’s not easy to trace the wiring in the transmitter and I could only hope that there were no nasty faults deep down in the “jungle” of wiring near the RF output stages in particular. Of course, if there were any shorts on the HT line, this would have shown up as soon as I applied power to the receiver earlier on. With this in mind, I applied power to the transmitter stages and all appeared normal. Both valve stages have protective bias applied. This bias is -4V in the case of the 3S4 in the oscillator and -10.5V for the two parallel 3A5s in the RF power amplifier (PA) stage. Next, I attached a 50W dummy load (this acts as an artificial antenna) to the transmitter, so that the signal would not be heard outside my home. I then clipped a test lead between the end of the changeover relay coil and the chassis and endeavoured to tune the 3S4 oscillator stage. This tuning is accomplished by adjusting a preset tuning capacitor that’s adjacent to the crystal (either C31, C32 or C33). However, I could get no indication on the “grid” meter position of the main switch (S3). I checked the voltages (with dif- “This particular valve amplifier performs very well” Leo Simpson SILICON CHIP June 2008 A blend of quality components and modern design Beautifully finished in 7mm brushed aluminium Four stereo analog inputs Gold plated connectors and selectors Extended bandwidth of 10Hz to 90kHz Carefully chosen design layout and wiring location Direct input coupling improves transient response Specialised wide-bandwidth audio output transformers Class A/B pentode output using genuine Russian-made Electro-Harmonix EL34 valves Matched pairs, factory bias adjusted Stainless steel heat shields improve overall efficiency High quality capacitors Beautiful in looks, design and listening The A3500-SS is an exclusive and advanced version developed by Stones Sound Studio. Available now from ELECTRONIC SERVICES AUSTRALIA 138 Liverpool Rd, Ashfield NSW (Locked Bag 30, Ashfield NSW 2131) Ph: (02) 9798 9233 Fax: (02) 9798 0017 Web: www.wagner.net.au June 2008 91 This view shows the top of the portable battery that’s used to power the TRP-1. It not only supplies +150V for the HT rail but also -10.5V to bias the valves and +1.5V for the valve heaters. ficulty) on the 3S4 and found that they were in the range I would expect while transmitting, ie, 90V on the plate and 50V on the screen. However, the 3A5 valves were drawing no discernible plate current due to the standing bias applied to the output stage, so I assumed that the 3S4 wasn’t oscillating. I tried another 3S4 with exactly the same results, then took a close look at the wiring around the 3S4 but this was all correct. I then tested the two driver coils (L5 & L6) using my Leader transistor dip meter but got no indications of resonance. The meter is just not sensitive enough to give a reading. Next, I checked the bias voltage applied to the secondary of the microphone transformer and got -10.5V. I then measured on the side going to the taps on the driver coils and found nothing. I had tested the continuity Some parts in the TRP-1 are difficult to access, particularly around the transmitter output stage. 92 Silicon Chip of both audio transformers before and they had proved to be in good order, so I rechecked the secondary of the microphone transformer and it too was OK. However, the multimeter was indicating a short from this point to ground. There aren’t many components in this part of the circuit so I removed both 3A5 valves and the short disappeared. Subsequent checking showed that that a grid in one 3A5 had shorted to the filament. I replaced the faulty 3A5 and the short cleared. I then proceeded to go through the tune-up procedure again. With crystals fitted to the three crystal sockets, I turned the transmitter on and was then able to tune coils L5 and L6. The tuned circuits are adjusted via trimmer capacitors C31, C32 & C33 and the tuning is at optimum when the maximum grid current is indicated on the meter. It’s necessary to check a few times that the crystal-controlled oscillator operates each time the PTT switch is operated. If this doesn’t happen reliably, it is necessary to slightly detune the relevant tuned circuit so that the oscillator does start reliably. That done, all that remained was to adjust C23 and C24 for maximum output. The output of the transmitter varied from around 1.5-2.3W. The transmitter was now working well but I had to find a suitable microphone insert to suit the set, as the original was missing. I have good sup- ply of old mobile radio microphones, both carbon and dynamic types, and after a bit of searching I found a carbon insert to suit the microphone case used on the set. With the insert installed and a new plug fitted to the lead, it was time to see if the microphone worked. I switched on the scope, placed the probe near the antenna lead to the dummy load and pressed the PTT switch. The result was an expanded pattern on the scope when I spoke into the microphone, showing the normal envelope modulation pattern for an AM transmitter. At this point, the restoration was complete. Note, however, that a licence is required to operate a transceiver like this. In my case, I have crystals that would allow me to use the transmitter on the 3.5MHz amateur band. Summary In summary, the TRP-1 is an interesting little transceiver designed for use in relatively remote locations. The receiver is sensitive and easy to tune but because the dial drive has very little reduction, it’s important not to tune too fast to avoid missing stations. The transmitter also tunes up quite nicely and has a quite reasonable output of between 1.5W and 2.3W. Its main drawback is that it is capable of being over-modulated by the simple modulator, which will cause “splatter” on adjoining channels. Using four triode sections in parallel in a transmitter is risky in my opinion. However, Pye achieved stability in this configuration, partly through the use of the 50W plate stopper resistors. Access to the workings under the chassis varies from reasonable to virtually impossible. It suggests to me that the transceiver’s physical layout had been finalised and the designers then ran into problems with the neutralised 4-triode RF power output stage. As a result, they had to cram more parts into an already crowded chassis to fix the problem. I am unsure as to why all valves are enclosed in shielded valve sockets. Perhaps it was to make sure the valves didn’t work out of their sockets in the course of the set being bumped around. Finally, I don’t understand why both a 3S4 and a 3V4 were used at different locations in the set. Either one would have worked quite OK in each position, with one less valve type needed SC in the parts inventory. 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 Confusion over ignition MAP sensor I’ve recently started to build the Programmable Ignition System for cars (SILICON CHIP, March, April & May 2007) but I am stuck at the MAP sensors. The article states a Sensym Module ASDX015A24R is suitable device for non-turbo cars. My problem is that when analysing the datasheets for the Sensym module it is not really clear if these devices will actually measure vacuum; they seem to specify only 0 to 15 psi not 0 to -15 psi? Would you mind commenting? (G. L., Mount Evelyn). • The 0-15 psi range relates to pressure referenced to a vacuum (0 psi). These sensors have two pressure ports but one is sealed off while the second port is open and measures the external pressure. This type of sensor is called an “absolute pressure sensor” because they measure pressure with respect to a vacuum (0 psi). So a 15psi measurement is normal atmospheric (air) pressure (1013hPa or thereabouts) and 0 psi (0 hPa) is when measuring a vacuum. The Sensym sensor specified is suited to measuring from 0-15 psi and that is the range from a vacuum through to atmospheric pressure. That makes them suited to normally-aspirated car engines where the manifold pressure varies from atmospheric through to reduced pressure. Those engines that have supercharger or turbocharger boost will require a sensor that can measure above atmospheric pressure, at say 2-bar (30 psi) or even 3-bar for higher boosted engines. Audio/video switcher wanted Has SILICON CHIP ever done a project whereby several units can be connected to a multi-controller which only has a couple of leads going to a TV? I have a VCR, DVD player and also a set-top box to connect up. (S. W., Grovely, Qld). • We described a 4-Channel A/V Selector in the April 2006 issue. This will switch composite video or S-video, together with L&R audio switching. Errata for Radio & Hobbies What a wonderful resource the DVD-ROM of Radio, TV & Hobbies is. It is absolutely fascinating. I marvel at the commitment to scan all those magazines. I am looking to build the “Twin 10 Watt Amplifier For Stereo” from January, 1959 and the “New Control Unit” from the May 1960 issue of Radio, TV & Hobbies. I haven’t been able to find any Notes or Errata on these projects by browsing the DVD and wondered if your records showed anything? (D. S., via email). • Back in those days there was very little published Errata and it certainly wasn’t archived in the way we do today for SILICON CHIP. Having said that, we could not recommend that old amplifier and preamplifier. We have to say that all the old EA amplifiers were pretty mediocre by the standards of the day as compared to, say, the Mullard 5/20 or Quad valve designs. Knock sensor filter networks I bought the Knock Sensor kit (SILICHIP, June 2007) which I plan to use independently of the Programmable Ignition System, as I am already running a Microtech Fuel and Ignition programmable ECU. I have assembled the Knock Sensor kit but in the instructions it tells me that the bandpass filter is set between 4.8-6.4kHz. I have done a bit of research and CON Relay Fault In The Studio Series Stereo Preamplifier Some time ago, I bought a Studio Series Preamplifier kit. However, when I put it together and tried it for the first time, it didn’t work. The fault is that the relays are not switching on any of the inputs. I managed to confirm that the rest of the preamplifier is working and then tried to find out what is wrong with the input switching. My findings are: • Q1-Q5 are soldered correctly. • The voltage on all transistor emitters is about +5V. • The base voltage of the selected siliconchip.com.au transistor is about +0.96V and the collector voltage of the selected transistor is about +0.35V. • The base voltage of the unselected transistors is about 1.7-1.8V and the collector voltage of the selected transistors is about 1.13V. • If I put 5V of correct polarity across the relay diode, the relay energises as it should. Could you please advise the correct base and collector voltages and give me a clue as to what is wrong and if it could be rectified? (H. B., via email). • The base and collector voltages for transistors Q1-Q5 are incorrect. If an input is unselected, the base of its transistor should be at +5V and the collector at 0V. When selected, the transistor base should be about +4.3V and the collector at about 5V to apply voltage across the relay coil. Check that the correct transistors have been used, as they give voltages that suggest that they are either NPN transistors or have been incorrectly oriented on the PC board. Q1-Q5 should be PNP BC327 types. June 2008 93 Question On NiMH Charger I wish to use an NiMH charger (SILICON CHIP, September 2007) to charge a 24V battery pack. However, the voltage required (36V) is above the specifications for this particular circuit. I presume the voltage limit on this circuit is set by the maximum supply voltage of the LM358 op amp (32V). Is this correct? I realise I could use the earlier Power Tool Charge Controller (SILICON CHIP, December 2006) but this doesn’t have the current limiting features I require and would involve a more elaborate current limiting scheme. Is it possible to supply the LM358 from the 5V regulated supply by rerouting the wiring to pin 8? Or can I substitute an op amp with a higher maximum supply voltage, such as the LM833? (S. H., via email). • The circuit could be used for the apparently, based on my engine’s bore size of 81mm, the resonant knock frequency is around 7kHz (based on the formula: Resonant knock frequency = 900/(p x cylinder radius). In the instructions for the kit, it tells me that the IC1b high-pass filter is governed by the 6.8nF capacitors and the 10kW and 2.2kW resistors. And the IC1a low-pass filter is governed by the corresponding 12nF and 3.3nF capacitors and the 5.6kW and 2.7kW resistors. 24V battery pack if the supply rails to REG1 and IC2 are limited. The LM317 can handle 40V between input and output but a diode (1N4004) should be placed between input and output (anode to output) to prevent damage to the regulator if the input is shorted. IC2 can be supplied from a zener diode limited supply with either a 10V zener diode in series with the pin 8 supply to give the required voltage drop from 36V to 26V or more conventionally with a series resistor and zener reference. A 2025V zener would suit running at about 20mA, ie, use an 820W 1W resistor. You cannot use an LM833 because the input does not operate at the ground (pin 4) supply. The LM358 can be used with an input at the ground supply. Could you please tell me if there is a formula that I can use to change the aforementioned resistor and capacitor values to adjust the high-pass and lowpass cut-off points? I would like the bandpass range to be roughly between 6.5kHz and 7.5kHz and if I know the formula I could experiment with the values to achieve the greatest accuracy. (R. T., via email). • The Knock Detector from the June 2007 issue was designed to be used in conjunction with the Programma- ble Ignition System. This is because the knock sensing circuit monitors the signal all of the time, while the Programmable Ignition board only checks the output from the Knock Sensor board around the firing point. This means that the Knock Detector may not be suitable for use with other ignition systems. The formula for calculating the knock frequency does also depend on other factors apart from just the cylinder bore. It is also dependent on cylinder shape and the materials used in the engine. The 4.8-6.4kHz range for our detector was considered the best for most engines. As far as adjusting the filter cut-off points, these are complex and require some component juggling. You could use the Spice programs located at the sites below. Choose the 2nd order Butterworth response and a gain of 1. You need to set the frequency required and the program will calculate the values. The Active HP Filter site is for the high-pass filter, while The Active LP Filter site is for the lowpass filter. http://www.beis.de/Elektronik/Filter/ ActiveHPFilter.html http://www.beis.de/Elektronik/Filter/ ActiveLPFilter.html Adding a relay to Speaker Protector Is your recently published Universal Speaker Protection & Muting Module (SILICON CHIP, July 2007) capable of providing current for two relays? Perhaps Q4 would only need the ad- Speed Controller For Xbox Fans I have put together the 12-24V Motor Speed Controller (SILICON CHIP, June 1997) for the purpose of controlling the 12V thermo fans for my Xbox 360. At 12V, they are quite noisy so I just wanted to be able to adjust the speed of the fans accordingly. I have two problems. (1) There is a high-pitched squeal coming from the motors. I have fitted the diode and capacitor before the fans and have tried 1mF, 0.22mF and 0.33mF capacitors as well but they didn’t help. What can I do to remove this noise as it defeats the purpose of the kit? 94 Silicon Chip (2) I installed a larger pot to make it easier to adjust and so I could mount it where I needed it but when you turn it, the fans are at full power and I have only used maybe one third of the dial. Is there a way to make use of the whole dial, thereby making it easier to adjust? (J. B., via email). • The speed controller switches the power on and off at a fast rate to reduce power to the motor. With some motors, the windings or the laminated core will produce an audible tone at this switching frequency. You may be able to reduce the noise by changing the frequency. You can vary the 10kW resistor at pin 6 of IC1 from 2kW to 500kW to get a change in frequency from 30Hz to about 10kHz. Use a 500kW trimpot (wiper connected to one end) with a series 2.2kW resistor to replace the 10kW resistor. Adjust this trimpot for minimum noise. The control pot can be made to work over a wider range by adding a 4.7kW resistor in series at each end of the pot. So one end of the pot connects to ground (0V) via a 4.7kW resistor and the opposite end goes to +5V via a second 4.7kW resistor. siliconchip.com.au dition of a heatsink or would other modifications be necessary? I could imagine that someone with a multichannel amplifier for home theatre or bi-amping would find it useful to run two relays. In my case, I wish to use your module to remove turn-on thump in a headphone amplifier that is often connected directly to my CD player. The player is also used for the family stereo and rather than change leads when I want to use the headphones I wish to use a second relay with normallyclosed contacts acting to bypass the headphone amplifier when power is off and to disconnect the bypass when power is on. Perhaps if you could provide a figure for the current handling of the circuit, I could substitute a pair of lower power relays as one solution. (K. W., Newport, Vic). • To run two relays in parallel, change Q4 to a BC327 which has a higher current rating than the specified BC556. No other changes are required. Speed control for diesel shunter I am intending to build a 5-inch gauge diesel shunter driven with a 12V 18A DC motor and want to use a speed control and drive it forwards and backwards. Do you have a kit that I can use? (B. K., via email). • Perhaps the most appropriate circuit would be the Reversible Speed Control in the April 2007 issue, rated at 12V or 24V and 20A. Flexible switching for ceiling fan I have a question regarding the connection of a ceiling fan. My electrician told me that it was not possible to connect the light for the ceiling fan into a 3-way switch. Essentially the fan has a remote control that allows you to turn the light on and off. I want to be able to use a wall-mounted switch as well to turn the light on and off. I understand that the output from the remote control unit doesn’t have the ability to connect to the 3-way switch, as it is essentially a 2-way switch but would it be possible to do this using a relay? (A. F., via email). • The remote control to drive the light on or off probably uses a Triac siliconchip.com.au Amplifiers And Hum Problems I have two amplifiers which my Dad made and which look like Studio 200 versions judging by the MJ15003 and MJ15004 output transistors. He also had some old SILICON CHIP pages from 1987 & 1988 which describe the Studio 200 (February 1988) and what looks like the full article from the earlier version with other output transistors. The latter text mentions using different Polyswitches for 4-ohm or 8-ohm loads. I was thinking of adding wires to the PC board terminals and up to a switch and then through either of the Polyswitches and back down to the board. The reason is that I am not sure what impedance speakers I might end up with. Can you see any problem with that or is there a more involved way to achieve the same objective? Also, I would appreciate any tips you might have for reducing hum from my guitar amplifier. Any lead I plug into the input results in a lot of hum, increasing with the volume adjustment. It is a brand new Roland guitar amplifier and it is not to do with the guitars that are plugged in. They are a Taylor Acoustic with Fishman pickup and a Les Paul with hum-bucker pickups. There are no single-coil “strat” guitars and not a fluoro for miles. I even turned off every circuit breaker except the one supplying the power point and unplugged every appliance on that circuit too. to provide the switching of the lamp. This is therefore not suited to adding an external switch for 2-way switching and nor is it suitable for controlling a relay. It may be easier to dispense with the remote control and just have a wall-mounted switch for the lamp or use two-hand held remotes, with one placed on the wall where the 2-way switch is required. A question of PC board layout I am from the University of Western Australia Motorsport Team (UWAM) The symptoms are: with nothing plugged in and volume up full, there is no hum; with lead and guitar plugged in, heaps of hum; with lead only, heaps of hum and with just an empty jack plug plugged in, heaps of hum. Touching the earth of the jack plug cancels the hum almost totally. As is the way, I took it back to the shop and it didn’t do it in the shop. The shop guy said it must be relevant to my venue. I tried running an earth wire from the power point through a 50kW pot and on to the earth of the jack plug going to the input of the amplifier but no luck. I also tied one of those clip-on “dongle like things” to no avail. Across the road is a large shopping centre, with the usual electrical gear and mobile phone towers on top. The electric train line is about 700 metres away. Because there is no noise with nothing plugged in, I’m guessing it’s RF noise, although the input jack might have a shorting arrangement internally. (L. K., via email). • We would be inclined to install Polyswitches for the 4W condition and leave it at that. In practice, how likely are you to seriously over-drive the speakers anyway? As far as your hum problem is concerned, there appears to be something funny about the earth connection on your jack plug or the sockets themselves. Evidently, the earth side is not making good contact. and I have a couple of questions you might be able to answer. We are building an open-wheeled racer and are trying to put all of the circuits on as few boards as possible. Is there a problem with putting highamp circuits near microprocessors and is there a way of avoiding said problem? Also, what are some good noise reduction techniques that we could employ to ensure the best quality signal, especially given that everything is constantly moving throughout the race? (Z. B., via email). • You can certainly have high currents flowing on a PC board with a micro on it. Just have a look at the 40A June 2008 95 Variable Frequency Supply For Induction Motors I have a number of of fractional horsepower induction motors collected from old home appliances and picked up at auction sales. However, they would be a lot more useful if I could vary their speed. I know I can use universal (series) motors with an SCR speed control circuit but it is very hard to run something at a quiet constant speed under a varying load. My problem at the moment is a low-cost scroll saw with a 200W motor running at a constant speed. It would be much more versatile if I could run it fast or slow. Would it be possible to build a 200W inverter with a variable frequency instead of a fixed 50Hz output? It wouldn’t need to be pure sinewave either. And rather than use Speed Controller in the March & April 2008 issues of SILICON CHIP. However, it does require careful layout of the PC board to ensure that the high currents do not flow in the signal sections of the microcontroller and that the high currents do not induce unwanted signal voltages into sensitive parts of the circuit. Remote control fault in preamplifier I have built the Studio Series Preamplifier and all is good except I cannot get the IR remote control to work. The micro is working since the dry contact inputs work and the unit steps through the LEDs when in set-up mode. I have put a CRO on pin 2 of the processor and the demodulated IR pulses are present and at a good level. I have used the exact remote as described in the April 2006 article. I am beginning to think that the crystal is not running at 4MHz however I can’t get a conclusive reading off the crystal (pins 4 & 5). Any ideas of how I can figure this out from here? (M. S., via email). • There are several remote controls listed in the April 2006 issue: AIFA Y2E, RA7 and BC3000. Use set-up code 191 for TV. Make sure that the remote is encoded with this number correctly and that the TV button is pressed to 96 Silicon Chip a hefty transformer or a switchmode power supply to go from 12V or 24V DC up to 240VAC, could one not rectify the 240VAC mains AC to DC and then chop it back to AC that could be varied from say 20-100Hz? (K. C., Invercargill, NZ). • It is possible to make an inverter to run at a different frequency depending on its design. It is also possible to rectify and filter the mains and then regenerate a different mains frequency. You will find that the inverter rating will need to be much greater than the motor rating in order for it to start successfully. Some ideas could be obtained from our 2kW Sinewave Inverter (October 1992 to February 1993) and the 200W Modified Square Wave Inverter from February 1994. select TV on the remote. Then with JP1 in place in the receiver, press one of the remote’s numeric keys twice. On the first press, the receiver’s ACK (acknowledge) LED should flash once and after the second press it should flash five times. If this doesn’t happen then the remote has not been received correctly and the receiver will not respond. If the crystal is incorrect in its frequency, the LEDs will not respond in the set-up. Crystal frequency measurement must be made with a highimpedance low-capacitance probe. Use an oscilloscope probe on a 10:1 setting. Additions to relay selector circuit I found a “Circuit Notebook” item in the January 2006 edition for a pushbutton relay selector. Could this circuit be modified so that it does not turn one relay off before activating the next (ie, so that it gives the option of multiple “lives”?). (D. M., Camden, NSW). • In order to modify this circuit to allow more than one relay to be activated at a time, you’d need to use diodes (ie, 1N4148) to drive the relay driver transistors from more than one output of IC2. For example, in order to have both relay 1 and relay 2 on together, you’d need to have an additional selector pushbutton switch connected between (say) IC2’s output 5 (pin 1) and pin 9 of IC1c, to create a fifth (1+2) selection setting. Then you would also use a pair of 1N4148 diodes to connect between the O5 output of IC2 and the gates of Q1 and Q2, with a 100W resistor in series with each diode. Then when you pressed S6, the extra selector button, the counter would stop at the O5 position and both relay drivers Q1 and Q2 would be turned on together. Testing a CDI system Is it possible to check a capacitor discharge ignition for faults with just a multimeter? (K. W., Maryborough, Vic). • Yes, it is possible. However, be careful not to touch the CDI except with the multimeter probes. With the CDI powered up, test the high voltage supply which should be at around 300VDC if it has an inverter (ie, similar to our Multi-Spark CDI described in the September 1997 issue). If the high voltage is from a coil in the generator (see SILICON CHIP, May 2008), you should get some voltage when the motor is turned over. A typical figure would be about 50VDC on a multimeter. You should then discharge the capacitor, using a 1MW resistor connected with insulated probes to the capacitor leads. Once discharged, check the voltage again before touching the CDI. Next, check the SCR. Measure between the anode and cathode for a resistance greater than 100kW. Applying +5V to the gate input via a 100W resistor (and the 0V supply to ground) should cause the anode-to-cathode resistance to drop to a low resistance (less than 10W). If all tests prove OK, then the CDI should work. Attenuator wanted for Minispot oscillator Shouldn’t the Minispot oscillator (SILICON CHIP, January 2008) have some way of attenuating the output level, so as to not overload the input to the IF stage, causing AGC to cut in and incorrect alignment to occur? Would you use a pot? If so, what siliconchip.com.au size and how should it be connected? We are talking about a high impedance circuit. (J. L., via email). • The Minispot 455kHz Modulated Oscillator was intended as a very low cost and simple circuit which can be used to align the IF stages of an AM radio. As the circuit stands, you can “attenuate” its RF output simply by moving it further away from your radio and the level will fall in proportion to the square of the distance between it and the receiver. There is no easy way to add an attenuator. Parts for Prescaler project I am trying to gather together all of the components for the prescaler project designed by Jim Rowe (October 2006). The ADCH-80 A wideband RF choke and the MC10EL35 JK flipflop do not seem to be readily available. Do you have any suggestions for sources of supply or alternative parts? (N. M., Mt Pleasant, Qld). • You should be able to obtain the ADCH-80A wideband RF choke from the Australian representatives for Mini Circuits, Clarke & Severn Electronics. Phone (02) 9482 1944 or www.clarke. com.au The MC10EL35 and other On Semiconductor ECL devices should be available from Future Electronics Phone (07) 3886 4933 or www.futureelectronics.com How to record teletext sub-titles When watching many prime-time TV programs I prefer to mute the sound and rely on the subtitles available on Notes & Errata +Vdd SUPPLY PIN 1 OF CON3 (MCLR/Vpp FROM PROGRAMMER) R 47k D A ds/PIC Programmer, May 2008: in the May 2008 issue (p67) describing the dsPIC/PIC Programmer, we explained that the MCLR-bar/VPP line was deliberately switched between 0V and +13V. This was done to avoid possible damage to the microcontroller when it is in the ZIF socket. However, if you wish to use the external programming header (CON3) with a microcontroller on a breadboard, for example, you should connect pin 1 of CON3 (the MCLR-bar/VPP line) as shown in the accompanying diagram, adding a resistor (R) and diode (D) to the breadboard. Teletext page 801. This is because I often cannot distinguish the words from the foreground music. But I cannot find any way of recording the program to retain these subtitles. I tried a set-top box which claimed compatibility with Teletext and it was OK for direct reception but not for recording. I also tried recording from the “TV out” sockets of a TV set which had this feature but again with no success. I asked several suppliers but the most useful answer I got was: “that’s a good question”. Can anyone do better? (R. S., Armidale, NSW). • We put your question to Alan Hughes, who wrote the recent series of on digital TV. This is his answer: K MCLR/Vpp PIN OF MICRO ON BREADBOARD The diode and resistor allow the microcontroller to run when the MCLR-bar/VPP line from the programmer is at 0V. There will be no possibility of damaging the microcontroller in this case as the microcontroller is accessed outside the ZIF socket. Hence the diode and resistor allow the microcontroller’s MCLR input pin to switch between VDD and VPP . This is more convenient while still developing the software. The PGC, PGD and GND lines can be connected directly to the pins on the microcontroller, as explained in the article. No videocassette machine is capable of recording teletext subtitles in their undecoded form. The reason the VCR cannot record teletext is that the luminance channel of a VCR is up to 3.1MHz where as the teletext needs the full 5MHz. The solution is to use a Personal Video Recorder (PVR) which will only record digital TV broadcasts. So in Armidale, NSW, you will be able to record all stations except NBN (but all stations in Armadale, WA). The PVR will have a choice on whether to record the subtitles and on playback you can choose to watch them or not. Check the menus in the shop . It will be in the SC installation menu. Then try it. 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. siliconchip.com.au June 2008 97 Silicon Chip Back Issues 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. 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. April 1994: Sound & Lights For Model Railway Level Crossings; Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. 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. 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. 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. 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 1999: Build A Digital Anemometer; DIY PIC Programmer; Build An Audio Compressor; Low-Distortion Audio Signal Generator, Pt.2. 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. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Carbon Monoxide Alarm. November 1996: 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; Repairing Domestic Light Dimmers.. 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. 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 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. 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 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. 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 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. 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 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. 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. 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. 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. 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. 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. October 1997: 5-Digit Tachometer; Central Locking For Your Car; PCControlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3. 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. 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. 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. 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. 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. January 1998: 4-Channel 12VDC or 12VAC Lightshow, Pt.1; Command Control For Model Railways, Pt.1; Pan Controller For CCD Cameras. 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. 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. August 1995: Fuel Injector Monitor For Cars; A Gain Controlled Microphone Preamp; Identifying IDE Hard Disk Drive Parameters. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; Build A 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. May 1996: High Voltage Insulation Tester; Knightrider LED Chaser; Simple Intercom Uses Optical Cable; Cathode Ray Oscilloscopes, Pt.3. How To Order: February 1998: Telephone Exchange Simulator For Testing; Command Control For Model Railways, Pt.2; 4-Channel Lightshow, 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. 10% OF SUBSCR F TO IB OR IF Y ERS OU 10 OR M BUY ORE Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. Price: $A9.50 each (icl. GST) in Australia or $A13 each overseas. Prices include postage and packing. Email: silicon<at>siliconchip.com.au 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 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. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Parallel Port Interface Card; Telephone Off-Hook Indicator. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; Safety Switch Checker; Sine/Square Wave Oscillator. March 2000: Resurrecting An Old Computer; 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Build A Glowplug Driver. May 2000: Ultra-LD Stereo Amplifier, Pt.2; LED Dice (With PIC Microcontroller); 50A Motor Speed Controller For Models. 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. August 2000: Theremin; Spinner (writes messages in “thin-air”); Proximity Switch; Structured Cabling For Computer Networks. 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. October 2000: Guitar Jammer; Breath Tester; Wand-Mounted Inspection Camera; Subwoofer For Cars; Fuel Mixture Display, Pt.2. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar 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 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 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. 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. 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. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Tele 98 Silicon Chip siliconchip.com.au phone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; Backing Up Your Email. August 2001: DI Box For Musicians; 200W Mosfet Amplifier Module; Headlight Reminder; 40MHz 6-Digit Frequency Counter Module; Using Linux To Share An Internet Connection, 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. 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. December 2001: IR Transceiver For PCs; 100W/Ch Stereo Amplifier, Pt.2; Pardy Lights Colour Display; PIC Fun – Learning About Micros. 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. 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. 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. 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. 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. 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. 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. 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. Toslink Digital Audio Converter; Build A 2.4GHz Wireless A/V Link; A High-Current Battery Charger For Almost Nothing. July 2006: Mini Theremin Mk.2, Pt.1; Programmable Analog On-Off Controller; Studio Series Stereo Preamplifier; Stop Those Zaps From Double-Insulated Equipment. August 2006: Novel Picaxe-Based LED Chaser Clock; Build A Magnetic Cartridge Preamplifier; An Ultrasonic Eavesdropper; Mini Theremin Mk.2, Pt.2. 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. September 2006: Thomas Alva Edison – Genius, Pt.1; Transferring Your LPs To CDs & MP3s; Turn an Old Xbox Into A $200 Multimedia Player; Picaxe Net Server, Pt.1; Build The Galactic Voice; Aquarium Temperature Alarm; S-Video To Composite Video Converter. 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. October 2006: Thomas Alva Edison – Genius, Pt.2; LED Tachometer With Dual Displays, Pt.1; UHF Prescaler For Frequency Counters; Infrared Remote Control Extender; Picaxe Net Server, Pt.2; Easy-ToBuild 12V Digital Timer Module; Build A Super Bicycle Light Alternator. 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. November 2006: Radar Speed Gun, Pt.1; Build Your Own Compact Bass Reflex Loudspeakers; Programmable Christmas Star; DC Relay Switch; LED Tachometer With Dual Displays, Pt.2; Picaxe Net Server, Pt.3. December 2006: Bringing A Dead Cordless Drill Back To Life; Cordless Power Tool Charger Controller; Build A Radar Speed Gun, Pt.2; Heartbeat CPR Training Beeper; Super Speedo Corrector; 12/24V Auxiliary Battery Controller; Picaxe Net Server, Pt.3. January 2007: Versatile Temperature Switch; Intelligent Car AirConditioning Controller; Remote Telltale For Garage Doors; Intelligent 12V Charger For SLA & Lead-Acid Batteries. February 2007: Remote Volume Control & Preamplifier Module, Pt.1; Simple Variable Boost Control For Turbo Cars; Fuel Cut Defeater For The Boost Control; Low-Cost 50MHz Frequency Meter, Mk.2; Bike Computer To Digital Ammeter Conversion. March 2007: Programmable Ignition System For Cars, Pt.1; Remote Volume Control & Preamplifier Module, Pt.2; GPS-Based Frequency Reference, Pt.1; Simple Ammeter & Voltmeter. October 2002: Speed Controller For Universal Motors; PC Parallel Port Wizard; Cable Tracer; AVR ISP Serial Programmer; 3D TV. 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. April 2007: The Proposed Ban On Incandescent Lamps; High-Power Reversible DC Motor Speed Controller; Build A Jacob’s Ladder; GPSBased Frequency Reference, Pt.2; Programmable Ignition System For Cars, Pt.2; Dual PICAXE Infrared Data Communication. November 2002: SuperCharger For NiCd/NiMH Batteries, Pt.1; Windows-Based EPROM Programmer, Pt.1; 4-Digit Crystal-Controlled Timing Module. 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. May 2007: 20W Class-A Amplifier Module, Pt.1; Adjustable 1.3-22V Regulated Power Supply; VU/Peak Meter With LCD Bargraphs; Programmable Ignition System For Cars, Pt.3; GPS-Based Frequency Reference Modifications; Throttle Interface For The DC Motor Speed Controller. April 2005: Install Your Own In-Car Video (Reversing Monitor); Build A MIDI Theremin, Pt.1; Bass Extender For Hifi Systems; Sports Scoreboard, Pt.2; SMS Controller Add-Ons; A $5 Variable Power Supply. June 2007: 20W Class-A Amplifier Module, Pt.2; Knock Detector For The Programmable Ignition; 4-Input Mixer With Tone Controls; Frequency-Activated Switch For Cars; Simple Panel Meters Revisited. 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. July 2007: How To Cut Your Greenhouse Emissions, Pt.1; 6-Digit Nixie Clock, Pt.1; Tank Water Level Indicator; A PID Temperature Controller; 20W Class-A Stereo Amplifier; Pt.3; Making Panels For Projects. June 2005: 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. August 2007: How To Cut Your Greenhouse Emissions, Pt.2; 20W Class-A Stereo Amplifier; Pt.4; Adaptive Turbo Timer; Subwoofer Controller; 6-Digit Nixie Clock, Pt.2. July 2005: Wi-Fi, Pt.3; Remote-Controlled Automatic Lamp Dimmer; Serial Stepper Motor Controller; Salvaging & Using Thermostats; Unwired Modems & External Antennas. September 2007: The Art Of Long-Distance WiFi; Fast Charger For NiMH & Nicad Batteries; Simple Data-Logging Weather Station, Pt.1; 20W Class-A Stereo Amplifier; Pt.5. August 2005: Mudlark A205 Valve Stereo Amplifier, Pt.1; Programmable Flexitimer; Carbon Monoxide Alert; Serial LCD Driver; Enhanced Sports Scoreboard; Salvaging Washing Maching Pressure Switches. October 2007: DVD Players – How Good Are They For HiFi Audio?; Electronic Noughts & Crosses Game; PICProbe Logic Probe; Rolling Code Security System, Pt.1; Simple Data-Logging Weather Station, Pt.2; AM Loop Antenna & Amplifier. 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. 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. February 2003: PortaPal PA System, Pt.1; SC480 50W RMS Amplifier Module, Pt.2; Windows-Based EPROM Programmer, Pt.3; Fun With The PICAXE, Pt.1. 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). 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. May 2003: Widgybox Guitar Distortion Effects Unit; 10MHz Direct Digital Synthesis Generator; Big Blaster Subwoofer; Printer Port Simulator; PICAXE, Pt.4 (Motor Controller). 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. 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. September 2005: Build Your Own Seismograph; Bilge Sniffer For Boats; VoIP Analog Phone Adaptor; Mudlark A205 Valve Stereo Amplifier, Pt.2; PICAXE in Schools, Pt.4. October 2005: A Look At Google Earth; Dead Simple USB Breakout Box; Studio Series Stereo Preamplifier, Pt.1; Video Reading Aid For Vision Impaired People; Simple Alcohol Level Meter; Ceiling Fan Timer. November 2005: Good Quality Car Sound On The Cheap; Pt.1; PICAXE In Schools, Pt.5; Studio Series Stereo Headphone Amplifier; Build A MIDI Drum Kit, Pt.1; Serial I/O Controller & Analog Sampler. 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. December 2005: Good Quality Car Sound On The Cheap; Pt.2; Building The Ultimate Jukebox, Pt.1; Universal High-Energy Ignition System, Pt.1; Remote LED Annunciator For Queue Control; Build A MIDI Drum Kit, Pt.2; 433MHz Wireless Data Communication. 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 2006: Pocket TENS Unit For Pain Relief; “Little Jim” AM Radio Transmitter; Universal High-Energy Ignition System, Pt.2; Building The Ultimate Jukebox, Pt.2; MIDI Drum Kit, Pt.3; Picaxe-Based 433MHz Wireless Thermometer; A Human-Powered LED Torch. 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. 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. December 2003: 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. 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. 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. siliconchip.com.au February 2006: PC-Controlled Burglar Alarm, Pt.1; A Charger For iPods & MP3 Players; Picaxe-Powered Thermostat & Temperature Display; Build A MIDI Drum Kit, Pt.4; Building The Ultimate Jukebox, Pt.3. March 2006: The Electronic Camera, Pt.1; PC-Controlled Burglar Alarm System, Pt.2; Low-Cost Intercooler Water Spray Controller; AVR ISP SocketBoard; Build A Low-Cost Large Display Anemometer. April 2006: The Electronic Camera, Pt.2; Studio Series Remote Control Module (For A Stereo Preamplifier); 4-Channel Audio/Video Selector; Universal High-Energy LED Lighting System, Pt.1; Picaxe Goes Wireless, Pt.1 (Using the 2.4GHz XBee Modules). May 2006: Lead-Acid Battery Zapper ; Universal High-Energy LED Lighting System, Pt.2; Passive Direct Injection (DI) Box For Musicians; Picaxe Goes Wireless, Pt.2; Boost Your XBee’s Range Using Simple Antennas; Improving The Sound Of Salvaged Loudspeaker Systems. June 2006: Pocket A/V Test Pattern Generator; Two-Way SPDIF-to- November 2007: Your Own Home Recording Studio; PIC-Based Water Tank Level Meter, Pt.1: Playback Adaptor For CD-ROM Drives, Pt.1; Rolling Code Security System, Pt.2; Build A UV Light Box For Making PC Boards. December 2007: Signature Series Kit Loudspeakers; IR Audio Headphone Link; Enhanced 45s Voice Recorder Module; PIC-Based WaterTank Level Meter; Pt.2; Playback Adaptor For CD-ROM Drives; Pt.2. January 2008: PIC-Controlled Swimming Pool Alarm; Emergency 12V Lighting Controller; Build The “Aussie-3” Valve AM Radio; The Minispot 455kHz Modulated Oscillator; Water Tank Level Meter, Pt.3 – The Base Station; Improving The Water Tank Level Meter Pressure Sensor. February 2008: UHF Remote-Controlled Mains Switch; UHF Remote Mains Switch Transmitter; A PIR-Triggered Mains Switch; Shift Indicator & Rev Limiter For Cars; Mini Solar Battery Charger. March 2008: How To Get Into Digital TV, Pt.1; The I2C Bus – A Quick Primer; 12V-24V High-Current DC Motor Speed Controller, Pt.1; A Digital VFO with LCD Graphics Display; A Low-Cost PC-to-I2C Interface For Debugging; One-Pulse-Per Second Driver For Quartz Clocks. April 2008: How To Get Into Digital TV, Pt.2; Charge Controller For 12V Lead-Acid Or SLA Batteries; Safe Flash Trigger For Digital Cameras; 12V-24V High-Current DC Motor Speed Controller, Pt.2; Two-Way Stereo Headphone Adaptor. May 2008: Replacement CDI Module For Small Petrol Motors; High-Accuracy Digital LC Meter; Low-Cost dsPIC/PIC Programmer; High-Current Adjustable Voltage Regulator. PLEASE NOTE: issues not listed have sold out. All listed issues are in stock. We can supply photostat copies of articles from sold-out issues for $A9.50 each within Australia or $A13.00 each overseas (prices include 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 June 2008 99 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. 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, PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* 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. PRACTICAL GUIDE TO SATELLITE TV 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. 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. 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. See Review March 2010 See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z 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. 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. 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 PRACTICAL RF HANDBOOK by Ian Hickman. 4th edition 2007 $61.00* by Douglas Self 2nd Edition 2006 $69.00* by Carl Vogel. Published 2009. $40.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *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 PAYPAL (24/7) INTERNET (24/7) MAIL (24/7) PHONE – (9-5, Mon-Fri) eMAIL (24/7) FAX (24/7) To ilicon Chip Use your PayPal account www.siliconchip. Call (02) 9939 3295 with silicon<at>siliconchip.com.au Your order and card details to Your order to PO Box 139 Place100 S com.au/Shop/Books silicon<at>siliconchip.com.au Collaroy NSW 2097 with order & credit card details with order & credit card details (02) 9939 2648 with all details Your You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. Order: 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. 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, PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* 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. PRACTICAL GUIDE TO SATELLITE TV 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. 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. 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. See Review March 2010 See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z 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. 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. 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 PRACTICAL RF HANDBOOK by Ian Hickman. 4th edition 2007 $61.00* by Douglas Self 2nd Edition 2006 $69.00* by Carl Vogel. Published 2009. $40.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *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 PAYPAL (24/7) INTERNET (24/7) MAIL (24/7) PHONE – (9-5, Mon-Fri) eMAIL (24/7) FAX (24/7) To siliconchip.com.au June 2008 101 Use your PayPal account www.siliconchip. Call (02) 9939 3295 with silicon<at>siliconchip.com.au Your order and card details to Your order to PO Box 139 Place com.au/Shop/Books silicon<at>siliconchip.com.au Collaroy NSW 2097 with order & credit card details with order & credit card details (02) 9939 2648 with all details Your You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. Order: ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST MARKET CENTRE Cash in your surplus gear. Advertise it here in SILICON CHIP CLASSIFIED ADVERTISING RATES Advertising rates for these pages: Classified ads: $29.50 (incl. GST) for up to 20 words plus 85 cents for each additional word. Display ads: $54.50 (incl. GST) per column centimetre (max. 10cm). Closing date: 5 weeks prior to month of sale. To book your classified ad, email the text to silicon<at>siliconchip.com.au and include your name, address & credit card details, or fax (02) 9939 2648, or post to Silicon Chip Classifieds, PO Box 139, Collaroy, NSW, Australia 2097. _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $__________ or please debit my o Visa Card o Master Card Card No. Signature_____________________________ Card expiry date______/______ Name _________________________________________________________ Street _________________________________________________________ Suburb/town ______________________________ Postcode______________ Phone:______________ Fax:______________ Email:___________________ FOR SALE 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 SIMPLE PIC DEVELOPMENT. Lightweight script runs on 12F683 devices, etc. Free for green use. Offers invited. www.slgnps.com LEDs! Nichia superbright oval LEDs and 5mm Agilent (HP) LEDs - brandname quality LEDs at Chinese LED 102 Silicon Chip prices! Osram surface mount range and other NOS standard and superbright brand name LEDs from just a few cents each. Cree XR-E LEDs, LED drivers, kits and other interesting stuff. www. ledsales.com.au MicroByte Electronics: PIC Micros – Development Board – Development tools & Components. Phone: (03) 9378 4288. info<at>microbyte.com.au; www. microbyte.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 KIT ASSEMBLY KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand * Small production runs. Phone Keith 0409 662 794. keith.rippon<at>gmail.com WANTED CUSTOMERS: Truscotts Electronic World – large range of semiconductors and passive components for industry, hobbyist and amateur projects including Drew Diamond. 27 The Mall, South Croydon, Melbourne. (03) 9723 3860. electronicworld<at>optusnet.com.au siliconchip.com.au Satellite TV Reception 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°. 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 C O N T R O L S You get results faster with the world’s easiest controllers! best v alue! Do you have wireless problems? Telelink has wireless solutions! If you want the right ‘wireless’ ingredients for a successful project recipe, THINK Telelink! Don’t want to be confused by wireless gobbledegook and confusing buzz words? TALK to Telelink! We will give you honest advice so that you can make the right purchase decision for your OEM low power wireless requirements. Browse our website for more information about our products. If you have any questions speak with a Telelink Communications representative. At Telelink we sell solutions, not problems! VIDEO - AUDIO - PC distribution amps - splitters digital standards converters - tbc's switchers - cables - adaptors genlockers - scan converters bulk vga cable - wallplates DVS5c & DVS5s High Performance Video / S-Video and Audio Splitters MD12 Media Distribution Amplifier QUEST ® Quest AV® 01010101 HQ VGA Cables Telelink Communications www.telelink.com.au e-mail Jack Chomley – jack<at>telelink.com.au or call (07) 4934 0413 or 0428 199 551 VGA Splitter VGS2 AWP1 A-V Wallplate Come to the specialists... QUESTRONIX ® Quest Electronics® Pty Limited abn 83 003 501 282 t/a Questronix ELNEC IC PROGRAMMERS MS120OEM216 $149 1-off Developer’s Kit $193 includes programming cable & software Made in Australia - enthusiastic users world-wide splat-sc.com Battery Packs & Chargers High quality Realistic prices Free software updates Large range of adaptors Windows 95/98/Me/NT/2k/XP CLEVERSCOPE USB OSCILLOSCOPES 2 x 100MSa/s 10bit inputs + trigger 100MHz bandwidth 8 x digital inputs 4M samples/input Sig-gen + spectrum analyser Windows 98/Me/NT/2k/XP IMAGECRAFT C COMPILERS Siomar Battery Engineering www.batterybook.com Phone (08) 9302 5444 DOWNLOAD OUR CATALOG at www.iinet.net.au/~worcom WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au Hi-Tech WIN System & History Cleaner Everything someone has ever done on your computer can be traced. Go to www.cleansitesystem.com Order today for FREE BONUS siliconchip.com.au ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 GRANTRONICS PTY LTD www.grantronics.com.au Products, Specials & Pricelist at www.questronix.com.au fax (02) 4341 2795 phone (02) 4343 1970 email: questav<at>questronix.com.au www.dontronics.com has 300 selected hardware and software products available from over 40 world wide manufacturers, and authors. Olimex Development Boards & Tools: ARM, AVR, MAXQ, MSP430 and PIC. Atmel Programmers And Compilers: STK500, Codevision C, Bascom AVR, FED AVIDICY Pro, MikroElektronika Basic and Pascal, Flash File support, and boot loaders. PICmicro Programmers And Compilers: microEngineering Labs USB programmers, adapters, and Basic Compilers, DIY (Kitsrus) USB programmers, MikroElektronika Basic, Pascal, DSpic Pascal Compilers, CCS C, FED C, Hi-Tech C, MikroElektronika C, disassembler and hex tools. CAN: Lawicell CANUSB, CAN232 FTDI: USB Family of IC ‘s. FT232RL, FT2452RL, also BL and others. 4DSystems LCD/Graphics: Add VGA monitor, or OLED LCD to your micro. Simple Serial I/F. Heaps And Heaps Of USB Products: TTL, RS-232, RS-485, modules, cables, analyzers, CRO’s. Popular Easysync USB To RS-232 Cable: Works when the others fail. Only one recommended by CBUS. Money back guarantee. www.dontronics-shop.com June 2008 103 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. RFMA RF Modules Australia Low Power Wireless Connectivity Specialists Applications: TX2H-433-64 Rural UHF FM Transmitter UHF Narrowband Transceiver Utilities In Stock NOW! In Stock NOW! Industrial Range: 500m Range: 500m Commercial Power: 25mW Power: 10mW Data rate: 64kbps Government Data rate: 10kbps 33mm x 23mm x 12mm Meter Reading Receiver: RX2A-433-64 RADIOMETRIX: Low Power, Licence Exempt Radio Modules NiM2-434.650-10 RF Modules Australia. P.O. Box 1957 Launceston, TAS., 7250. Ph: 03-6331-6789. Email: sales<at>rfmodules.com.au. Web: rfmodules.com.au FISCHERTECHNIK ROBOTIC KITS An extensive range of construction kits are now available. Controlled by the ROBOPro interface and flowchart style software. Communicates with the PC via COM, USB or RF data link. The fischertechnik range includes kits for the junior engineer through to training models for schools and universities. Interface drivers and C language compiler examples included. Extensive range of spare parts stocked. We specialise in: Mini lathes, milling m/c. Data logging, test and measurement equipment. Rezap battery chargers. Ultra-Violet torches. Weather stations. Power supplies. *Free Varta alkaline batteries with all orders. www.procontechnology.com.au P.O. Box 655 Mt.Waverley VIC 3149. Phone: 1300304125 Fax: (03) 98306481 email: procon<at>tpgi.com.au Issues Getting Dog-Eared? Keep your copies safe with these handy binders Available Aust. only. Price: $A13.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. Buy five and get them postage free! 104 Silicon Chip REAL VALUE AT $13.95 PLUS P&P Advertising Index Altronics.................................. 80-83 Aztronics........................................ 8 Amateur Scientist CDs............... IBC Av-Comm................................... 103 Clean Site System...................... 103 Computronics............................. 103 Dick Smith Electronics............ 20-23 Dontronics.................................. 103 Ecowatch.................................... 102 Emona Instruments........................ 6 Force Electronics........................... 8 Front Panel Express..................... 11 Furzy Electronics............................ 9 Grantronics................................. 103 Harbuch Electronics..................... 79 Hare & Forbes................................ 7 IMP Printed Circuits..................... 29 Instant PCBs.............................. 102 Jaycar........................ IFC,49-56,104 JED Microprocessors..................... 5 Keith Rippon............................... 102 LED Sales.................................. 102 Microbyte Electronics................. 102 Ocean Controls............................ 10 Ozitronics..................................... 79 Procon Technology..................... 104 Quest Electronics....................... 103 RCS Radio................................. 102 RF Modules........................OBC,104 Sesame Electronics................... 102 Silicon Chip Back Issues......... 98-99 Silicon Chip Binders.............. 67,104 Silicon Chip Bookshop........ 100-101 Radio, TV & Hobbies DVD-ROM... 29 Rockby Electronics......................... 3 Silicon Chip Subscriptions........... 57 Siomar Battery Industries........... 103 Soundlabs Group......................... 48 Splat Controls............................. 103 Tekmark Australia......................... 11 Telelink....................................... 103 Truscotts Electronic World.......... 102 Wagner Electronics................. 47,91 Worldwide Elect. Components... 103 PC Boards Printed circuit boards for SILICON CHIP designs can be obtained from RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. siliconchip.com.au STIC FANTAIDEA GIFT UDENTS FOR SFT ALL O S! AGE THEAMATEUR SCIENTIST An incredible CD with over 1000 classic projects from the pages of Scientific American, covering every field of science... THE LATEST VERSION 4 – WITH EVEN MORE FEATURES! Arguably THE most IMPORTANT collection of scientific projects ever put together! This is version 4, Super 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. ONLY 62 $ 00 PLUS $10 Pack and Post within Australia NZ P&P: $AU12.00, Elsewhere: $AU18.00 “A must for every science student, science teacher, science lab . . . or simply for those with an enquiring mind . . .” 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 V2 review in SILICON CHIP, October 2004. . . or read on line at siliconchip.com.au This is the ALL-NEW Version 4 . . . it’s even BETTER! HERE’S HOW TO ORDER YOUR COPY: BY PHONE:* (02) 9939 3295 9-5 Mon-Fri BY FAX:# <at> (02) 9939 2648 24 Hours 7 Days BY EMAIL:# silicon<at>siliconchip.com.au 24 Hours 7 Days BY MAIL:# BY PAYPAL:# PO Box 139, Collaroy NSW 2097 silicon<at>siliconchip.com.au 24 Hours 7 Days * Please have your credit card handy! # Don’t forget to include your name, address, phone no and credit card details. BY INTERNET:^ siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information There’s also a handy order form inside this issue. Exclusive in SILICON Australia to: CHIP siliconchip.com.au siliconchip.com.au April June 2008 105