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SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings.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.10; October 2008 SILICON CHIP www.siliconchip.com.au Features 10 CleverScope CS328A USB Dual-Channel 100MHz Scope Purr-fect: Picaxe-08M 433MHz Data Transceiver – Page 14. 14 Picaxe-08M 433MHz Data Transceiver USB Clock With LCD Readout – Page 18. This USB oscilloscope provides a large range of functions, including data logging. An optional signal generator is also available – by Mauro Grassi Purr-fect: the HopeRF 433MHz Transceiver Module & the Picaxe-08M are a marriage made in heaven – by Stan Swan 84 Exposing PC Boards In A Modified Microwave Oven Here’s a novel approach to exposing photo PC boards – cook ’em in a modified microwave – by Graeme Rixon 94 Cent-a-meter Owl: Watching Your Power Consumption Electricity rates are on the rise, so it’s important to keep tabs on your power consumption. The Cent-a-meter Owl will keep you power wise – by Stan Swan Pro jects To Build 18 USB Clock With LCD Readout, Pt.1 It connects to your PC’s USB port and synchronises to your PC and ultimately to an internet time server for accurate time keeping – by Mauro Grassi 30 Digital RF Level & Power Meter Digital RF Level & Power Meter – Page 30. Want to measure small RF signals? This easy-to-build unit measures signals from below 50kHz to above 500MHz, indicates the signal level in volts & dBV and shows the power level in both milliwatts & dBm – by Jim Rowe 62 Versatile Special Function Timer This multi-purpose timer operates from a 12V supply and offers accurate timing periods ranging from 0.1s to 16.5 minutes – by John Clarke 68 Railpower Model Train Controller, Pt.2 Pt.2 this month has the full construction details for our new high-performance train controller. We also describe how the controls work – by John Clarke Special Columns 44 Serviceman’s Log Watch Out For Mura Faults On LCD Panels – by the TV Serviceman 57 Circuit Notebook (1) Tester For Ultrasonic Devices; (2) USB-Controlled Desk Lamp; (3) Tacho Interface For Diesel Motors; (4) Smart Pool Pump Controller; (5) Picaxe-Based Mosfet Tester 88 Vintage Radio The AWA Radiola 653P AC/Battery Portable – by Rodney Champness Departments   2 Publisher’s Letter   3 Mailbag 43 Order Form siliconchip.com.au 82 Product Showcase 97 Ask Silicon Chip 101 Market Centre Versatile Special Function Timer – Page 62. October 2008  1 SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor John Clarke, B.E.(Elec.) Technical Staff 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 Smart power meters will jack up your electricity bill! How many people have heard about the new “smart” power meters which are due to start being rolled out in Sydney and no doubt, other state capitals, very soon? Smart power meters sound like a good idea but what do they do? In fact, they have an inbuilt timer and the ability to charge different electricity tariffs, depending on the time of day. The idea is that they will charge more for electricity in peak periods and less in off-peak times. That sounds good, doesn’t it? After all, the electricity grid presently comes close to being overloaded in the summer months and any measures to reduce demand must be regarded as worthwhile, mustn’t they? You might be silently nodding but wait until you read how much it will cost you. In Sydney, there will be three residential tariffs, called PowerSmart Home: (1) Peak, from 2PM to 8PM on working weekdays; (2) Shoulder, from 7AM to 2PM and 8PM to 10PM on working weekdays and 7AM to 10PM on weekends and public holidays and (3) Off-peak, all other times. So far that seems reasonable, but here is the shocker: the Peak rate will be 30.25 cents per kilowatt-hour. That is more than double the present Sydney residential rate (from Energy Australia) of 13.97 cents per kilowatt-hour (for the first 1750kWh) which has only just increased by 8.5%! The Shoulder tariff will be 10.89 cents per kilowatt-hour and the off-peak rate will be 6.05 cents per kilowatt-hour, a little more than the present off-peak hot water rate (Off Peak 1). All these prices include GST. It is not clear whether separately metered off-peak hot-water systems will be all lumped into the one PowerSmart Home tariff or not. I suspect they will be, so charges for hot water will go up correspondingly, depending on when the hot water systems are turned on by the Zellweiger control tones (by remote control, of course). So what are the PowerSmart Home tariffs likely to mean for the typical household? Remember that the Peak tariff period of 2PM to 8PM, in most households, is when most people cook and eat the evening meal, watch TV (in an air-conditioned living room), use the computer and so on. You don’t have much choice about this, do you? Just as an exercise, I decided to calculate the effect of the new tariffs on my own most recent electricity bill, for the period from 24/05/08 to 26/08/08. The total bill was $308.78 which is probably on the low side for a household of three adults during winter. I estimated that 60% of our power consumption would be in the peak period, 30% in the shoulder period and 10% in the off-peak period. I also assumed that my present charges for off-peak hot water would be same although they are actually likely to increase. Apart from off-peak hot-water consumption, the power component of the bill was for 1674kWh. After crunching the numbers, my electricity bill would increase from $308.78 to $443.58, an increase of 43%! And that’s for a pretty modest electricity consumption. Living as we do in one of the mildest parts of Sydney, we do not have an airconditioner. Nor do we have a power-hungry large-screen plasma TV or a swimming pool with its power-hungry pump. Or a large two-door fridge with an ice-maker. Or a spa. Or a lot of wasteful 12V halogen downlights. Thank goodness for that! Make no mistake: when people realise just how punishing these new tariffs are, they will be outraged. And they will be forced to change their power consumption habits. But people on low incomes who are already very careful in everything they do will find it tough. The power authorities and the politicians have kept pretty quiet about this, haven’t they? I wonder why? I wonder if it has anything to do with the attempt to sell off the electricity distributors in New South Wales? Leo Simpson siliconchip.com.au 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”. Australia’s first production electric vehicle I would like to correct your comments regarding the electric bike in the May 2008 edition. In 1979, a company called “Silent Power” built Australia’s first production electric vehicle. They were fully compliant road registered in both NSW and Qld. A total of 12 were produced and sold to various authorities for evaluation. Only one was ever sold to the public, to a person on the Gold Coast. They were based on a Suzuki Carry Van and ran on 96V with 190Ah batteries. The range was 80km and top speed was 80km/h. Kevin Hill, Kurnell, NSW. Prius is highly fuel-efficient There seems to be a misconception in the community that the Prius and other hybrids are only fuel-efficient on short trips, such as around town. Nothing could be further from the case. Paul Smith of Port Macquarie in his letter headed “Comment on Prius Battery Life” (SILICON CHIP, May 2008) suggests that “the extra weight of the Prius [because of its battery] means that when it is used for any purpose other than city driving, it will not achieve better mileage than many conventional petrol vehicles”. Having owned and driven a Prius since August 2005 and kept a record of my fuel consumption, I can assure him that he is mistaken. Around Sydney my car achieves between siliconchip.com.au 5.2 and 5.6l/100km but out on the open road fuel economy improves considerably. On the run from Sydney to Port Macquarie, a journey I take frequently, my Prius achieves 4.6-4.7l/100km and from Port Macquarie to Lismore it gets even better, between 4.5 and 4.6l/100km. That is travelling at or just below the legal speed limit in each case. I haven’t come across any other petrol-engined car of equivalent size or weight that can get anywhere near those figures; most use 50% to 100% more fuel. The Prius computer manages the battery level brilliantly. I have rarely seen the battery full and never empty. It balances the energy source so that when the battery is approaching full it makes the electric motor do more work and the engine less, and vice versa when the battery gets low. So far my fuel consumption has been remarkably consistent which suggests that the battery, after three years, is still in excellent condition and showing no sign of ageing. No doubt the new model Prius battery has an even greater capacity and longer life than mine. Hugh Buckle, East Ryde, NSW. Flashing problems with compact fluorescents Now that your magazine has dared to enter the sacred ground of the Australian licensed electrician I thought some of your readers would be interested in the following phenomenon. As a grumpy old electrician, I was intrigued by the strange behaviour of these new high-efficiency light bulbs installed in my home. Having installed one in our bedroom, we found it quite disconcerting to have the light giving off a flash of light every 15 seconds, (quite a good flash too, similar to a small camera flash.) Next day, after normal checks for leakage across the switch and light socket and finding no fault, I came to the following conclusion. The 15W lamp being a fluorescent type uses what could be described as a pulse mode power supply, powered from a capacitor kept charged via a bridge rectifier from the mains, all contained in the lamp base. I surmised that the leakage was capacitive, between the Active and return switch wires. In this instance, Active and Neutral supply came directly to the light socket; the Active using the loop terminal then to the switch and back to the light via a switching pair. This pair was sufficiently long as to act as a small capacitor and allow the rectifier to charge the CFL’s internal capacitor slowly until enough voltage was available to fire the light which then immediately discharges the capacitor and so the cycle repeats. Testing the theory on the workbench, I found that the light could be made to flash repeatedly, several flashes per second by placing a small capacitor (0.1mF) across the switch with the switch in the off position. The same affect occurred with a long October 2008  3 The best way to back-up a computer Poor Serviceman! Reading his tale of woe of computer corruption in the July 2008 issue reminds me of my own experience. I had a very refined system running, with multiple applications and many tweaks and service packs for them, numerous preference settings for Windows, as well as little tricks of my own, such as an exclusion dictionary for Word that pulls up oddments such as “exit” when I mean to type “excite”. There were also lots of Visual Basic 6 (the real Visual Basic) applications such as my company accounts and countless other things (my desktop is just about full!). It all took years to do. Then one day I (that is to say, my computer) caught a virus. I chose to clean off the disk and reload everything from scratch. Although I had written an 11-page manual to expedite this very task, the whole process took about length of twin cable, open-ended but across the open switch terminals. So we have now reverted to the original 60W incandescent lamp. Still dealing with these new lights, they can also play tricks with wireless door chimes if mounted in close proximity, especially when starting up from cold – we were blaming the neighbour’s kids! Wilf Hodges, Oatlands, Tas. Comment: you are absolutely correct in your analysis that the wiring capacitance causes the flashing. We have covered this topic some time ago. The suggested cure is to connect a small capacitor across the socket for the CFL. Depending on how much wiring is involved, you may have to use a value of between .01mF (10nF) and 0.1mF (100nF) 250VAC class X2. Stop the gripes Hi to everyone at SILICON CHIP. You guys do a great job and we (your readers) really do appreciate all the work you guys put into the magazine. I know it may sometimes seem that you are not appreciated, especially after some of the gripes I’ve seen in the Mailbag pages. 4  Silicon Chip three weeks which I really couldn’t spare from my busy days. So when it was over, I bought an imaging program and simply saved an image of the whole lot on a very inexpensive external (USB) hard disk. This took much less than an hour and a trial restore I ran took 1.5 hours while we were out walking on the beach. So that’s my basic set-up. If I ever have the problem again I may lose some very recent information but at least I can restore my basic system very quickly. And of course, I can always save successive images. And talking of hard disks, it is a constant amazement to me how far we have progressed in a few years. My first hard disk was 8Mb and cost $9,999. Surely 8Mb would be more than enough for a lifetime (or so I thought then)! The external drive I just bought for my backup image was 240Gb and cost $110. Alan Ford, Salamander Bay, NSW. showroom a few weeks back, even though I fully intended to purchase the TV). SILICON CHIP is an Aladdin’s Cave of information and I for one think that equipment reviews, new technology articles and relevant current affairs are very important. The current debate on electric vehicles is very interesting and the bottom line is this: an answer to the fossil fuel problem has to be found unless we all go back to riding horses and making candles. SILICON CHIP has to cater for a wide range of readers, from professionals to hobbyists. As the only dedicated electronics magazine currently available in Australia, that is a hard slot to fill and keeping everyone happy is simply not possible. I for one will continue to subscribe to what I (and a great many others) believe is a complete, reader-orientated publication. Dave Sargent, Howard, Qld. To be honest, those readers who write comments like “stop using imperial measurements in the magazine or I will stop buying it” are idiots! We all deal with Imperial measurements everyday; even tyres use these measurements (most rim sizes are in inches – 155 x 13 means 155mm nominal inflated section width and a 13-inch rim) so does that mean those people will stop buying tyres? The people who also say “stop putting equipment reviews in the magazine” should also pull their heads in. This is an industry-level publication and in some areas, SILICON CHIP sets the standards for many areas of the electronics industry. The equipment reviews are a very important part of those standards. If I am going to spend $10,000 or more on a piece of workshop or test equipment, I want to know what it can do, what it cannot do and how easy it is to operate, upgrade and what accessories are available. Most suppliers will not “loan” a $14K piece of equipment to a prospective buyer for a road test. Even most electronics suppliers do not allow tampering with the equipment on display (I was asked not to “play” with a plasma TV in a national supplier’s Refrigerator schematic wanted I was hoping that someone might be able to help me find the schematic for the electronic temperature control of a Whirlpool model WR127S refrigerator. There is a wiring diagram on the back of the fridge but no circuit for the electronics. This is a reasonably new unit but I am running it from a solar electric system and would like to investigate the possibility of modifying the controls so that the inverter does not have to run 24 hours a day. If anyone has any info on this or has completed a similar modification I would love know. David Robson, 854 Monkey Gully Road, Goughs Bay, Vic 3723. Some rechargeables have low capacity I thought I’d share my experience with “MP” brand rechargeable batteries. These batteries are commonly available via eBay and local computer fairs and are packaged in a reasonably professional blister pack complete with an insert that is mostly free of the grammatical horrors that often accompany siliconchip.com.au S-VHS recorders can cope with Teletext sub-titles The June 2008 “Ask SILICON CHIP” had an item on “How To Record Teletext Sub-titles”. In the answer, Alan Hughes said that “no videocassette machine is capable of recording teletext subtitles in their undecoded form”. That is NOT correct. Although normal VHS recorders cannot, S-VHS (Super-VHS) recorders can easily record all the undecoded teletext information along with the picture (all 999 pages, not just the subtitles). My JVC HR-DVS1 recorder can even record all the teletext data perfectly when recording S-VHS in long-play (LP) mode. The reason is, of course, that S-VHS recorders DO have a full 5MHz bandwidth. You should be able to buy a secondhand S-VHS recorder at a bargain price these days, as everyone is switching over to digital PVRs. Geoff Nicholls, Hamburg, Germany. We asked Alan Hughes to comment: it is true that it is possible that an S-VHS recorder has enough bandwidth to record teletext. I did not include S-VHS because these recorders were sold in Australia only in very small numbers. This is because they had a premium price, came on the market towards the end of the VHS era, and TVs with S-video inputs were rare. This situation may be different in Germany. The age of most of these recorders will generally mean that the video heads are likely to be worn by now. Chinese-made products. The claimed capacity is 2500mAh and of course, I didn’t expect them to come in at anywhere near that rating. For comparison, I have a set of 2500mAh Energizer cells and they weigh around 29g each. The MP cells weigh 21g. However, what I didn’t quite expect was an actual capacity of well under 300mAh, and that’s being generous, with a constant 200mA load. When used in more realistic scenarios, these cells don’t seem to have a capacity of more than a few hundred mAh. Basically, they’re not worth siliconchip.com.au This reduces the reliability of the teletext signal. It is also becoming difficult to buy blank VHS video­ tapes. A further complication now is that the S-VHS or VHS video recorder will have to be fed with a set-top box, as the shutdown of analog will start at the end of 2009 in Australia. Using a set-top box as a program source also has the disadvantage of not being able to be used to control channel selection & channel change, using the recorder’s timer. An SVHS recorder cannot record the HD programs which are not simulcast on analog. A Personal Video Recorder or a set-top box has to be purchased before the end of next year. The set-top box’s composite output, (with visible subtitling) can be recorded on VHS tape, however once recorded the subtitles cannot be removed. A Personal Video Recorder can be programmed to record the programs when required and will change channels, along with recording two programs simultaneously. PVRs can record the digital signal including the subtitling. On replay, you can select if you wish to view the subtitling or not. This arrangement will result in wide screen images of better quality (some video recorders will cut the edges off a widescreen image to make the image narrow screen (4:3)). An added advantage is that High Definition signals are available which are of much higher quality than is available from an SVHS recorder. Alan Hughes. the effort of charging them. The real kicker is the claim that the batteries can “protect the environment [sic]”, given that they will end up in landfill shortly after being opened. Ben Low, Wollongong, NSW. Planet Jupiter Receiver is worthwhile It was wonderful to see the “Jupiter Radio Receiver” project in the August 2008 issue of SILICON CHIP. This is indeed a fascinating area of shortwave listening. Using my own amateur radio gear, I have heard the decametric noise 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 October 2008  5 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 Electric cars could have add-on battery packs The problem with electric cars is the weight, bulk and cost of enough batteries to get enough range for a wide range of use. You either have to always carry around far more batteries than you usually need, or like Chevrolet’s Volta or the plug-in hybrid Prius, carry the weight of a petrol/diesel/LPG motor that on most common trips won’t need to start. The answer is to design the car with only enough batteries to do most day-to-day trips, maybe 100km, and add extra range on the occasions when you need it. You could put more batteries or a motor-generator in a trailer and hitch it up when you need to take a longer trip. It would cut the weight of electric cars. It would cut the size because the extra baggage space that longer trips require could be achieved with the trailer. It would also cut the major component of electric car running costs, ie, battery replacement. It would allow easy recovery of electric cars that from Jupiter on several occasions. A couple of points: it is probably best to listen when the Earth’s own ionosphere is “dead”, such as during coronal mass ejections, etc, as although such solar activity messes up ionospheric propagation around the Earth, this sort of situation makes it easier to hear the decametric noise from Jupiter. The Earth’s ionosphere is more transparent (offers less attenuation) to signals coming from outer space in the 20MHz range. However, the balun diagram made me smile, as the diagram shown is not really a balun, more like a conventional transformer for power frequencies. This note shows the sort of balun used for this kind of application, a 1:1 current mode or “choke” balun: http://users.catchnet.com. au/~rjandusimports/balun_winding. html Felix Scerri, VK4FUG, Ingham, Qld. Comment: in essence, the only difference between the balun we show on page 40 of the August 2008 issue and 6  Silicon Chip had run out of charge on the road. Just tow a trailer out, plug it on the back and drive home. If they were standardised, they could be shared between multiple electric cars in the family or company. You wouldn’t even need to buy/own your own battery or charger trailer if they were standardised. They could be rented and swapped at stations on the outskirts of cities and every couple of hundred kilometres down main roads. It would allow electric cars to be viable with currently available low-cost battery technology. Oh, yes, and it could also be used as a trailer. Gordon Drennan, Burton, SA. Comment: interesting idea, Gordon. In fact, it probably would not be hard to modify an existing petrol generator, presently sold for emergency 240VAC power, to do the job. Add a fuel tank and it would not be a big installation job on a trailer. Still, if you have a 1.5-tonne car, the necessary petrol generator would need a large power output in order to drive the car when used by itself. those referred to in your URL is that the latter use a bifilar winding. Our design is correctly termed a balun. More projects should be available as kits I am wondering what the criteria is for projects that are engineered and published in SILICON CHIP magazine to become a kit available through the common electronic stores for people to build? I ask because there are two projects that I am interested in: the “GPS-Based Frequency Reference” published in March 2007 and now the most recent “Planet Jupiter Receiver”, both by Jim Rowe. Why are such interesting projects that obviously involved a considerable amount of time spent in designing and prototyping not available as kits? It must be disappointing not seeing projects turn into kits. Why can’t SILICON CHIP organise this? Clint Jeffrey, VK3CSJ, via email. Comment: it is disappointing when projects do not become available as siliconchip.com.au In your editorial in the August 2008 issue, I think you have confused VIR with TRS. TRS, or “tough rubber sheath” cable, came in after VIR and is often in poor condition. It was certainly around in WW2. It seems to fail in two ways: either the rubber siliconchip.com.au + + + ++ ty Quali many – r e nG i G Made by HAME e d a M + ++ + + + + + + Vulcanised India-rubber wire + ++ + + + + + + ++ + + LCR-Bridge HM8118 The bridge to success. Hopefully I’m not dragging this topic out too long but I would just like to share my views on this and to consider some of the current terminologies regarding electric motors generally. First, I think the term “brushless DC motor” is valid, because when describing a motor as AC or DC, it refers to the type of power supply that the machine requires rather than what happens internally within it. However, I have been thinking that the recent correspondence on all this has highlighted what seems to be a slight over-sight in the industry. That is, the electronically commutated motor, as far as I know, does not appear to have a formalised term to distinguish it from other machines. I believe that this is something that should be addressed as I know that some people confuse these with stepper motors. As a comparison to other types of electric motors with standard terminologies that we generally all know about, the examples are: induction motor (AC only), synchronous (AC only), universal (AC or DC) and DC motors – permanent magnet or shunt wound brush type. Then there are the electronically-driven ones of which there appear to be two main types: stepper motor and the electronic commutated type, which tend to be labelled as “brushless DC”. Where it can get a bit grey is that in both these types of motors, if the drive electronics is included as an integral and necessary part of the machine, both could be classed as brushless DC. They both require a DC supply. So, unless I am very wrong with my observation here and with this type of electric motor so common now, what about giving it a proper name? And the most obvious thing would be to call it what it is : an “Electronic Commutated” motor. Which is a bit of a mouthful, so an EC motor perhaps? Grant Saxton, Cambridge, New Zealand. ++ + + ++ More on Brushless DC motors + ++ + + + + ++ kits but that is the decision of the kitset suppliers, not us. We provide them with information before publication but they make their own decisions. And while we would like them to support every design that we publish, that is probably not economically viable. However, there is nothing to stop new players coming into the market to provide this service. We would be delighted to see new competitors to the existing suppliers. In the meantime, even though kits are not available, it should possible to build any project we describe, as the parts are usually available. Altronics are making the Jupiter Radio Receiver available as a kit – Cat. K-1127. ✔ Basic Accuracy 0.05 % ✔ Measurement functions L, C, R, |Z|, X, |Y|, G, B, D, Q, Θ, Δ, M, N ✔ Test frequencies from 20 Hz to 200 kHz ✔ Up to 12 measurements per second ✔ Parallel and Series Mode ✔ Binning and limits for parts sorting (optional) NEW eration button op 200 k H z ne push Intuitive o one glance ameters at ar p t en m re All measu n, , productio ce in R&D n n re fe re o The new d educati service an ✔ Internal programmable voltage and current bias HM8118 ✔ Transformer parameter measurement ✔ External capacitor bias up to 40 V ✔ Kelvin cable and 4 wire SMD Test adapter included in delivery ✔ Galvanically isolated USB/RS-232 Interface, optional: IEEE-488 Rohde & Schwarz (Australia) Pty Ltd Unit 2, 75 Epping Road, North Ryde, NSW 2113 sales<at>rsaus.rohde-schwarz.com October 2008  7 Mailbag: continued Do not use 240VAC power boards for 12V equipment My ham equipment comprises three items powered from a 12V (SLA) battery. I have found it impossible to buy, from electronics stores, suitable plugs and sockets to carry the 12V power to my equipment. The attached photo shows how I have utilised low-cost, but rugged 240VAC power This is a really BAD idea. Never ever fit boards, to provide this function. 240VAC mains plugs to low-voltage gear The 3-pin plugs were $2 each and do not use power boards for anything and the power board was $4. other than intended purpose. I have used the Active pins as the 12V positive and the Neutral if this was a common practice, it pins for 12V negative. would only be a matter of time before Hope this idea catches on. someone plugged 12V gear into a D. J., Tweed Heads, NSW. 240VAC outlet. Comment: we agree that cheap rugIn short, this is a very bad idea ged 12V connectors are not readily that could easily result in a fatalavailable but using 3-pin 240VAC ity. While they are not as easy to mains plugs and a power board is plug in or disconnect, we strongly just asking for trouble. While it may recommend that you use DC supply never happen in your household, connectors from a computer. becomes very brittle or it turns to a sticky mess. It is the cable with the black sheath and no earth wire and it should be replaced. By contrast, the rubber in VIR is protected by a waxed cotton coating. Cotton itself has a proven life of over 500 years when kept in appropriate conditions. I have seen 70-year old VIR that has been in appropriate conditions; that is, protected in conduit, not having been exposed to excessive heat or any chemical contamination, and not damaged during installation, which is in superb condition with the outer waxed cotton shiny and bright, and the rubber still flexible. Age is not necessarily a problem with cables. There are still 11kV paper-insulated lead-sheathed cables in London, which in the right conditions are still in service. The right conditions in this case are on level or slightly sloping ground, otherwise the oil in the paper drains to the low point, and away from DC railways. The stray ground currents from the DC railways cause the lead sheath to pit. Graham Shepherd, New Town, Tas. Comment: since the wiring in most old homes has been subjected to far less than ideal conditions, it should all be replaced and upgraded to the latest standard. Flexible switching solution for ceiling fan I think you may have misunderstood the question concerning flexible switching for a ceiling fan, from A.F. in “Ask SILICON CHIP” (June 2008). If A.F.’s remote-controlled ceiling fan is like mine, when power is first applied it does not turn the fan or light on; the remote must be used to turn either on. While this is “correct” if the fan is permanently connected to the mains, it is a nuisance if connected Australia’s Lowest Priced DSO! Now you’ve got no excuse ... update your old analogue scopes! Whether you’re a hobbyist, TAFE college or university workshop, the GW GDS-1022 has the price and performance for you. GW GDS-1022 25MHz 25MHz Bandwidth, 2 Ch 250MS/s Real Time Sampling 4k Memory Per Channel TFT Colour Display 19 Auto Measurements Built-in USB & SD Card Slot GW Brand - 28 years in Australia Sydney Melbourne Tel 02 9519 3933 Tel 03 9889 0427 Fax 02 9550 1378 Fax 03 9889 0715 email testinst<at>emona.com.au 8  Silicon Chip Brisbane Tel 07 3275 2183 Fax 07 3275 2196 Adelaide Tel 08 8363 5733 Fax 08 83635799 Perth ONLY $ Tel 08 9361 4200 Fax 08 9361 4300 web www.emona.com.au 549 inc GST EMONA siliconchip.com.au via a light switch (as would be the case if it replaces an existing light) as it renders the light switch effectively useless – the switch will turn the light off but to turn the light back on, first the light switch must be turned on and then the remote used. The easy solution is to leave the light switch permanently on and use the remote to turn the light on and off (which is why they provide a wall holder for the remote – so you can stick it on the wall next to the switch!). This is a nuisance, as you’re bound to flip the light switch first and only reach for the remote when nothing happens! It’s also inconvenient if you want the fan controlled from somewhere other than near the light switch. A better solution, which I used, is to invert the light-switching signal within the controller. Then the light comes on when the power is applied, so the light switch works without requiring the remote. Provided the light switch is on, the remote functions perfectly normally, with full control of light and fan. I inverted the light signal using a 4011 quad NAND gate (although any inverting gate could be used), paralleling all inputs and outputs. The chip leads were trimmed as short as possible, inputs and outputs parallel­ ed via short lengths of wire, and four flying leads attached (power, ground, in & out). The chip was then covered in two layers of heatshrink tube. It was connected in series with the controller’s light output by lifting one end of a transistor’s base resistor and interposing it in-between. Power was taken from the power pins on the controller chip (found by careful inspection). The chip, in its heatshrink ‘cocoon’, was tucked in a corner of the controller case. This has been operating perfectly for two years, with the light exclusively switched using the light switch. As the fan is in my bedroom, the remote is by the bedside table so I can easily adjust the fan during the night. Although you do have to remember to leave the light switch on if you think you’ll want the fan during the night! Just remember to turn the light off using the remote. Apart from the convenience, another advantage is that when the light switch is off, the fan is really off siliconchip.com.au HOPERF Digital Sensors RF IC & Modules Semiconductor Devices SAW Devices Distributed in Australia by Microzed Computers Pty. Limited Phone: 1300 735 420 Fax: 1300 735 421 www.microzed.com.au – no standby power consumption, no chance of fire, no chance of interference turning it on. Adam Webb, Adelaide, SA. Transformer query for frequency indicator I found your “Frequency Indicator For Generating equipment” in the May 2008 issue very interesting and informative. However, I noticed one minor discrepancy in the circuit. The power supply uses a 9V transformer and a 7809 voltage regulator. According to the data sheet, the input voltage for the 78XX series regulators must be (at least) 3V greater than the output voltage. In my opinion, a 12V 100mA rated transformer will be a good choice. T. K. Hareendran, Kerala, India. Comment: a typical 9V transformer will deliver 10 or 11VAC when lightly loaded, as this 100mA-rated transformer will be. When rectified by diode D1 and filtered, the resulting DC input to the 7809 regulator can be expected to be at least 14V; more than adequate for the regulator to work as SC specified. October 2008  9 CleverScope CS328A USB dual channel 100MHz mixed signal oscilloscope Hooked up to a desktop or laptop computer, this USB oscilloscope and its supplied PC software provide a large range of functions, including data logging. With the optional signal generator you can also test audio equipment, measure THD and do frequency sweeps. C LEVERSCOPE is the New Zealand-based company behind the CS328A, a dual channel 100MHz mixed signal USB oscilloscope with two analog and eight digital input channels. With optional accessories two units can be linked to double that number of channels. 20mV/div to 20V/div (using a x1 probe). The vertical resolution of the digitising system is 10 bits for the basic model and you can increase this to 12 or 14 bits by purchasing an additional sampler board. Unlike some USB oscilloscopes, this one has a deep memory of 4Mpts (Million Points) for the basic model. Main specifications Front and rear panel connections The CleverScope CS328A provides two analog channels The front panel of the CS328A comprises three BNC and eight digital channels (the corresponding analog only connectors (two for the analog channels and one for the model is the CS320A). Its analog bandwidth is 100MHz external trigger), two RJ45 sockets (for connecting the eight (measured at the -3dB point), while the digital sampling digital inputs), two probe compensation terminals and two rate is 100MS/s (millions of samples per second). There LEDs, green for power and red to indicate triggering. is a hardware 25MHz anti-aliasing filter On the back, there is the USB port, a for better spectrum analysis. BNC connector for the signal generator The vertical sensitivity ranges from Review by Mauro Grassi output and the power input jack and 10  Silicon Chip siliconchip.com.au At left: the CS328A along with its two analog and two digital “probes”. On the laptop screen is the supplied PC software used to control the USB ’scope. A sinusoidal wave is shown in the scope graph window while smaller windows are shown around it. All controls stem from the control panel shown at top right. Windows can be shown or hidden from the control panel. an RS422 port. The optional RS422 link cable forms a 100 Mbit/s communication link between the two. When you connect the two CleverScope CS328As together in this way, you effectively have a four channel analog scope with 16 digital inputs and a single user interface. Probes and accessories The CS328A is supplied with two switchable (x1, x10) 100MHz analog probes. Also included are adaptors that connect to the two front panel RJ45 jacks allowing you to connect up to eight (two lots of 4) digital inputs. The CS328A is controlled using the supplied PC software for Windows. The software is controlled from the main window and secondary windows become visible as needed. Like other oscilloscopes, the CS328A has an “Auto Set” button, which will analyse the signals and choose the vertical and timebase settings for displaying them on your PC screen. The signal window also has small buttons, whose function is selected by hovering over them with a mouse. These allow you to either zoom in or out or scale the window to fit the signal. Triggering and acquisition modes Each analog channel can be AC or DC-coupled and the triggering supports high and low frequency rejection for greater noise immunity. Although this oscilloscope has an operating bandwidth of 100MHz, as is usual with any wideband digital it is often better to limit the bandwidth to get a better display – with less noise. In this case you Fig.1: the scope graph window showing the digital channels. The triggering is set to a rising edge on digital channel 1. A low frequency square wave is shown, with the decoded logic values. The voltage threshold for the logic decoding can be defined. siliconchip.com.au Specifications at a glance: Analog input channels: ....2 Digital input channels:...... 8 Analog bandwidth:............DC to 100M Hz Sampling rate:..................100MS/s simu ltaneous on both channels Memory depth:.................4Mpts .........................................(8Mpts with optional memory upgrade) Vertical sensitivity: ...........20mV/div Vertical resolution: ...........10, 12* or 14 bits* Size:..................................153 x 195 x 35mm (*depends on optional module) can switch to 20MHz band limiting. Triggering on a preset pattern on the digital channels is also possible. To do this, you select a state for each of the eight digital channels. The signals must match the pattern for the trigger to occur. For example, you   can trigger on a rising or falling edge, or an absolute high or low level of for that channel. There are two trigger sources. The primary one is an edge trigger., while the secondary trigger allows you to select the number of times that the primary trigger must occur for the secondary trigger to be flagged, among other modes. You can then select the trigger source among either. The acquisition modes include peak detect (for capturing fast glitches) and repetitive waveform modes. The latter mode works by assuming that the signal is periodic and filling in subsequent cycles. This mode substantially increases the resolution of periodic waveforms which may be important for high frequency signals. Optional signal generator Although it is not installed as standard, the CS328A can be enhanced with a signal generator module. This works at up to 10MHz and you can select sine, triangular and square wave modes. You can also select a sweep mode Fig.2: a relatively high frequency triangular wave shown on the scope graph using the repetitive waveform acquisition mode. The triangular wave is at a frequency around 2MHz and was generated using the optional signal generator module of the CS328A. October 2008  11 Fig.3: the maths equation builder window. We have selected to apply the equation X2-X3 to a sinusoidal wave. The result is shown in the maths graph window. The maths graph window is a separate window that can display up to eight user-defined maths traces. Fig.4: the Fourier Transform window is shown. The input is a low frequency waveform at around 20kHz. The small window at the top left corner inside the spectrum graph window shows information about the signals. You can choose a log plot rather than a linear one too. which allows you to measure the frequency response of a filter, for example. seen in a separate “Signal Info” window. The range of available measurements includes the RMS and peak-to-peak voltage, as well as maximum and minimum levels. The THD of the signal can also be measured; very useful for audio work. Equation builder and signal analysis The MATHs functions of the software are quite powerful. It lets you define up to eight different expressions which are displayed in a separate window. Apart from the usual arithmetic functions, you can use functions to build up more complex expressions. For example, you can use trigonometric functions and integration. Many different modes for the Fourier Transform are implemented and can be displayed in a separate window. There is also a power spectrum mode for the Fourier Transform. This lets you see the power of your signal in terms of the equivalent power of a periodic signal at the signal’s fundamental frequency (ie, the first harmonic). The software allows you to view information about the analog channels in a separate window. The fundamental frequency as well as the vital statistics of the signal can be Exporting data Using the CS328A to acquire information about a signal is easy, since the control software is already running on your PC. You can copy and paste graph and data tables to other applications. This is especially useful for writing reports and presentations. You can also export data files from the logging window to embed in your spreadsheet. The software settings can be made permanent, useful for classrooms because the settings for a lesson can be preloaded and will be available when the students first start using the oscilloscope. You can also control the oscilloscope remotely using a LAN connection on your PC, for more advanced applications. Front and rear panels (top and bottom, respectively) of the CleverScope CS328A USB Oscilloscope. The two RJ45 sockets at left of the front panel are for the digital inputs; the “Chan A” and “Chan B” at right are the analog. USB connection is via the socket on the rear panel, along with RS422 link, signal generator and power. 12  Silicon Chip siliconchip.com.au        Fig.5: the signal information window, with expanded controls for data logging. This shows logging of the minimum and maximum voltage levels of the input signal. The logging rate of 10Hz is shown, as well as the instantaneous vital statistics of the analog channels. Other optional accessories The CS328A can be enhanced with other optional modules. Firstly, you can improve the vertical resolution from 10 bits to 12 and 14 bits using optional sampler boards. You can also purchase a 5ns delay line to double the sampling rate to 200MS/s by using both channels simultaneously for the same signal. Although the memory depth is large for a USB oscilloscope at 4Mpts, you can even double that by adding extra memory. And you can also buy more exotic probes than the ones supplied, including fully isolated probes (handy for high voltage work) as well as current sensing and differential probes.   Conclusion The idea behind USB oscilloscopes makes economic sense, cutting costs by avoiding duplication, especially in the display, buttons and knobs. Much of the data analysis can also be left to the power of your PC, avoiding the need for a powerful DSP or processor. The storage capacity of a common PC far exceeds the amount of non-volatile memory in standalone oscilloscopes and the PC can itself be upgraded in the future. USB oscilloscopes are therefore a very good idea for entry-level use because they are much more affordable than stand-alone ones. Clearly, you lose the portability of a standalone unit that may be crucial if working in the field. However, with laptops becoming ubiquitous and almost feather-weight, this disadvantage is fast fading into irrelevance. As USB oscilloscopes go, this one is a winner. Its best features include its deep memory, its relatively high bandwidth and the many features of the included PC software, which is comprehensive. The CS328A is available in Australia from Grantronics, Phone (02) 9896 7150; web www.grantronics.com.au The price is $1590 plus GST. In New Zealand, it is available from CleverScope Ltd, Epsom, Auckland. Phone (09) 524 7456. www.cleverscope.com SC siliconchip.com.au               October 2008  13 by Stan Swan 2nd Generation UHF Telemetry for the PICAXE PURR-FECT! Telemetry (from the Greek tele = remote and metron = measure) refers to the remote measurement and reporting of information, typically using wireless links to carry the data. Such technology is well established in climatic monitoring (especially temperature), water management, motor sport, security, medicine, defence and even space – Martian probe style. W ireless telemetry (using high voltage valves) was utilised even back in grandpa’s era. Perhaps one of the more exotic installations was the World War II German automatic weather station “Kurt”, secretly installed on the Canadian coast by a U-boat in 1943. Its 150W short-wave transmitter, powered by an array of nickel-cadmium and dry-cell batteries, produced 14  Silicon Chip coded signals (derived from weather sensors) receivable thousands of kilometres away in Europe. Distant Atlantic weather conditions could then be monitored but – fortunately for Allied shipping – jamming thwarted the station’s eventual mission! Modern motor racing telemetry allows trackside engineers to view and interpret live race data and use it to rapidly tune their racecar at even- tual pit stops. When every second counts, the ability to promptly work on tele-monitored faults can make for improved race performance. Such “mission critical” applications usually have heavy duty telemetry budgets but the availability of cheap data modules in recent years has allowed UHF wireless data links to proliferate, with many homes even now having several quietly at work – siliconchip.com.au siliconchip.com.au SUITABLE ANTENNA ~170mm WHIP OR YAGI I/O PINS (CHANNELS) CON1 DB9 1 6 7 8 9 2 3 22k 4 5 2 1 7 IC1 6 PICAXE-08M 10k 3 TO PC SERIAL PORT 4 8 5 0 ANT HOPERF HM-TR UHF DATA TRANSCEIVER ON +5V NC GND DATA GND +5V typically at 433.920MHz. As wireless links on the higher (near microwave) 1.8-2.4GHz bands are almost line of sight (LOS), many field telemetry setups in fact prefer low UHF (300-900MHz) or even lower VHF (30-300MHz), as this ensures better signal penetration of vegetation and buildings. The popular 434MHz slot, globally reserved for low power (25 mW) unlicensed Industrial, Scientific and Medical (ISM) wireless data, increasingly abounds with weird signals arising from home weather stations, power meters, car locks, garage door openers, security systems and wireless doorbells. In many suburbs at peak times, a UHF scanner tuned to 434MHz can issue sounds akin to an African dawn chorus! Although now very cheap, these consumer devices typically encode the serial data using ASK (Amplitude Shift Keying) on/off streaming and may be prone to interference from neighbouring services. However, it’s no good complaining – LIPD (Low Interference Potential Device) users on this 1.740MHz-wide (433.050 to 434.790MHz) spectrum slice have no prior channel rights. Failing repositioning, superior FSK (Frequency Shift Keying) encoding approaches may be needed instead. FSK data is largely immune to amplitude-modulated impulse noises – a major FM broadcast radio benefit, of course. The crashes and static you hear on an AM radio station as a thunderstorm approaches (even hundreds of kilometres away) are virtually nonexistent on an FM radio station. Fortunately most 434MHz services are very low power (a few milliwatts) and of very short range (a few tens of metres) and all are usually distinc- ZW-3100 (tx) and ZW-3102 (rx) gave a good account of themselves, with ranges to several hundred metres in open areas. Although this hardly gave the Bathurst Supercar “tele-techo’s” a scare, serial data rates in the 300-2400 bps range readily allowed PICAXE-monitored transducers to be wirelessly read and remotely recorded. However, such links were only one way (simplexbroadcast only), with no easy method to correct corrupted data, although CRC software evolved to at least detect possible errors. For 2-way (½ duplex- 2-way radio style) another tx/rx pair could have been added but the resulting cost 1 2 3 4 5 6 1 4.5V 2 330Ω λ SC 2008 RED LED 8 4 1 Picaxe serial encoding – uhf TRANSMITTER Circuit diagrams for the HopeRF UHF transceiver, powered by a PICAXE 08M. The code for the PICAXE is shown overleaf, while the programming for the transceiver can be downloaded from the HopeRF website. Note that there are slightly different connections for the transmitter (above) and the receiver (below). SUITABLE ANTENNA ~170mm WHIP OR YAGI I/O PINS (CHANNELS) CON1 DB9 1 6 7 8 9 2 3 4 5 TO PC SERIAL PORT 10k 22k 2 1 7 IC1 6 PICAXE-08M 3 4 8 5 0 ANT HOPERF HM-TR UHF DATA TRANSCEIVER ON +5V DATA GND NC GND +5V The HopeRF module that has Stan so excited this month! Shown here approximately life size, it operates in the 434MHz “LIPD” band and mates perfectly with Stan’s other favourite toy, the PICAXE. tively encoded to match their sender. Hence although receiving neighbouring wireless doorbells may occur, yours can easily be re-coded to use different data signals, even though spectrum noise may still decrease sensitivity (and thus range). Regular readers may recall the July 2003, December. 2005 and January 2006 SILICON CHIP articles on serial telemetry using cheap 434MHz transmitters (tx) and receivers (rx), controlled by PICAXE-08Ms. Cheap 434MHz wireless data units and PICAXEs are almost made for each other! Although any of the cheap modules then on sale could have been used, it was found the ~$10 Jaycar 1 2 3 4 5 6 1 4.5V 2 330Ω λ SC 2008 GREEN LED 8 4 1 Picaxe serial decoding – uhf RECEIVER October 2008  15 ANTENNA ANTENNA HOPERF TRANSCEIVER MODULE TRANSCEIVER MODULE 1 2 3 4 5 6 1 2 3 4 5 6 PICAXE08M 330Ω A K 22kΩ 5 3 2 PICAXE08M 4.5V (eg, 3xAA) (RS232) 330Ω A LED 10kΩ K TRANSMITTER LED 22kΩ 5 3 2 4.5V (eg, 3xAA) (RS232) 10kΩ RECEIVER Protoboard wiring for the transmitter and receiver. Differences in the receiver board are subtle – connection to the HopeRF module is to pin 2 and LED drive is different. The LEDs are perhaps overkill as the HopeRF module has red & green SMD LEDS on the modules. There are some differences between these layouts and the photograph shown earlier. doubling, multiple module mounting and “push to talk” control software became daunting. Given the continuing integration and refinement of electronic circuitry, it became apparent that classic 20th century 434MHz units were well overdue for enhancement and I for one have been watching for successors. Features hankered after included better use of the 434MHz spectrum, improved receiver sensitivity and faster data speeds. We’re in an era when electronic finesse often comes with trivial price tags but the only offerings that had arisen were for wellheeled professionals. It was hence with some anticipatory hand rubbing that the wireless data products of Chinese firm Hope Microelectronics (www.hoperf.com) were greeted! The firm, based in the mega factory Pin 6: Enable Pin 5: Configure Pin 4: DRX Pin 3: Ground Pin 2: DTX Pin 1: VCC SMA Antenna Socket Atmel ATMega48 44-pin 20MHz 4kB 8-bit SMD microcontroller 16  Silicon Chip city of Shenzhen (nearby to Hong Kong), produce a broad range of highly integrated UHF wireless data units at budget prices. Some of their offerings blending both transmitter and receiver into one package. Such a data transceiver combination naturally makes for great convenience and reduced circuit layout and is recommended, since prices are only slightly more than equivalent discrete units. Their six-lead HM-TR especially appealed, as it promised interferenceimmune FSK, programmable settings (via an on-board ATMega micro with 32-byte buffer), sensitive reception, rapid send/receive switch-over, data status lights and a quality SMA antenna outlet (gold plated!) – all for not-much-more than a classic 433MHz tx/rx pair. Combined with easy serial links to MAX232 Connection and construction details for the HopeRF HM-TR. Various pins are connected depending on whether it is in transmit, receive or configuration modes. our ever faithful PICAXE workhorses, these “transparent” data units look just what the doctor ordered. The units are programmable (using software downloadable from the HopeRF site) and a simple ~4.5V (3 x AA) breadboard setup with a repositioned PICAXE cable allows configuration tweaking. Frequencies cover four UHF bands (315/433/868/915MHz), complying with US FCC and European ETSI regulations, although some may be outside legal ISM slots. Transmitter power attenuation, receiver bandwidth, frequency fine tuning and the usual plethora of serial baud rates and communications protocols can also be set. As PICAXE serial works normally at 2400 bps, 8 data bits, no parity and 1 stop bit (2400,8,N,1) this was also written to the HopeRF transceiver – out-of-the-box default settings are at 9600 bps and 434MHz. When wired for communication, subsequent breadboarding of a PICAXE-08M-controlled pair – one transmitting (tx) and the other receiving (rx) – proved very straightforward indeed. The unit’s tiny SMD red (transmit) and green (receive) LEDs indicate tx/ rx status, so the extra LEDs (and dropping resistors) added to the controlling PICAXEs may not be strictly needed. However, as their inbuilt 32-byte buffer needs filling before wireless data is sent, the extra LEDs confirm data handling at the PICAXE itself. As ranges were of keen interest, siliconchip.com.au CON1 DB9 1 2 3 4 5 6 1 6 7 8 9 * MODULE ENTERS CONFIGURATION MODE WHEN PIN 5 IS PULLED HIGH (IE, TO +4.5V) 2 4 3 5 TO PC SERIAL PORT ON +5V DATA GND NC GND* ANT HOPERF HM-TR UHF DATA TRANSCEIVER 4.5V CONFIGURATION MODE To get the HopeRF module into configuration mode, all you have to do is take pin 5 from low to high. To program, you can use the same DB9 serial port connector as used for the PICAXE programming. simple code (using ASCII “85” for 10101010 strings) was passed between the pair to allow a distinctive “purr” when heard via a UHF scanner. A small piezo across the winking receiver LED will also give this output, in my case bemusing passers-by who thought I had a contented cat in my jacket! Using the supplied 434MHz “rubber ducky” antenna, line of sight (LOS) links of 0.5-1km proved feasible (the latter across water), although vegetation and wooden buildings cut this to about 200 metres. Since the transmitter is only rated at 5mW and was found pleasingly “clean” on a spectrum analyzer, this testifies to a sensitive receiver. The quality SMA sockets allow an external antenna to be attached, although it’s probably best to use SMA-BNC adapters (such as Jaycar’s) to utilise more standard connectors. As even a “cotanga” Yagi will give 6dB gain (enough for range doubling), simple Yagis at each end should give a 6dB+6dB = 12dB gain, allowing point to point links of perhaps several kilometres – four times that of the basic supplied antenna. As it’s apparent that the HopeRF HM-TR data transceiver offerings look worthy of a “2nd generation 434MHz” title (especially when PICAXE driven), a more demanding half-duplex data workout will be presented in a follow-up article. Stay tuned! Australian suppliers for Hope Electronics are MicroZed Computers on the NSW Central Coast, phone 1300 735 420 (www.microzed.com.au). References, links and software are hosted at www.picaxe. orconhosting.net.nz/hoperf.htm SC Transmitting PICAXE code Receiving PICAXE code purrtx: serout 2,n300,(85,85,85,….,85,b1) pause 500 goto purrtx purrrx: serin 2,n300,b1 pulsout 1,200 goto purrrx Here’s the code you’ll need to get the two modules talking . . . or at least purring . . . to each other! siliconchip.com.au The configuration software (downloadable from www. hoperf.com) is very simple to use – much esier than some of the software we’ve used in recent times. Advantest R41310 Spectrum Analyser display of HopeRF HM-TR serial (300bps) data transmitter on 434MHz. Note the “pure” output! 4dBm transmitter and supplied “rubber duck” antenna was approximately 1m away from a short pickup wire connected to the SA antenna input. Other UHF signals visible in the “grass” are from unknown external sources – a lot of devices use 434MHz! Range testing near Wellington harbour gave ~1km LOS with the rubber duck antenna. By attaching a simple Yagi antenna at both ends, data links over water as far as the island 5km away should be possible. October 2008  17 For the advanced constructor . . . USB Clock With LCD Readout Pt.1: By MAURO GRASSI This LCD USB Clock connects to your PC’s USB port. It synchronises its time with your PC – and ultimately an internet time server – when your PC is on to maintain accurate timekeeping. It can also operate on its own using battery back-up and has user-selectable display modes. A LL RECENT PC OPERATING systems, including Windows, provide services for NTP (Network Time Protocol), a protocol that’s used to synchronise your PC’s local time with an internet time server. This USB Clock in turn synchronises with your PC’s clock and provided you boot your PC regularly (and synchronise it to an internet time server), it will maintain accurate timekeeping. 18  Silicon Chip In operation, the USB Clock is powered via the PC’s USB port when the PC is on. This also charges an internal NiMH battery. This battery powers the clock when the PC is off or when the clock is disconnected from the USB port. When the PC is off, the clock’s timekeeping is maintained by a 32.768kHz watch crystal. This is accurate to within ±20ppm, giving a timekeeping accuracy of better than two seconds a day in stand-alone mode. Control software By now, you’ve probably guessed that the LCD USB Clock is based on a microcontroller. In this case, we’re using a PIC18F4550 micro to provide all the necessary functions. In addition, a small command-line program (usbclock.exe) is used to siliconchip.com.au change the USB clock’s settings and to synchronise the clock’s time with your PC’s clock. This will be described next month. We’ll even show you how to set-up your Windows operating system (using an entry in the Start-up folder) to automatically synchronise the USB Clock to the PC’s clock each time the machine boots. That way, you can install the software and forget it. In fact, this system will even take care of daylight saving time shifts. When your PC automatically adjusts for daylight saving it automatically adjusts the USB clock as well (when it is next synchronised). Display modes This clock doesn’t just tell the time. Oh no! – that would be far too easy. Because it’s got a microcontroller, we can do all sorts of other stuff as well, such as displaying the time in either 24-hour or 12-hour format, displaying the date, displaying the charging current or the battery voltage and having the display scroll. Basically, there are 12 different display modes and Table 2 shows the complete list. So how do we step through these different display modes? Well, you can either do it by repeatedly pressing the front-panel pushbutton switch (S1) or you can use the usbclock.exe program. For example, if you press the switch once, the backlight comes on. Press it again and the LCD shows the day and the month in DD:MM format (ie, mode 1). Press it again and the display steps to mode 2 to show the year and so on. As stated, there are 11 display modes in all, the last two bringing up scrolling displays. Mode 9 scrolls the time and the date, while mode 10 scrolls the time only. Prefer to control the clock via your computer’s keyboard instead? No problem – just type usbclock.exe -z:X at a command prompt, where “X” is a number between 0 and 11, depending on the mode you want displayed. Want to display the date? Type usbclock -z:1. Want to display the battery charging current? Type usbclock -z:4. Once the selected mode has been displayed, the display automatically reverts to the default display mode at the end of a preset time-out. This preset time-out has a default value of siliconchip.com.au Main Features • Automatically synchronises its time with your PC and by extension, an internet time server. • Internal rechargeable battery to keep the time while disconnected from the PC. • • • 4-digit LCD with optional dimming LED backlight. • • • Low-power CMOS design for extended battery life. All settings are changed by connecting to a PC. Can display supply voltage and battery charge status, as well as date and time. Automatic backlighting mode. Displays time in either 24-hour or 12-hour format. 30 seconds but this can be changed if you wish. Naturally, you can also change the default display mode if you want. For example, you might want the LCD to shows the date (mode 1) by default instead of the time (mode 0). We’ll talk more about this in Pt.2 next month. Backlight display modes An optional LCD backlight module allows the display to be read in the dark. There are three different userselectable modes for this backlight: (1) Backlight always on mode: in this mode, the backlight is always on when the clock is plugged into a USB port. (2) Automatic mode: the backlight automatically switches on between 6pm and 6am (ie, between 1800 and 0600 hours), which means that the backlight automatically switches on at night. Note: the unit must be connected to a USB port for this mode to operate. (3) Pushbutton only mode: in this mode, the backlight comes on for a preset time only when the front-panel pushbutton is pressed. The default time is five seconds but this can be set for longer periods if necessary. When the clock is operating from battery power, only the third backlighting mode (ie, pushbutton mode) is available. In addition, the backlighting function is automatically disabled if the battery discharges below a preset voltage. This is done to conserve battery life and maintain timekeeping when no USB power is available for extended periods. The current drain without backlighting is typically below 1mA. This increases to about 200mA when the backlight is on at 100% duty cycle. How it works Fig.1 shows the complete circuit of the LCD USB Clock. As can be seen, it consists of a microcontroller (IC1), an LCD and a bit of supporting circuitry. The LCD is driven via two D-type octal transparent latches (IC2-IC3). These latches are needed only because there are not enough I/O pins available on the microcontroller. In operation, the microcontroller loads a 16-bit word into the latches to drive the segments of the LCD. Just how the LCD is driven is explained in some detail later in the article. Power for the circuit is derived from the USB port on the computer and is fed to pin 1 (+V) of a USB Type B socket. This pin is nominally at +5V although in practice it can be anywhere between 4.75V and 5.25V, ie, 5V ±5%. Advanced Constructors Only This project uses a number of surface-mount ICs (including the microcontroller) which means that very good soldering skills are necessary in order to build it. In addition, you may have to fiddle with your PC’s firewall (if you use a third-party firewall) and the one on your modem as well, to get your PC to synchronise with an internet time server. As such, we regard this project as being suitable for advanced constructors only. October 2008  19 Pin Function Details 1 VPP Programming voltage (typically 13V) 2 PGC Programming clock signal 3 GND Ground reference 4 GND 5 VDD Ground reference Supply voltage (typically 5V) 6 PGD Programming data signal Table 1: this table shows the pinout of the ICSP (in-circuit serial programming) header CON1. It can be used to program IC1 in-circuit using a programmer like the dsPIC Programmer featured in the May 2008 issue. Other programmers like Microchip’s PICKit2 can also be used, by connecting the pins appropriately. Diode D1 provides reverse polarity protection for the USB Clock’s circuitry. It also ensures that, when the PC is switched off (but the USB cable is left connected), the battery cannot discharge back into the PC’s USB port. When USB power is applied, the supply rail sits at about 4.4V. This is sufficient to power the circuit and to trickle-charge the three AAA NiMH cells used for back-up battery. The 4.4V supply rail is bypassed using a 47mF electrolytic capacitor. Two 3.3W resistors connected in parallel (to give 1.65W) are used to limit the charging current through the battery. In addition, the voltage across these resistors is directly proportional to the charging current and this voltage is applied via a 15kW resistor to the AN1 (pin 20) input of IC1. As a result, the applied voltage is digitised and the resulting value then used by the firmware to detect when the USB cable is disconnected. When that happens, the battery supplies power for the clock and the AN1 input sits at a small negative voltage with respect to ground. The 15kW resistor in series with the AN1 input limits the input current to avoid damage to this input, while the 100nF monolithic capacitor is used to bypass the applied voltage signal. The other 100nF capacitors are used to bypass the main supply rail, while the 220nF capacitor is used to bypass the output of IC1’s internal 3.3V regulator at pin 37 (this is used to run the on-board USB transceiver). Crystal clocks A 20MHz crystal (X1) is used for the USB system and as the system clock. This crystal is connected between pin 30 & 31 of IC1, while the two associated 15pF capacitors provide the correct load to ensure that the oscillator starts reliably. An internal PLL multiplication stage and division stage are then used to derive a 48MHz clock which is used by the USB system. Crystal X2 is a standard 32.768kHz watch crystal (32,768 = 215) and is used for timekeeping. Its tolerance is less than 20ppm (parts per million) and it gives quartz watch accuracy, typically a second or two per day (or a minute per month at worst). However, this is only relevant if the USB Clock is not synchronised regularly with the PC. The two associated 22pF ceramic capacitors provide the correct loading for this crystal. Measuring the supply voltage As mentioned above, IC1’s VUSB pin (pin 37) is the output of the microcontroller’s internal 3.3V voltage regulator. This output is fed directly to the AN0 ADC input at pin 19. Since this voltage sits very close to 3.3V, this allows the microcontroller to measure its own supply voltage. This can be used to detect a low voltage condition and thus disable the backlight operation accordingly. Backlight circuit Display Mode What’s Shown On The LCD 0 Time is shown as HH:MM (hours:minutes) with the colon toggling at 2Hz (eg, 22:25 indicates it is 10:25pm). 1 Date is shown as DD:MM (day:month) (eg, 17.07 indicates 17 July). 2 Date is shown as YYYY (year) (eg, 2008 indicates the year 2008). 3 Time is shown as MM:SS (minutes:seconds) with the colon toggling at 1Hz (eg, 25:59 indicates 25 minutes and 59 seconds past the hour). 4 Battery charging current is shown in amps (eg, C.074 indicates 74mA). 5 Supply voltage is shown in volts (eg, b4.48 indicates 4.48V). 6 Battery charge state is shown in % (eg, b100 indicates 100% charge). 7 Shows the current backlight PWM Duty cycle as a percentage (eg, P080 indicates 80% duty cycle). 8 The current state of the USB enumeration is shown as a number (eg, Usb6 indicates the clock is CONFIGURED and ready to receive data). 0: DETACHED state      4: ADDRESS PENDING state 1: ATTACHED state         5: ADDRESSED state 2: POWERED state         6: CONFIGURED state 3: DEFAULT state 9 The time and date are shown as a scrolling string. 10 The time is shown as a scrolling string. 11 Displays firmware version (eg, F1.00 refers to version 1.00). Table 2: the USB Clock has 12 display modes as listed here. You step through them by repeatedly pressing switch S1 or by using the usbclock.exe program. 20  Silicon Chip The backlight consists of four LED pairs connected in series (note: these are part of a complete module). This is preferable to a parallel connection because it ensures that the LEDs have exactly the same current flowing through them at all times, thus ensuring equal brightness. The downside of a series connection is that you need a much higher driving voltage, in this case around 16V since the forward voltage drop of each LED pair is around 4V. This stepped-up voltage is derived using IC4 which is an LM3519 “High-Frequency Boost White LED Driver”. In operation, IC4 works from a supply rail as low as 2.7V and can generate a constant 20mA through the LEDs. A 3.3mH RF choke, Schottky diode D3 and the 4.7mF & 22mF bypass capacitors complete the backlight driver. The brightness of the backlight is controlled via the enable (EN) input (pin 1) of IC4 using PWM (pulse width modulation) from pin 36 (CCP1) of IC1. The PWM frequency generated by IC1 is around 30kHz and the duty-cycle siliconchip.com.au 2008 3 2 35 32 38 39 19 37 22pF 15pF Vss 6 29 CCP1 RD0 RC6 RC7 RD4 RD5 RD6 RD7 RB0 RD3 RB1 RB2 RB3 RB4 RA2 RD2 Vss 25 26 27 17 15 13 16 12 18 36 40 44 1 2 3 4 5 8 41 9 10 11 14 21 RA5 24 23 RA4 22 RA3 RE0 RE1 RE2 PGD PGM ICPGD PGC RD1 AN0 VUSB T1oscIN T1oscO OSC2 MCLR ICPGC IC1 PIC18F4550 OSC1 D+ D– USB CLOCK 220nF 22pF X2 32.768kHz 15pF 31 30 43 42 2x 3.3 4a (LCD p21)/4b (IC2 p9) 4f (LCD p22)/4c (IC2 p8) 4g (LCD p23)/4d (IC2 p7) 3b (LCD p24)/4e (IC2 p6) 3a (LCD p25)/DP3 (IC2 p5) 3f (LCD p26)/3c (IC2 p4) 3g (LCD p27)/3d (IC2 p3) COL (LCD p28)/3e (IC2 p2) 2b (LCD p29)/DP2 (IC3 p9) 2a (LCD p30)/2c (IC3 p8) 2f (LCD p31)/2d (IC3 p7) 2g (LCD p32)/2e (IC3 p6) 1b (LCD p34)/DP1 (IC3 p5) 1a (LCD p35)/1c (IC3 p4) 1f (LCD p36)/1d (IC3 p3) 1g (LCD p37)/1e (IC3 p2) 100nF K 15k 4 3 6 2 A 1 S1 11 1 7 6 5 4 GND LE D0 D1 D2 D3 D4 D5 D6 D7 2 3 4 5 6 7 8 9 IC3 74HCT573 8 A K D2: 1N4148 Vcc 4.7 F 16V DP2 10 3 DP3 4 EN GND LE D0 D1 D2 D3 D4 D5 D6 D7 2 3 4 5 6 7 8 9 GND 2 Vout LEDrtn IC4 LM3519 SW 5 A A IC2 74HCT573 Vcc 4 3 K K 22 F 16V K   A 100nF OPTIONAL BACK LIGHTING LED MODULE 10 19 18 17 16 15 14 13 12 O0 O1 O2 O3 O4 O5 O6 O7 20 Vcc OE D3 1N5819 11 1 Vcc D1, D3:1N4004, 1N5819 1 Vin 3.3 H 6 COL 9 10 11 12 13 14 15 16 17 18 19 20 19 18 17 16 15 14 13 12 O0 O1 O2 O3 O4 O5 O6 O7 20 Vcc OE 3 2 1 DP1 2 : 8.8.8.8 1 Fig.1: the circuit of the LCD USB Clock is based on a microcontroller (IC1) and a 4-digit LCD readout. Power comes from the USB port of a PC or from a 3.6V rechargeable NiMH battery. IC4 and its associated circuitry are used only for the optional backlighting feature. SC  4 1 X1 20MHz USB TYPE B SOCKET 20 RA5 AN1 RA4 A NC 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 COM1 COM1 RA2 CON1 NC RB4 5 RA5 1f 1e RB3 15k D2 RA2 1a RB2 – RA4 1b 1c 1d RB1 Vdd RB4 2g 2e Vdd RE0 NC 1g NC NC DP1 100nF RB3 2f 2d 3x 15k RB2 2a 2c 100nF RB1 2b DP2 28 RD7 COL 3e RB0 7 RB0 3g 3d RD7 47 F 16V RD6 3f 3c RD6 K RD4 3a DP3 RD5 D1 1N4004 RD5 3b 4e RD4 Vcc RC7 4g 4d RC7 3.6V BATTERY CON + 2 RD2 4f RD2 NC RE0 RC6 4a 4b 4c RC6 siliconchip.com.au October 2008  21 4 L1* LK1 220nF 1 CON1 2 LK6 LK7 LK8 5 6 LK9 – + IC1 1 PIC18F4550 (TQFP-44) IC4* 12 D3* LCD MODULE 100nF 100nF 23 34 1 22 F* 3.3 3.3 04110081 LK2 LK3 15k* + 15k 15k 3 2 4.7 F* D2 15k LK5 1 LK4 X2 D1 BACKLIGHT SOCKET* K 3 3.3 H 15k 100nF 4 Fig.2: follow these layout diagrams to install the parts on the top side and on the underside of the PC board. The parts marked with an asterisk are installed only if the optional backlighting is required (see text). 1 1 IC2 74HC573D 15pF 22pF + 18001140 X1 47 F USB TYPE B SOCKET IC3 74HC573D 15pF 22pF + 100nF CON2 TOP OF BOARD UNDERSIDE OF BOARD These two photos show the fully-assembled USB Clock module from the top (left) and bottom (right). is set by the firmware. In particular, the firmware automatically reduces the duty-cycle (and thus the backlight brightness) if it detects that the battery is “buckling” under the load. Note that IC4’s “shutdown” current is less than 1mA, making it ideal for battery-powered applications. Pushbutton switch Six-way header CON1 is used to connect pushbutton switch S1 between pins 12/16 of IC1 and ground. Pins 12/16 are normally pulled high via a 15kW pull-up resistor but are 22  Silicon Chip pulled low each time S1 is pressed. This switch is used to turn on the backlighting and to step through the different display modes (see Table 2). In addition, CON1 can also be used to program the microcontroller in circuit (ie, it also functions as an ICSP header). ICSP (in-circuit serial programming) is a vital requirement for any SMD microcontroller, as these are more difficult to program out of circuit than standard through-hole parts. If you purchase the USB Clock as a kit, the microcontroller will be preprogrammed and so you will not need to use this connector. By contrast, the “home-brew” constructor can use this connector to program the microcontroller using the hex file that’s available in the October 2008 download section of the SILICON CHIP website. The ICSP pin connections for CON1 are shown in Table 1. The other header, CON2, is used to connect the rechargeable battery pack (3 x 900mAh AAA NiMh cells). Driving the LCD The firmware is responsible for all the clock functions, as well as driving siliconchip.com.au This photo shows the fully-assembled PC board before installation of the backlight and the LCD. Note the foam blocks which are used to support the backlight. the LCD. In operation, the display segments are driven by a square wave with a frequency of about 25Hz. A segment is on whenever its driving signal is out of phase with the backplane signal (at pins 1 & 40). Conversely, a segment will be off whenever its driving signal is in phase with the backplane drive. The segment contrast is proportional to the RMS of the voltage applied to the segment relative to the backplane. Basically, we need 33 driving signals (28 for the LCD’s four 7-segment digits, four for the decimal points and the colon and one to control the backplane). In this circuit, however, the microcontroller (IC1) drives the display segments using just 18 lines. It does this by driving 16 segments directly, while the other 16 segments are driven by loading two 8-bit bytes (ie, from the same microcontroller outputs) into D-type octal transparent latches IC2 & IC3. This latching occurs very quickly (within nanoseconds), thus ensuring that the segment drive is very close to 50% duty cycle. This is important to minimise the DC offset across the LCD segments, as excessive DC offset can destroy this kind of display. Fig.3: the 20-pin socket strip for the backlight is modified by removing the pins indicated in red. The pins are removed from the 20pin socket strip by cutting them off flush using sidecutters, as shown at left. The photo above shows the modified socket strip. Pin 27 of the microcontroller provides the LCD’s backplane signal. This directly drives pins 1 & 40 of the LCD. a custom Microchip driver (MCHPUSB). Each time the host program on the PC sends a 64-byte packet, the microcontroller in the USB Clock decodes it (according to the sent command) and updates its settings accordingly. The time is sent as a time data type, consisting of the hours, minutes, seconds, day of the week, day of the month, day of the year and year. In addition, the microcontroller keeps an internal record of the last Full-speed (12Mbps) USB2.0 Another job of the firmware is to service the USB2.0 port. Endpoint 0 is implemented, as that is mandatory for any USB device. Endpoint 1 is implemented as well and uses 64-byte data packets. These packets are used to communicate with the host program (usbclock.exe) on the PC via Table 3: Resistor Colour Codes o o o siliconchip.com.au No.   4   2 Value 15kW 3.3W 4-Band Code (1%) brown green orange brown orange orange gold brown 5-Band Code (1%) brown green black red brown orange orange black silver brown October 2008  23 Backlight & LCD Options If you decide to omit the back­light, use the reflective LCD module from Jaycar (Cat. ZD-1886). Reflective LCD modules reflect the polarised ambient light to create the contrast for the segments. However, they do not let light pass through from underneath and are therefore unsuitable for backlighting. If you do wish to have a backlight, you must use a trans-reflective LCD module instead (eg, Farnell Cat. 1989340). A trans-reflective LCD module differs from a reflective module in that it lets some light pass through from underneath, thus making it suitable for backlighting. The specified reflective and trans-reflective modules are pin-for-pin compatible, so either will work in this circuit. They are both 4-digit static LCD displays that consume very little power and so are ideal for battery-powered applications. The backlight plugs into the modified centre socket strip, so that it sits directly under the LCD. successful synchronisation with the host. If the packet is successfully transmitted, the USB Clock sends a 64-byte packet back to the host program. It contains information on all the relevant settings of the USB Clock and these can be accessed by running the usbclock. exe program with the information option (ie, by typing usbclock -i). We’ll explain how to use the command line program usbclock.exe to communicate with and synchronise the USB Clock next month. This program can also be used to change various default settings. Construction Building the USB Clock requires good soldering skills, since a number of SMDs (surface mount devices) are used. However, the SMDs used have a relatively large pin spacing, so the job should still be relatively straightforward. All the parts are mounted on a single PC board coded 04110081 and measuring 63 x 78mm. Fig.2 shows the parts 24  Silicon Chip layout and wiring details. Note that those parts marked with an asterisk are installed only if you intend fitting the optional backlight. Note also that if the backlight is fitted, you will need to use a transreflective 4-digit LCD, as specified in the parts list. Begin by inspecting the PC board for hairline cracks in the tracks and for shorts between closely-spaced tracks. That done, start the assembly by installing the wire links. There are nine of these, including one under the righthand side of the LCD. Use tinned copper wire for the links. It can be straightened by clamping one end in a vise and then stretching it slightly by pulling on the other end with a pair of pliers. The resistors go in next. Table 3 shows the resistor colour codes but you should also check each one using a DMM before soldering it into circuit. The three diodes are next on the list. Note that these are all mounted vertically on the board. Make sure that all the diodes are correctly oriented and note that that D1 is a 1N4004 while D3 ia a 1N5819. The 3.3mH RF choke (L1) can now be soldered into place. This also mounts vertically on the board. It looks like the resistors, so don’t get it mixed up with these parts (it should have a very low DC resistance). Now fit the four ceramic capacitors (2 x 15pF & 2 x 22pF). These are all located immediately to the left of the USB socket. Once they’re in, install the five monolithic capacitors (4 x 100nF & 1 x 220nF) and the three electrolytics. Make sure that the electrolytics are all correctly oriented. Follow these with the two crystals (X1 & X2). The 32.768kHz watch crystal (X2) has very delicate leads so be careful with these. This crystal should be mounted so that it sits horizontally on the PC board. Secure X2 in place with a small dab of silicone to prevent it from moving and fracturing its leads after it has been installed. Cutting the IC sockets The next step is to cut the two 40-pin IC sockets in half to obtain three 20-pin strips (the remaining strip is discarded). Two of these 20-pin socket strips are used to mount the LCD while the other is used to mount the backlight module. We recommend that you can leave part of the middle connecting bar on the top socket strip (see photos) to provide support for the backlight module. The two socket strips for the LCD module should now be soldered into position. siliconchip.com.au This life-size view shows the completed unit before the lid is fastened into place. Take care to ensure that the LCD is the right way around and be sure to install the battery with the correct polarity. The socket strip for the backlight module can now also be mounted but first you have to remove a number of pins. This is done by snipping them off using side-cutters, as follows: beginning on the left, remove two pins, then leave one, remove two, leave two, remove two, leave two, remove two, leave two, remove two, leave one, remove two (ie, 12 removed in total). Fig.3 shows the pattern. The modified socket strip can then be soldered into place. We also suggest adding a couple of foam pads as shown in one of the photos to provide additional support for the backlight module. Once these socket strips are all in place, install the USB socket and the 6-pin and 2-pin headers (CON1 & CON2). That completes the top of the PC board, apart from plugging in the backlight module and the LCD. Leave these two components out for the time siliconchip.com.au Soldering In The Surface-Mount ICs The PIC microcontroller (IC1) is mounted by soldering pins 21 & 22 (topright of IC1) first. Any solder bridges between pins (eg, as indicated by the red circles in the centre photo) can be cleared using solder wick. The photo at right shows IC3 & IC4 mounted position while above is a close-up of IC4. Make sure that all ICs are correctly oriented. October 2008  25 Parts List 1 PC board, code 04110081, 63 x 78mm 1 Type B USB socket (Jaycar PS-0920; Altronics P-1304) 1 Deluxe Hand Held Case, 79 x 117 x 24mm, with battery compartment (Altronics H-8976) 1 transreflective 4-digit + colon LCD (Farnell 1989340)*, OR 1 reflective 4-digit + colon LCD (Jaycar ZD-1886) 1 20MHz crystal, HC49US case (X1) (Jaycar RQ-5299) 1 32.768kHz watch crystal, ±20ppm (X2) (Altronics V-1902) 1 SPST momentary pushbutton switch (S1) (Jaycar SP-0656) 1 3.3mH RF Choke (Jaycar LF1516, Altronics L-7016)* 2 40-pin DIL IC sockets 1 6-way header, 2.54mm pitch (CON1) 1 2-way header, 2.54mm pitch (CON2) 3 900mAh (or better) NiMH AAA rechargeable batteries with solder tabs (Jaycar SB-1724) 1 50mm dia. x 300mm length of Thermotite heatshrink (Jaycar WH-5580) (for battery pack) 1 Type A to Type B USB cable (Altronics P-1911A, Jaycar WC-7700) 2 header plugs (2.5mm pitch) (RS Components Cat. 311-6209) 1 120mm-length of medium-duty hookup wire (red) 1 120mm-length of medium-duty hookup wire (black) being. They go in after the four SMD ICs have been installed. Soldering the SMD ICs The four SMD ICs (IC1-IC4) are installed on the copper side of the PC board – see Fig.2. To install them, you will need a soldering iron with a finepointed tip, some very fine resin-cored solder, a pair of self-closing tweezers and a good light. A magnifying lamp is also handy or failing that, a magnifying glass so that you can inspect the soldered leads for possible shorts. Begin by installing IC2 & IC3, the two 74HC573D latches. These have a larger pin spacing than IC1 and so are 26  Silicon Chip 1 30mm length of 0.7mm tinned copper wire 4 6g self-tapping screws Semiconductors 1 PIC18F4550-I/PT microcontroller (TQFP44 package) programmed with 0411008A (IC1) (Farnell 9321365) 2 74HC573D octal D-type transparent latch (SO20 package) (IC2-IC3) (Farnell 1201326) 1 LM3519MK-20 LED driver IC (SOT-23 6 package) (IC4) (Farnell 1312717)* 1 LTR24S360-4YG LED backlight module (Farnell 1208878)* 1 1N4004 diode (D1) 1 1N4148 Signal diode (D2) 1 1N5819 Schottky diode (D3)* Capacitors 1 47mF 16V electrolytic 1 22mF 25V electrolytic* 1 4.7mF 16V electrolytic* 1 220nF monolithic 4 100nF monolithic 2 22pF ceramic 2 15pF ceramic Resistors (0.25W, 1%) 4 15kW 2 3.3W 1 15kW* Footnote Parts marked with an asterisk (*) are required for the optional LCD backlighting only. a good place to start. First, position IC2 on the PC board and “clamp” it in place using the selfclosing tweezers (or a clothes peg). Check that it is correctly oriented (ie, with pin 1 positioned as shown on Fig.2), then carefully solder pin 10 to its pad. Now do the same for pin 20 which is diagonally opposite. The IC will now be firmly anchored in place and you can remove the tweezers and carefully solder the remaining 18 pins. Repeat this procedure for IC3, then move on to IC1 (the PIC microcontroller). IC1 is slightly more difficult to install because its pins are closer to- gether. As before, take care to ensure that it is properly oriented and clamp it accurately in position before soldering its pins. In this case, the best pins to solder first are pins 21 and 22 at top right (see photo). These are soldered to the same pad, so they’re easier to deal with. After that, solder pin 1, then remove the clamp and solder the remaining pins. The trick here is not to apply too much solder. Use it sparingly and be sure to solder each pin quickly. You don’t want to apply too much heat for too long, otherwise you could damage the IC. Don’t worry if you get solder bridges between adjacent pins at this stage – just move onto the next pin and keep going. After you’ve finished soldering the 44 pins, you can remove any solder bridges using solder wick. This is done by laying the wick along the pins and then applying the soldering iron to the wick to “suck” up the excess solder (see photo). IC4 (LM3519) can now be installed. It’s quite small and comes in a 6-pin SOT-23 package. Once again, make sure it is correctly oriented before soldering its pins. Pin 1 is adjacent to the chamfer along one edge of its body (see Fig.2). In practice, it’s easiest to solder pin 6 first, since its PC pad is larger than the others. The remaining five pins can then be carefully soldered. It’s now a good idea to carefully inspect each IC with a magnifying glass to make sure that everything is correct. In particular, look for solder bridges and for pins that haven’t been soldered. Note: for further information on soldering SMDs, refer to the feature article in the March 2008 issue of SILICON CHIP. LCD & backlight installation Now that the ICs are all in place, install the backlight module into its IC socket strip, then fit the LCD module. Take care with the orientation of the LCD – pin 1 goes to bottom left. Making the battery pack The battery pack consists of three NiMH AAA cells with solder tabs. These are connected in series as shown in Fig.5 to give an output of 3.6V. To make up the pack, first lay two siliconchip.com.au batteries together side-by-side but facing in opposite directions. Solder their tabs together, then sit the third battery in the channel formed by the first two and solder its tabs. It’s then just a matter of adding the output leads (red for positive, black for negative) and using some heatshrink to secure the cells into a pack. The output leads are terminated in a 2-pin header and this should be fitted before the leads are connected to the battery. Warning: be careful not to short any of the cell terminals or the output leads. NiMH batteries can supply lots of current. Fig.4: switch S1 connects to pins 2 & 4 of CON1 via a 2-pin header plug. TO CON1 VIA 2-PIN HEADER PLUG PIN 2 S1 PIN 4 Fig.5: the battery pack is made up by connecting the NiMH cells in series. Use heatshrink sleeving to secure the cells together in one pack. AAA NiMH CELL TO CON2 VIA 2-PIN HEADER PLUG + AAA NiMH CELL – AAA NiMH CELL Final assembly The assembly can now be completed by installing it in the specified case. As shown in the photos, the PC board is secured to integral stand-offs in the bottom of the case using four 6g self-tapping screws. The battery sits in a separate compartment and is plugged into CON2 but don’t do that just yet. Next, you will have to drill a hole in the lid of the case for the switch and cut out a window for the LCD. The front panel artwork shown in Fig.6 can be used as a drilling template (either copy the artwork from the magazine or download it from the SILICON CHIP website and print it out). Once you have the artwork, attach it to the front panel using double-sided tape, then drill the hole for the switch. Use a small pilot drill to begin with, then carefully enlarge it to 10mmdiameter using a tapered reamer. The window for the LCD is best made by drilling a series of holes around the inside perimeter. The centre-piece is then be cut out using a small hacksaw and the job filed to a smooth finish. The drilling template should now be removed and a new front-panel artwork printed out. This should be protected by covering it with some wide strips of clear adhesive tape before cutting it out and attaching it to the front panel. It can be affixed using double-sided tape or by using a thin smear of silicone sealant. nated in a 2-way header which is then plugged into pins 2 & 4 of CON1. MODE 10mm BACKLIGHT 51 x 23mm LCD CUTOUT USB CLOCK SILICON SILICON CHIP CHIP www.siliconchip.com.au Fig.6: this full-size artwork can be used as a drilling template. Cut out the holes in the front panel label using a sharp hobby knife, then mount the switch in position and attach a couple of 100mm-long flying leads. These leads are then termi- Testing Assuming IC1 is programmed, apply power by plugging the battery pack into CON2. Be sure to connect the battery the right way around, as there is no on-board protection against a reversed battery connection. As soon as you apply power, the LCD should show a default time of 12:00, assuming that the battery is charged. If the battery isn’t charged, then you will have to apply power by plugging the USB Clock into the USB port of your PC. The clock should then briefly flash the word “SYnc” and then repeat this every 15 seconds, indicating that it hasn’t been synchronised. If it does that, then it is working correctly and the lid can be attached. It’s now simply a matter of installing a driver plus the usbclock.exe program on your PC and then running the program to synchronise the USB Clock. We’ll describe just how this is done in Pt.2 next month. We’ll also show you how to synchronise your PC to an internet time server and describe how to run usbclock.exe automatically each time SC your PC starts. Issues Getting Dog-Eared? Keep your copies safe with our handy binders Available Aust, only. Price: $A14.95 plus $10.00 p&p per order (includes GST). Just fill in and mail the handy order form in this issue or ring (02) 9939 3295 and quote your credit card number. siliconchip.com.au October 2008  27 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 By JIM ROWE T RADITIONALLY, RF level/power meters have been quite expensive beasts costing many hundreds of dollars, even secondhand. Small wonder that many of us have simply had to do without them. Such RF level/power meters have always been expensive because of the measurement technique they used: converting the RF energy into heat and then measuring the temperature rise using a sensitive thermocouple system. Luckily for us, advancing semiconductor technology now provides an easier way: the wideband logarithmic amplifier/detector IC. Its DC output is closely proportional to the logarithm of the RF input voltage. We can achieve the desired result by combining one of these chips with an “intelligent” metering circuit, capable of processing this logarithmic DC voltage to indicate both signal level and the corresponding power level. In a nutshell, our circuit uses an Analog Devices AD8307AN logarithmic amplifier/detector to convert RF signals into DC which is processed by a PIC microcontroller. The micro uses some fairly fancy maths routines to work out the signal level and power, which is then displayed on a standard 2-line LCD panel. The whole set-up works from a 9V battery or DC plugpack and draws less than 35mA. The AD8307 log amp/detector Digital RF Level & Power Meter Need to measure small signals at radio frequencies? Here is a low-cost digital level and power meter which will allow you to measure RF signals from below 50kHz to above 500MHz. As well as indicating the signal level in volts and dBV, it also shows the corresponding power level (into 50 ohms) in both milliwatts and dBm. 30  Silicon Chip To help understand logarithmic amplifier/detector ICs, take a look at Fig.1. This gives a simplified view inside the AD8307AN device. The incoming RF signals are passed through six cascaded wideband differential amplifier/limiter stages, each of which has a gain of 14.3dB (about 5.2 times) before it enters limiting (ie, clipping). This gives a total amplifier gain of about 86dB or about 20,000 times. The outputs of each amplifier/limiter stage are fed to a series of nine fullwave detector cells, along with similar outputs from three cascaded passive 14.3dB attenuator cells connected to the input of the first amplifier/limiter. The differential current-mode outputs of all nine detector cells are added together and fed to a “current mirror” output stage, which effectively converts them into a single-sided DC output current. Because of the combination of cascaded gain and limiting in the amplifiers (plus an internal offset compensation loop), the amplitude siliconchip.com.au Specifications SIX 14.3dB GAIN, 900MHz BW AMPLIFIER/LIMITER STAGES +INP INTERC. SET –INP • 3x PASSIVE ATTENUATOR CELLS MIRROR Iout NINE FULL-WAVE DETECTOR CELLS WITH DIFFERENTIAL OUTPUT CURRENTS – ALL SUMMED ENB BAND-GAP REFERENCE AND BIASING OUT 25mV/dB 12.5k INPUT OFFSET COMPENSATION LOOP Fig.1: block diagram of the AD8307AN amplifier/detector IC. The incoming RF signals are passed through six cascaded wideband differential amplifier/limiter stages and these in turn drive full-wave detector cells (see text). 4.7 TO MAIN BOARD (CON1) 100nF 47nF 8 Rin* 7 VPS IN H 6 EN 4 OUT IC1 AD8307AN 5 INT 47nF 1 10 IN L COM 2 OFS INTERCEPT ADJUST SLOPE VR2 ADJUST 50k 1 2 3 4 VR1 50k 100nF 3 100nF 51k SC RF LEVEL & POWER METER 33k HEAD END CIRCUIT Fig.2: the head-end circuit is based on the AD8307AN. The incoming RF signals are fed to pins 8 & 1 via 47nF capacitors, while the detected output appears at pin 4 and is fed to pin 3 of a type A USB socket. of this output current is closely proportional to the logarithm of the RF input voltage, over an input range of 100dB from about -93dBV (22.4mV) up to +7.0dBV (2.24V). In fact this “logarithmic law” relationship is linear to within ±0.3dB over most of the range. The output current Iout increases at a slope of very close to 2mA per dB increase in RF input level. This current passes through an internal 12.5kW resistor, resulting in a DC output voltage which increases at the rate of 25mV/dB. This slope can be fine tuned using an adjustable external resistor in parallel with the 12.5kW internal resistor. So what’s that “intercept set” input for? This allows us to adjust the DC offset in the output current mirror, which adjusts the effective “zero level” point of the chip’s output current and siliconchip.com.au • • • • • Input impedance: 50W (can be changed to 75W or 1.1kW) Measuring frequency range: from below 50kHz to above 500MHz Maximum input signal level: 2.238V RMS (+7.0dBV) Minimum input signal level: 22mV RMS (-93dBV) Maximum input power level: 100mW into 50W (+20dBm) Minimum input power level: 1nW (0.001mW/-60dBm) Measurement linearity: approximately ±0.3dB Measurement accuracy: approximately 0.2% Power requirements: 9V DC at 35mA (no backlight) or 120mA with backlight CON5 USB TYPE 'A' SOCKET * Rin = 100 //220 //220  FOR 50  INPUT 2008 • • COM RF INPUT CON4 • voltage, ie, the “origin” from which the output slope rises. You can think of it as setting the detector’s zero point. Head-end circuit It’s desirable to separate the RF detector section from the rest of the meter circuitry, partly because it is the only section handling RF signals and partly because it has very high gain and is therefore susceptible to electromagnetic interference. The AD8307AN and its accompanying components are therefore mounted on a small “head-end” board which in turn is mounted inside a small diecast aluminium box, for shielding. The circuit of this head-end section is shown in Fig.2 and involves little else apart from the all-important AD8307AN (IC1). The incoming RF signals are coupled into the inputs of IC1 via two 47nF capacitors, with Rin providing the desired 50W input termination. (Rin is a combination of paralleled surface-mount chip resistors, to give a value of 52.4W with very low parasitic inductance. As the input impedance of the AD8307AN is itself very close to 1.1kW and this is in parallel with Rin, the resulting total input resistance is very close to 50W). Trimpot VR1 and its 33kW series resistor are connected between the output (pin 4) of IC1 and ground, so they are effectively in parallel with the 12.5kW resistor inside the chip itself. This allows the output slope of the detector to be fine tuned to a value of 20mV/dB, when the meter is calibrated. Trimpot VR2 is used to adjust the DC voltage fed to pin 5 of IC1. This is the “intercept set” input, so VR2 effectively becomes the detector’s zero set adjustment. The head-end section connects to the main meter unit via a standard USB cable. This cable carries the detector’s output voltage to the main board via pin 3 of CON5 and also supplies IC1 with +5V power via pin 1. Main circuit The processing part of the circuit is shown in Fig.3. Here is where the real “work” is done, by the firmware October 2008  31 Volts, dBV, Milliwatts & dBm The RF Level and Power Meter described in this article gives four indications for every measurement: the RF input voltage (in volts or millivolts), the corresponding value in dBV, the corresponding power level in the meter’s 50W input load (in milliwatts or microwatts) and the corresponding value in dBm. The voltage and power levels probably need no explanation but I should perhaps explain the significance of the two decibel readings. For many years, engineers working in the communications and RF fields have found it convenient to describe signal amplitude and power levels in decibels, because of the very wide ranges involved – from microvolts (mV) to kilovolts (kV), and from nanowatts (nW) to kilowatts (kW). Because decibel scales are logarithmic, they make it easier to work with signals varying over such wide ranges. To describe the voltage gain of an RF amplifier in terms of decibels, for example, we simply take the base-10 logarithm of the voltage gain (Vout/Vin) and multiply this figure by 20. So a voltage gain of 10 corresponds to +20dB, a gain of 100 corresponds to +40dB, a gain of 1000 corresponds to +60dB and so on. Similarly an attenuator which reduces the voltage level by a factor of 10:1 can be described as having a “gain” of -20dB. Get the idea? When we’re describing power levels rather than voltage, the power gain of an RF amplifier can be found by again taking the base-10 logarithm of the power gain (Pout/Pin) but this time multiplying the figure by 10. So a power gain of 10 times is +10dB, while a power gain of 100 times is +20dB and so on. (If you’re a bit puzzled by the difference between voltage and power when calculating the decibels, it’s merely because power increases with the square of the voltage. That’s why we multiply the log of voltage ratios by 20 but we only multiply the log of power ratios by 10). dbV and dBm So what’s the difference between “dBV” and “dBm” figures? Well, these are both decibel scales but in this case they are used to compare one specific voltage or power level with a known reference value, rather than to compare two specific values. So the contractions dBV and dBm indicate that the figures they accompany are absolute, rather than relative. “dBV” is a voltage level expressed in decibels with reference to 1.000 volts. So +6dBV (2V) is 6dB greater than 1V, while -20dBV (100mV) is 20dB smaller than 1V. So expressing a voltage in dBV merely indicates that it is measured on a decibel scale which refers to 1.00V as its 0dB point. Similarly, “dBm” is a power level which is expressed in decibels with reference to a specific reference power level of 1mW (milliwatt); in other words, on a decibel scale where 1mW corresponds to 0dB. So +10dBm corresponds to 10mW, +20dBm to 100mW and -30dBm to 1mW (microwatt). There is another “absolute” decibel scale used for expressing voltage levels, the dBm scale. This refers to a level of 1mV (microvolt) as its 0dB point. So +120dBm is the same as 0dBV, while 0dBu is the same as -120dBV. One last point: since the dBV and dBm scales are “absolute”, surely they can be related to each other? Yes they can but to work this out you need to know the impedance level – because that is what relates voltage and power in any circuit. In most RF work, the impedance level is 50W. At this level, a voltage of 1V corresponds to a power level of 20mW (12/50), so 0dBV equals +13dBm. On the other hand -30dBm (= 1mW) corresponds to 7.07mV, or -43dBV. In other words, there’s a fixed 13dB difference between the two scales. This difference changes with impedance level, though. For example when the impedance level is 600W, 0dBm or 1mW corresponds to 0.7746V or -2.218dBV, so there’s a fixed 2.2dB difference between dBm and dBV. Older RF level and power meters often indicated in just dBm or perhaps in dBV as well. If the user wanted to know the actual voltage and power level, they had to either refer to a chart or grab a calculator and work them out. This could be pretty tedious, and that’s why we’ve given this new RF Level and Power Meter the ability to calculate and display not just dBm and dBV but the equivalent volts and milliwatts as well, for every measurement. 32  Silicon Chip running inside the PIC16F88-I/P micro (IC3). The PIC16F88-I/P device is well-suited to this application, as it includes an analog-to-digital converter (ADC) module with 10-bit measuring resolution. The ADC is also flexible in terms of its operating mode, with a choice of positive and negative reference voltages and also a 7-channel input multiplexer. We take advantage of these features by using a positive reference voltage of 3.50V which is fed into pin 2 of IC3 and by using three of the ADC input channels to allow firmware selection of the measuring range via pin 1 (AN2), pin 18 (AN1) and pin 17 (AN0). Why do we need three ranges? Because it allows us to get higher measuring resolution when the RF input signals (and hence the output voltage from IC1) are quite small. For these signals, we are able to amplify the DC output voltage from IC1, in order to use a larger proportion of the ADC’s measurement range of 0-3.5V and hence increase the measurement resolution. We provide the three ranges in the following way. The incoming DC voltage from IC1 enters via pin 3 of CON1, and is then passed through a simple input protection circuit using diodes D1 & D2, the 100nF capacitor and the 100W and 1MW resistors. It is then fed to the paralleled inputs of op amps IC2b, IC2c & IC2d. Each of these provides a different amount of gain, to change the effective slope of the log-law input signal. The gain for the normal default measuring range is 1.75, provided by IC2b with its 1.5kW and 2.0kW feedback resistors. This gives the incoming DC signal an effective slope of 1. x 20 or 35mV/dB, translating to a total span of 100dB for the ADC’s 3.5V measuring range. For signals of less than 223.9mV (-13dBV), we select the output from IC2d, configured for a gain of 2.19. This gives the incoming DC signal an effective slope of 43.74mV/dB, translating to a total ADC measuring span of 80dB. Then for signals of less than 22.39mV (-33dBV) we select the output of IC2c, with a gain of 2.916. This gives the incoming DC signal a slope of 58.32mV/dB, which translates to a total span of 60dB. Using this approach we obtain much better measuring resolution for these much smaller signals. The siliconchip.com.au siliconchip.com.au October 2008  33 2 3 4 1 100nF D2 100 A K A K D1 1M +5.00V 100nF 6 5 13 12 9 IC2c 4  LED1 330 7 1.5k 2.4k 14 3.9k TP1 2.0k 2.0k 220k 2.0k 220k TPG 1 18 17 2 2.2k RB4 AN2 AN1 Vss 5 10 11 3 CLKo 15 9 RB3 8 RB2 7 RB1 6 RB0 IC3 PIC16F88-I/P AN0 RB5 RA4 4 14 Vdd MCLR Vref+ 12 RB6 13 RB7 16 RA7  LED3 +3.50V K A MAIN BOARD 11 IC2b IC2d 8 200 6.8k  LED2 3.0k K A IC2: LM324N 10 K A RF LEVEL & POWER METER USB TYPE 'B' SOCKET CON1 100nF +5.00V 6 4 Vdd 2 SET 5.00V 330 TPG D3 K A K D1,D2: 1N4148 A TP2 (2.0MHz) IN K A 5 R/W IC2a LEDS 2 3 A OUT ADJ 1 3 LM317T IN – + CON3 9–15V DC INPUT OUT CON2 CAL/MOD OUTPUT LCD VR4 10k CONTRAST 68k 1.5k 9V BATTERY S2 POWER CONTRAST 470 F 16V K D3 1N4004 16 x 2 LCD MODULE VR3 100 220 F ADJ OUT D7 D6 D5 D4 D3 D2 D1 D0 GND 1 14 13 12 11 10 9 8 7 EN RS S1 SELECT RANGE 10k 100nF 120 REG1 LM317T Fig.3: the main-board circuit is based on an LM324 quad op amp (IC1) and a PIC16F88 microcontroller (IC3). The incoming signal is fed to paralleled op amp stages IC2b-IC2d, each operating with a different gain to provide three ranges. Their outputs in turn drive the ADC inputs of IC3 which processes the signals and drives a 16 x 2 LCD module. SC 2008 FROM HEAD END (CON5) TPG TP3 ALTRONICS 16X2 LCD MODULE Z-7000A OR Z-7011 (B/L) A 18090240 8002 C K RE W OP/LEVEL FR LATI GID )DRA O B NIA M( RETE M 14 330 SET 5.00V TP3 5.00V REG1 LM317T 1 2.0k 4148 LED2 –20dBV LED3 –40dBV 470 F 2 3 CON1 POWER S2 4004 0dBV 1M 4148 100nF D2 LED1 4 100nF D3 S1 2.4k 220k 1 100 330 3.9k 220k RANGE SELECT D1 1 IC2 LM324N 2.0k 2.0k 100nF 220 F 1.5k CAL OUT CON3 9–15V DC IN TPG CON2 INPUT FROM HEAD END 68k LCD CONTRAST 1.5k TP2 (2MHz) 200 6.8k 2.2k 10k 3.0k 100 VR3 120 TPG TP1 (3.50V) IC3 PIC16F88 -I/P 100nF 10k RBL* VR4 TPG 18  0.5W 1 + – BATTERY * SEE TEXT Fig.4: follow this parts layout diagram and the accompanying photograph to build the main board. Both IC2 and the PIC16F88 microcontroller (IC3) should be installed in sockets. outputs from op amps IC2c, IC2d & IC2b are fed directly to the AN0, AN1 & AN2 (ADC) inputs of the PIC and its firmware selects the appropriate ADC input channel by stepping from one range to the next each time you press the range select button (S1). To indicate which range is currently selected, the firmware switches on LED1, LED2 or LED3 and automatically changes the scaling factor, so that the displayed values are correct. After performing the calculations for each measurement, the firmware then displays the results via the LCD module. Power supply The complete circuit runs from 5V DC, which is derived from either a 9V 34  Silicon Chip battery or a plugpack supply of similar voltage, using regulator REG1, an LM317T adjustable device. We use this rather than a fixed regulator because this allows us to set the supply rail accurately to 5.00V. We need to do this because the 3.50V reference voltage for the PIC’s ADC is derived directly from the 5V rail, via a voltage divider using 3.0kW, 6.8kW and 200W resistors. This reference voltage for the ADC is fed into pin 2 of the PIC, which is configured as the Vref+ input. Notice that there are a number of test points provided in the main board circuit, to allow more convenient setup and calibration. TP1 allows you to measure the ADC reference voltage, so you can adjust trimpot VR3 to achieve exactly 3.50V at pin 2 of the PIC. TP3 also allows you to measure the 5.00V rail directly, if you wish, while TP2 allows you to check the PIC’s internal clock oscillator. This runs at 8MHz, which means that the signal available at TP2 should be very close to 2MHz (Fc/4). So if the PIC is running correctly, you will find a 2MHz square-wave of 5V peak-topeak at TP2. Finally, the fourth op amp, IC2a, is provided purely as a voltage follower/ buffer from the output of IC2b (the default ADC driver). Its output is made available via CON2, to allow you to monitor the amplified output voltage from the AD8307AN head-end extersiliconchip.com.au nally, with a DMM or oscilloscope. This could be convenient for calibration and also for looking at any amplitude modulation of the RF signals being measured. Note that any observed modulation envelope is likely to be distorted because of the logarithmic response of the head-end amplifier. 51k 4 3 2 10 100nF 100nF 1 VR1 50k 33k TOP VIEW OF HEAD END BOARD SIDE OF BOX CON4 CON5 1 100 220 47nF 220 BNC INPUT SKT TO MAIN BOARD CON5 2 3 4 47nF Fig.5: these two diagrams & the above photo show the parts layout on the head-end board. Use a fine-tipped soldering iron to solder the SMDs to the copper side of the PC board and take care to ensure that IC1 is correctly orientated. Do not use a socket for ICs – it must be soldered directly to the PC board. C 2008 04208082 siliconchip.com.au 50k 100nF IC1 AD8307 Construction As noted earlier, the project is comprised of two parts: the AD8307AN head-end fitted into a small metal box for shielding and the main meter circuitry which is fitted into a UB1-size plastic jiffy box (158 x 95 x 53mm). The two are connected together using a standard USB interconnect cable. The meter’s main circuitry is all fitted on a PC board coded 04210081 and measuring 146 x 84mm, and with a recess in each corner so that it fits neatly behind the lid of the UB1 box. The head-end circuitry is installed on a second PC board coded 04210082 and measuring 43 x 44mm. There is actually a third PC board for this project, coded 04210083 and measuring 95 x 38mm. This is for an optional 20dB/50W attenuator, to allow measurements of higher-level signals. The location and orientation of all parts mounted on the main board are shown clearly in the board overlay diagram of Fig.4. Note that connectors CON1, CON2 and CON3 are all mounted directly on the board, along the righthand side. Power switch S2 also mounts directly on the board, with its connection lugs passing through the board and soldered to pads underneath. Range select switch S1 can be mounted in the same way or mounted on the box lid with its leads extended through the board using short lengths of tinned copper wire. The three range indicator LEDs are again mounted directly on the board, with the underside of their bodies spaced up by about 14mm so that the LEDs just protrude through the matching holes in the front panel (ie, the lid) when the board is mounted behind it. Use sockets for IC2 & IC3, rather than soldering them directly to the board. There are four wire links on the board and it’s a good idea to fit these before any of the components so that they’re not forgotten. The test point terminal pins can also be fitted at this VR2 4.7 8002 C 28080240 COPPER SIDE OF HEAD END BOARD The head-end board is attached to a panel-mount BNC socket and mounted upside down inside a diecast metal case. A type A to type B USB cable connects the unit to the main PC board. stage, along with the two further pins used for the optional battery connections. By the way, these last two pins are mounted from the rear, to make the battery connections easier. Mounting the LCD module The LCD module used for this project is the Altronics Z-7000A or Z-7011, with the second type number signifying the version with backlighting. Regardless of which version you use, the module is mounted above the main board using four M3 x 15mm machine screws, with M3 x 6mm tapped Nylon spacers used as standoffs. Then nuts are fitted under the board to hold everything together – but with one Nylon flat washer under the nut at lower left, to ensure that it doesn’t short-circuit October 2008  35 What The Firmware Does As we explain in the main text, the AD8307 chip in the RF Meter’s “head end” detects the incoming RF signals and converts them into a DC voltage according to a logarithmic conversion scale. A PIC micro then measures and converts this into the equivalent RF voltage and power readings, under the control of a firmware program. To do this, it makes use of a suite of maths routines made available to PIC programmers by Microchip Technology Inc, the manufacturers of the PIC family of micros. These routines are used to perform 24-bit and 32-bit floating-point addition, subtraction, multiplication and division, base-10 exponentiation, fixed-point multiplication and division, and floating-point to ASCII conversion. Without going into much detail, the PIC firmware program works through the following sequence in making each measurement: First it directs the PIC’s 10-bit analogto-digital converter module to take a measurement of the DC output voltage from the AD8307 chip. It then converts that into 24-bit floating-point form, after which it is multiplied with a pre-calculated scaling factor (24-bit also) for the currently chosen measurement range. The resulting product is then divided by the ADC’s full-scale value of 3FF (in 24-bit FP form), to give the measurement value in what I call the “raw dB” form. This is essentially a 24-bit number varying between 0 and 100. This raw dB value is then used to calculate the equivalent dBV value, by subtracting decimal 93 (in 24-bit FP form) and also the equivalent dBm value (for 50W impedance level) by subtracting decimal 80 (again in 24-bit form). These values are then saved for display but also used to calculate the actual voltage and power levels. The dBV value is used to calculate the equivalent voltage by first dividing it by decimal 20 (in 24-bit FP form) and then raising decimal 10 to that power using EXP1024, the Microchip 24-bit floatingpoint base-10 exponentiation routine. This is equivalent to calculating the antilog­ arithm, so we end up with the equivalent voltage value in 24-bit FP form. After saving this for display, the program then does the equivalent calculation for power, taking the dBm value and first dividing it by decimal 10 and then again raising decimal 10 to that power using EXP1024. This gives the equivalent power in milliwatts, which is again saved for display. Once all four parameters have been calculated, the final steps of the measurement sequence involve taking each 24-bit parameter and processing it for display on the LCD module. For the dBV and dBm figures, this means working out the correct polarity indication (+ or -) and then using a Microchip routine called Float_ASCII to convert the numbers themselves into ASCII digits for display. Things are a little more complicated for the voltage and power values, because these must first have their 24-bit binary exponents analysed to work out their scaling, the position of their decimal point and the most convenient multiplier to give them (eg, milli or micro). After this is done, they are again converted into the equivalent ASCII digits using Float_ASCII. As you can see, there’s quite a bit of mathematical jiggery-pokery involved but luckily most of this is performed by Microchip’s fancy maths routines. The full source code for the firmware will be available on the SILICON CHIP website, along with the source code for the floating point maths routines it uses (in a file called FPRF24.TXT) and, of course, the assembled hex code of the complete firmware ready to burn into a PIC. a PC board track close by. The 14 main connections to these modules are all in a horizontal row at lower left. To make these connections reliably but in a manner which allows easy removal and replacement of the module if this is ever needed, I elected to use a custom-made 14-way plug and socket system. The socket was made from one side of a 28-pin IC socket, cut away neatly and then mounted on the top of the main board. To mate with this socket, I made a plug from a 14-pin length of SIL pin strip, the pins of which were soldered to the pads on the underside of the module. This must be done carefully, so that there is enough clean length of each pin extending down to mate with the socket clips (this is easier to do than to describe). Backlit LCD module This larger-than-life-size view shows how the LCD module is connected to the main PC board. A 14-pin header is soldered to the LCD module and this plugs into a matching 14-pin socket strip cut from a 28-pin IC socket. 36  Silicon Chip If you use the backlit LCD module (Z-7011A) you will have to connect its “A” & “K” terminals (for the backlight siliconchip.com.au A A 19 61 16 63 x 16mm LCD WINDOW 26 63 HOLES A: 3.5mm DIA., COUNTERSUNK 7 24.5 D B HOLES B: 3.5mm DIA. CL HOLES C: 6.5mm DIA. (RIGHT-HAND SIDE OF BOX) 24.75 8.25 B 12 HOLE E: 9mm DIA. 17.75 12 (BOX LID) HOLE D: 11mm DIA. B 7.5 B 15.25 7.5 E B A A 21 3 C 9.5 11.5 C 9 30.5 CL ALL DIMENSIONS IN MILLIMETRES Fig.6: this full-size diagram shows the drilling details for the plastic case that’s used to house the main PC board. The large cutouts can be made by drilling a series of holes around the inside perimeter, then knocking out the centre piece and filing the job to a smooth finish. LEDs) to the main PC board. This can be done using short lengths of tinned copper wire. Similarly, resistor RBL (18W 0.5W) is installed only if you are using this module. It gives a nominal LED current of about 80mA. Once all of the components are mounted on the main board, it can be placed to one side while you assemble the head-end board. Head-end board assembly The board overlay diagrams for the siliconchip.com.au head-end board are shown in Fig.5. The USB type A socket CON5 mounts on the top of the board, along with the two trimpots, three 0.25W resistors and three 100nF monolithic capacitors. IC1 should be soldered directly into the board, to ensure an absolute minimum of input lead inductance. The remaining surface-mount components all mount on the copper side of this board, ie, the two 47nF input coupling capacitors and the three resistors used for the RF input termination. Solder these components carefully using a fine-tipped iron, using the “tack first to hold it in position” technique to avoid damaging either the parts or the board pads. When you have finished wiring up this board, place it aside also while you prepare the meter’s two boxes by drilling and cutting the various holes in them. These are all shown in the drilling diagrams (Figs.6 & 8), so the job should be quite straightforward. To complete assembly of the headend unit, first mount the BNC input connector CON4 in the hole at the October 2008  37 Table 3: Resistor Colour Codes No.   2   1   1   1   1   1   1   1   1   1   3   2   2   1   1   1   1   1   1 o o o o o o o o o o o o o o o o o o o o Value 220kW 68kW 51kW 33kW 10kW 6.8kW 3.9kW 3.0kW 2.4kW 2.2kW 2.0kW 1.5kW 330W 200W 120W 100W 18W 10W 4.7W Fig.7: when the unit is first turned on, it displays “Silicon Chip RF Level/Pwr Meter” as shown at top. The display immediately above shows typical level (top line) and power readings. 4-Band Code (1%) red red yellow brown blue grey orange brown green brown orange brown orange orange orange brown brown black orange brown blue grey red brown orange white red brown orange black red brown red yellow red brown red red red brown red black red brown brown green red brown orange orange brown brown red black brown brown brown red brown brown brown black brown brown brown grey black brown brown black black brown yellow violet gold brown 5-Band Code (1%) red red black orange brown blue grey black red brown green brown black red brown orange orange black red brown brown black black red brown blue grey black brown brown orange white black brown brown orange black black brown brown red yellow black brown brown red red black brown brown red black black brown brown brown green black brown brown orange orange black black brown red black black black brown brown red black black brown brown black black black brown brown grey black gold brown brown black black gold brown yellow violet black silver brown end of the metal box, with the lug of its earthing washer orientated at “3 o’clock” so that once the mounting nut is fully tightened, it can be bent around at 90° ready to be soldered to the PC board copper (along from the socket’s centre spigot). Then mount the head-end PC board upside down inside the upper part of the box, ie, with the trimpots underneath and facing the matching adjustment holes in the top of the box. The board is mounted using two A M3 x 10mm tapped Nylon spacers as standoffs, with M3 x 6mm countersink-head screws holding the spacers inside the box and pan-head M3 x 6mm screws attaching the board assembly to them. Once the board assembly is mounted in position, you can solder the centre spigot and earthing lug to their respective pads on the board to complete the input connections. The USB cable’s type-A plug can then be mated with socket CON5 at the other end of the B C 39 (CENTRE LINE) 5 25.5 12.75 A B A 13.5 31.5 HOLES A: 3.5mm DIAMETER, COUNTERSUNK HOLES B: 3.5mm DIAMETER HOLE C: 9.5mm DIAMETER 7.5 46 5 (UNDERSIDE OF BOX) (ALL DIMENSIONS IN MILLIMETRES) Fig.8: here are the drilling details for the metal case that’s used to house the head-end board assembly. 38  Silicon Chip siliconchip.com.au RF INPUT (Zo = 50) Pmax = 500mW RF LEVEL & POWER METER SILICON CHIP SLOPE ADJUST LCD CONTR SET 5.00V CAL OUT SILICON CHIP RANGE RF LEVEL & POWER METER SENSOR HEAD RF INPUT Zo = 50 Pmax = 4W (+36dBm) INPUT FROM SENSOR SELECT INTERCEPT ADJUST POWER 0dBV SILICON CHIP 20dB (10:1) RF ATTENUATOR (0 – 500MHz) –20dBV –40dBV 9–15V DC INPUT OUTPUT Zo = 50 Fig.9: this full-size artwork can used to make the front panels of the various units, including the Sensor Head case and the optional RF Attenuator (see text). The artwork can also be downloaded from the SILICON CHIP website. The main PC board is attached to the lid of its case via four M3 x 15mm tapped spacers. Four M3 x 6mm countersinkhead screws secure the lid to the spacers, while four M3 x 6mm pan head screws are used to secure the PC board. siliconchip.com.au October 2008  39 Optional 20dB (10:1) RF Attenuator board, after which the cable can be fitted with its P-type clamp, which is then fastened into the box using an M3 x 10mm countersink-head machine screw with a nut and lockwasher. The cable is then looped around and fed out of the box via a rounded slot cut in the end and the box lid screwed on to complete the assembly. Initial checkout At this stage you should be ready to give your RF Level & Power Meter a preliminary functional checkout, because this is easiest done before the main board is attached to the lid/front panel of the main box. Don’t worry 40  Silicon Chip 27k INPUT 2.7k SC 2008 OUTPUT 4 x 1k 16 x 1k 5 x 330 820 P You will have noticed from the specification panel that the maximum input level of the basic power meter is essentially +7.0dBV, corresponding to 2.238V, 100mW into 50W and +20dBm. As this may be a little low for some applications, we have designed a compact 20dB (at 50W) wideband attenuator which may be used to extend the meter’s range up to 22.38V (+27dBV) and +40dBm (10W) – although it may not be able to cope with 10W of input power for more than a few seconds if you have to use 0805-type SMD resistors. SMD resistors are used low parasitic inductance and capacitance but they do have a fairly low power dissipation (especially the 0805 size). So try to use the larger 1206 size resistors if you can get them, especially in the input leg. Otherwise the continuous input power rating will be limited to about 4W. Despite this limitation, this attenuator can be built quite cheaply and would make a handy optional extra for the meter for those who want to be able to measure higher RF levels. Please note, however, that when the attenuator is connected ahead of the meter’s head-end, the meter itself won’t be able to allow for the extra 20dB of attenuation. This means that you’ll need to add 20dB to the readings yourself, although this shouldn’t be too much of a chore. 10:1 (20 B) RF ATTENUATOR (50, 5W MAX INPUT) Fig.10: the circuit for the optional 20dB RF attenuator uses a standard pisection configuration. The resistors are all surface mount types. All you need to do is add 20dB to the dBV and dBm readings. You will have to multiply the voltage reading by 10 and multiply the power reading by 100. short pieces of tinned copper wire (leaded resistor lead offcuts) are used to make the connections from the earthing lug of each socket to the earthy side of the board copper. Construction details Shield plate The circuit for the attenuator is shown in Fig.10 and it is a standard pi-section type. Everything fits on a small PC board measuring 95 x 38mm and coded 04210083, which fits in a second diecast aluminium box identical to that used for the head-end. Fig.11 and the photos show the parts layout on the PC board. Note that the board assembly is supported behind the box lid simply by soldering the input and output pads to the “active” spigots of the BNC connectors. Multiple As you can see from the internal photos, the prototype attenuator has a small shield plate which was mounted vertically across the centre of the attenuator, to reduce the possibility of RF energy radiating past the attenuator pad at the highest frequencies. This is probably gilding the lily but you may want to add such a shield to your attenuator also. It can be cut from a small rectangle of blank PC board and is supported by soldering it to four PC board terminal pins fitted to the earth copper at the centre of the main board. if S1 (the range select button) hasn’t been mounted on the main board at this stage – it’s not really necessary for this operation. To begin, make sure that IC2 & IC3 have both been plugged into their sockets the correct way around and then set trimpots VR3 and VR4 to the centre of their ranges. After this, connect the main board to a suitable source of 9V DC, either via a battery connected to the pins at the bottom of the board or a plugpack lead plugged into CON3. There’s no need to plug in the lead from the head-end as yet. When you apply power via switch S2, LED1 should light and you should be greeted by a reassuring glow from LED1 and “Silicon Chip RF Level/Pwr Meter” on the LCD, although you may have to adjust trimpot VR4 before this message is displayed clearly and with good sharpness. Note that this greeting message only lasts for a few seconds, after which it is replaced by the meter’s normal display of readings. If all is well so far, you can now set the Vref+ voltage at pin 2 of IC3 to 3.50V. This is done with one adjustment. Connect your DMM to TP1 and its nearby TPG pin and then adjust trimpot VR3 until you get a reading as close as possible to 3.50V. This should also set REG1’s output to close to 5V. siliconchip.com.au oo 330 330 330 820 330 1k 1k 27k 1k 1k 330 2.7k 1k 1k 1k 1k 1k 1k 1k 1k (INPUT) 1k 1k 1k 1k 1k 1k 1k 1k o SILICON CHIP 04209083 (OUTPUT) 20dB RF ATTENUATOR Fig.11: follow this diagram to build the RF Attenuator board. The copper side of the board carries the SMDs plus four PC stakes to support the central shield plate (see photos below). The BNC input and output sockets are mounted on the other side of the board. Above: because RF signals are involved, the RF Attenuator must also be housed in a metal diecast case. Left: the RF Attenuator board is secured to the lid of the case via the BNC input and output sockets. Note how the central shield plate (consisting of blank PC board material) is supported by soldering it to four PC pins in the centre of the attenuator’s PC board. Use your most accurate DMM when making this adjustment because to a large extent, the accuracy of this setting will determine the accuracy of your RF Level Meter. That completes the initial set-up, although if you have access to a scope or a frequency counter you may want to check the PIC’s clock signal at TP2 and its TPG pin. You should find a 5V peak-to-peak square wave with a frequency very close to 2MHz. Main box assembly You are now ready to mount the main board assembly behind the lid of the main box (the lid becomes siliconchip.com.au the front panel). It attaches to the lid via four M3 x 15mm tapped spacers which are fastened using M3 x 6mm countersink-head screws. The board is then attached to the spacers using four pan-head M3 x 6mm screws. You will need to remove the upper mounting nut from switch S2 so that the threaded ferrule of S2 can pass up through its matching hole in the lid during this assembly. You also need to make sure that LEDs 1-3 are positioned so they pass up through their corresponding holes in the lid. If you have elected to mount S1 on the lid before this assembly, you’ll also need to ensure that its connection lugs or their extension wires pass down through their corresponding holes in the board. When this part of the assembly is complete, the top nut for S2 can be carefully refitted to the top of the switch ferrule and the lower nut and its lockwasher underneath carefully wound up to support the lid. Your meter’s main board assembly should now be complete and can be lowered into the box. This needs to be done with the righthand side angled downwards, so that the outer sleeve of RCA connector CON2 slips into its hole in the side of the box, allowing the lid assembly to be swung down as October 2008  41 Parts List 1 PC board, code 04210081 (146 x 84mm) 1 PC board, code 04210082 (43 x 44mm) 1 Jiffy box, UB1 size (158 x 95 x 53mm) 1 diecast aluminium box, 111 x 60 x 30mm 1 16x2 LCD module, Altronics type Z-7000A or Z-7011A (with backlight illumination) 4 M3 x 6mm tapped Nylon spacers 4 M3 x 15mm machine screws 1 SPST pushbutton switch, momentary (S1) 1 SPDT mini toggle switch (S2) 1 USB type B socket, PC-mounting (CON1) 1 RCA socket, PC-mounting (CON2) 1 2.5mm concentric DC socket, PC-mounting (CON3) 1 14-way SIL socket (half of 28pin IC socket) 1 14-way length of SIL terminal strip 1 18-pin IC socket 1 14-pin IC socket 4 M3 x 15mm tapped metal spacers 4 M3 x 6mm countersunk machine screws 5 M3 x 6mm pan head machine screws 5 M3 nuts, with star lockwashers 1 M3 Nylon washer 8 1mm-diameter PC board pins 1 PC-mount type A USB socket, PC-mounting (CON5) 1 panel-mount BNC socket 2 10mm long M3 tapped Nylon spacers 2 6mm long M3 machine screws with lockwashers 2 6mm long M3 countersunk machine screws 1 USB cable, standard type A to type B 1 P-type 5mm plastic cable clamp 1 10mm long M3 countersunk machine screw 1 M3 nut, with flat and star lockwashers well. The self-tapping screws supplied can then be used to fasten the lid assembly inside the box. the head-end into CON1 on the main board, then fit a 50W termination load plug to the RF input of the head-end so that it has a nominal RF input of “zero”. Now turn on the meter’s power switch (S2) and check the LCD readout after the greeting message has been replaced by the normal readings. Pay particular attention to the dBV reading, because initially you’ll probably find that it shows a figure rather higher than it should. After leaving it for a few minutes for the circuit to stabilise, try adjusting the “Intercept Adjust” trimpot (VR2) on the head-end carefully with a small screwdriver or alignment tool, to reduce the reading down to the lowest figure you can – ideally below -80dBV. Final adjustment Now we come to adjustment and calibration. To do this, you’ll need an RF signal generator which is able to supply an RF signal (preferably unmodulated) of known level. If you don’t have access to such a calibrated generator, an alternative is to use an uncalibrated RF oscillator with another RF measuring instrument of some kind to let you adjust its output to a convenient level – such as 1.0V RMS. The calibration process is quite simple. First, plug the cable from 42  Silicon Chip Semiconductors 1 AD8307AN log detector/amplifier (IC1) 1 LM324N quad op amp (IC2) 1 PIC16F88-I/P microcontroller (IC3) programmed with 0421008A firmware 1 LM317T adjustable regulator (REG1) 1 3mm green LED (LED1) 1 3mm orange/yellow LED (LED2) 1 3mm red LED (LED3) 2 1N4148 diodes (D1,D2) 1 1N4004 diode (D3) Capacitors 1 470mF 16V electrolytic 1 220mF 10V electrolytic 7 100nF monolithic 2 47nF ceramic, 1206 SMD chip Resistors (0.25W 1%) 1 1MW 3 2.0kW 2 220kW 2 1.5kW 1 68kW 2 330W 1 51kW 2 220W (0805 SMD) 1 33kW 1 200W 1 10kW 1 120W 1 6.8kW 1 100W 1 3.9kW 1 100W (0805 SMD) 1 3.0kW 1 18W 0.5W 1 2.4kW 1 10W 1 2.2kW 1 4.7W Trimpots 2 50kW mini horizontal trimpot (VR1,VR2) 1 100W mini horizontal trimpot (VR3) 1 10kW mini horizontal trimpot (VR4) Optional 20dB attenuator 1 PC board, code 04210083, 95 x 39mm 1 diecast aluminium box, 111 x 60 x 30mm 2 BNC sockets, panel-mounting 1 27kW resistor, 1206 or 0805 SMD chip 1 2.7kW resistor, 1206 or 0805 SMD chip 20 1kW resistor, 1206 or 0805 SMD chip 1 820W resistor, 1206 or 0805 SMD chip 5 330W resistor, 1206 or 0805 SMD chip 4 1mm-diameter PC pins The next step is to remove the 50W termination plug from CON4 and instead connect a cable from the output of your RF generator. Set the generator to some convenient frequency (say 100MHz) and of course with a known RF level – say 1V (0dBV). It’s then a matter of adjusting the ‘Slope Adjust’ trimpot (VR1) on the head-end unit – again with a small screwdriver – until you get a reading of +00.0dBV on the LCD. Once that’s done, your RF Level and Power Meter is finished, set-up and ready for use. Finally, note that you will have to power this device from a plugpack if you use the backlit LCD, as the current SC is too high for battery power. siliconchip.com.au SILICON CHIP Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 www.siliconchip.com.au PRICE GUIDE: SUBSCRIPTIONS YOUR DETAILS (Note: all subscription prices include P&P). (Aust. prices include GST) Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Please state month to start. 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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, October Australia 20972008  43 10/08 SERVICEMAN'S LOG Watch Out For Mura Faults On LCD Panels While sales of large-screen plasma and LCD TV sets are booming, people are still confused as to the choice: plasma or LCD? This situation has recently become a little clouded as “Mura” faults become evident on some LCD panels. The real kicker is that Mura faults may not be evident when you buy your set. I am often asked what type of flatscreen television to buy these days. Should I get an LCD or a plasma display panel? My rule of thumb at this moment in time (because there are a lot of new technologies in the pipeline which will eventually supersede what we have now) is that for anything larger than 104cm (42-inches), you should buy a plasma set; for anything smaller, get an LCD set. Mostly this rule is governed by value for money, as large plasma sets are cheaper than large LCDs. Each system has its pros and cons and though there are many diehards who will not be weaned from CRT TV, I personally think the pictures on LCD and plasma displays are utterly fantastic. In the history of CRT television, the price has dropped from the equivalent price of a house in 1939 to less than a week’s supply of groceries. The price of thin flat-panel TVs has dropped a similar amount but in less than 10 years. Probably due to the lower voltages used, LCD TVs have smaller boards than their plasma counterparts and are therefore more reliable. As usual, most faults are in the power supply units, backlight inverter panels (for LCD sets) and smashed display panels. One aspect which should be considered when shopping for a plasma or LCD set is power consumption. While big plasma sets have bright, contrasty pictures, their power consumption should make you think twice. Typically, a large plasma set will pull 500 watts or more while a large LCD set will probably be under 200 watts. Plasma’s high heat output might be good in the middle of winter but it will add substantially to your airconditioner’s summer load, so you effectively pay twice for that big power draw; first in the plasma set itself and second, while the air-conditioner removes all that unwanted heat from the room. Look at it this way: watching a large plasma set in an air-conditioned room in summer probably means a total power demand of around 1kW and even more if your room is lit by an The dark curved vertical band (arrowed) on this LCD panel is a typical Mura fault but other defects can also occur. 44  Silicon Chip Items Covered This Month • • • • • Mura faults in LCD panels NEC PXT42SV1B plasma TV Acer Veriton 3500 desktop PC Commodore VL distributor Sanyo CP14G1(A) TV set array of 12V 50W halogen lamps. So do your sums and then think carefully about it. Mura faults Recently, a subtle LCD problem has been brought to my attention. It is not always visible and depends a lot on the luminance intensity. The effect can briefly be described as a faint ghost-like film or shadowlike watermark stain defect called a “Mura”, a Japanese word meaning blemish, or in the Australian vernacular, “Your Panel is Cactus Mate”. In any case, it equals a serious hole in your wallet. An accompanying photo shows just one effect. Not to be confused with dead pixel drop-out, which has four classes and six sub-categories, Mura is a luminosity variation defect. It’s caused by process flaws in the cell assembly which affects the transmission of light through the display. There is no standard by the manufacturers for this problem but there is a 15-phase (algorithm rules), 23-class scheme of classification. There are five Mura effects: (1) Lack of homogeneity. (2) Cell size and distribution. (3) Variations in distance between the sealed panel and the liquid crystals. (4) Colour filter variations. (5) Backlighting flaws. Some Mura effects are there from new and others develop slowly over time and are sensitive to heat and pressure. Some you can even move slightly with your fingers. There is software, called “Murasiliconchip.com.au Tool”, to determine which phase and class the Mura is. There are also other software “fixes” that are supposed to reduce the effects, which are very subjective. Unfortunately, there is no permanent fix for Mura other than panel replacement. As in the manufacture of watch movements, LCD panels are not graded until the manufacturing process is completed. They are then ranked from A+ to B- and priced accordingly. When you buy your LCD, you are not told what quality your panel is but you can generally assume that the price you paid reflects that quality. As time goes by, there are going to be interesting subjective judgements as to what is and what is not acceptable for a warranty replacement for a Mura fault. Most people will just have to live with it, so it is probably best not to know about it or you will just keep looking for it! An intermittent plasma set An NEC PXT42SV1B plasma TV came in with the reported fault that it was dead. I plugged it in and it worked faultlessly. A week later it was still working and the client picked it up, as we just could not fault it. A week later again and it was back in with the same complaint. Once again, it worked for us but this time we tested it more thoroughly with a variety of inputs. After a lot of messing around and talking to other members of the family, it turned out that the principal fault wasn’t that the set was dead but that it intermittently had no picture. siliconchip.com.au To begin with, it worked fine on all sources but gradually we could see that the picture was dropping out on AV1 and TV Tuner. The sound was always OK and it was also OK on Component Video. By using another video monitor on the video output we could see that the problem was on the CVBS line, near the video input switching. Using an oscilloscope, we could see the signal coming out of pin 20 of IC N903 (M52797SB) to surface-mounted transistor V904. However, it wasn’t always coming out of this emitter follower (BC847) to pin 2 of X905. Heating and freezing this small NPN device confirmed our diagnosis. We replaced it with an ordinary BC547, taped down to the PC board, and that fixed the problem. Dead PC power supply If a generic computer comes in dead and it is the power supply that has failed, it’s cheaper to buy a new case and power supply and just transfer everything into it rather than buy a new supply or try to fix it. The other option, of course, is to salvage a secondhand power supply from a wrecked computer. However, a branded PC like the Acer Veriton 3500 desktop PC which I was asked to repair recently has a custombuilt case with a miniature power supply. The supply in this machine had failed, so there was nothing for it but to repair it. When I opened it up on the bench I found that the 5A fuse had blown but there seemed to be no other obvious symptoms. I gingerly connected it to the AC power via a 150W globe and when I switched it on smoke was immediately released from a number of the resistors connected to the power transistors. A new set of resistors and transistors plus replacement of all the low-value electros fixed the power supply. Once this was done, I could go on to address the other fault that it was booked in for, namely that it was booting up into a low-resolution (640 x 480) display. My first step was to go to the Settings tab in the Display Properties dialog but I found that couldn’t change the resolution from 640 x 480. However, that wasn’t the only problem. The machine couldn’t connect to a network, there was no sound and I couldn’t access many of the programs even though I had administrator powers. Reinstalling SP3 made no difference. I began by copying all the “.inf” and “.sys” files it was asking for whenever I October 2008  45 Serviceman’s Log – continued attempted to use the USB drive across from another computer (via a floppy disk). Eventually, I got the USB drive working and then copied across all the .inf and .sys (driver) directories. This improved access to some programs and I was then able to get onto the Acer website and download all the motherboard drivers for this Acer S88M. Once these drivers were installed, it all worked perfectly. But why weren’t they already installed? I then discovered that the XP installation’s serial number didn’t match the number printed on the Microsoft label on the front of the computer. Replacing the power switching transistors, their associated resistors and all the low-value electrolytic capacitors fixed this Acer PC power supply. From there, it wasn’t hard to work out that someone had reformatted the hard drive and reinstalled XP onto it but they hadn’t used the original Acer OEM discs. Commodore VL distributor Murphy’s Law (the Fourth Law of Thermodynamics) broadly states that “if anything can go wrong, it will”, and millions are spent every year by industries attempting to prevent its consequences. I mention this in passing, to help illustrate the next two stories. A good mechanic friend of mine had a VL Commodore (1986-88) with a Nissan RB30-E 3-litre EFI 6-cylinder engine come into his workshop. The electronic fuel-injection of the VL Commodore was very advanced technology at the time, using sequential injection, hot-wire air-mass sensing and an ignition timing map incorporated into the ECU (Electronic Control Unit) instead of centrifugal and vacuum advance mechanisms on the distributor. A crank sensor built into the distributor housing sends signals to the ECU for fuel and spark timing, along with RPM information. The sensor has two separate optocouplers (within the same housing) which generate six pulses per revolution and 360 pulses per revolution from a common slotted disc (ie, the distributor rotor plate). The failure rate of these sensors was high, with most the result of excessive heat – intermittent operation was the order of the day. The optocoupler sensor eventually became available as a separate part and was sold as a one-piece plastic case assembly. To fit the new sensor, the slotted disc was removed and a new unit secured with three screws. This was a very common service fault in the 1990s. This particular VL came into the workshop after a new sensor had been fitted by another mechanic but the car now exhibited a misfire on cylinder 5 at engine idle. Further investigation showed the electronics to be functioning correctly: six nice square wave pulses per revolution plus 360 square wave pulses per revolution could be seen from the second optocoupler. My friend substituted another complete distributor which cured the misfiring. So what could it be? Further inspection revealed that the rotor plate was located to the distributor shaft with one flat on the round shaft (or ‘D’ style) so it could be fitted only one way – or could it? If this plate is fitted upside down, the relationship between the six pulse slots (especially the wider slot for cylinder 1) is different with respect to the ignition rotor. Inverting the plate so that it was the right way up cured the fault. More Murphy My next story involves a large wellknown brand of plasma TV. It came into a friend’s workshop under warranty and the fault was a picture with 46  Silicon Chip siliconchip.com.au ration to see what would happen. Well, you can guess what happened. The set now worked perfectly and the board was undamaged. He is now the owner of beautiful plasma set and everyone is happy! Why doesn’t Murphy’s Law ever work like this for me? Sanyo CP14G1(A) TV set Above: fitting the Commodore VL distributor rotor plate upside down causes misfiring problems. multi-coloured stripes. My friend diagnosed the fault as being on the lower Y-drive board and ordered another one. Eventually it arrived and he fitted it but unfortunately, it now gave no picture while the sound was still OK. Well, was it the new board or was it the expensive display panel? The agency was out of stock of either and so new ones were backordered from the overseas factory. As time went by, the client became very frustrated with the delays and eventually the manufacturer’s agent arranged to replace the set in conjunction with their insurance company. As a result, my friend was left with the old set for spares. He was about to remove the new board and send it back for a credit when he noticed that it was possible to connect this board upside down. Seeing that nothing could be lost, he reconnected it in the opposite configu- siliconchip.com.au My next story comes from R. M. of Ascot Vale, Victoria and concerns a Sanyo CP14G1(A) TV set. Here’s how he tells it: I’m no expert in things electronic. In fact, I’m mainly self-taught, with most of my electronics knowledge derived from reading magazines like “Electronics Australia”, ETI, AEM and SILICON CHIP. My first electronics magazine was EA May 1966 and I’ve purchased all issues of SILICON CHIP since issue No.1. I’ve worked in IT for some time, including a stint at two radio stations in Brisbane as their computer technician for about a year. During that time, I absorbed a lot of real-world expertise from the technicians at the stations, fixing and configuring a lot of non-computer equipment when they moved studios several years ago. Anyway, enough of my background. We have a small Sanyo portable colour TV – model CP14G1(A) – and it simply failed without warning one night, going into standby and staying there. And so, having also built a few projects and fixed a few audio equipment problems in my life, I thought it was about time I tackled my first “telly”. My partner’s diagnosis was that it was the “redundancy chip” that all modern appliances now have, which makes them fail just outside the warranty period. I said that there was no such thing and that if I could fix the set then well and good. I am not one who likes to throw things away if it can be avoided, particularly if they are only going to end up as landfill. When I removed the back, I found that it was very well made and there were no components which showed any visible signs of distress. I applied power but there was no glowing filament in the CRT, no static from the EHT and no sound. However, the standby LED was on and my initial summation was that either the power supply was faulty or a protection circuit was shutting the set down. At this stage, a circuit was necessary and so I searched the internet, hoping to find one that I could download free of charge. Unfortunately though, all sites required some sort of payment with no guarantee that the circuit was a correct. Feeling somewhat frustrated by this, I decided that I may as well pay the manufacturer for the circuit. As a result, I rang Sanyo on the 1300 number listed on their website and was put through to the service department. I must say that the service I received was first class and they sent me the complete service manual in PDF format by email immediately, free-of-charge. They also invited me to call their technicians if I had difficulty with the repair, an offer that I was later to take up. After tracing the circuit, I measured October 2008  47 Serviceman’s Log – continued all of the supply rails and found them to be spot on, the exception being the B+ rail which was 1.1V high. However, I didn’t consider this to be a concern as there was obviously no load on this rail. Next, to determine if I had a protection issue, I lifted D467 and found that I now had working sound and tuner functions but no picture. What’s more, the CRT heater was still off and there was no EHT static. This looked like a very simple fix – it was obvious that the horizontal output transistor had probably blown, as this is the most likely cause of such symptoms. Unfortunately, my snap diagnosis proved to be incorrect because after replacing the transistor, the situation was unchanged. It was now time to analyse the problem more methodically and that meant getting out the CRO. The horizontal output section is quite simple. In fact, many of the components depicted on the circuit diagram are not installed in some models and that was the case with this set. I printed out enlarged copies of the sections I needed and obliterated the 48  Silicon Chip non-installed components. There was not much left – a couple of capacitors, two transformers a couple of transistors and that was it. I knew that the output transistor was OK as I had replaced it and I also knew that there was insufficient heater voltage to light the tube. As a result, I used an ohmmeter to check the continuity of the heater, various output transformer windings and the yoke. All were continuous but I had only a vague idea as to whether the readings I was getting were OK. It was time to turn it on and poke around with it live again. This requires a great deal of caution as there are bare mains tracks and high DC voltages over much of the area that I was interested in. To get around this problem, I soldered fly leads to the points I wanted to measure, connected the DMM to these leads and remotely powered the set to take readings. All the voltages were correct except for the heater. I was aware of the fact that the heater AC operates at a high frequency and that this could affect my DMM reading but the filament wasn’t glowing either. The CRO revealed a perfectly-shaped waveform from the collector of the horizontal driver transistor (Q431) but this was badly distorted on the other side of the coupling transformer at Q432’s base. So it was beginning to look like a faulty coupling transformer. However, before jumping in and replacing it, I decided to take advantage of the kind offer to speak with a Sanyo technician. The person I spoke to was very helpful and said that they never see this model in the workshop, probably because for the cost of a commercial repair you could have a new set. He also told me that the problem was most likely the output transistor. I told him that I had replaced this transistor and described the voltages and waveforms I had seen. He then suggested that the flyback transformer was probably faulty so a new one was ordered. It cost less than $40.00 (including postage) and duly arrived a few days later. I’m sure that you can imagine my disappointment and frustration when it was installed and there was no change to the symptoms! At this stage, I put the set to one side for a few days while I pored over the circuit diagram. Was there something I had missed? I came up with a blank and eventually decided to ring Sanyo again to discuss the problem. A different but equally helpful service technician immediately suggested the output transistor or the flyback transformer. When I told him that these had already been replaced, he said that they had a technician there who was a “guru” with that circuit and that he might be able to suggest something. I spoke to the guru and he immediately suggested the 24LC16B memory chip which is an I2C device. Apparently, the horizontal output frequency can differ from the CPU frequency, as the CPU is clocked by a ceramic resonator which is prone to drift with age. In response, the CPU writes differing “offsets” to the memory chip but when these go outside set parameters the CPU thinks that the output frequency has gone haywire and shuts the set down as part of its x-ray protection. Because the voltages were OK around the horizontal output section, this was the most likely cause. I stated that I had a good waveform on Q431’s collector and he asked about its voltage. I was unable to answer as I hadn’t checked the voltage but I told him that the waveform looked the same as in the manual. His response was that while it might look the same, it’s amplitude had been diminished by the CPU and it was this that was causing the horizontal output section to fail. The best way to fix it would be to erase the 24LC16B and go through the setting-up procedure. However, to ensure reliability, a new blank EEPROM was the best way to go. It cost just a few dollars and I immediately fitted it when it arrived a couple of days later. And that was it. After firing up the set and initialising the new EEPROM, I had picture again. All I had to do then was spend an hour or so feeding new settings into the EEPROM to complete the job. Of course, this repair would not have been economical on a commercial basis but I learned a bit about TVs and saved the set from going to the tip. As for the “redundancy chip”, perhaps my partner was closer to the truth than SC I care to admit! siliconchip.com.au DVR CAMERA KIT WITH 2 X DOME & 2 X IP56 IR CAMERAS DVR uses MPEG-4 compression and comes complete with two mini-dome indoor cameras and two weatherproof outdoor cameras with infrared night vision. Package also includes 4 x 20 metre pre-wired camera connecting cables and power supply. DVR is Pelco-D and network compatible and comes complete with a 250GB hard drive. Camera Specifications. • Resolution 350 TV lines • Light sensitivity 0.6 Lux (0 lux with IR) • Viewing angle 70° Was $999 While Stocks Last 30FF % O 12” 300 WATT FULL RANGE SPEAKER Rated at 300 watts RMS this wide range speaker is % ideally suited for use as a foldback speaker on stage F O F or as reinforcement in an existing system. The box features an eight-ohm, 12" sub-woofer for rumbling bass and a horn tweeter to give crisp, clear mid range and high frequencies. • Frequency Response: 40Hz to 18kHz • Enclosure Size: 650(W) x 330(H) x 440(D)mm Was $139 $ 699 Cat: QV-3064 A PA system in a box with 3 channels of balanced and unbalanced inputs and RCA inputs for an auxiliary source. The ideal small PA for schools, sports organisations, churches, weddings, conferences or solo acts. • 12" speaker • 200WRMS power output • Dimensions: 600(H) x 410(W) x 325(D)mm Was $399 28 $ $300 12” AMPLIFIED PA SPEAKER 99 $ $40 RACE INTO BLUETOOTH® CAR KIT WITH FM TRANSMITTER Pair this Bluetooth FM transmitter with your Bluetooth enabled mobile phone and it will % transmit voice call signals to your car's FM OFF radio allowing you to talk hands-free. Load your USB drive or SD/MMC card with MP3s and plug it in for a cheaper alternative to a fullblown car audio player upgrade. 2.5mm plug to 3.5mm plug cable included for connection to CD players, iPods or virtually $ 95 any audio device. Cat: AR-1860 Was $89.95 JAYCAR for 33 $30 Ideal for network installers or technicians and allows the user to easily check cable integrity or measure AC & DC voltage, etc. without needing to carry two separate devices. See catalogue for full specifications. • Size: 162(H) x 75(W) x 44(D)mm Was $79.95 $ 12V 5 STAGE CAR & MOTORBIKE CHARGER A truly versatile % charger suitable for F O F wet cell, gel and AGM SLA batteries from 1.25Ah to 120Ah. Computer controlled for optimum performance and rain proof as well. • Short circuit & reverse polarity protection • Anti-spark protection • 1.8m charging cable, with interchangeable fly leads • Size: 175(L) x 60() x 45(H)mm $ 95 Was $79.95 25 $20 59 Cat: MB-3604 25F%F O $20 CAT II AUTORANGING DMM This Cat II DMM is suitable for voltages up to 600VAC and has 15mm high digits for easy reference. Features include: • Overload protection • 10A current • Diode check Supplied with: • Rubber holster • High quality leads Was $19.95 ms in-store * selected ite 50 14.45 59 95 Cat: XC-5078 240VAC UNIVERSAL BATTERY CHARGER $14 $100 2 IN 1 NETWORK CABLE TESTER & DMM 59 An economical unit that can charge Ni-MH % batteries as well as Ni-Cd batteries. It has a discharge function for proper OFF Ni-Cd battery cycling and a battery tester for 1.2 & 1.5 volt batteries. Recharges AAA, AA, C, D & 9V batteries. • Includes battery tester for 1.2V - 1.5V cells • Operates from 240V 50 mains socket • Energy Authority approved • 200(W) x 50(H) x 95(D)mm $ • Will not discharge 9V batteries Cat: MB-3505 Was $28.95 O 299 Cat: CS-2517 Cat: CS-2516 25F%F ON SELECTED ITEMS THROUGHOUT OCTOBER $ Buy 2 for $50 Buy 3 for $60 29 UP TO% 5O0FF O $5 $ 14 95 Cat: QM-1524 10% OFF ALL OTHER DMM’s MAINS POWER METER Know how much an appliance is costing to run and track the actual power being used. Simply plugs into a normal power point and turns it into a real-time power monitoring outlet. You can enter the local price of your electricity and the meter will tell you exactly how much the appliance is costing to run. Also displays instantaneous voltage or current being drawn as well as peak levels etc. • Requires 2 x LR44 batteries • 10A max rating Was $39.95 25F%F CAN SIZED 150W 12VDC - 230VAC INVERTER Designed to fit into your car's drink holder, this can sized inverter alleviates the need for permanent mounting. Featuring a 150W output, this inverter is deceptively small but still has the grunt to power everything from battery chargers right through to your laptop computer. Was $49.95 $ 39 95 20F%F O $10 Cat: MI-5121 95 Cat: MS-6115 While Stocks Last - No Rainchecks 1 NEW THIS MONTH 4 Way A/V Stereo Distribution Amplifier * selected items Designed to split a stereo A/V signal across 4 channels without loss of image or sound quality. You can wire any room where you would like to access audio and video from a central source. You can also use it to record to up to four sources at the same time. 12VDC operated. Mains plugpack and input cable included. • Composite video input 1-3Vpp; 75 ohms • Stereo audio input -20dB; 25k ohms • 4 x Composite video outputs 1Vpp output; 75 ohms • 4 x Stereo audio outputs $ 95 • RCA Input & output connectors • Size: 176(W) x 90(H) x 25(D)mm Cat: AC-1646 69 2 Way Digital A/V Selector Excellent 7” monitor featuring a memory card slot that supports SD, MMC, MS, XD and CF cards and USB port so you can interface a laptop or PC game console. It will play MP3, MP4, AVI, WMA files & has a built-in FM transmitter & stereo IR sound output for use with headphones etc. • Overall dimensions (folded): 280(W) x 200(D) x 34(H)mm Was $249 $70 Retro CD Player with iPod Docking Station 28F%F O $ 179 Cat: QM-3764 20F%F Selector Switches O Smart and stylish design that will suit the home or office, this unit features a CD player, iPod not AM/FM radio, alarm clock, included USB port, full function remote control and an iPod docking station. What more could you ask for? • CD, CD-R, CD-RW, MP3 & WMA compatible • Recharges iPod batteries • Measures 340(L) x 270(D) $ x 172(H)mm Cat: GE-4067 Was $199 2 Way A/V Selector Switch 'Retro' Wooden Stereo AM/FM Radio If you prefer to use component video rather than composite, you can use this selector to switch between 2 video or coax digital audio sources. • 2 component videos input to 1 output • 2 digital coax audios input to 1 output • 2 stereo audio inputs to 1 output $ 19 95 Cat: AC-1647 Easy to use AV switches! Switch between two composite video & stereo audio sources. • Channel separation: 60dB <at> 1kHz • Cross-talk: 70dB <at> 1kHz • 135(W) x 50(D) x 32(H)mm $ 9 95 Cat: AC-1650 2 Way A/V Selector Switch with S-Video The unit accepts 2 sets of composite or S-video inputs in addition to stereo audio. • Cross-talk: 70dB <at> 1kHz • Channel separation: 60dB <at> 1kHz • RCA connectors for audio and video • Dimension: 180(W) x 35(H) x 70(D)mm $40 159 Stylish wooden-cased AM/FM radio with a distinctly 'retro' look but has a modern high quality sound through its stereo speakers at a very affordable price. A great gift idea for radio buffs or lovers of all things retro. • 340mm wide • 240VAC powered Was $39.95 $ 29 95 Cat: AR-1779 $ 16 95 Cat: AC-1651 4 Way A/V Selector Connect up to four AV devices such as DVD players, VCRs or gaming consoles with a single output to your TV and $ 95 switch between them as required. Cat: AC-1652 • Composite and S-video inputs • Dimensions: 190(W) x 112(D) x 47(H)mm 19 6 Way Speaker Selector with Impedance Matching Connects up to 6 pairs of speakers to your amplifier, and select any number of those pairs to play your music simultaneously. The outputs are all impedance matched to prevent damage to the output stage of your amplifier. • Solid metal construction • Compatible with amplifiers up to 150 watts per channel • Terminals accept up to 14-gauge wire $ • Built-in protection circuit • Dimensions: 285(W) x 180(D) x 55(H)mm Cat: AC-1683 129 2 7" LCD Roof Mount Monitor with Media Player $10 Video Enhancer & Stabiliser with S-Video Removes additional hidden signals from commercial videos and DVDs (such as copy protection) which can interfere with picture quality. • Power supply & RCA cable included $ Was $129.95 99 Cat: AR-1822 25F%F O in-store Audio 2 Way Input Switch With 2 sets of RCA sockets for input and 1 set for output to an amplifier, selection is easy via the pushbuttons on the front of the unit. • Size: 160(L) x 100(D) x 40(H) mm Was $16.95 35F%F O $ $7 9 95 Cat: AC-1656 Stereo Bluetooth Adaptor Add Bluetooth capability to virtually any audio output device. Just connect your iPod, mobile phone, CD player, or anything with a 3.5mm audio socket to the Bluetooth adaptor & you can transmit stereo audio signals wirelessly. • Function range: 10 metres • Size: 54 (H) x 40(W) x10(D)mm Was $69.95 28F%F O $20 $ 49 95 Cat: AR-1854 Dual Alarm Clock Radio with CD Player 40F%F O Wake up to CD, radio or buzzer with this full-featured clock radio/CD player. It includes two alarms, large easy-toread green LED display, and battery backup. Requires 9V battery for battery backup. • Programmable CD player with CD-R/CD-RW playback • Dual alarms with indicator LEDs • 3.5mm headphone jack $ 95 • 230(L) x 195(W) x 90(H)mm Was $69.95 Cat: GE-4061 39 $30 8 Way Speaker Selector with Impedance Matching 23F%F O $30 95 20% Spread speakers OFF all through your house. Lets you simply and safely select which speakers you want on. The rear terminals are proper speaker spring terminals - not tiny little screw terminals like on some of our competitors - and includes an impedance matching network to keep a constant load on the amplifier. Power Handling: 100W RMS $ Was $249 199 $50 Cat: AC-1682 WHILE STOCKS LAST - NO RAIN CHECKS NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER Active 12" 150W Subwoofer Add this high-performance powered subwoofer to your existing system and add some real kick to your home theatre system. The cabinet is finished in a timber veneer and houses a 12" driver and amplifier. The amp is rated at 150 watts RMS, has auto power-on, level adjustment, crossover frequency adjustment, phase reversal switch, high and line level inputs as well as high and line level outputs. Line level connectors are gold plated RCA while high levels are via spring loaded clips. $ • Frequency response: 20 - 150Hz • Dimensions: 350 (W) x 440 (H) x 420(D)mm Cat: CS-2457 199 DJ Mobile 19" Rack Frame With a total of 18 units available, you'll be able to fit all your rack gear and keep it completely portable. Ideal for DJs, PA techs, sound engineers or guitarists with large rack setups. The top section can be rotated through a range of 45° for maximum flexibility. Sturdy steel construction with castors. • Hardware included • Dimensions: 530(W) x 1050(H) x 500(D)mm *Equipment not included $ 79 95 Cat: HB-6348 Free Call: 1800 022 888 for orders! www.jaycar.com.au * selected items Professional DJ's Direct Drive Turntable 30 % This excellent turntable OFF packs a real punch and has all the features of more expensive turntables, plus a few extras of its own. Push button reverse, pitch adjustment, & track lighting, etc. Even has streaming USB digital & analogue output. • Mains powered 240VAC 50Hz $ • 450(L) x 380(W) x 120(H)mm Was $349 Cat: AA-0495 $110 239 *Bonus FREE Cartridge - Value $49.95 5 Input Stereo DJ Mixer A quality built; mini sized audio mixer; this is suitable for most DJ applications. • Stereo LED VU meter • 6.35mm headphone socket with volume control • Microphone talk over • Cross fader channels A&B • Hi gain output to amplifier • Desk standing or console mountable • Measures 330(L) x 122(W) x 39(H)mm • 1 year warranty $ • Includes AC plugpack Was $99 Cat: AM-4200 30F%F O 69 $30 Mini Disco Set Rotating Mirror Ball and Spotlight 25FF % O Create a dazzling display of lights and effects. Consisting of a rotating mini mirror ball and an adjustable LED spotlight, you can create a disco effect to any decorations or displays. • Mirror ball with motor power supply: DC 3V or 2 x AA batteries (required) • Mini LED light Power supply: DC 4.5 (3 x LR44 batteries included) Was $19.95 $5 $ 14 Cat: SL-2927 'Roadies' Cable Tester The heavy gauge metal case of this versatile cable tester will withstand just about anything the road or the 'roadie' can throw at it. Enables quick, convenient and reliable continuity testing of the most popular types of cables. • Requires 1 x 9V battery • 102(W) x 45(H) x 142(D)mm Was $34.95 95 30F%F O NEW THIS MONTH in-store DJ Dual CD Player Great value DJ dual CD player with more than enough features for you to give a professional showing at your next party. Grab a set of our party speakers, an amplifier and away you go! • 8 times-oversampling 1 bit D/A converter • 3 different scan speeds $ • 20 track program play • 25 second anti-shock Cat: AA-0490 • Rugged rack mountable chassis Was $399 Not Available In All 2.4GHz AV Sender/Receiver 50F%F O 199 $200 Stores Stereo Pro-Swivel Headphones 33FF Cat: AR-1837 Dual Channel AV Sender O 19 95 $10 Cat: AA-2053 Portable Wireless PA Amp & Microphone 30F%F O The system is ideal for small public address applications and consists of a compact yet powerful amplifier with a built in crystal locked radio receiver and wireless microphone. The mic. is attached to a small ear-hook gooseneck that allows 'hands free' operation. • 20WRMS output • 6 inch speaker $ • 260(H) x182(W) x 125(D)mm Was $99 Cat: AM-4075 69 Dynamic Unidirectional Professional Microphone 69 39 % These great looking prostyle headphones are ideal for DJs and other professionals. They feature an in-line volume control and a unique ear cup swivel action. • 32 ohm impedance • 40mm driver diameter • Full range response $ • 100 dB sensitivity Was $29.95 Send your audio and video all over the house wirelessly on the 2.4GHz band. Use your cable TV, CD, DVD remote to change channels, volume and settings from the receiver end of this 2.4GHz system. Send stereo audio and video pictures around your home, shop or office, allowing you to watch video or listen to hi-fi quality stereo sound anywhere. Send surveillance $ 95 camera images to another part of the building. All without the need to run cables. Cat: AR-1836 Features a phase-locked loop (PLL) electronic circuit that constantly adjusts, locking onto any input signal and avoiding any reception drift. $ 95 Spare receiver available separately Allows you to connect two AV sources to the transmitter, share them around the house, and select either of them from the other room, without the hassle of running wires all over the house. The sender operates in the 2.4GHz band for audio and video signals and at 433MHz for the infrared remote control repeater function. The sender can be connected to any two devices such as your TV, Hi-Fi sound system, video recorder, DVD player, set top box, or cable TV system. $ 95 A selector button on the receiver allows selection between the two connected Cat: AR-1838 devices. Additional Receivers $ 95 with remote extender available separately Cat: AR-1839 89 49 Basic Function Remote Control $30 20F%F O With professional styling, it features a cardioid polar pattern for reduced background noise and feedback. Ideal for use in theatres, nightclubs, public address systems and recording. Supplied with a 4m cable to 6.5mm plug. • Freq Resp: 60-12 kHz $ 95 • Output Imped: 600ohms Was $24.95 Cat: AM-4099 All the basic functions you need for the spare telly. • Volume, channel up/down, power on/off, TV/AV etc. • Battery included $ 95 • Size: 108(H) x 48(W) Cat: AR-1707 x 10(D)mm 14 Universal Learning Remote with A/C Control NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER Pre-programmed with thousands of devices, and able to learn and control up to 8 different devices. It can also be programmed with two macro functions and will retain all your data even if the batteries go flat. $ 95 • Backlit LCD • Audible reminder Cat: AR-1726 • Requires 3 x AAA batteries • Dimensions: 200(L) x 55(W) x 26(D)mm Cup-Holder FM Transmitter and iPod® Dock CAT 5/6 HDMI Extender $ 23 95 Cat: AA-0404 $11 19 $5 34 WHILE STOCKS LAST - NO RAIN CHECKS Listen to your favourite iPod tunes through the FM radio in your car - dock and charge your iPod ® at the same time. This unit stays in your cup holder and is powered by your car's cigarette lighter outlet. It's compatible with most iPod® models, MP3 players, CD players and other media devices. • Last frequency memory • Backlit LCD • 82(Dia) x $ 78(H)mm ® iPod not included ® 69 95 Cat: AR-1869 4 Way AV Component Distribution Amplifier Offering the extra flexibility of component video, this AV distribution amp allows you to take advantage of HDTV on digital pay-TV and free-to-air. Distributes one set of component and stereo audio inputs to four outputs. Mains adaptor included. • Supports up to 1080p resolution • Power supply: 12VDC 500mA • 190(W) x 90(H) $ 95 x 23(D)mm 99 Cat: AC-1648 3 Way Audio Selector Many audio amplifiers don't provide enough inputs for all your components. Solve that problem easily with this 3-way audio switcher. It takes up to three stereo RCA inputs and provides a single stereo RCA output. Easy-to-use pushbutton front panel. • 3 stereo pairs of RCA inputs • 133(W) x 42(H) $ 95 x 85(D)mm 14 One of the disadvantages of HDMI is the limited range of cabling before extenders are needed. This extender allows you to transmit over Cat 5 or 6 cables, thereby significantly reducing cable costs over long distances. Both unshielded twisted pair (UTP) and shielded twisted pair (STP) cables may be used, however $ shielded is recommended. Cat: AC-1655 Free Call: 1800 022 888 for orders! www.jaycar.com.au 129 Cat: AC-1699 3 NEW THIS MONTH Apache 4 Channel RC Helicopter Four channels gives you the full range of control up/down, forward/back, bank-left/right & rotate-left/right. Finished in jungle camo. • 20 minutes charge gives about 10 minutes flight time • Rechargeable 7.4V 1000mA Li-Po battery • Frequency: 40MHz • Requires 8 x AA batteries (for controller) • Recommended for ages 10+ $ 169 Wireless Colour LCD Weather Station Wireless outdoor temperature and hygrometer sensors transmit data to the LCD receiver which displays temperature, humidity, heat index and dew point levels, the time, barometric pressure and comfort index, and forecasts the weather through 5 weather icons. Outdoor sensors require 5 x AAA batteries. • Plugpack for main unit included. • 170(L) x 95(H) x 50(D)mm (including stand) Was $149.95 50FF % O $ $75 Cat: GT-3263 Mini 3 Channel IR Helicopter Ready to fly chopper that fits in the palm of your hand. A pre-installed 3 channel proportional wide beam infrared control system allows you to control the elevation, rotation and front-back pitch. Stable and easy to fly. • Charge time of about 20 minutes gives 6-7 minute flight time • 160(L) x 80(W) x 130(H)mm • Suitable for ages 8+ $ * selected items 74 95 Cat: XC-0342 Wireless Weather Station with Outdoor Sensor 15F%F O This attractive home weather station not only displays current weather data, it also forecasts the weather for the next 12 hours and shows the moon phase as well as the current time & sunrise/sunset times. • Measures indoor and outdoor temperature & humidity, & air pressure • Shows temperature, humidity & air pressure trends • Up to 30m transmission range $ 95 • Indoor display: 225mm wide Cat: XC-0339 Was $69.95 $10 59 39 95 Cat: GT-3272 Chinook 2 Channel IR Helicopter Model Boeing CH-47 Chinook IR chopper made of durable foam to take all the knocks of flying around the lounge room. Twin dual rotors for stable flight and easyto-use single-handed joystick remote with up/down, left/right turn controls. • Recharges in 20 minutes for 8 minutes of flight time • Remote unit requires 4 x AA batteries • Size: 210(L) x 130(W) x 165(H)mm • Recommended for ages 8+ Roll-Up USB Chess Game Play against the computer or a real opponent. This game can also suggest moves and hints if you need a bit of help. You can even pause or save the game and come back later. Chess Board, pieces and software included. 3 skill levels • Easy store roll-up board measures 260mm square Was $59.95 $20 33F%F O $ 39 95 Cat: GE-4094 Roll-up USB Piano $ This roll-up keyboard can be used anywhere there's a computer handy. It has a four octave range, membrane keys and full polyphonic capability. It also has 135 sounds built in including piano, organs, strings, horns, woodwind plus sound effects. • Windows 2000 or XP • Dimensions: 750(L) x 155(W)mm % Was $69.95 59 95 Cat: GT-3261 USB Missile Launcher with Webcam Upgrade to the latest in workstation weapons. Co-developed with Microsoft, this USB missile launcher is equipped with a detachable Webcam and software, which allows you to communicate via the MSN Instant Messenger service. Navigate and hone-in on your target via the on-board crystal clear Webcam for a more accurate shot. Also now with added sound effects, it will produce a swooshing sound of a missile and siren. The fun is endless! Invite friends from different parts of world and declare war or remotely log on to your home machine and blast any unsuspecting target that comes too close to your machine! • 3 foam WMDs included • Shoots up to 5 metres • Dimensions: 110(W) x 125(D) x 185(H)mm • For full specification see website $ 89 95 Cat: GE-4084 4 $ 49 95 Cat: GE-4076 28FF O $20 in-store 30F%F Pink 18 Piece Tool Kit with Metal Case Finally a tool kit that is made for women! It contains all the tools we need, none of the tools we don't need and... It's PINK! Includes an easy-to-follow 20 page instruction booklet. • Matching gloves and bandana included Was $59.95 $ O $20 39 95 Cat: TD-2068 7" Electronic Picture Frame A fantastic way to show off your digital images or movies. You can have multiple images in a slide show, a single image, or thumbnails. You can also play a backing music track or show video clips. Power adaptor included. • Resolution: 480 x 234 pixels • Supports: SM, SD, XD, MS & MMC card formats • Supports: MPEG(1,2,&4) + JPEG $ Was $179 40F%F O $80 99 Cat: QM-3765 TAKE AN EXTRA 10% OFF ALL DISCOUNTED GIFTS & GADGETS LOOK FOR THE PURPLE TICKETS INSTORE Massager Seat Cover with Heater 20F%F O Enjoy the relaxing massage action of this seat cover in the privacy of your own home, in your car, at work or in the office. With 6 powerful massage motors, it will instantly soothe and relieve neck, shoulder, back, hip and thigh problems. • Mains power adaptor and cigarette lighter socket plug are also included. Was $49.95 $ 39 95 $10 Cat: GH-1754 WHILE STOCKS LAST - NO RAIN CHECKS NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER NEW IN OCTOBER Remote Control LED Clock with Temperature Display LCD Alcohol Tester Be mesmerised by this amazing clock! Suitable for waiting rooms or entrance areas, this tranquil clock is equally at home in the kitchen or the $ office. The hours and minutes are Cat: AR-1796 displayed on the easy to read 70mm high 7-segment digital display, and the seconds by an analogue incremental display - a second mark lights up as each second passes. It can be wall or table mounted and runs on main power adaptor (included). • Remote controlled (requires 4 x AAA batteries) • 12 or 24hr operation with temperature display • Mains adaptor included • Stand included • Measures: 280(Dia) x 30(D)mm 129 Don’t get behind the wheel if you're over the limit. Test yourself first with your own breathalyser. It takes a reading in less than five seconds and can sound an alarm at a preset level. $ 95 • Accuracy of .04mg/L • Backlit LCD Cat: QM-7296 • Requires 3 x AAA batteries Please note: this product is intended to give an indicative reading only and is carries no guarantee of accuracy. Jaycar accepts no responsibility for any consequence arising from the use of this device. 69 Basic model also available, which measures up to a blood alcohol level of 0.2%. $ 29 95 Cat: QM-7298 Free Call: 1800 022 888 for orders! www.jaycar.com.au NEW IN 2008 * selected items 28 Hr Digital Voice Recorder 25F%F This is a stylish digital voice recorder with the features to match. You can record up to 28 hours of voice messages in manual or automatic voice activation mode. • 4 message folders, each folder can hold up to 99 messages • Voice activated recording function • 36(W) x 118(H) x 17(D)mm $ 95 Was $79.95 128MB Digital Voice Recorder Cat: XC-0277 with USB available separately XC-0279 Was $119.95 Now $99.95 Save $20 O $20 59 USB 2.0 Graphics Adaptor 20FF % An excellent USB to VGA adaptor that allows you to connect a second display device and is perfect for viewing large spreadsheets or running two different applications in full screen mode, without overlapping windows. • Requires Windows 2000, XP, or Vista • Supports resolution up to 1280 x 1024 • USB powered • Software included • 80mm long $ Was $99 O 79 $20 Cat: XC-4874 Windows Media Centre Remote Control 40F%F O A Windows Media Centre PC can revolutionise your home entertainment and this remote will put you in command. The remote will let you control the system as easily as you now control the TV. Requires 3 x AAA batteries • 210mm long Was $24.95 $10 $ 14 95 Cat: XC-4889 25F%F MPEG-4 Media Player O This fantastic player will accept hard drives up to 500GB so you can store and play a massive volume of music or movies etc. It has composite, S-Video and component video output with stereo and digital (SPDIF) audio output and will play MPEG movies, MP3 sound and JPG images. Connects to your computer via USB. Hard drive not included. • Power supply: 1m USB lead, 1.5m AV lead and stand included Was $199 $50 $ 149 Cat: XC-4866 USB Optical Mouse/Skype Phone Looks just like a normal USB optical wheel mouse, but if you flip up the lid you'll find a fully operational Skype phone. The phone works with common VoIP systems and allows you to make free calls to other computers & low cost calls to landlines & mobiles. • Choice of ring tones $20 • Hands-free speaker phone • Fully functional keypad and LCD • VoIP service cost vary. Please check with your service provider. Was $59.95 USB Missile Launcher Mk II With full 360° control you can fire at someone up to 7m away. Software is included which provides precision control and full sound effects. Also includes a target for practice and honing your skills. Ready! Aim! Bullseye! • 3 soft foam missiles • Stands This month only buy a Missile Launcher 120mm high and get 1 packet of Was $59.95*ORRP SPARE MISSILES 33FF % O $20 Two versatile UHF transceivers with all 38 legal channels utilised as well as CTCSS sub channel calling, auto muting & scrambling. Range of accessories available for both. 20FF% O Cat. DC-1045 With a 1.5W hi-power mode for up to 8km range and 500mW power saving mode and features dualwatch, VOX, and a built-in stop watch. Was $89 Now $69 Cat. DC-1060 $20 USB Missile Launcher $ 39 95 Cat: XM-5136 30F%F+ O O $ NEW IN 2008 149 Piece Pink Tool Set Everything the handy woman could ever possibly need. Finished in bright pink, the kit contains a hammer, long nose pliers, multigrips, tape measure, screwdrivers, shifting spanner, shears, driver with 20 bits, 8-piece Allen key set, 6 jewellers’ screwdrivers plus an assortment of nails, screws and other fasteners. Includes an easy-to-follow How-to 20 page booklet on each tool and common household tasks. $ 95 • Case measures: 250(W) x Cat: TD-2075 322(H) x 65(D)mm 39 NEW IN 2008 NEW IN 2008 These allow you to greatly extend your cable range using conventional Cat 5e cable, enabling you to increase the propagation distance or pipe your A/V signals over standard network cable runs. Three types available for complete flexibility: Component Video & Digital Audio Cat. QC-3682 $44 95 Composite Video & Audio Cat. QC-3684 $49 95 Rhinestone USB Keyboard Cat: GE-4074 This stylish pink and white rhinestone keyboard features 21 hot keys including 3 ACPI keys for easy access to the Internet, email and multimedia applications. Compliment it with some of our other desktop Bling items such as the USB mouse, tape dispenser, calculator and more for the desk every woman craves. Compatible with Windows 95/98/ME/NT/XP $ 95 • Measures: 460(L) x 180(D)mm 49 Cat: GH-1899 USB Bluetooth Dongle Class 1 $20 Cat: GE-4072 NEW IN 2008 Cat 5 Video/Audio Extenders 34 95 WHI LE STOCKS LAST - NO RAIN CHECKS NEW IN 2008 149 $25 O 29 95 10FF% Just clip this handy bit of kit to any A4 piece of paper, start writing or drawing and everything you enter will be captured electronically and stored in your computer. Includes Notes Manager software so you can edit, e-mail and organise your notes, drawings and sketches. Ideal for students or in the office. Full mouse $ functionality when working online • Standard off-the-shelf ink refills Cat: XC-0355 Cat. QC-3680 $39 95 40FF% Missiles locked and loaded! The launcher is connected to your PC via USB port, and the software is included to navigate the missiles trajectory, the launcher pans 180 and tilts up to 45 degrees. It will launch the missiles with realistic sound effects! The missiles are made from harmless soft foam so it is safe to use at home or in the office. Software compatible with Windows 2000 and Windows XP. • Spare rockets available GE-4073 • Requires 3 x AA batteries Was $49.95 *ORRP $ Infrared Digital Pen & Notetaker Component Video FREE! 38 Ch UHF CB Radio with Scrambler & CTCSS Up to 10km Transmission Range. Max output is 3 watts with 1W battery saver mode. Supplied with a high gain (168mm) antenna fitted with an SMA connector to allow the use of external antennas. Was $169 Now $149 in-store NEW IN 2008 Hydrocar Educational Clean Energy Kit The Hydrocar generates electricity by consuming hydrogen stored in the on-board cylinder. The hydrogen reacts with oxygen which is also stored on the car. Unlike fossil fuels, hydrogen power produces 0% emissions and could be viable alternative. The kit includes everything you need to build your own Hydrocar and learn about this revolutionary energy technology. Come complete with comprehensive, easy to read instruction manual. • Requires 2 x AA batteries • Car measures: 220mm long • Recommended for ages 12+ • NOTE: Use DISTILLED water - any $ other kind will destroy the membrane 129 Long range wireless connectivity. Convert your PC to Bluetooth quickly and easily. Communicate with phones, PDAs, headsets and other devices. Fast data transfer, V1.1, V1.2 and V2.0 compliant. • Range: up to 100m • Transfer rate: 3Mbps $ 95 • Operating system: Windows 98, Cat: XC-4896 ME, 2000, XP 29 Universal 90W Laptop Power Supply with LCD This laptop power supply has adaptors to fit the major manufacturers' power sockets. It also displays the output voltage and automatically adjusts the output for the adaptor used. • 138(L) x 58(W) x 37(H)mm • Will charge newer Dell model Laptops! Cat: KT-2526 Free Call: 1800 022 888 for orders! www.jaycar.com.au $ 59 95 Cat: MP-3474 5 NEW IN 2008 USB Digital Storage 40MHz 2 Channel Oscilloscope * selected items A PC-based digital storage 'scope for less than the cost of an analogue CRO. PC-based instruments are the way to go smaller, lighter and cheaper, they offer as-good or better performance than the analogue equivalents, with the advantages digital operation offers, such as trace storage and memory capability. Probes included. • AC or DC coupling $ • Storage formats: .txt, JPEG, BMP, MS Word or Excel Cat: QC-1931 • Size: 188(L) x 98(W) x 30(H)mm 499 Solar Hydrogen Generation Kit Another truly excellent educational alternative energy kit. Learn all about the finer points of hydrogen and solargenerated emission-free energy. The kit contains everything you need to get your own solar hydrogen experiment up and running. Instant renewable energy - just add distilled water. Kit contents: • 1 watt solar panel, cables, 0.3 watt fuel cell, hydrogen & oxygen tanks, gas container, tubing & syringe • Comprehensive instruction booklet $ 95 • Solar panel size: 155(L) x 125(W)mm • Recommended for ages 12+ Cat: KT-2524 99 Keycase Mini Driver Set Handy set of mini bits and driver in a convenient key-sized storage case. $ 95 12 bits: Flat: 1.5, 2, 2,5mm Cat: TD-2105 Phillips: 1.5, 2, 2,5mm Torx: T5, T7, T8, T9. T10 Case size: 95(H) x 60(W)mm 14 Ultra-Low Distortion 135WRMS Amplifier Module Kit This ultra low distortion amplifier module uses the new ThermalTrak power transistors and is largely based on the high-performance Class-A amplifier which was featured in SILICON CHIP during 2007. This improved circuit has no need for a quiescent current adjustment or a Vbe multiplier transistor and has an exceptionally low distortion figure. Kit supplied with PCB and all electronic components. Heat sink and power supply not included. Output Power: 135WRMS into 8 ohms and 200WRMS into 4 ohms $ 95 Freq Resp at 1W: 4Hz to 50kHz Cat: KC-5470 Harmonic Distortion: <0.008% from 20Hz to 20kHz 89 6 50F%F O A professional meter jam-packed with features, it is virtually indestructible, with overload protection on all ranges. It also boasts a lifetime warranty. Features include capacitance and frequency test, auto/manual ranging, analogue bargraph, temperature, data hold & more! Was $379 $190 $ 189 Cat: QM-1625 10% OFF ALL DMM’S Explore the wonders of Science with these easy to build and fun to learn kits. 25 projects to choose 95 from. Suitable for ages 8+. Liquid-Powered Clock Cat. KJ-8850 • A high-tech experiment introducing young minds to electrical energy & basic chemistry. Balloon Racer Cat. KJ-8860 • Discover the concept of propulsion while building a racing car. ALL KITS Robotic Ball Collector Cat. KJ-8870 Were $9.95ea • Assemble a robot and gain a practical NOW $6ea understanding of robotic fundamentals. Microscope with Accessories Cat. KJ-8880 • Construct a working microscope and learn how to make a prepared specimen slide. Volcanic Eruption Cat. KJ-8890 • Find out why volcanoes erupt and how the pressure is derived from magma and gas. Balloon Racer Microscope with Accessories Liquid Powered Volcanic Clock Eruption $3 29 $70 25F%F The powerful 130 watt variable speed 240VAC motor and a comprehensive array of tools make this hobby grinder/drill kit one of the most versatile around. • 240VAC operation • Speed range 8,000 to 30,000RPM • Thumb-wheel speed control • Case size: 260(W) x 300(H) x 60 (D)mm Was $79.95 O $20 $ 59 95 Cat: TD-2454 Two Speed 'T' Bar 4.8V Cordless Screwdriver 33F%F O The clever design minimises slippage or head damage while the T-bar handle gives you precise control. The power button falls naturally under your thumb and is easily operated for long periods without fatigue. • Overall length 200mm $ 95 • Mains charger include Was $29.95 Cat: TD-2492 19 Temperature Controlled Soldering Station Robotic Ball Collector For crimping F, N, BNC, TNC, UHF, ST, SC & SMA connectors onto coax cable. Adjustable crimping force and ratchet mechanism for repeatability. Four hex crimping dies: 1.72mm, 5.49mm, $ 95 8.23mm and 9.14mm. Cat: TH-1833 Was $39.95 279 148 Piece 240 Volt Precision Grinder/Drill Set Electrical Science Kit Experiments Hex Ratchet Crimping Tool O Velleman Personal Oscilloscope is a complete portable unit at the size and cost of a good multimeter. Features include high contrast LCD with wide viewing angle, full automatic setup for volt/div & time/div; true RMS and dB measurements, screen hold function; low battery detection and auto power off. Ask in store for full details. Was $349 $ Cat: QC-1916 KITS FOR 40% OFF FULL RANGE KIDS OFF SCIENCE TIME KITS 20F%F 10MHz Personal LCD HandHeld Oscilloscope 25F%F O $10 $10 33F%F O The soldering station features a high quality ceramic heating element for accurate temperature control, which is adjustable between 200 and 480°C. The soldering pencil is light weight, making it comfortable for use for extended periods. • Temp. Range: 200 - 480°C • Accuracy: +/-10°C $ Was $99 $30 69 Cat: TS-1560 WHILE STOCKS LAST - NO RAIN CHECKS AUTOMOTIVE KITS AUTOMOTIVE KITS AUTOMOTIVE KITS AUTOMOTIVE KITS AUTOMOTIVE KITS Power Supply Kit for Ultra-LD Mk2 200W Amplifier (KC-5470) The amp module (KC-5470) is powered using an unregulated rail only. This power supply kit is specifically designed to provide a balanced +/- 55VDC supply to power this fantastic amp kit. It has two LEDs, which illuminate when power is present on the rails and the assist in slowly discharging the filter caps when power is switched off. • Kit includes PCB & all electronic components. True RMS Commercial Grade DMM in-store Hand Controller for Digital Adjusters $ 54 95 Cat: KC-5471 Digital Fuel Adjuster This LCD hand controller is required during the initial set-up procedure. It plugs into the main unit and can be used while the engine is running or stopped. You can set all the initial parameters and also program the ignition advance/retard curve. Kit supplied with silk screened & machines case PCB, LCD & all electronic components. • Must have all D25 $ 95 pins connected. 59 Cat: KC-5386 Ref: Performance Electronics for Cars - Silicon Chip Magazine. Gives you complete control of the air/fuel ratio at 128 points across the entire engine load range and provides incredible mapping resolution and brilliant drivability. It uses the Handheld Digital Controller - KC-5386 (available separately) so there is no need for a laptop. Supports both static and real-time mapping. Kit supplied with a solder masked PCB with overlay, machined case with processed panels, $ 95 programmed micro & all electronic components. 79 Cat: KC-5385 Free Call: 1800 022 888 for orders! www.jaycar.com.au NEW IN 2008 * selected items 25F%F 4 Stage 12V Battery Charger Maintain your battery in top condition with this intelligent 12V SLA mains charger. The charger features LED status indicators and incorporates a four stage charging system that automatically switches to maintenance mode once the charge is complete. Fully protected. • 175 (W) x 140(L) x 50(H)mm $ Was $119.95 O $30 89 95 Switchmode Dual Stage Lead-Acid Battery Float Chargers These fully automatic chargers use switchmode technology to efficiently charge high capacity sealed and unsealed lead acid batteries. Simply plug them onto the battery and forget - the batteries will fast charge, then automatically switch to float (trickle) charge when full. 20FF % O Now $63.95 $79.95 $79.95 Save $16 $20 $20 Plugs into a vehicle's cigarette lighter socket and lets you recharge your cordless drill on a building site or your rechargeable RC models when you don't have mains power or a generator. Automatic battery voltage detection. Manual charge current adjustment • Discharge button • LED charge status indication % • Reverse polarity, short-circuit & OFF overload protection Was $59.95 20 $ 30F%F O $ The powerboard has 4 normal outlets and 4 more in a master slave set up. When the device connected to the master outlet is turned on, it automatically turns on the 3 slave outlets. Great for computers, peripherals or home theatre systems etc. Also includes phone line protection. • Surge and spike protected $ 95 •10A total loading with resettable circuit breaker Cat: MS-4062 Was $59.95 $12 This rugged inverter will deliver 600 watts of continuous power and is ideal for running a 68cm TV, kitchen appliances, or fluorescent lamps from a 12V DC supply. Electrically isolated. 242(L) x 91(W) x 58(H)mm $ Was $229 17F%F O $40 189 Cat: MI-5108 50% OFF TOGGLE SWITCHES LOOK FOR THE BLUE TICKETS INSTORE 12VDC & 240VAC Smart 4%F Battery Charger 2 This microprocessor controlled OF charger will accept a combination up to 10 x AA or AAA cells and 2 x 9 Volt Ni-MH or Ni-Cd batteries. The integrated discharger can help minimise memory effects and negative Delta V sensing unsure maximum battery life. Includes charging timer. Individual LEDs show $ 95 battery status. • 220mm wide Cat: MB-3551 Was $59.95 44 12/24V 30A Solar Power Controller Cat: MB-3630 Free power from the sun. Charges 4 x AA Ni-Cd batteries anywhere. Ideal for camping, boating, or other remote locations. • Size: 67(W) x 30(H)x 96(D)mm Was $21.95 O $15 47 95 Solar Battery Charger 8 Way Powerboard with Master/Slave Control 600W 12VDC to 230VAC Modified Sine Wave Inverter 12V Charger for Ni-Cd/Ni-MH Batteries $12 20F%F 47 Cat: MB-3624 Was 12V <at> 6A Cat. MB-3610 $79.95 12V <at> 12A Cat. MB-3612 $99.95 24V <at> 6A Cat. MB-3614 $99.95 in-store 14 95 $7 Cat: MB-3502 Maintain your battery system in peak condition with this excellent charge controller. It features 30A capacity, temp. compensation & full overload protection. Multi-mode operation. • Battery capacity: 50 - 5000Ah $ • 162(L) x 148(W) x 58(H)mm Was $229 Cat: MP-3124 199 13F%F O Rechargeable 35W HID Spotlight If you need serious light power, HID is the only way to go. Compared with quartzhalogen, HID has far longer bulb life, uses less energy and is much brighter. With a pounding 3300 lumens, this spotlight is ideally suited to search and rescue, boating, professional shooters, security or other highpower applications. It's housed in a tough weather-resistant ABS housing and has a handy shoulder strap for extended use. The built-in rechargeable battery gives about 50 minutes of continuous use and it recharges either from the mains plugpack or a car cigarette lighter socket. 12V, 35W • Battery: 12V 7AH rechargeable lead acid • Mains adaptor: 15VDC 500mA $ • Dimensions: 300(L) x 210(Dia)mm 149 Cat: ST-3369 Pure Sine Wave Inverters These inverters provide clean 230VAC power to run sensitive electronic equipment such as clocks, TVs, electronic From scales, etc. from your $199 car's battery. We have models suitable for running your laptop in the bush to powering a small microwave in a motor home. They have fan assisted cooling and electrical isolation for safety. 180 WATT MI-5160 • Power surge 300W • Weighs 1kg • 240(L) x 119(W) x 60(D)mm $199.00 380 WATT MI-5162 • Power surge 650W • Weighs 1.1kg • 240(L)x119(W) x 60(D)mm $229.00 600 WATT MI-5164 • Power surge 1000W • Weighs 1.4kgs • 300(L) x 119(W) x 60(D)mm $349.00 Powertech Monocrystalline Solar Panels These monocrystalline panels are more efficient than polycrystalline panels and are as strong and tough as the better known brands, but at a more attractive price. Sizes range from 5 watts to a massive 175 watts. 5W Cat. ZM-9091 10W Cat. ZM-9093 20W Cat. ZM-9094 65W Cat. ZM-9096 80W Cat. ZM-9097 120W Cat. ZM-9098 $ 175W Cat. ZM-9099 99 Cat: ZM-9091 $30 $ AUTOMOTIVE KITS Mixture Display Kit For Fuel Injected Cars NEW IN 2008 $ NEW IN 2008 This very simple kit will allow you to monitor the fuel mixtures being run by your car. This type of sensor is also known as an E.G.O. (exhaust, gas, oxygen) monitor. You can use it as a tuning tool, to help in vehicle modification or simply to see the behaviour of the engine control module. Indication is via 10 LEDs to show mixtures rich, lean and normal. The circuit connects to the EGO sensor mounted in the exhaust manifold and the cars battery. $ 95 • PCB, LEDs & components supplied. 14 Cat: KC-5195 $ If you lose your air conditioner's remote control there's no need to wait for the manufacturer to send you a replacement. This unit identifies over 40 preset popular air conditioning brands with digital searching, but will also auto-search for other brands not so commonly used. With a 3-step set up it's so easy to use your air conditioner will be operational in next to no time. • Easy 3-step set up • Requires 2 x AAA batteries • Dimensions: 130(H) x 55(W) x 22(D)mm 699 239 Cat: ZM-9094 Cat: ZM-9097 Universal Air Conditioner Remote Control Refer: Silicon Chip November 1995 THOUSANDS SOLD! NEW IN 2008 $ Cat: ZM-9093 WHILE STOCKS LAST - NO RAIN CHECKS AUTOMOTIVE KITS 149 549 Cat: ZM-9096 $ $ 19 95 Cat: AR-1729 1,050 Cat: ZM-9098 Note: Pictures may vary from models shown Free Call: 1800 022 888 for orders! www.jaycar.com.au $ 1,399 Cat: ZM-9099 7 * selected items HID TORCHES RECHARGEABLE 20FF O Burn time over a 100mins and is housed in a sturdy weatherproof aluminium casing. • Supplied with car and $ mains chargers, lanyard & filters for varying Cat: ST-3362 applications. • Dimensions: 72(Dia.) x 380(L)mm Was $449 349 $100 $100 • Serves as a hand or head-lamp • Will run continuously for over 115mins on a single charge. • Waterproof • Includes both car and mains charges • Torch size: 80(L) x 50(dia)mm Was $ $349 279 8 ZONE 2 PARTITION ALARM PANEL Limited Stock - No Rainchecks LOW COST RFID ACCESS CONTROL KEYPAD A low cost RFID unit that is designed to control door strikes in home or business installations. It allows access by RFID card, password, or a combination of both. Push button exit and duress output signal. 12VDC powered. • Read range: 140mm(Max.) • Operating temperature: -15°C to 55°C • Housing material: ABS • RFID tags to suit: Key Fob Type - Cat. ZZ-8950 Credit Card Type - Cat. ZZ-8952 Lanyard Type - Cat. ZZ-8953 Was $79 $ 39 Cat: LA-5124 YOUR LOCAL JAYCAR STORE 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) Liverpool Ph (02) Newcastle Ph (02) Penrith Ph (02) Rydalmere Ph (02) Sydney City Ph (02) 8 50F%F O 6021 9699 9709 9678 9369 9905 4620 4365 9439 9476 9821 4965 4721 8832 9267 6788 4699 2822 9669 3899 4130 7155 3433 4799 6221 3100 3799 8337 3121 1614 ExView CCD-equipped camera dramatically improves low-light performance. With 8 protection zones including % 2 zones for panic and duress alarms, the control panel is OFF designed for home and office protection. The system gives local alarm warnings and is supplied with one alarm control panel and one master control keypad. Programmable user codes, delays and alarm duration. • Operating voltage: 16-18VAC • Entry delay: 15 - 90 seconds • Exit delay: 60 seconds • Alarm duration: 3 - 5 minutes or unlimited • Alarm outputs: 12VDC, 2.5A • Backup battery: 12V, 7.2Ah available separately SB-2486 • Suitable 16-18VAC plugpack: MP-3022 Dimensions: Control panel - 168(W) x 168(H) x 78(D)mm Keypad - 117(W) x 117(H) x 27(D) mm $ Was $199 25 15F%F • Flickerless • Auto Iris Control • Automatic White Balance • Back Light Compensation • 2 Stage Automatic Gain Control • High Speed Electronic Shutter O $40 Sensor: 1/3" Sony ExView HAD CCD Sensor resolution: 380 Horizontal TV Lines $ 500 x 582 pixels Min illumination: 0.05 lux Cat: QC-3298 Power requirements: 24VAC/12VDC Power consumption: 5W / 295mA Max Was $249 209 4 INPUT USB VIDEO RECORDER 4eyeGrab is a surveillance device that allows you to record 4 camera inputs at the same time on a PC. It connects to the USB 2.0 port and makes real-time monitoring a breeze with 4 composite video inputs to accept any camera. Cameras not included. • Single/four screen display • Camera ID, date & time display Was $149 $ 99 30F%F O $50 Cat: QV-3081 COLOUR CAMERA KITS 2 WIRE CONNECTION A simple 2 wire combined arrangement for power and video make this system a snap to % install. The system uses a CMOS image sensor with 350TV line resolution. The main unit will OFF automatically sense signal cable tampering or incorrect wiring and alert you with a warning signal. Kit includes camera, system unit, 25m of connecting cable, & mains adaptor. • CMOS sensor • 350 TV lines Two versions available: • Colour Dome Camera Kit Cat. QC-3264 • Outdoor IP56 rated Colour Camera Kit Cat. QC-3266 30 $50 149 $40 Australia Freecall Orders: Ph 1800 022 888 EXVIEW HAD COLOUR CCD CAMERA - PRO STYLE 399 $80 Cat: ST-3366 $70 20 HID Rechargeable Head Torch 269 Cat: QV-3098 Add a monitor and you have a complete surveillance system. With 2 or 4 colour IR cameras, this processor turns any standard TV or monitor into a multiplexer. Displays a single camera view, or % multiple combinations of different camera views including one or two picture-in-picture F F O or automatic sequencing. Supplied with remote control. Size: 105(L) x 85(W) x 55(H)mm Two versions available: • Two colour CMOS cameras $ plus Quad Processor Unit $70 Cat: QV-3095 Was $349 • Four colour CMOS cameras $ plus Quad Processor Unit $100 Cat: QV-3099 Was $499 For serious outdoor and underwater lighting - Up to 50m underwater. Was $449 Cat: ST-3364 279 QUAD PROCESSOR & COLOUR CAMERA KITS 21W Waterproof HID Rechargeable Torch 349 Surveillance on a budget. It works by recording images to an SD memory card as JPEG or video AVI when motion is detected. View the events % on a monitor or any media player that accepts SD cards. OFF Two cameras are included with IR LEDs for night use. Mains adaptor included. • 195(L) x 135(W) x 45(H)mm Was $349.95 $ 95 20 24W HID Rechargeable Torch, $ DIGITAL SURVEILLANCE EVENT RECORDER % These are the brightest torches we have ever seen. They use the same Hi-Intensity Discharge (HID) technology that is used in expensive European luxury car headlights to produce a staggeringly bright beam that seems to go forever. Three models are available. IN OCTOBER in-store Was $149.95 $20 95 Cat: LA-5361 Taren Point Tweed Heads Wollongong VICTORIA Coburg Frankston Geelong Melbourne Ringwood Springvale Sunshine Thomastown QUEENSLAND Aspley Cairns Ipswich Maroochydore Mermaid Beach Ph (02) 9531 7033 Ph (07) 5524 6566 Ph (02) 4226 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 Ph (07) (07) (07) (07) (07) 3863 4041 3282 5479 5526 0099 6747 5800 3511 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) 9250 8200 Northbridge Ph (08) 9328 8252 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 $ 129 Was $229 $80 Cat: QC-3264 NEW ZEALAND Christchurch Ph Dunedin Ph Glenfield Ph Hamilton Ph Manukau Ph Newmarket Ph Palmerston Nth Ph Wellington Ph Freecall Orders Ph $ 149 Cat: QC-3266 (03) 379 1662 (03) 471 7934 (09) 444 4628 (07) 846 0177 (09) 263 6241 (09) 377 6421 (06) 353 8246 (04) 801 9005 0800 452 9227 Prices valid to 31st October 2008 Free Call: 1800 022 888 for orders! www.jaycar.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. S1 1N4148 220k 220k 3.3M 2 3 7 6 IC1 10 F 16V K VR1 500k IC2: 4093B 4.7nF 1 D1 1N4148 IC2a 3 2 4 33k A 5 K A IC2b 4 9 6 7 IC1: CA3140 220k This circuit was designed to test an ultrasonic rangefinder but could also be used to test car reversing sensors or any other device based on 40kHz ultrasonic transducers. It uses a 40kHz transducer as the input device and its received signal is amplified by op amp IC1 which has a gain of 100, as set by the 33kW and 4.7nF siliconchip.com.au 12 9V BATTERY IC2d 13 IC2c 3.9M 11 22k nal. The resultant positive signal is fed to Schmitt trigger IC2b which switches its pin 4 output low when signal is present. This is inverted by IC2c which then gates on oscillator stage IC2d. This runs at about 5kHz to drive a piezoelectric transducer. The current consumption is only a few milliamps and can easily be supplied by a small 9V battery. Graham Jackman, Oakleigh East, Vic. ($40) D1 1N4004 A OPTO1 MOC3021 K VR1 100k 2 4 L1 A2 TRIAC1 BT137X 4 G A1 220 1k 100  A  1 1 F 16V 240V LAMP 680 6 1 USB IN PIEZO SOUNDER 1.8nF 3.3MW resistors. Its output signal is then squared up by IC2a, the first gate of a 4093 quad Schmitt trigger. IC2a is biased by trimpot VR1 to a point just below that required to give a positive output at pin 3, when no signal is present. When a signal is received, the resulting 40kHz square-wave from IC2a is rectified by diode D1 which charges a 4.7nF capacitor to detect the very short bursts of 40kHz sig- USB-controlled desk lamp This circuit will switch on a 240VAC-powered desk lamp whenever it is dark and your PC or laptop computer is on. It uses the 5V rail from the USB outlet to control the circuit. This 5V rail is fed via diode D1 to optocoupler OPTO1 and transistor Q1. Q1 is biased by a voltage divider consisting of trimpot VR1, the 1kW resistor and the light dependent resistor LDR1. If there is plenty of ambient light, the resistance of LDR1 will be low and Q1 will be held off. When it is dark, the resistance of LDR1 rises to a high value, allowing transistor Q1 to conduct and light the LED in 10 220k 40kHz SENSOR Tester for ultrasonic devices 14 8 LDR1 B N C E Q1 BC337 BT137X BC337 B 1N4004 A K the optocoupler. This turns on the associated internal Triac which then turns on the mains Triac to switch on the lamp. Trimpot VR1 is adjusted to set the E C A1 A2 G light level when the lamp comes on. Note that the specified Triac is a BT137X with an insulated tab. T. K. Hareendran, Kerala, India. ($40) October 2008  57 Circuit Notebook – Continued Circuit Notebook – Continued REG1 78L05 OUT 4.7k 16 4.7k Vdd 100nF 10 O11 O10 CP O9 100nF O8 O7 2.2k B K D1 1N4001 C E K Q1 BC547 O4 O3 11 A O2 MR O1 Vss O0 A 14 11 100 100 F 10 12 13 4 IC1 O6 4040B O5 2 10k GND 100 F (D12) 1 15 3 5 IC2: 4013B 9 PROGRAMMING DIODES TO BATTERY + TERMINAL OF ALTERNATOR +12V/ +24V IN 6 8 7 5 6 5 3 4 6 3 7 9 K 8 A (D2) D S 14 Vdd 1 Q IC2a CLK Vss 7 R Q 4.7k + 10k 'COIL' 2 C B E 4* 2 Q2 BC547 – 10k 1 POSITION * ALSO EARTH PINS 8,9,10,11 BC547 1N4001 A Tacho interface for diesel motors This interface circuit allows the use of a conventional automotive tachometer with any diesel engine which has a belt-driven alternator to charge the battery. It will operate on either 12V or 24V systems and requires no modification to the tachometer or the engine itself. Automotive alternators are 12pole, 3-phase devices which deliver 36 AC cycles per revolution. This AC signal is superimposed on the DC output fed to the battery. By taking into account the drive ratio between the alternator and the engine pulleys, the AC signal can be adapted to drive a conventional automotive tacho. The AC pulses from the BAT terminal of the alternator are fed to transistor Q1 via the 100nF capacitor and 2.2kW resistor. Diode D1 protects the transistor’s base against negative swings of the AC signal. The amplified signal is used to clock IC1, a 4040 12-bit binary counter with a Schmitt trigger input. Diodes are used on the selected outputs of IC1. In conjunction with a 4.7kW resistor, these act as an AND 58  Silicon Chip K TACHO/ REV COUNTER D2-D12: 1N4148 A K gate to detect a high level when the programmed count is reached. The divided signal from the diode AND gate is used to clock IC2a, half of a 4013 flipflop. This divides the signal by two and gives a pulse output with a 50% duty cycle. This is fed to Q2 to drive the “coil” input of an automotive tacho. The tacho is set for an 8-cylinder motor. This means that it is expecting to “see” four pulses for each revolution of the engine. The required division ratio is then a function of the number of alternator pulses in one revolution (ie, 36) multiplied by the ratio of the engine pulley to the alternator pulley. The required division ratio from IC1 = (36 x R)/4 (x2) where R is the aforementioned pulley ratio, 4 is the number pulses per rev at the tacho and 2 is the division provided by IC2. To give a worked example, if the engine pulley is 150mm and the alternator pulley is 100mm in dia­ meter, the ratio between the two is 150/100 = 1.5. From there, 36 multiplied by 1.5 = 54 and this is divided by 4 and multipled by 2 to get a division ratio of 27. Referring to Table 1, four program- 78L05 COM B E IN C OUT Table 1: Programming IC1 Pin 9 7 6 5 3 2 4 13 12 14 15 Position 1 2 3 4 5 6 7 8 9 10 11 Value 1 2 4 8 16 32 64 128 256 512 1024 ming diodes will thus need to be inserted in the following positions: Position 5 = value 16 Position 4 = value 8 Position 2 = value 2 Position 1 = value 1 These values are added together to give a total division of 27. The circuit can be built on a scrap of prototyping board inserted into the tacho housing. The terminal of the tachometer normally connected to the “COIL” or “CB” is now connected to the interface. Dayle Edwards, Taylorville, NZ. ($60) siliconchip.com.au REG1 7805 OUT GND 100 µF 16V A ~ + IN T1 6.3V BR1 – 2200 µF 35V 240V MAINS INPUT 240V ~ 6.3V N A 47Ω D3 +5V 4.7k MAN S1 AUTO A LED1 Q1 PN100 D5 4.7k A 10nF K E 100k 120Ω 47Ω 10nF C B 2x 10k E PUMP PRESSURE SWITCH 3 4 NC P4 2 SER IN P0 IC1 PICAXE -08M A Q3 PN100 P1 P2 10nF 7 4.7k 6 E 100k Q2 PN100 D6 A E K D1 560Ω 5 (PUMP ON SENSING) K 6.3V A T2 A Vss 8 2x 100nF C B 4.7k 1 Vdd P3 RLY2 20A K D4 +5V NO C B OFF HIGH INT BLUE K E A OUT N A REMOTE SWITCH BOX N PUMP CHLORINATOR CONTROLLER RLY1 20A K IN CT K 4.7 µF 22k D2 ZD1 4.7V 4.7k K A TO PUMP 240V A 6.3V N 10 µF LED D5–D6: 1N4148 A D1–D4: 1N4004 K Smart pool pump control This project stemmed from the intermittent failure of a non-return valve on a swimming pool pump that was installed in a shed, two metres above the water line. This caused the pump to run dry for extended periods on several occasions, damaging the pump. The PICAXE monitors a pressure switch and the pump sense line (pin 5) which is activated by a commercial chlorinator. When the chlorinator is in standby mode, the program checks the position of both contacts siliconchip.com.au A K A B K ZD1 K in the pressure switch to ensure the switch is working correctly. The commercial chlorinator switches on in response to its set program and the pump is turned on via the normally closed (NC) contacts of relays RLY1 & RLY2. The pump sense power supply, in parallel with the pump, generates 4.7V and is connected to P2 (pin 5) of the PICAXE. A small transformer (T2) was used here because it gives full isolation. The program is directed to pressure check and allowed 10 seconds to build up pressure via an interrupt. While in “Normal” the pressure A 7805 PN100 C E GND IN GND OUT switch and pump sense are constantly checked and the program will loop until the chlorinator turns the pump off, the pressure is too low or the pressure switch fails. Membrane pressure switches exposed to chlorine can be unreliable, so the switch is checked for failure, no response or stuck on or off. When the pump is turned off or the pressure is lost, the program checks after five seconds to see if the pump has been turned off. If so, it returns to “main” via “return”. This is necessary to reset the interrupt. If the pressure has not built up or has . . . continued on page 60 October 2008  59 Circuit Notebook – Continued PICAXE-based Mosfet tester Although Mosfets are quite tolerant with respect to parallel operation, it’s worthwhile matching them in applications like audio power amplifiers and switchmode supplies. One of the most important para­ meters to match is the gate-source threshold voltage. This PICAXE circuit uses an op amp, an adjustable voltage regulator and an LCD module. It can test both N and P-channel devices, with selectable drain loads of 0.25mA and 2.5mA. It will display the threshold voltage in 100mV increments and indicate whether a faulty device is open or shorted. The software assumes an AXE033 LCD display. Other displays may require the SEROUT instructions to be changed. Initially, the PICAXE will idle and wait for the Reset pushbutton to be pressed. It will then jump to a routine to detect whether an N or P-channel Mosfet is being tested, dependent on the setting of switch S2. Assuming that N-channel is selected, the LCD screen will be updated with the message “N-channel”. To start, IC1 will initialise the PWM output to zero. The PWM output is integrated by a low-pass filter consisting of two 22kW resistors and two 4.7nF capacitors. IC2b, half of an LMC6482 CMOS dual rail-to-rail op amp, buffers the filtered signal. IC2b applies the voltage to the gate of the device under test. Since the PWM is zero, the gate voltage is zero and the Mosfet should not be conducting. If it does, the voltage at the drain of the Mosfet becomes lower than the 2.5V reference voltage fed to the input of IC2a which is connected as a comparator and its output goes high. The software tests immediately for this condition and if asserted, branches out to a stop_fail routine which displays a “fail” message on the LCD and waits in a loop for the reset button to be pushed again. If a good Mosfet is under test, the routine will start incrementing the PWM output in 2% steps, which after being integrated, will be in 100mV steps. This incrementing voltage is applied to the Mosfet gate. The LCD is simultaneously updated with the value. The process loops until the gate threshold voltage is reached. This causes the drain voltage to exceed 2.5V and comparator IC2a then changes states to a logic high and the program branches to a stop_done routine, which will display a “done” and the “x.x volts” threshold voltage on the LCD display. It then waits again for the reset button to be pressed. Fernand o is this m Garcia onth’s winne Peak At r of a las Instrum Test ent If the maximum threshold voltage of 5V has been reached and the Mosfet is still not conducting, again the software will branch to the stop_fail routine and wait to be reset. Semiconductor vendors usually specify the gate-source threshold for small-signal Mosfets as the voltage where the drain current is 0.25mA. For higher power Mosfets, it is best to test at a higher current. Switch S3 provides drain current settings of 0.25mA and 2.5mA. If a P-channel Mosfet is to be tested, switch S2 reverses the polarity of the drain and source connections to the device under test and this tells the software, to branch to the P-channel routine, which will initialise the PWM count from 100% and ramp down towards zero. This means that the gate voltage starts at 5V and ramps down, necessary because the source is now at 5V. The gate threshold voltage is still the absolute value with respect to the source and the LCD will show the correct gate-source voltage differential. It will also alert the user by displaying a “P-channel” message on the LCD. Otherwise, the operation is identical to the N-channel case, terminating the sequence and displaying the voltage once the threshold voltage is reached. This time, the comparator will change state to a logic zero, a Smart pool pump control . . . continued from page 59 been lost but the pump is on, the program loops in “pressurefail” and power to the pump is turned off. Reset is only possible by powering down, correcting the fault and returning power to the circuit. If the pressure switch has failed, the program loops in “switchfail”, power to the pump is turned off and a manual reset is also required. A remote switch box with a high intensity LED indicator is located near the skimmer box. The switch is used for vacuuming, as it allows the pump to be switched on independently of the chlorinator. 60  Silicon Chip In manual mode, transistor, Q1 switches the pump and sense voltage supply on via the normally off (NO) contacts of relay RLY1. The PICAXE then checks the pressure and switch in the same way. If there is a switch failure or pressure failure condition, pin 1 of the PICAXE switches on transistor Q2 and relay RLY2 via diode D6 and the pump is switched off. The normal mode for the remote switch is the auto position. The LED will flash briefly every four seconds when the system is in standby, flash slowly when the pressure has not built up or has failed and flash quickly to indicate pressure switch failure. It is on when the pump is running normally. This allows easy observation of the status of the system from inside the house, day or night. The relays should be heavy-duty units with 240VAC 20A contacts. Jaycar has suitable relays; Cat SY4042 (12V 160W coil). Paul Walsh, Montmorency, Vic. ($60) Note: the software (poolpumpcontroller.bas) can be downloaded from the SILICON CHIP website. siliconchip.com.au REG1 LM317T +5.00V OUT IN ADJ 120 9V BATTERY CON1 DC INPUT 10 F 1 2 330 3 SET 5.00V 4 VR1 100 5 6 7 2x 10k 100nF 100nF RESET S1 +V SerIN OUT5 IN4 OUT4 IN3 IN2 IC1 OUT3 PICAXE-14M OUT2 8 9 10 Vdd 11 12 IN1 OUT1 IN0 SerO/ 13 OUT0 SER IN SERIAL LCD MODULE 0V GND 14 10k 22k 22k G 5 6 IC2b 4.7nF 10k 2 D 3 S N-CH/P-CH 7 100nF 1.1k DEVICE UNDER TEST S2 IC2: LMC6482 4.7nF S3 LO/HI 1k LM317T 8 1 IC2a 4 1M 10k OUT ADJ OUT fact that is also accommodated by the software. The circuit’s current consumption is low enough for it to be powered by a 9V battery or a 9V DC plugpack. The output of the LM317 regulator must be adjusted to exactly 5.00V IN with trimpot VR1. Note that IC2 will tend to oscillate if driving a capacitive load such as that presented by a Mosfet’s gate. As such, it is imperative that its output be decoupled by the 1kW resistor. The LMC6482 CMOS dual rail-to- rail op amp is available from www. futurlec.com Fernando Garcia, Brownsville, Texas, USA. Note: the software (PicaxeMosfet. bas) can be downloaded from the SILICON CHIP website. Contribute And Choose Your Prize As you can see, we pay good money for each of the “Circuit Notebook” items published in SILICON CHIP. But now there are four more reasons to send in your circuit idea. Each month, the best contribution published will entitle the author to choose the prize: an LCR40 LCR meter, a DCA55 Semiconductor Component Analyser, an ESR60 Equivalent Series Resistance Analyser or an SCR100 Thyristor & Triac Analyser, with the compliments siliconchip.com.au 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 silicon<at>siliconchip.com.au or post it to PO Box 139, Collaroy, NSW 2097. October 2008  61 A multi-purpose timer with external triggering and several modes of operation Design by JOHN CLARKE Special Function Timer This automatic timer has a wide range of applications whereby a timing cycle is initiated in response to a trigger signal. There are quite a few uses for it in a car or you could use it on a model railway layout, in a home security system or whatever. T HIS PROJECT WAS originally presented as a “Versatile Auto Timer” in our book, “Performance Electronics for Cars” but since it has considerably wider applications than in cars, we have decided to give it a wider audience by publishing it in SILICON CHIP with an updated microcontroller, the PIC16F628A. Since it is based on a microcontroller, it can be easily configured to give a wide range of times and triggering options. As well, it can run as a “one-shot”, giving a fixed ON time for a device after being triggered or it can cycle the device on and off repeatedly 62  Silicon Chip after being triggered. There are a number of triggering operations. For example, you could just use a pushbutton to start the timer or it might be triggered by the application or removal of more than 6V to the input. As you might imagine, there are any number of applications for this timer in a car. For example, it could run a fan for 10 minutes at the push of a button or it could run the ventilation fan for a couple of minutes every 10 minutes when the car is locked in a sunny car park. When you come back to the car, it would not be stifling inside and there would not have been too much drain on your battery. Or what if you have a model railway layout with points switching? Say you have just changed over the points and you want lights to flash and bells to sound at a road crossing for three minutes after? That’s a job for this timer. There are many others. Basically, the Special Function Timer is just a small PC board with a 12V relay on it. You can run it anywhere that 12V DC is available. Want to run it off 24V DC? Simple; just substitute a 24V relay. Want to run it at 6V? Again, it is simple; just substitute a 6V relay. siliconchip.com.au D1 * +11.4V REG1 1N4004 LM2940-5 A +12V K IN ZENER, 1N4004 +5V OUT GND 100 µF* 16V 10 µF 100nF 16V 10k A K 10k LED BC327, BC337 GND B * USE 1N5819 FOR 6V SUPPLY * 1k FOR 6V SUPPLY 4.7k FOR 24V SUPPLY * 10k SIGNAL INPUT A RB6 RB4 10k K MCLR 10k Q1 BC337 ZD1 16V 1W B 150Ω 6 RB5 RB0 RB7 1nF IC1 PIC16F628A 100k SC  2004 RB1 RA4 RA3 X1 4MHz 15 OSC1 RA2 OSC2 RA1 OUT GND RB2 RB3 16 22pF 22pF SPECIAL FUNCTION TIMER A 10 2 11 Vss 5 RA0 7 3 9 +11.4V COM 4 13 8 BCD SWITCH 0–9 (1's) 1 A 8 TP1 LM2940CT-5 IN S1 12 C E C 4 14 Vdd USE 100 µF 35V FOR 24V SUPPLY K E +5V S2 λ LED1 D2 1N4004 K BCD SWITCH 0–9 (10's) 1 K 2.2k* 2 COM 4 A 8 Q2 BC337 10k 2 B NO COM NC E +5V 1 NO COM NC C RELAY1 18 17 100 µF* 16V LK2 10k LK1 LK3 1-SH H/L x10 ALT L/H x0.1 TRIGGER MULTIPLIER (OPEN = x1) MODE Fig.1: the circuit is based on a PIC16F628A microcontroller that’s programmed to provide a timed output after being triggered. The output at pin 2 drives a double-pole relay via transistor Q2. OK, there are a couple of other component variations which might need to be made and we will detail those later in this article. Circuit description The full circuit is shown in Fig.1. As already noted, it is based on IC1, a PIC16F628A microcontroller programmed to provide a timed output after being triggered. The output drives a relay which is closed during the timing period. A LED also lights whenever the relay is activated. The relay has changeover (DPDT) contacts so that it activates or de-activates a circuit for the set time. The time duration is set using two 10-position BCD (binary coded decimal) rotary switches that provide a timing range of 1-99 seconds in steps of one second. A separate jumper connection (link LK3) selects either x 0.1, x1 or x10 multipliers of the set time siliconchip.com.au duration. In the standard x1 position (LK3 open), the time duration is in seconds, as already noted. When LK3 is in the 0.1 multiplier position, the timer provides 0.1s to 9.9s timing periods, selectable in 0.1s steps. Similarly, when LK3 is in the x10 multiplier position, it allows timing from 10s through to 990s, in steps of 10s. Three modes are available: (1). The standard one-shot mode provides a timing period where the relay is activated for the set period after triggering. (2). The alternating mode switches the relay on and off at the rate set by the time selection rotary switches. (3). The variable on/off alternating mode allows you to independently set the length of the on and off periods when the timer is alternating. The triggering options are a rising edge or falling edge trigger for the one-shot mode, or a low-to-high (L/H) or high-to-low (H/L) signal for the alternating mode. These options are set using links LK1 and LK2. The trigger signal is applied via a 10kW resistor and 16V zener diode ZD1 to limit transient voltages. This Main Features • Triggered on rising or falling voltage (user selectable) • One-shot or alternating (pulse) operation • Pulse mode can be set for variable on/off periods • Precise 0.1s to 16.5-minute timing period • Relay output with dual doublethrow contacts rated at 5A • LED indicator for timing October 2008  63 10k x10 MULTIPLIER (OPEN = x1) + 100 µF* O NNO C 10k NC CN 1 C 4 LED1 A 2.2k* COM s'PERIOD 01 SWITCHES 1nF A D2 K Q2 S2 10'S 18001150 NC CN 901 S1 1'S 23 10k LK3 COM 8 C 2 150Ω x0.1 D1: 1N4004 1 C 4 NO C ON X1 4MHz L/H H/L 1-SHOT ALT ZD1 10k 10k A 1 23 901 INPUT 100nF 22pF IC1 PIC16F628A BC337 K TP1 456 +12V DNG GND Q1 D1* NI 2 1 + GND K s'1 8 C 2 456 LM2940-5 100k 10k REG1 LK2 LK1 78 ➡ + A 78 ➡ + RE MIT OTUA TP GND 22pF 10k 10 µF 100 µF* RELAY 1 K BC337 * SEE TEXT & CIRCUIT FOR 6V & 24V OPERATION Fig.2: follow this parts layout diagram to build the Special Function Timer. Jumpers LK1-LK3 are installed to suit your application (see Fig.1 & Figs.3-6). Link LK1 sets the mode (1-shot or alternating); LK2 sets the input signal trigger sense (low to high or high to low); and LK3 sets the timing multiplier. BCD switches S1 & S2 set the timing period. Resistor Colour Codes Value 4-Band Code (1%) 5-Band Code (1%) 100kΩ 10kΩ 2.2kΩ 150Ω brown black yellow brown brown black orange brown red red red brown brown green brown brown brown black black orange brown brown black black red brown red red black brown brown brown green black black brown effectively clamps the signal at a maximum of +16V and -0.6V above and below ground. This signal then drives transistor Q1 via another 10kW resistor. Q1’s collector inverts the input signal and drives pin 6 of IC1 via a 10kW pull-up resistor and a 150W series resistor. A 1nF capacitor filters any high-frequency voltage fluctuations, while the pin 6 input of IC1 includes an internal Schmitt trigger to ensure a clean signal for measurement. Rotary BCD switches S1 & S2 are monitored by IC1’s RB1-RB7 and RA4 inputs. The RB inputs are normally held high via internal pull-up resistors within IC1, while RA4 has a 10kW pullup resistor to ensure it is high unless pulled low via S2. In operation, the switches provide a unique BCD (binary coded decimal) code on these inputs for each setting and these codes are processed by the program within IC1 to determine the timing period. The RA0 and RA1 inputs of IC1 are held either high or low via links LK1 and LK2 to select the Mode and Trigger options. The RA2 input operates slightly differently. It can be held either high or low using the x10 or x 0.1 jumper (LK3) and this level is checked by IC1. Initially, this pin is set as an output and is driven low. The pin is then set as an input and the level is checked. If the input is high, then IC1 “knows” that the x10 jumper must be in place. The pin is then set as an output and is set high. When set as an input again, the level is checked and if it is low, then the x0.1 jumper must be in place. If the level does not change in both cases, then the input must be open-circuit and the microcontroller assumes the setting is for the x1 range. The RA3 output drives transistor Q2 which in turn switches on the relay. Q2 also turns on LED1 to indicate when the relay is activated. Diode D2 prevents damage to Q2 from any backEMF spikes produced when the relay coil is switched off. IC1 is operated at 4MHz using crystal X1. The two 22pF capacitors provide the correct loading for the crystal, so that the clock starts reliably. Power supply Power for the circuit is derived via the vehicle’s fuse box if used in a car or truck and is fed via diode D1 which provides reverse polarity protection. Alternatively, the circuit may be powered from a battery or other source of DC power at 6V, 12V or 24V, depending on the relay fitted (see parts list). If the circuit is run from 6V, then D1 should be changed to a 1N5819 Schottky diode to minimise voltage Looking for real performance? • • • • Learn how engine management systems work Build projects to control nitrous, fuel injection and turbo boost systems Switch devices on and off on the basis of signal frequency, temperature and voltage From the publ ishe rs of 160 PAGES 23 CHAPTE RS Build test instruments to check fuel injector duty cycle, fuel mixtures and brake & temperature Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas $A26.00 via airmail. Order by phoning (02) 9939 3295 & quoting your credit card number; or fax the details to (02) 9939 2648; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 64  Silicon Chip Intelligent turbo timer I SBN 09585 2294 9 78095 8 -4 TURBO BO OST & nitrous fuel con 5229 46 $19.80 (inc GST) NZ $22.00 (inc GST) trollers How engin e management works siliconchip.com.au Helping to put you in Control Control Devices New PLC With Analogs This PLC is great value. Features 9 Digital in, 10 Relay out, 8 Analog In and 2 Analog Out. Can accept quadrature encoder input and high speed counters $425+GST. This view shows the fully assembled unit, which was built from a Jaycar Auto Timer kit. Note that if your kit comes with a PIC16F628A for IC1, then IC2 is left out of circuit. Conversely, if you get the original kit with a PIC16F84 microcontroller, then IC2 must be installed. drop and reduce the possibility of regulator dropout. Conversely, if the circuit is run at 24V, the two 100mF capacitors should be rated at 35V instead of 16V. In addition, the current-limiting resistor in series with LED1 will need to be varied according to the supply voltage: 1kW at 6V, 2.2kW at 12V and 4.7kW at 24V. The +5V rail for IC1 is derived from an LM2940CT-5 regulator which is designed specifically for automotive applications and includes transient voltage protection. The 100mF capacitor at REG1’s input provides further transient voltage suppression. other suppliers will have the PC board encoded as 05110081. When assembling the PC board, make sure that you insert the polarised components the right way around. These parts include the two rotary switches, diodes, ICs, LED1, the transistors, the voltage regulator and the electrolytic capacitors. You should also carefully compare the photos with the parts layout diagram (Fig.2) to avoid making any mistakes. If you are assembling a PIC16F84 version of the circuit, make sure that you do not swap the MC34064 for one of the transistors – that could lead to smoking components! Construction Testing All of the timer components are mounted on a PC board which measures 106 x 61mm. A complete kit of parts for the 12V version of the kit is available from Jaycar Electronics (Cat. KC5379). In this case the PC board will have the code number 05car81. However, since this is the previous version of the circuit which was based on a PIC16F84, it also needs an MC34064 5V supply supervisory chip. This device performs a power-on reset for IC1 to ensure that pin 4 of IC1 is only switched high when the supply is above about 3.5V. For voltages below this, IC1 is held in the reset state. We expect that, once existing stocks are exhausted, Jaycar will upgrade their kit to use the PIC16F628A, in which case the MC34064 is simply omitted from the PC board. Kits from The timer should now be benchtested for correct operation and to configure it for your application. This will also allow you to become familiar with the way it works. First, connect +12V and 0V to the timer. Also connect a floating lead to the input, so that you can trigger the unit. Now place the Mode and Trigger links (LK1 & LK2 respectively) in their upper positions (as viewed with the PC board orientated as in Fig.2) and remove the multiplier link. Turn the upper BCD switch to “2” and set the lower switch to “0”. The timer is now configured for Alternating Mode, L/H (Low-to-High) Trigger and two seconds. When you connect the floating lead to +12V, the LED should light and the siliconchip.com.au New Logomatic Serial Data Logger Has a USB connection so it appears as a flash drive. Logged serial data is saved on micro-SD media as text files. Download to a PC over USB connection or remove microSD card and insert into a card reader. $89.95+GST Humidity Temperature Controller The N322RHT has 2 relay outputs which can be configured independently as control or alarm, either for temperature or relative humidity. A Relative Humidity and Temperature included. $195+GST USB-RS422/485 Converter Our popular isolated converter can be configured for four-wire RS422 and two-wire RS485 networks. Transmission rates to 1Mbps From $129+GST Signal Isolators and Converters TxIsoBlock and TxIsoRail are programmable isolated transmitters. Convert Pt100 and thermocouples to 4-20mA or 0-10V. TxIsoBlock is a head mount unit and TxIsoRail is a DIN rail mount unit. Non-isolated models also available From $89+GST Contact Ocean Controls Ph: 03 9782 5882 www.oceancontrols.com.au October 2008  65 +12V S1 1'S 1 8 0ra c 5 0 CN COM ON STD BOOT SWITCH C 1 23 901 NI 2 1 + NO C ON 10k DNG GND 23 901 1-SHOT INPUT S2 10'S CN s' 0 1 x10 CHASSIS (0V) + Fig.3: want to automatically switch a 12V lamp or some other load off after a preset time? This one-shot set-up will do the job. Note the position of link LK1. +12V PUSHBUTTON SWITCH CHASSIS (0V) DNG +12V INPUT S1 1'S ON C 23 901 NI 2 1 + 1 23 901 1-SHOT GND NO COM S2 10'S 1 8 0ra c 5 0 s'1 CN HIGH C ON + GOING 10k RE MIT OTUA + 78 ➡ 66  Silicon Chip s'1 78 ➡ Note: change the 2.2kW resistor in series with LED1 to 4.7kW for 24V operation or to 1kW for 6V operation. Also, change D1 to 1N5819 for 6V operation. HIGH 78 ➡ 24V & 6V Operation RE MIT OTUA + GOING + 456 Resistors (0.25W, 1%) 1 100kW 1 2.2kW 7 10kW 1 150W STD BOOT LAMP 456 Capacitors 2 100mF 16V PC electrolytic OR 2 100mF 35V PC electrolytic, for 24V operation 1 10mF 16V PC electrolytic 1 100nF MKT polyester (code 104 or 100n) 1 1nF MKT polyester (code 102 or 1n) 2 22pF ceramic (code 22 or 22p) CHASSIS (0V) 456 Semiconductors 1 PIC16F628A microcontroller programmed with 0511008A. hex (IC1) 1 LM2940T-5 low dropout regulator (REG1) 2 BC337 NPN transistors (Q1,Q2) 1 5mm red LED (LED1) 1 16V 1W zener diode (ZD1) 2 1N4004 1A diodes (D1,D2). Note: D1 should be 1N5819 for 6V operation +12V 456 1 PC board coded 05car081 or 05110081, 105 x 60mm 1 4MHz crystal (X1) 1 18-pin DIL socket for IC1 5 PC-mount 2-way screw terminals with 5mm pin spacing 2 BCD PC-mount rotary switches (S1,S2) 1 12V PC-mount DPDT 5A relay (Relay1) OR 1 6V PC-mount DPDT 5A relay (Relay1: Altronics Cat S4188C) for 6V operation OR 1 24V PC-mount DPDT 5A relay (Relay1: Altronics Cat S4195C) for 24V operation 1 70mm length of 0.8mm tinned copper wire 3 3-way headers, 2.54mm spacing 3 jumper shunts, 2.54mm spacing 2 PC stakes (for test points) +12V 78 ➡ Parts List LOAD CN s' 0 1 x1 + CHASSIS (0V) Fig.4: this is the set-up to use if you want to turn a load (eg, a lamp) on at the press of a button and then have it turn off at the end of a preset timing period. Link LK1 is again in the 1-shot position. relay should click in. Two seconds later, the LED should go out and the relay should turn off. This process should then keep repeating for as long as you have the signal wire connected to +12V. Setting the timing The rotary switches set the time duration. Set the upper switch to “7” and the cycling will slow to 7 seconds on, 7 seconds off. Now set the lower rotary switch to “1” while leaving the upper switch at “7”. The time period will now be 17 seconds on, 17 seconds off. If you leave the rotary switches set to 17 (top one on 7 and bottom one on 1) and place the multiplier link in its uppermost position, the time shown on the rotary switches will be divided by 10, giving a 1.7 second on and off time. Move the multiplier link to its bottom position and the rotary switch time will be multiplied by 10, ie, giving 170 second (2 minutes and 50 seconds) on and off times. In summary, the upper rotary switch shows units and the lower switch shows tens. The multiplier can be set in three positions: (1) Link LK3 removed, so the time dissiliconchip.com.au +12V HEAVY DUTY RELAY CHASSIS (0V) RE MIT OTUA s'1 DNG +12V CN 901 COM S1 1'S CHASSIS (0V) ON C 1 901 23 INPUT 456 NI 2 1 + 23 78 ➡ GND 1-SHOT 456 GOING LOW NO 1 8 0ra c 5 0 10k + C ON + IGNITION SWITCH S2 10'S CN LOAD 78 ➡ s' 0 1 x10 + CHASSIS (0V) Fig.5: this 1-shot set-up will continue to supply power to a load (eg, a car radio or the headlights) after the car’s ignition has been turned off. The heavy-duty relay is included to ensure reliable operation with high-current loads. Note the location of link LK2 compared to the other set-ups (ie, it’s fitted in the H/L position). +12V SWITCH CHASSIS (0V) 901 456 23 78 ➡ DNG GND +12V S1 1'S ON 23 901 INPUT COM C 456 NI 2 1 + 1 NO S2 10'S 1 8 0ra c 5 0 s'1 C ON PULSE HIGH CN +GOING 10k RE MIT OTUA + LOAD CN 78 ➡ s' 0 1 x10 + CHASSIS (0V) Fig.6: in this set-up, LK1 is in the “ALT” (or pulse) position and so the load (eg, a lamp or a siren) pulses on and off according to the period set by the BCD switches (and link LK3). The switch simply turn the circuit on or off. played on the rotary switches equals seconds; (2) Link LK3 at top position, so the time displayed on the rotary switches equals seconds divided by 10; and (3) Link LK3 at bottom position, so the time displayed on the rotary switches equals seconds multiplied by 10. Now try the one-shot mode by moving LK1 to its bottom (1-shot) position. Then remove the multiplier link and set the rotary switches to give a 5-second timing period (ie, bottom switch on “0” and top switch on “5”). Now when you connect the signal input lead to 12V, the relay will click siliconchip.com.au in for five seconds and then switch off. If you disconnect and then reconnect the signal input within the timed period, the timer will start counting again – so the timing period is from the last sensing connection. In practice, you can set the positions of the rotary switches and multiplier link to give any time period you want from 0.1 seconds to 990 seconds (16.5 minutes). Variable alternating mode Once you’re familiar with the oneshot and alternating modes, you can try out the variable on/off alternating mode. This gives you the option of different “on” and “off” times. This mode is activated as follows: (1). Set the timer to alternating mode (link LK1 in upper position). (2). Set the top rotary switch (S1) to the number 7. (3). Temporarily connect TP1 to TP GND (these are the two test pins near the top rotary switch). Note: this needs to done for a least 2s before the change occurs. In this mode, the bottom rotary switch sets the length of time the relay is closed and the top rotary switch sets the length of time the relay is open. For example, if you set the top switch to “3” and the bottom switch to “1”, with the multiplier link (LK3) removed, the relay and its accompanying LED will cycle on for 1 second, off for 3 seconds, on for 1 second, etc. If you want to change back to standard alternating mode, set S1 to the number 7 and again temporarily connect TP1 to TP GND for at least 2s. High to low triggering Up until now, you have been triggering the timer by connecting the floating lead to +12V. Now let’s configure it to trigger when the floating input lead is disconnected from +12V. To do this, move the Trigger Mode link (LK2) to its lower position (H/L) and then check that the timer starts when the floating input lead is disconSC nected from +12V. October 2008  67 Building the Railpower IV Part 2: Construction and setting it up Last month we presented the circuit, specifications and parts list for our new high-performance Railpower IV model train controller. Now it’s time for the construction details – and we show you how to set it up for best performance. C onsidering that the new Railpower IV has such a lot of features and gives great performance, its construction is relatively simple compared with our previous Railpower designs featured in 1988, 1995 and 1999. This is mainly as a result of using the PIC16F88 microcontroller. And whereas our two previous designs used front panel LEDs and an analog meter, this latest design uses a 2-line alphanumeric LCD panel. All our previous designs used one large PC board but this latest Railpower uses two PC boards. The main board accommodates the power transformer and most of the circuitry, including the microcontroller, while the verticallymounted display board is for the LCD panel and four pushbutton switches. The main board measures 217 x 102mm and is coded 09109081while 68  Silicon Chip the display board is coded 09109082 and measures 141 x 71mm. These PC boards are housed in a plastic instrument case measuring 260 x 190 x 80mm. The rear panel is made from aluminium sheet. It provides heatsinking for the four Darlington power transistors used in the H-bridge motor drive circuit. You can begin construction by checking each of the PC boards for defects such as shorts or breaks in the copper tracks and to see that all holes have been drilled correctly to suit the various components. The holes for the mounting screws, the LCD mounts and for REG1 need to be 3mm in diameter. The four holes to mount the transformer are 4mm in diameter. Note that there are different mount- by JOHN CLARKE ing positions for the Altronics and Jaycar LCD panels (the board has been designed to accommodate either). Main board assembly Fig.1 shows the component overlay diagram for the main PC board. Start by inserting the resistors in the main board, taking care to place each in its correct position. Use the resistor colour code table (see last month’s issue) as a guide to each value. You can also use a digital multimeter to check each resistor – this is a good idea as it easy to misread colour codes. Next install the wire links and the PC stakes for the motor outputs and the ‘track’ LED. A 3-way pin header is used for connecting speed potentiometer, VR1. Install diodes D1-D7, taking care with their orientation. Note that D1-D4 are 1N5404 types, D5 & D6 are 1N4004 siliconchip.com.au and D7 is a 1N4148. The socket for IC1 can now be mounted, taking care with its orientation (leave IC1 out of its socket for now). Then install IC2, again taking care with its orientation. The capacitors can go in next. The five electrolytic types must be oriented with the polarity as shown. The crystal can then be mounted as well as the piezo siren. The 3-terminal regulator (REG1) is attached to the PC board together with a U-shaped finned heatsink. Bend the regulator leads at right angles to fit into the holes provided. First secure it with an M3 x 10mm screw and nut and then solder the three leads. Then install trimpot VR2 (10kW), the 2-way screw terminal block (CON3) and the 10-way IDC vertical header (CON2), mounted with the orientation slot as shown. The transistors can then be mounted. All the small-signal transistors (Q5-Q10) are BC337 types. Just push them in and solder the leads. The TO220 transistors are BD650 (Q1 & Q2) while Q3 & Q4 are BD649s’s. Mount Here’s the two-line alphanumeric display (in this case the Jaycar model with backlight) which gives you all the information you need about your settings. Here it is showing the train speed at about 56% of the maximum speed set (90%). Inertia is on (indicated by the “I”) and the lock is on (shown by the padlock being closed). As you enter other modes, the information on the display changes to reflect those modes. them their full lead length and with about 1mm of lead below the PC board for soldering. The power transformer (T1) is mounted on the PC board using four M4 screws and nuts. A 6.4mm spade terminal is attached to one corner, as shown, to earth the transformer body back to the rear panel. You’ll need to scrape off some of the varnish coating from around the hole. A star washer between the transformer mounting foot and the spade terminal then ensures a good contact. To obtain the current rating required, two secondaries are wired in parallel, with heavy-gauge insulated hookup wire connecting the appropriate terminals, as shown in the photographs and in fig.1. In the case of the Altronics (Powertran) M-2165L transformer, connect together terminals A to F and terminals C to D. Two wires, again heavy duty insu- Inside shot of the Railpower IV, in this case fitted with the Altronics LCD and transformer. siliconchip.com.au October 2008  69 lated hookup wire, are then run from transformer secondary terminals to the adjacent 2-way screw terminal block (CON3). In fact, we used the same lengths of wire to connect the two terminals on the transformer and the terminal block. size and location depend on whether the Altronics or Jaycar LCD modules are used. The larger holes can be initially 12V (”C”) 9V (”B”) NC 9V (”E”) NC 12V (”D”) D5 0V (”F”) D1 5404 100 µF 25V D2 5404 CON3 18090190 L ORT N O C ET O MER DERARF NI RELL ORT N O C RE W OP ESLUP T1 (12V/60VA) D3 5404 REG1 7805 D4 5404 2200 µF 25V 2200 µF 25V 10 µF LINK6 LINK1 10k LINK2 Q6 2.2k 10k 2.2k LINK4 10nF Q4 Q8 LINK5 Q9 Q10 Q2 LINK3 100k 100k 100k 4148 1k 10k 15k 5.1k D7 100 µF Q1 1k 10M 1 2.2k X1 2MHz 0 + 100nF 100nF 10nF Q5 10k 1 27pF 1k IC2 74HC00 IC1 PIC16F88-I/P CON2 27pF 22 µF D6 Q7 10k Q3 VR1 (LOCAL SPEED) OVERLOAD PIEZO SIREN VR2 10k 0.1 Ω 5W + 70  Silicon Chip 0V (”A”) 1 2 Several holes need to be drilled in the front panel for the pushbutton switches, the potentiometer and the IR detector (IRD1). As well, a cut-out is required for the LCD module – the NEUTRAL TERMINAL ON IEC CONNECTOR 9 10 Working on the case ACTIVE – TO MAINS SWITCH (ON IEC CONNECTOR) 240V PRIMARY WINDING Assembling the display board Insert the five resistors and trimpot VR3 (10kW). The 100mF & 10mF 16V electrolytic capacitors must be laid on the sides before they are soldered into place. The connections for the LCD modules are made with socket strip and with header terminal strips. You can use a 14-pin DIL (dual in-line) socket strip for the Jaycar LCD and a 14-pin SIL strip for the Altronics LCD. They can be made by cutting a 14-DIL IC socket to produce two 7-way strips. These can be placed side by side for the DIL or in-line for the SIL strip on the display PC board. The header terminal strips are soldered to the LCD module. Install them with the longer pins sticking up through the LCD module PC board and then solder them in place on the topside of the module. The excess lead length on the topside is then cut short with side-cutters. You can then plug the LCD into place on the display board. Secure the module using four tapped 6mm spacers plus Nylon washers to increase height to about 7mm. These are secured in place with 8-M3 x 6mm screws. The four pushbutton switches are mounted on the PC board, oriented with the flat side as shown in the component overlay diagram. The infrared detector (IRD1) is mounted with its full lead length so it can be bent over at right angles so that its lens lines up with the hole in the front panel. Finally, fit the 90-degree IDC connector (CON2). You can make up the IDC lead with 10-way IDC cable, making sure that the red strip side is as shown on both the main board and display board sockets. The IDC cable can be compressed into its fittings by clamping up in a vise drilled to 5mm to start with and successively drilling larger holes. It can then be carefully reamed out to the required diameter. But why bother DIRECTION LED (BICOLOUR) 2.2k TO TRACK Fig.1: component overlay for the main PC board, with a similar-size photo at right for comparison. This has the back panel already fitted. siliconchip.com.au with all that? Why not use the correct size drill to make the holes in one go? The reason is that it is almost impossible to drill large round holes in sheet material – usually they tend to to be triangular rath- Not shown here are the front panel connections – LED, pot and display board. Be careful with the pot wiring – it’s easy to get it around the wrong way! siliconchip.com.au er than circular. The display cut-out is made by drilling a series of holes around the perimeter of the cut-out, knocking out the piece and then filing it to shape. Finally mark out and drill the four mounting positions for the display PC board. The rear panel is made from 1mm or thicker aluminium, to provide a heatsink for the four power transistors. The panel needs holes for the IEC mains connector, earth lug, binding post terminals and the four transistor mounting holes. The hole positions for the transistors can be marked out by mounting the main PC board into the case using the four self-tapping screws. Push the transistors flat against the rear panel and mark out their hole positions. These should be drilled to 3mm and any sharp edges around the hole removed with a countersinking drill bit. Don’t fit the transistors until you are finished all holes, just in case a tiny bit of swarf causes a short. Position of the holes for the binding posts is not critical – just don’t fit them too close together and so make attaching wires difficult. When the holes are drilled, reamed and de-burred, attach the binding posts to the rear panel and tighten their nuts with a spanner. Likewise, the IEC connector position (with its integral fuse and switch) is not too critical – use the photographs as a guide. The IEC connector clips into a 47 x 28mm vertical rectangular cutout. At this size, it is a tight fit so that there is no likelihood of it being dislodged. The wiring inside the case can now be completed, as shown in Fig.4. Fig.3 shows how the power transistors are mounted, using an insulating bush and washer as shown to ensure they are insulated from the aluminium panel. The earth lugs are attached using a star washer between each eyelet. The mains wiring is done with the brown and blue wires already connected to the specified transformer. Both are about 100mm longer than is required so the offcut from the Active (brown) wire is used to make up the ~50mm fuse-to-switch link on the back of the IEC connector. Green/yellow-striped wire is used solely for the earth connections – one from the October 2008  71 28090190 1 14 1 100 µF 16V S1 S2 IEC socket earth pin to the rear panel and one from the transformer to the same point on the rear panel. Together, these require only 150mm or so of wire. This coloured wire must not be used for any other wiring. We used insulated 4.8mm crimped quick connectors for all wires going to the rear of the IEC connector and insulated 6.4mm crimped quick connectors to the earth connections, as shown. If for some reason you need to use any other wire for the mains wiring, ensure that is 250VAC-rated 7.5A wire, with brown used for Active and blue for Neutral. For safety, all the mains wiring must be tied with cable ties so that they cannot come adrift. The exposed area at the rear of the IEC connector where the Active connects to the fuse should be covered with a liberal coating of neutral cure Silicone sealant. 72  Silicon Chip IRD1 (LIES FLAT) VR3 10k 10 µF 16V S3 S4 The wiring to the transformer secondary and to the binding posts is made with heavy duty hookup wire. Note that the two 12V windings are connected in parallel. Connect the two 0V connections together and the two 12V connections together. Before mounting and connecting the potentiometer, its shaft may need cutting to length to suit the knob to be used. Power up Note of the following tests and setup need the tracks connected and a loco on them until indicated. Check your wiring carefully, including the insulated covers over all the quick-connect terminals (these ensure that there are no dangerous voltages exposed with power connected so that you can safely work on the project without it being sealed inside a case. There are no dangerous voltages on 1k LINK10 1k 1k 4x 1k RESISTORS AND LINK 10 ARE ALL UNDER LCD MODULE 470Ω (BLUE DOTTED LINE SHOWS POSITION FOR ALTERNATE LCD DISPLAY MODULE – JAYCAR QP 5516 ) 1k ALTRONICS Z-7001 LCD MODULE SHOWN 1k 1k lcd display 1k YALPSID RELLORTNOC REWOP ESLUP LINK10 1k CON1 Fig.2: the component overlay for the display board with a matching photo below. The PC board has provision for either the Jaycar QP5516 or the Altronics Z7100 LCD modules – this shows the Altronics version which connects to the PC board via the single row of 14 header sockets at the bottom of the display board (the Jaycar version was shown in the photos last month. It connects via the dual row of sockets on the left side of the board). Note the inset above – four resistors and a link are actually under the Altronics LCD module. Also note that for minimum height, the electrolytic capacitors and the infrared receiver are installed parallel with the PC board. any tracks or pads on the PC board as the transformer is directly wired to the IEC connector). Speaking of the IEC connector, make sure there is a 1A fuse inside its fuse holder. You open this by gently levering up the tab on the fuse holder underside with a tiny flat screwdriver. And as mentioned earlier, IC1 should INSULATING WASHER M3 NUT 10mm LONG M3 SCREW INSULATING BUSH Q1– Q4 REAR PANEL Fig.3: transistor mounting detail on the rear panel. siliconchip.com.au TOP TOP OF REAR PANEL IEC CONNECTOR WITH SWITCH & FUSE ACTIVE 2 x EARTHING LUGS SECURED WITH STAR WASHER, M4 SCREW AND NUT Q1 NEUTRAL 6.4mm SPADE LUG SECURED WITH STAR WASHER UNDER M4 NUT Q2 Q4 BINDING POSTS TO TRACK Q3 6.4mm SPADE CONNECTOR ON EARTH WIRE BOTTOM COVER LINK WITH SILICONE SEALANT 12V (”C”) 240V PRIMARY WINDING (WIRED IN) 18090190 L ORT N O C ET O MER DERARF NI RELL ORT N O C RE W OP ESLUP 0V (”F”) 1 9V (”B”) NC T1 (12V/60VA) K CART DEL 9V (”E”) NC CON3 0V (”A”) 4148 12V (”D”) + 1 + CON2 9 10 1 2 BOTTOM 1 2 (CON1) TO DISPLAY BOARD) JAYCAR(RIBBON CABLE TRACK LED DISPLAY PULSE POWER CONTROLLER DISPLAY LOOKING AT BACK OF FRONT PANEL AND DISPLAY PC BOARD “FOLDED OUT” VR1 (REAR VIEW) ALTRONICS DISPLAY 09109082 TOP Fig.4: this “opened out” view shows the wiring between the PC board and front/rear panels. not yet be in its socket. Apply power and check for 5V between pins 5 and 14 of IC1’s socket. This may range be between 4.9V and 5.1V. If the voltage is correct, switch off power and insert IC1 into its socket, taking care to install it the correct way around. Reapply power and adjust trimpot VR3, so the LCD is easily viewed with good contrast. Note that you need to wait a few seconds after powering down before reapplying power. If you rapidly switch the power on and off, the LCD module may not reset correctly. At this stage the display should show a left arrow, an ‘S’ for stop and an ‘I’ for inertia on the top right of the display. The lower line of the display should show a bar graph and a persiliconchip.com.au centage reading (0-100%) that varies depending on the setting of the Local Speed potentiometer. The pushbutton switches below the display serve different functions depending on the Mode selected. At power up, the display is in RUN mode where three of the switches control the Direction, Stop & Inertia. If the Stop switch is pressed, then the ‘S’ should disappear and the top line will now begin to show a bargraph that increases slowly up to the speed setting value shown on the lower line. The Lockout (padlock) symbol will show as the speed increases beyond the first few bars on the top line. You should be able to switch the Inertia on and off with the Inertia switch and change the direction arrow when the speed is below the lockout speed. The direction will only change when the padlock lockout symbol is not showing. If these tests are OK, then the display PC board can be attached to the front panel using 12mm tapped standoffs and M3 screws. Countersunk screws are used on the panel for a flush finish. Adjusting parameters You are probably now ready to try out the controller on your model railway layout. Connect the Railpower IV to the tracks by means of the terminals on the back panel and place a locomotive on them. Check that its speed can be controlled with the front panel knob. At this stage the maximum and minimum speed settings can be adjusted. October 2008  73 The Railpower IV rear panel, showing the positions of (from left) the track terminals, four transistor mounting bolts, earth bolt and the combination IEC mains input socket, fuse and power switch. Only the four transistor mounting bolt hole locations are critical – they need to line up with the transistors on the PC board. The IEC combo clips into a rectangular hole measuring 48 x 28mm – no screws are required. To do this, press the Inertia switch so that the ‘I’ is not displayed inertia disabled). This will allow the locomotive to respond instantly to speed settings. Now press the RUN switch and the display will now show the SET mode in which the three rightmost switches change their function to Function, Down and Up. Any changes made to the SET values are stored in memory unless they are changed again. Each press of the Function switch selects the following: MAXIMUM SPEED (self explanatory) MINIMUM SPEED (self explanatory) LOCKOUT SPEED (the maximum speed that reverse direction can be invoked) DEFAULT SPEED (the switch-on or default speed of the Railpower ) LOCAL/REMOTE (control is from front panel controls or infrared remote) CODE TV (the code from your particular infrared remote – see the infrared remote instructions) INERTIA (self explanatory) STOP (self explanatory) FEEDBACK (the degree which backEMF from the motor affects the Railpower) SPEED RAMP (the rate at which the speed setting changes under remote control) and PULSE (the frequency of the interrupted DC going to the tracks) Further details on what these mean and how to set them are shown in the programming panel overleaf. Opposite: Railpower IV front and rear panel drilling details, shown life size. The downloadable front panel on the SILICON CHIP website will not be dimensioned nor have the positional writing, so it can be printed and used direct. Radio, Television & Hobbies: the COMPLETE archive on DVD YES! NA R MO E THA URY ENT QUARTER C NICS O OF ELECTR ! Y R O T IS H 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 EA. 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. • Every issue individually archived, by month and year • Complete with index for each year • A must-have for everyone interested in electronics Please note: this archive is in PDF format on DVD for PC. Your computer will need a DVD-ROM or DVD-recorder (not a CD!) and Acrobat Reader V6 (free download) to enable you to view this archive. This DVD is NOT playable through a standard A/V-type DVD player. Exclusive to SILICON CHIP ONLY 62 $ + $ 00 7 P&P HERE’S HOW TO ORDER YOUR COPY: BY PHONE:* (02) 9939 3295 9-4 Mon-Fri BY FAX:# (02) 9939 2648 24 Hours 7 Days <at> BY EMAIL:# silchip<at>siliconchip.com.au 24 Hours 7 Days BY MAIL:# PO Box 139, Collaroy NSW 2097 * Please have your credit card handy! # Don’t forget to include your name, address, phone no and credit card details. 74  Silicon Chip BY INTERNET:^ siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information siliconchip.com.au L C 24mm 17mm 22mm 10mm 15mm 55mm 17mm FUNCTION DIRECTION 10mm 86mm POSITION OF DISPLAY PC BOARD BEHIND PANEL DOWN STOP CUTOUT FOR JAYCAR LCD (xx x xxmm) SET RUN 10mm UP INERTIA CUTOUT FOR ALTRONICS LCD (65 x 16mm) SILICON CHIP 45mm TRANSISTOR MOUNTING - 3mm 30mm SPEED 35mm CUTOUT 28 x 48mm IEC CONNECTOR FUSEHOLDER AND SWITCH 28mm 15mm 8mm GREEN: FORWARD RED: REVERSE DIRECTION RAILPOWER Iv EARTH BOLT 4mm 48mm 10mm 38mm October 2008  75 siliconchip.com.au 7mm 7mm 15mm 16mm 10mm PROGRAMMING YOUR RAILPOWER IV Maximum Speed Press the Function switch until MAXIMUM SPEED is displayed on the top line of the display. The lower line shows SET<at> 107? (180). The value 107 could be any number between 0 and 204 depending on the position of the Local Speed potentiometer while the number in brackets is the original default setting or your previous maximum speed setting. Typically, you will want no more than 12V DC applied if you are running HO or OO scale locomotives and no more than 9V DC if you are running N gauge. If in doubt, check the manufacturer’s recommendations. In fact, running an HO scale locomotive at its maximum of 12V will normally result in a scale speed of 180km/h so for the sake of realism and safety, you might want to reduce it somewhat. So to set the maximum speed, wind up the Speed control until you get the desired DC voltage across the locomotive’s motor or you obtain the maximum speed you require. Depending on the different types of locomotive on your layout, the MAXIMUM SPEED setting may have to be compromise. Once you have obtained the desired value, press the Up or Down switch and the display will momentarily show LOADED. Thus, the new maximum speed setting will be loaded and shown in brackets. The motor will now run up to this new maximum speed setting. Minimum Speed Now select MINIMUM SPEED and you can go through the same process. In this case the lower line shows SET<at> 107? (1). Again the 107 could be any number between 0 and 204 depending on the position of VR1, while the number in brackets is the actual minimum speed setting. Adjust the Speed control to a low setting that is just at the point where the motor stops (or is about to start) The SET<at> reading will probably be around 1 to 5, or maybe higher with motors that require more voltage to start. Again, you can store this value by pressing the Up or Down switch and the word LOADED will appear briefly. The stored value will show in the bracketed section of the display. Pulse At this point you will probably become aware of the noise the locomotive makes at the low speed settings. If it is quite apparent, you may want to change the PULSE setting. Initially, it will be 122Hz and that is probably the optimum setting with most model locomotives but give it a try at 488Hz or 1953Hz. Once you have decided on the PULSE frequency setting, you may need to go back and reset the MINIMUM SPEED. You cannot have the minimum speed setting the same as or larger than maximum speed setting. If you make a mistake here, to solve the problem, you need to redo the adjustments. Generally you would need to initially select 204 for the maximum and 0 for the minimum values first before readjusting the minimum and maximum values again for your requirements. Note that while the displayed numbers range from 0 through to 204 in increments of 1, the actual control is over 816 values. So depending on the resolution of the Speed control potentiometer, it is possible to obtain up to four speed settings between each value increment on the display. This extra resolution can be useful for the minimum speed setting. The stored values include this extra resolution. Note also that if you are using a standard 16mm potentiometer for the Speed control, this fine resolution probably will not be possible. Lockout & Default LOCKOUT and DEFAULT speeds can now be adjusted. Lockout sets the speed above which forward and reverse changes are prevented, ie, “locked out”. We suggest that you set it to a very low speed, similar to that used in shunting. The Default setting is the speed that is applied each time you turn on the Railpower when the remote control is used. It does not apply when you are using the front panel Speed control (local). Initial default settings for Maximum, Minimum, Lockout and Default are 180, 1, 8 and 64, respectively. Local/Remote This selects whether speed is controlled via the front panel Speed control or infrared remote control. You can toggle between either setting using the Up or Down switches. 76  Silicon Chip siliconchip.com.au Code Next, you need to select the CODE for the infrared remote control. You can select between TV, SAT1 or SAT2 using the Down switch. Normally, TV would be selected (the default setting). SAT1 or SAT2 are used when you have more than one Railpower controller used on the same layout vicinity. Note that there is a number in brackets (0 to 9) following the code selection. This sets the rate at which the Railpower decodes the infrared data, because some remote units are slow or fast compared with the correct data transmission rate of the RC5 code. The number can be changed using the Up switch. In practice you select the number that works best with your remote unit. Note that if you press the RUN/SET switch, the display is returned to the RUN mode showing the speed settings. You can then test the remote unit for reliability. You can quickly toggle between the settings mode and the CODE selection using the Mode switch. Inertia Inertia is the next selection. This selects the rate at which a locomotive changes its speed (accelerate or decelerate). The number is adjustable from 0 to 100, using the Up and Down switches. You will want to try several different values, depending on the size of your layout and the locomotives and length of the trains to be run. If you are using Inertia value of 60 or more, the locomotive will take several minutes to reach its set speed from a complete stop, or to go from the set speed to stop. Stop The Stop value is selected next and is the rate at which the locomotive comes to a halt when the Stop button is pressed. It also can be adjusted from between 0 and 100 but typically you will not want to use very high values otherwise it is too difficult to judge just when and where the locomotive will come to a halt. Feedback This value can be set between 0 and 100 and corresponds to the degree that the motor back-EMF affects speed regulation. A low value will mean that the locomotive will tend to slow down more when pulling a train up an incline. Hence, the setting you use will be a compromise between ease of running trains around the layout versus reality, ie, a heavy train should slow down when going up a hill unless the throttle is advanced. Also, trimpot VR2 also needs to be adjusted to provide optimum control. Generally, VR2 is set so the motor speed does not change much (when set to a slow speed) between when feedback values are 0 and at around 40 or 50. If in doubt, just set VR2 is to mid-point. Speed Ramp This value, adjustable from 0 to 255, selects the rate at which the Speed Setting will change when under infrared remote control. If 0 is selected, the speed setting will change slowly under remote control. In practice, a setting between 10 and 20 is fine. Any faster than that and you will find it tricky to make small changes in speed. Universal remote controls Further testing requires a universal or “pre-programmed” remote control. In this case, one with very few controls is the way to go. If you are going to build only one Railpower for your layout we suggest the AR-1703 from Jaycar. It is small and only has the control buttons you need. It does have one drawback and that is that it can only be used for the TV code. If you intend to have more than one Railpower on your layout, you will need a remote control with the SAT1 and SAT2 codes available. One such unit is the Altronics A-1009. Programming the remote The best approach is to initially program the remote control for a Philips brand TV (just follow the instructions supplied with the unit). In most cases, programming involves simultaneously pressing the “Set” button and the button for the item that is to be operated. In other words, press the “Set” and “TV” buttons together and enter a number for a Philips TV set. In this case, the Altronics A-1009 uses the number 026 for the TV code and 424 and 425 for SAT1 and SAT2, respectively. For the Jaycar AR-1703 use 11414. If you are using a different remote control, just select a number for a Philips TV set. If you later find that this doesn’t work, try another number for a Philips TV. Having programmed the remote, check that the Speed can be raised or lowered when the Volume Up and Down buttons are pressed. Check that the directions can be changed with the channel Up and Down buttons. Also check that the Mute button stops the loco and the Operate button switches Inertia on and off. SC siliconchip.com.au October 2008  77 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/ PRODUCT SHOWCASE Rabbit’s advanced Wi-Fi connectivity Rabbit’s new RCM5400W RabbitCore module series, which provides Wi-Fi/802.11b/g functionality, enables you to create low-cost, embedded wireless control and communications solutions. RabbitCore modules mount directly onto a user-designed motherboard and act as the controlling microprocessor for the system. Measuring only 47 × 72 × 14 mm, the Rabbit 5000 microprocessor-based RCM5400W series delivers the capability to integrate real-time control and Wi-Fi connectivity into your design. Additional features over the proven Rabbit 4000 microprocessor include hardware DMA, higher clock speeds, more I/O lines, six serial ports, and more instructions to reduce code size and improve processing speed. Applications include industrial control, remote terminal unit, serialto-ethernet bridge, building automa- tion, remote monitoring and communications and security and surveillance. A complete development kit is available which includes the RCM5400W microprocessor core module, development board with prototyping area, Dynamic C 10 development system and complete documentation on CD-ROM, serial cable for programming and debugging, Getting Started manual, and AC adaptor. PICAXE USB Programming Cable With so many PCs and laptops now not sporting serial ports, it was only a matter of time before Revolution Education released a USB version of the popular PICAXE programming cable. Here it is, courtesy of local agents Microzed. It’s not simply a cable – the USB “plug” also contains the smarts needed so the PICAXE chips can understand USB lingo. It’s 1.8m long and recommended retail price is $38.95. Contact: Contact: Unit 13, 82 Reserve Rd, Artarmon NSW 2064 Tel: (02) 9906 6988 Fax: (02) 9906 7145 Website: www.dominion.net.au PO Box 5103, Chittaway Bay NSW 2261 Tel: 1300 735 420 Fax: 1300 735 421 Website: www.microzed.com.au Dominion Electronics Microzed ANTRIM The long and the short of Powerboards! Australian electrical and telephone accessories company, Jackson Industries, has released two new model powerboards, both of which come with a lifetime replacement warranty. But that’s not the big story – one of the two is a massive two metres long, containing no less than ten outlets. With surge protection and overload protection inbuilt, the bright orange powerboard is made from metal for durability and also has inbuilt radio frequency interference filtering along with an illuminated on/off switch. The outlets are spaced 200mm apart, which means any plug-packs will easily fit on the board. The PT8282 2-metre powerboard is available nationally through Bunnings Warehouses and has a recommended retail price of $99.00 At the other end of the scale is the tiny PT2MICRO twinoutlet powerboard, intended mainly for travellers through Australia, NZ and 82  Silicon Chip China with standard 3-pin outlets, both of which are surge protected. Its 90cm power cord is designed to wrap around the powerboard case. A travel case is included which will fit the twin powerboard along with any extra mains cables and adaptors for other countries which you might need. It is priced at $16.95 and is available from Bunnings, K-Mart, Officeworks and BIGW. 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: Contact: Jackson Industries Norwest Busn Park, Baulkham Hills NSW 2153 Tel: (02) 9899 8833 Fax: (02) 9899 8378 Website: www.ji.com.au 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 Avcomm’s new model SSB/SW/AM/FM receiver Avcomm really hit a “sweet spot” in the market with their Degen 1103 HF SSB receiver, featured in SILICON CHIP in January 2007, with several hundred sold. Avcomm’s Garry Cratt said that most portable receivers on the market don’t offer SSB reception – and it seems that many listeners like to have this facility available. However, many users didn’t like the shared tune and volume controls and a few other “features” of the Degen – so Avcomm sourced an updated model to cater for those requests. The unit offers improved “S” meter (signal strength) display, a larger BFO for easier adjustment of SSB reception. The LCD display shows the frequency directly as entered, anywhere between 100kHz and 29999kHz. Several parameters previously embedded in software are now user selectable. These are AM channel spacing (User selectable: 9kHz or 10kHz) and the FM band frequency limits (88-108MHz or 76-108MHz). LW is user selectable On or Off. In addition the Tel: (03) 8677 1411 Fax: (03) 9011 6220 Email: sales2008<at>ozitronics.com STEPPER MOTOR DRIVERS Ideal for use with Serial Stepper Motor Controller kit featured in July 2005 issue. UNIPOLAR motor driver 8-30V DC <at> 6A PCB 80x50mm K179 - $27.50 BIPOLAR motor driver 8-30V DC <at> 6A max. K158 - $34.10 More kits & documentation available on website: www.ozitronics.com expanded memory capacity (600 channels) can now be arranged in groups. RF performance is identical to that of the popular Degen 1103, and the unit is now supplied with an approved regulated battery charger/power supply with RFI suppression. Retail price is $179 including the stereo earpieces, long-wire antenna and carry bag shown above. Contact: Avcomm Unit 24/9 Powells Rd, Brookvale NSW 2100 Tel: (02) 9939 4377 Fax: (02) 9939 4376 Website: www.avcomm.com.au PC-Programmable universal remote control There’s a huge variety of “universal” remote controls around – but this is one of the very few that’s programmable (via USB) from your PC. According to Wagner Electronic Services, programming this is as simple as connecting the supplied programmer module to your PC, running the supplied CD catalog program, then selecting the desired brand and clicking program. That should be a boon to all of the programming-challenged amongst us (eg, anyone over about 12 years of siliconchip.com.au Ozitronics age!) where most normal programmable remote controls require a PhD in button-pushing. Apprentice tool kits from Cooper Tools Each of the three new Apprentice Tool Kits from Cooper Tools has a range of specially selected tools to suit the apprentice electrician, carpenter or plumber. Each of the kits, individually valued at around $1200, is priced at just $799 and offers products including Crescent, HK Porter, Lufkin, Nicholson, Plumb, Weller and Wiss. The Cooper Tools Apprentice kits include more than $300 worth of additional tools and importantly qualify for government support for the apprentice under the TFYT program. However any tradie can also purchase any of these kits. Apprentice selecting these kits can be confident they will receive tools from a reputable supplier, backed by a quality guarantee and after-sales service, that will serve them well for years to come. Contact: Contact: 138 Liverpool Rd, Ashfield NSW 2131 Tel: (02) 9798 9233 Fax: (02) 9798 0017 Website: www.wagner.net.au 519 Nurigong St, Albury NSW 2640 Tel: (02) 6058 0334 Fax: (02) 6021 7403 Website: www.cooperhandtools.com.au Wagner Electronic Services : Cooper Hand Tools 300VA transformer for Ultra-LD Mk2 amplifier Harbuch Electronics have made available a 300VA toroidal transformer for the Ultra-LD Mk2 amplifier described in the August & September 2008 issues. Mindful of the fact that the windings of toroidal transformers can be prone to buzz, Harbuch have filled the centre of the windings with an epoxy resin. This will certainly quieten any tendency to buzz as well as providing a very secure anchor for the central bolt. The two 40V windings are each rated at 3.6A while the 15V winding, intended for the preamplifier and loudspeaker protection duties, is rated at 0.5A. The SC Cat No is PTT-5391. Contact: Harbuch Electronics 9/40 Leighton Place, Hornsby NSW 2077 Tel: (02) 9476 5854 Fax: (02) 9476 3231 Website: www.harbuch.com.au October 2008  83 Another reader’s approach to exposing photo PC Boards. . . Cook ’em in the old microwave! I decided to build the UV exposure box for photo-sensitive PC boards, as published in the November 2007 SILICON CHIP. The first thought I had was to use the timer module in an old microwave oven, instead of building the timer design used in the project. Then I thought: “Why not use the whole oven?” W hy not, indeed? I wouldn’t have the lid of the original design to clamp the transparency down onto the PC board but this could be overcome by making a platter and using a sheet of glass to apply enough weight to ensure intimate contact. When activated, the platter-motor of the oven, slowly rotates the PC board pattern within the UV light, providing a very even exposure of your pattern. I can obtain very even and consistent results with transparency film and about 30-40 seconds exposure time 84  Silicon Chip (although I tend to pre-heat the tubes for five minutes first). There is a significant difference in both light output and colour temperature between a just-turned-on tube and one which has been on for a few minutes. One big advantage of using an old microwave oven: just as when the oven was an oven, when the time is up, the oven beeps loudly at you, to tell you that your board has finished cooking exposing! By Graeme Rixon So I bought a secondhand microwave oven for $5 from my local refuse recycle centre, in a “working but no glass turntable” state. If your council has kerbside cleanups, you may well find one that’s about $5 cheaper. By far the majority of microwave ovens are discarded because a 30c high-voltage diode has blown. But we don’t even need that because we aren’t interested in the cooking side of things. The only things you need to check, when looking for an oven to convert, is that (a) the timer and its display works siliconchip.com.au WARNING: MICROWAVE OVENS CAN BE LETHAL! A microwave oven is a very dangerous device. Even service personnel who are very familiar with them will tell you they are not their favourite equipment to work on. A microwave oven operates at a potential of several thousand volts and contact with any part of the high voltage circuitry can be (and indeed has been) fatal. Even a microwave oven which has been turned off for some time may have enough energy stored to give a potentially lethal shock. NEVER operate a microwave oven without the cover on and secured and without the door interlocks operating. This article is intended for those who are experienced with mains device wiring in general and microwave ovens in particular. Follow exactly the steps outlined in this article regarding making the microwave oven safe before, and as you modify it. and (b) that the platter motor turns. It does not matter if the oven has a glass platter or not – I made my own from a sheet of MDF and an old speaker. Stripping the oven Stop! Don’t go in like a bull at a gate and start cutting wiring willynilly. If you don’t heed the warnings further on, that could be as far as you get. Forever. First step is to physically cut off the mains power lead outside the case so that no-one, yourself included, can possibly energise the oven without its cover on. OK, now that should render it harmless, right? Don’t you believe it! Even when not connected to power; even when it hasn’t been powered up for some time, a microwave oven can bite! Make no mistake – contact with the high voltage capacitor, even with the oven off, can be fatal – you have been warned. The high voltage capacitor must be safely discharged before you proceed any further. SILICON CHIP published an article in the August 2003 issue (pages 84-87) on how to re-use the timer module from a microwave oven and this covers the safety concerns well. The oven was carefully stripped of the magnetron, high-voltage transformer and capacitor, platter rollers, cooling fan, and oven light – these were simply discarded. All mains wiring was removed, so that a custom wiring loom could be installed. Once you have removed the capacitor, do not simply throw it in the bin without a shorting link across its terminals, as the voltage across these capacitors can regenerate over time. Maybe it’s not enough to kill but if the terminals are contacted with it is enough to give you, or the poor rubbish man or woman a bad jolt (especially with wet hands). To discard the capacitor, I re-used a simple spade-to-spade jumper lead from the original oven wiring and installed it across the capacitor terminals, before disposing of the unit. Failing this, a piece of bare copper wire twisted firmly around the terminals will do. With all the HT wiring, etc, out of the way, you can set about actually building the UV oven. We make use of the existing oven timer module, as more often then not, it contains its own power supply and transformer. All you have to do is connect the 240V AC mains to it, to have a fully functional timer, complete with output switching relay. All the features of the oven timer are used, such as the door-switch, which will stop the time and shutoff the tubes, if the door to the oven is opened while the tubes are running – the exact same concept that shuts off the magnetron when the oven was an oven. The tubes are 15W blacklight-white tubes (NEC type FL15BL) and they are fitted in rubber bushes, fixed to holes bored through the oven cavity. The bushes prevent the tubes breaking if the oven gets a bump. With the pilot holes for the tube placement marked and drilled, you then have to cut the large holes for the plugs to fit in the oven wall. I drilled the holes in the very oldfashioned way of marking the size of the hole for the plug using the pilot hole as a centre reference, and then drilling a series of small holes These two photos show the wiring between the starters (bottom of pics) and the tubes above. This wiring is the same as shown in the November 2007 article. Can you spot the really bad mistake? Using green/gold wire for ANYTHING but earth wiring is a big no-no, despite the clear warning sign printed on the side of the oven. Always remember that green/ gold is only for Earth, brown is only for Active and blue is only for Neutral. siliconchip.com.au October 2008  85 Inside the old microwave oven showing the positioning of the 15W blacklight fluoro tubes through the oven wall. The ballasts were fitted where the old high voltage transformer and capacitor were originally located and completely new mains wiring loom fitted. The timer has its own transformer; this is left intact and is used to switch the fluoros and turntable motor on and off. At the end of the chosen time, the “oven” dings to tell you the board is properly “cooked”! Once again, note our comments on the use of green/gold wire – it must not be used for anything but an earth connection. around the edge of the line, then using a metal cutting drill-bit to bridge all the small holes. The rough edges of the holes were filed a little, to take away the sharp points but there is no need to make the holes perfect – the rubber bushes will protect the glass of the tubes from any sharp edges from the holes. If you are prepared to sacrifice a hole-saw blade, one of these could be used to cut the holes instead. But as the walls of the oven are usually stainless steel, be prepared to blunt the hole-saw very quickly. Still, it will save you a significant amount of time. The rubber bushes I used are intended for use as body plugs. They are commonly used in the vehicle industry to seal holes in car bodies. The ones I used were 45mm in diameter and cost about $5 each. When purchased, these plugs are all rubber, and a suitably-sized hole has to be cut in each one, to allow the tube to pass through it. I made a “punch” to cut my holes out of an 11/16 socket from an old socket set, sharpened around the edge with a bench grinder. You then line up the socket and plug in a medium-sized vise (with a wood block behind the plug), and tighten up the vise hard to cut the hole through the plug. Ideally, you want a hole in the plug which is slightly smaller then the diameter of the tube, so that when the tube is inserted, it is a nice firm fit in the plug. Two of these plugs will hold the tube firmly in place within An old speaker frame is used to raise the 30cm MDF “platten” up closer to the UV tubes, for shorter exposure times. The speaker even comes with suitable mounting holes! 86  Silicon Chip the oven cavity, and protect the tube glass at the same time. My 11/16 “punch” gave me a nearperfect 24mm hole in the plug, making the tube a nice, firm-but-not-too-tight fit. Fit the plugs to the oven first, then insert the tube through them. Smear a little Vaseline around the inside edge of the hole in the plug, to aid in fitting the tube. If the turntable is missing (they usually are!) one can made from a circle of 12mm thick MDF - I traced around an old LP record to get the 12” size I wanted. Tracing around the centre hole in the record also gave me an accurate centre reference for the wood disc. The normal oven turntable position is really a bit too far away from the UV And here’s a shot showing how it all fits in. Actual distance between the tubes and PC board is not critical – about right is about right! siliconchip.com.au tubes, so I mounted mine on an old 8-inch speaker chassis. This was then mounted to the old oven platter-motor spigot. Find a suitable speaker – you can remove the cone and coil if you want to but it won’t matter if you don’t. A hole is then drilled directly through the magnet core and the platter-motor spigot is bolted to the speaker chassis magnet. That done, the speaker chassis is lined up and centred on the MDF disc and simply screwed on as if you were mounting the speaker in the normal way, making use of the speaker chassis mounting holes. The turntable assembly is then pushed onto the platter-motor driveshaft, in the middle of the bottom of the oven cavity. A Nylon washer smeared with Vaseline on both sides is placed between the platter spigot and the oven floor itself, to prevent binding. The PC board is placed facing upwards on the “turntable” and the transparency pattern then laid on top, A small sheet of 6mm thick glass then placed on top of that, to hold the pattern in close-contact with the board. This requires that you cut the normal A4 sized transparency to size but I only make small boards anyway – I have never needed to make A4-sized boards, so this is no real problem (for me). The electrical system is essentially the same concept as that published in the November 2007 issue of SILICON CHIP, except that the tubes are 15W types, and the ballasts are 30W type. I bought the tubes for $20 per tube, delivered by mail. Most lighting specialists will either have these tubes or be able to get them Finally, a shot with the lamps lit. The door interlock has been defeated for this photo but the interlock should be used so that when the door is open, the UV tubes go out. So are these tubes dangerous? No, not in normal use but you wouldn’t want kids staring into them for long periods. . . for you (they’re used in electronic bug killers to attract the bugs). The two ballasts are mounted to the base of the oven, where the highvoltage transformer and capacitor were. The starters are on the base of the oven, on the other side of the oven cavity. The starter sockets and ballasts were stripped from old light fittings. The connections to the tube terminals were made using 16 PC boardmount terminal blocks. As it happened, the terminal shape was round and fitted perfectly the connections to the tube filaments. The primary reason for choosing these was that I needed to bring the connections from the tubes out at right-angles to the tubes themselves, for neatness – and especially on the starter-side of the oven cavity, as there is not much room there. Each terminal was soldered to a 10A wire, by inserting the pin of the terminal into the centre of the strands of the wire, then soldering, so that the wire is connected centrally to the terminal pin, instead of soldered alongside. This produces a much neater looking connection between the terminal and the wire, when it is heatshrunk, over a side-by-side soldered connection. Wire was obtained by buying a 10-metre 10A extension cord, cutting off the plug and about three metres of cable (this becomes the oven power cord!), and the socket end of the extension lead right at the end. The socket is disposed of. The three cores of the extension cable ripped from the sheath provided about seven metres of blue, brown and yellow/green 10A wire with which to wire up the oven, at minimum cost. If you elect to use hookup wire instead, make sure it is rated at 250V AC or higher (ordinary electronic hookup wire is generally rated at 100-150V so is not suitable), hence the reason for using wires stripped from a mains extension cord. All mains terminal blocks in the oven had small pieces of insulating plastic underneath them to offer a little extra protection against a stray strand perhaps touching the oven case. The same plastic was also installed under all the starter sockets. The plastic came from an old DVD case, which was simSC ply cut up with big scissors. into MOTORS/CONTROL? Electric Motors and Drives – by Austin Hughes Fills the gap between textbooks and handbooks. Intended for nonspecialist users; explores all of the widely-used motor $ 55 types. Practical Variable Speed Drives – by Malcolm Barnes An essential reference for engineers and anyone who wishes to or use variable $ 94 design speed drives. AC Machines – by Jim Lowe Applicable to Australian trade-level courses including NE10, NE12 and parts of NE30. Covers all types of AC motors. $ 66 DVD Players and Drives – by KF Ibrahim DVD technology and applications with emphasis on design, maintenance and repair. Iideal for engineers, technicians, students, instal$ 85 lation and sales staff. There’s something to suit every microcontroller motor/control master maestroininthe the SILICON CHIP reference bookshop: see the bookshop pages in this issue Robot Builder’s Cookbook – by Jim Lowe For the first-time builder, advanced builder and robotics student. Provides a painless explanation $ 63 of robot programming. Switching Power Supplies – by Sanjaya Maniktala Theoretical and practical aspects of controlling EMI in switching power supplies. Includes bonus $ CD-ROM. 106 ! Audio ! RF ! Digital ! Analog ! TV ! Video ! Power Control ! Motors ! Robots ! Drives ! Op Amps ! Satellite siliconchip.com.au October 2008  87 Vintage Radio By RODNEY CHAMPNESS, VK3UG The AWA Radiola 653P AC/Battery Portable The Heyday Of Valve Portables First released in 1954, the AWA Radiola 653P was a 6-valve portable receiver that could operate from both batteries and mains power. It’s a good performer that’s easy to restore and get going. C OMMERCIALLY-manufactured portable valve radios first appeared around 1925 with the introduction of sets like the RCA26 6-valve receiver (see SILICON CHIP, August 2008). However, sets of the RCA26’s calibre were well before their time and 88  Silicon Chip weren’t particularly common. In fact, early portables varied greatly both in terms of quality and performance. From 1925 onwards, a few manufacturers dabbled in making “portables” using 2V valves and vibrator power supplies but serious pro- duction of Australian-made portables didn’t occur until 1939. That’s because commercially-viable portables had to wait until the introduction of the octal 1.4V battery valves that required only 90V of high-tension (HT) supply. From that time onwards portables became more popular, although World War II slowed their introduction considerably. The octal 1.4V valves were subsequently commonly used up until around 1950, sometimes in combination with the much later 7-pin miniature types. After that, the 1.4V 7-pin miniatures were used almost exclusively. The 1950s saw the development of good-performing 5-valve and 6-valve battery-portable receivers. These sets usually used a No.745 1.4V battery for the filaments and two No.482 45V batteries in series to give a 90V HT supply. This combination gave a battery life of around 300 hours. Mains/battery portables Because they could so easily be taken from room to room, many people also wanted to use portable sets in the home. As a result, the manufacturers developed portables that could be powered both from the mains and from batteries. This meant that the set could be run economically from the mains around the house, with the expensive batteries reserved for truly portable applications when no mains power was available. In many cases, the batteries used in these sets were smaller than those used in the battery-only portables and siliconchip.com.au This is the view inside the Radiola 653P 6-valve portable. Note that the chassis is mounted upside down, with the valves secured in place using valve clips. The batteries are normally stored in the space at bottom left. therefore had a shorter life. The AWA 653P AC/battery receiver described here was one such set. To get around this problem, some manufacturers at that time experimented with “reactivation”. This involved recharging the batteries from the mains (to a certain extent) to prolong their useful life. Unfortunately, I’ve been unable to find any literature that indicates just how successful reactivation really was. I suspect that, used correctly, it may have extended battery life by up to four times. Because reactivation was being used to recharge primary cells, set owners would have needed to watch out for leaking batteries. This could typically occur if the recharging process was not uniform in a cell, thereby causing some locations in a cell to be “eaten through” over a period of use and leak corrosive chemicals. In fact, the remaining HT battery from my set looks as though it siliconchip.com.au has suffered from this problem. The manufacture of valve portables (with or without reactivation) quickly ceased with the advent of transistor portables. The latter had many advantages: they were more compact, weighed less, consumed considerably less power and were much less expensive to run. The batteries in transistor sets not only lasted longer but also cost a fraction of those used in valve portables. AWA 653P 5/6-valve portable The AWA Radiola 653P first went on sale in 1954, a time that was right in the middle of the heyday of good valve portables. It can be powered from either mains AC or dry batteries and also includes provision for recharging the dry batteries. This set was housed the same plastic cabinet used for the battery-only version and measures 330 x 249 x 150mm (W x H x D), including the knobs and handle. As shown in the photos, the cabinet of my set is maroon and cream and features a slide-rule dial-scale at the top of the front panel. It weighs 4.7kg without batteries and just under 6kg with batteries. At the top of the set is a carrying handle which is made of hard rubber. This handle drops down onto the top of the cabinet when not in use. The control knobs were mounted at the ends of the cabinet. All in all, it’s quite attractive in appearance but like other portables, it wasn’t cheap. This set sold for 30 pounds and nine shillings in 1955, an amount that represented several weeks’ wages for the average person. Inside the set Turning two screws at the back through 90° and then laying the back down gives access to the inside of the set and to the batteries and AC power lead. As can be seen in the photos, the chassis is mounted upside down at the top of the cabinet, with the AC power supply at the right. The valves are all October 2008  89 This under-chassis view shows the unit prior to restoration. All but one of the large black paper capacitors were replaced with polyester types. The original power cord was secured using a knot, which is now illegal. This view shows the chassis after the paper capacitors had been replaced. An electrolytic filter capacitor was also replaced, along with two charred resistors. held in position by clips, so that they don’t fall out. The six-inch speaker is in the centre of the cabinet against the front, while the two batteries sit on the bottom lefthand side of the case and are held in place by brackets. The AC power cord is stored in the space to their right, beneath the power supply transformer. As in other valve portables of the 90  Silicon Chip era, this set employed a flat loop antenna. This is glued and held in place on the inside back panel of the set using clamps. Circuit details Refer now to Fig.1 for the circuit details of the AWA Radiola 653P. As shown, the tuned loop antenna (L1) is connected to a radio frequency (RF) amplifier stage based on a 1T4 valve (V1). Its output is then applied to tuned RF transformer L2/L3 and fed to a 1R5 converter valve (V2). Following V2, the signal is fed via 455kHz IF transformer L6 & L7 to IF amplifier stage V3 (1T4). This IF amplifier stage is neutralised via C17 in a bridge circuit. The amplified signal is then applied to a second IF transformer (L8 & L9) and from there to the detector/AGC diode in V4 (1S5). The detected audio is then fed via volume control R10 to a 1S5 pentode, amplified and fed to a 3V4 output stage. Note that when AGC/AVC is applied to series-connected filament valves, care must be taken to ensure that the AGC not only works but that the bias requirements for each valve are met. As a result, I noted the voltage at the positive filament terminal of each valve so that the bias could be determined (note: the filaments are connected in series). In this set, 9V is applied to V5, then 6V to V1, 4.5V to V2, 3.0V to V4 and finally 1.5V to V3 (note: V5 is a dualfilament valve). The AGC output from V4 is applied to V1 and V2 only. A voltage divider network from the +6V rail consisting of resistors R1, R2 & R5 operates with the AGC bias (at the diode output of V4) to provide effective AGC to the two controlled stages (ie, V1 & V2). However, V3 has no bias applied to it all and runs at full output at all times. By contrast, the 3V4 (V5) derives its bias from the +1.5V at V3’s positive siliconchip.com.au filament. This, together with the +6V at the 3V4’s negative filament terminal, gives a bias of around -4.5V. The power supply is more complicated than usual. That’s because, as previously stated, the set can run from either mains or battery power. In addition, the supply is capable of providing charging current for the battery reactivation process. The power switch has five positions labelled Full, Save, Off, AC and Reactivate. In the “Full” position, the 9V and 90V batteries are connected to the set. When switched to “Save”, a 1.8kW resistor is connected in series with the 90V battery to conserve power while in the “Off” position, both the batteries and the AC mains are disconnected. In the “AC” position, mains power is switched to the transformer which then feeds a 6X4 rectifier (V6). Approximately 120V DC is produced at the output of the rectifier and this is dropped to 9V by resistors R12 and R13 which are switched in series with the filaments and to 90V by R14 for the HT supply. Capacitors C28, C29a and C29b do the filtering. Note that because the rectifier is only a half-wave type, the filter capacitor values are considerably higher than for a full-wave system. This is necessary to ensure well-filtered supplies for the filaments and plates of the valves. Note also that the AC power supply circuit layout is rather unusual in that the plates of the 6X4 valve are wired to chassis while the cathode is connected to the relevant secondary of the power transformer. This is opposite to method used to wire power supplies in normal AC receivers. It’s done so that in the “Reactivate” mode, the 9V and 90V batteries are not connected to each other via a resistor string if the power is switched off at the mains instead of at the set. Finally, when the power switch is in the “Reactivate” position, the two anodes of the 6X4 are separated so that the charging circuit for each battery is entirely separate. In this case, one still goes to chassis but the other is now connected to the negative terminal of the 9V battery. Dismantling the receiver Dismantling this set for service is siliconchip.com.au Fig.1: the circuit is a 6-valve superhet with power derived either from the 240V AC mains or from a 90V HT battery and 9V filament battery. Power supply circuit straightforward. First, the three knobs are pulled off their control shafts although this was slightly difficult on this set because there was some paste or grease on the shafts that had partially solidified. Next, with the back of the set open, I pulled the 90V battery out (it was the only one fitted) and disconnected it. Unfortunately, the battery plug had corroded due to battery leakage and broke but I had some spares on hand. The antenna plug and the speaker October 2008  91 The flat loop antenna has its turns glued together and is clamped to the inside back of the cabinet. The attached note shows the valve locations and details how the batteries and power cord are stored. plug were also removed and the earth wire from the chassis to the earth terminal was desoldered. The covers over the handle mounting screws were then removed, followed by the two screws hidden under the two higher knobs. This gave me access to the chassis retaining screws which were also removed. That done, the chassis was lifted out of the cabinet, ready for restoration. Once the chassis was out, the cabinet was dusted out and washed using soapy water and a sponge. The knobs were then given the same treatment, with any remaining gunk on the knobs and on the control shafts removed using kerosene. Although the cabinet looked clean after this treatment, its surfaces were quite pitted due to a rather hard life. As a result, I attacked it using some automotive cut and polish cream and most of the marks disappeared. Some, however, were just too deep to be removed and so although the cabinet now looks quite reasonable, it’s certainly not in pristine condition. The chassis was cleaned using a kerosene-soaked kitchen scourer and the small amount of gunk that was on it came off quite easily. In fact, it came up quite well, with just slight discolouration in a few spots. Restoring the circuit In order to access the parts under the 92  Silicon Chip chassis, it’s first necessary to remove a metal shield that’s attached to the bottom. This is easily done by removing five self-tapping screws. With the shield removed, inspection of the under chassis components revealed that virtually nothing had been done to the receiver during its life. At this point, it was time to make a few basic checks before I risked applying power to the receiver. First, with the set turned off and disconnected from both AC power and the batteries, I checked the filament line for continuity. In practice, this involved checking between pin 7 of the 3V4 and chassis and I measured around 80W, which is the cold resistance of the filaments in the series valve string. This was a good start but I did notice that two 3W resistors, R12 and R13, had been charred and blackened due to overheating. That wasn’t so good, although both resistors still measured correctly. Next, I endeavoured to test all the electrolytic capacitors even though my capacitance tester only covers values up to 40mF. These checks revealed that C28 was down to just 0.18mF, which meant that it was virtually open circuit. It was replaced with a 500mF 25V electrolytic. The remaining electrolytics were all close to their correct values and so were left in circuit. The paper capacitors were the next suspects, as most prove to have excessive leakage resistance. In highimpedance circuits, this alters the operating conditions of the valves and causes lots of problems. Replacement polyester or similar capacitors are cheap but for the sake of authenticity, I only replace those capacitors with excessive leakage. If, for example, a paper capacitor is wired across a cathode resistor, I would not replace the capacitor, as even a capacitor with high leakage would not noticeably alter the operating conditions of the valve. The resistors were also checked and these were all within their tolerance range of 20%. However, I did subsequently find it necessary to add an 18kW resistor in parallel with R12 to obtain the correct voltage on the filament line, even though the resistors in this line were within tolerance. Sets of this era came fitted with 2-core (figure-8) power lead, so the chassis wasn’t earthed. A figure-8 lead was also necessary in this set so that it could be “folded” up and fitted inside the case when the set was used as a portable. In my case though, I wasn’t going to use the set as a portable, so this didn’t matter. As a result, I decided to earth the chassis in the interests of safety. This meant that I had to slightly enlarge the cable exit point in order to accommodate a 3-core cable. This cable was securely anchored using a cable clamp. Testing & troubleshooting At this stage, everything looked in order. Apart from the component changes, I had checked that there were no shorts on the HT line and had double-checked the filament supply line to ensure that no more than 9V would be applied to the valve filament string. It was time for the smoke test. I plugged the mains power cord into the wall socket, turned the set on and after about 30 seconds, the receiver burst into life. It didn’t exactly blast me out of the workshop but at least it was going. Next, I checked the voltages applied to the valves. The HT line measured 85V and there was only about 6.8V going to the filament line. I then checked the voltage across filter capacitor C29A and it measured around 105V but siliconchip.com.au should have been 120V. So both the HT and filament voltages were low, which explained why the output of the set was so low. But what was causing the problem? I checked the voltage across the transformer’s secondary winding and found it to be 130V. This is correct so I tried replacing the 6X4 rectifier and the voltage rose to around 89V on the HT line and to about 7.5V on the filament line. The HT voltage was now correct but the filament voltage needed increasing slightly. As a result, I tried connecting different value resistors across resistor R12 and finally settled on a value of 18kW, which brought the voltage up to 8V. This gave just over 1.3V across each of the 1.4V valve filaments, which is quite acceptable. Alignment Now that the voltages were correct, the set was performing quite well and it was time to check the alignment of the IF, RF and oscillator circuits. First, with the shield removed from the bottom of the chassis, I tweaked the four IF transformer adjustments while listening to a relatively weak station. They were all very close to correct alignment. Next, with the shield plate refitted, I checked the oscillator circuits and the only thing I found was that the dial pointer was slightly out of position. Once this had been corrected, no further adjustment of the oscillator circuit was necessary. The set was then reassembled so that the remainder of the alignment could be done. I began by tuning to the lowfrequency end of the dial (around 600kHz) and adjusting L3 for best performance. That done, I then tuned to 2QN Deniliquin (1520kHz) and adjusted trimmer capacitor C7, again for best performance. The final task was to align the loop antenna. There is no adjustment at the low-frequency end of the tuning range so only trimmer capacitor C2 has to be adjusted. However, this must be done correctly if the set is to perform well at the high-frequency end of the dial. The antenna alignment is done with the back on the set, using a screwdriver inserted into the top lefthand access hole. It’s then simply a matter of peaking the antenna trimmer (C2) for best performance at the high-frequency end of the dial (in my case, station 2QN). siliconchip.com.au Photo Gallery: AWA Radiola 573MA MADE BY AWA in the mid-1950s, the Radiola 573MA was a 5-valve mantel set housed in a two-tone Bakelite cabinet. This one is grey and cream but many colour combinations were available. Behind the grille is a red & black floral motif fabric. The valve line-up was as follows: 6BE6 1st IF/mixer; 6BA6 RF amplifier; 6AV6 detector/AGC/audio amplifier; 6AQ5 audio output and 6X4 rectifier. Photo: SILICON CHIP. Note that this adjustment is normally done with the batteries fitted (and the back closed). That’s because the proximity of the batteries and any metalwork affects the capacitance across the loop antenna and hence its tuning. In my case, however, I didn’t have any suitable batteries, so the adjustment was done without them. This didn’t really matter, since I don’t intend fitting batteries to the set. Once all the adjustments had been completed, the old Radiola 653P performed very well indeed. 6-90V DC-DC converter Back in the early 1960s, I serviced many of these sets, along with similar sets from other manufacturers. They were all good performers in the rural area in which I lived. Because 90V HT batteries are no longer available, running these receivers as portables is now impractical unless you have a 6-90V DC-to-DC converter. Fortunately though, one member of the Historical Radio Society of Australia (HRSA), Tony Maher, has developed such devices so that radios like this can be used as portables. The 653P can be awkward to service, although access for maintenance while the radio is inoperative is quite reasonable except around the power switch. That said, it’s a set that performs well and is a good unit to have in any vinSC tage radio collection. 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! October 2008  93 Cent-a-meter “Owl”: watching your energy consumption by Stan Swan 94  Silicon Chip siliconchip.com.au A long with food and water, reliable electricity supplies are rightly considered an essential of modern life, even with the environmental issues regarding power generation. Mains electrical energy may well be a must-have but it’s certainly not free. And today’s switched-on consumers often face energy “bill shock”. Electricity may be hazardous but this has always been assumed to one’s health rather than wealth! In spite of improving appliance efficiency and better-insulated homes, soaring electricity bills often are due to ignorance about just “Watt” in their home is using the family “Joules”. Incidentally, the Joule is the unit of energy while Watt is the unit of power. Watts and Joules are related: Energy = Power x time, so 1 Joule = 1 Watt x 1 second. By contrast, 1-kilowatt-hour “unit” on your electricity bill is equivalent to 1kW for 1 hour = 1000W x 3600s = 3.6 megajoules (MJ). Consumers’ attempts to ease electricity consumption, both sensible (energy-efficient lamps and appliances) and half-baked (wrapping in blankets/sitting around a candle/ cold showers), may be futile if the true culprit is a powerhogging beer fridge in the garage or the pool pump being on for unduly long times. Short of balancing on a chair while trying to read a dusty switchboard meter, it’s not easy to relate high power consumption (arising perhaps from an earlier cold spell) to accounts received weeks later. Behaviour modification usually best occurs when associated with feedback at the time – you don’t stop a dog chasing cars by scolding it weeks later! Fortunately a range of electrical energy monitoring devices is now available. These fall into distinct classes, either simple plug-in units ideal for monitoring single appliances or switchboard-installed whole-of-house models. The Australian-designed Cent-a-meter, reviewed by SILICON CHIP in October 2003, is the best known of the latter type and has had justifiably wide uptake. With a simple clamp sensor installed on the switchboard’s insulated Active wire, it monitors the total household current. This value is transmitted (as a 433MHz data signal) to its portable, LCD-fitted receiver nearby. Features of the original Cent-a-meter included: • Near-instantaneous response to total household load changes • Convenient un-tethered viewing of the display, perhaps even at your bedside to reassure you that things are turned off. • Temperature and humidity displays. • A wide dynamic power range. • A convenient wireless display. However, issues arising have included: • Only apparent power (Volt.Amps) is being monitored, giving deceptive readings for many standby and inductive appliances. • No computer linking (serial or USB) is provided. • Battery life (3 x AA alkalines) on the receiver display is only a few months. (The sender batteries have similar life.) The recent release of an improved Cent-a-meter “Owl”, now apparently sourced from the UK, addresses some of these shortcomings, although its price has increased to siliconchip.com.au The complete Cent-a-meter OWL system: wireless data unit at left, sensor almost hidden at rear and the sometimes confusing display unit at right. around $200. Aside from date and time, its most obvious improved feature is the ability to store readings and thus show accumulated energy usage and running costs over time. Battery life is also said to be improved but my measurements (of several milliamps) indicate that only a few months could still be expected from three alkaline AA cells. For prolonged use a plug-in AC adapter should really be used for the LCD. Wireless coverage of both units (through timber-frame NZ houses) has been found to be a good 30m, with no noticeable susceptibility to interference. Evidence of a more sensitive (three channel) receiver in the new display may usefully boost ranges. What Watts? Due to the very nature of the current transformer clamp pickup, the new Cent-a-meter still does not respond to true billable “Watts” power as does a normal switchboard watthour meter. This means that the Cent-a-meter indicates higher power consumption than will actually be the case when motor driven appliances are being used, although the results will be pretty close for resistive loads (arising from mainly lighting, cooking and heating etc – by far the largest domestic usage), so this may not be too crucial overall. Further deviations may well arise from supply level variations (assumed to be 230V although in Australia it is typically 240V and often higher. Hence, overall it is debatable if A close-up of the inductive pick-up, designed to clamp on to the main Active cable in the rear of the switchboard. October 2008  95 From the publishers of SILICON CHIP PERFORMANCE ELECTRONICS FOR CARS NOT A REPRINT: More than 160 pages of new and exciting projects never published before – all designed to get top performance from your car. FASCINATING ARTICLES: 7 chapters explaining your car – engine management, car electronics systems, etc ADVANCED PROJECTS: You’ll build controllers for turbo boost, nitrous, fuel injection and much more! We explain the why as well as the how to! Available direct from the Publisher ($22.50 inc postage): Silicon Chip Publications, PO Box 139, Collaroy NSW 2097. Ph (02) 9979 5644; Fax (02) 9979 6503; email silchip<at>siliconchip.com.au; or via our website: www.siliconchip.com.au 96  Silicon Chip showing detailed power costs would really be merited. Setup and display Setup of the “Owl” unit should be easy enough for those used to modern appliance interfaces but multiple menus (selected by the three front buttons) make setting some options (currency units etc) rather a chore. Somewhat annoyingly, a strange 10-segment digit has been used for the largest LCD values and although these are readily visible, their “bumpiness” makes for awkward at-a-glance reading. Several users considered the LCD itself rather “too busy”, with the actual running costs etc difficult to spot amongst a sea of digits and display options. Despite politician’s and vested interest groups’ best endeavours, to most families greenhouse gas values are usually of much less interest than the dollars involved! In spite of four energy tariff options provided, a further complication arises due to the fixed line charges often levied by many energy suppliers. Typically, these are 50c$1 daily and for light users (perhaps away on holiday or someone particularly careful with their usage) the monthly bill may be more due to fixed charges than energy actually consumed. Thus even with accurate settings and a resistive load, a typical “ma and pa” Cent-a-meter user may find they receive a bill significantly above what their “Owl” indicates. Of course, ever-present GST will bias this even further. With experience the new “Owl” will provide a useful guide to the level of one’s likely power bill and it can alert consumers to wasteful energy consumption patterns. Note also that the clamp connection for the Cent-ameter should only monitor the Active wired going to the main watt-hour meter. If should not monitor the current drawn by any off-peak hot-water service as the tariff is markedly different, at least it is in most parts of Australia where off-peak tariffs are much lower than the general domestic tariff. Having said that, the fact that the Cent-a-meter monitors “whole-of-house” consumption, spotting the energy hog culprits may be complicated by concurrent activity from other appliances. For such detective work an individual plug-in unit may be better. Given standing non-energy charges and power factor issues, it’s likely that the Cent-a-meter’s indicative cost readings may only be a rough guide to the actual monthly bill. However, if 25% of energy consumption is indeed able to be saved as claimed, then the purchase cost could be covered in just a season. Maybe it could be as simple as “persuading” a household perennial radiator hog to chip in for their fair share of the bill. You can’t beat an investment like that. Of course – thanks to the wireless fed display – late night monitoring of teens watching the plasma TV in the lounge, or messing up the kitchen, may be done from the comfort of one’s bed – or even beside that beer fridge in the garage! SC The Cent-a-Meter Owl is available online from www. centameter.co.nz for $NZ189.95 + $19.95 P&P (~$AU172) or from www.todae.com.au for $AU199.95 inc P&P. 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 Query on bias in Ultra-LD Mk2 The description of the bias compensation circuit for the Ultra-LD Power Amplifier Mk.2 in the August 2008 issue states that a voltage of 70-100mV across the 0.1W emitter resistors gives a quiescent current of 70-100mA per transistor. In fact the current would be 700mA-1A. This would in turn suggest that the amplifier was dissipating around 200W at idle. Wouldn’t the actual voltage be 7-10mV? Furthermore, in the absence of an adjustment, how can you guarantee that the quiescent current settles at a level that is optimum for crossover distortion purposes? Wouldn’t the actual bias current be highly dependent on the characteristics of Q10 and Q11? Would a standard Vbe multiplier arrangement where DQ12/DQ13 and DQ14/DQ15 were wired in parallel and Q10/Q11 were at ambient temperature be a better way to do this? Wouldn’t that guarantee optimal thermal tracking? (F. Z., Barrack Heights, NSW). • The voltage across the emitter resistors should be 7-10mV (not 70100mV). This was corrected in the September 2008 issue. Also in September, we included details of how to vary the bias, if necessary, because we have found that there can be a larger than expected variation in the voltage drop across the internal diodes of the transistors. This adjustment will cope with any variations in the Vbe of the drivers as well. We have not used a trimpot for this adjustment – we prefer to do without trimpots if possible and we think that, in most cases, no adjustment will be needed. By the way, our circuit is not much different in principle from the On Semiconductor application note AND­ 8196/D which can be downloaded as a pdf from the onsemi website: http:// onsemi.com In fact, the published bias circuit will always give much tighter compensation than a Vbe multiplier which effectively monitors the average of the Vbe drops (of driver and output transistors) at “arms’ length” rather the very precise tracking made possible by the internal diodes. In any case, regardless of which bias stabilisation scheme is used in a class-B amplifier, the driver transistors should be on the same heatsink as the output transistors because any variation in the Vbe of the driver transistors will affect the overall quiescent current. Using the speed control with shunt motors I know the 12V-24V High Current Motor Speed Controller (SILICON CHIP, March & April 2008) was designed to handle permanent-magnet DC motors. What do you need to change or modify in the circuit to allow the use of serieswound and shunt-wound motors? (J. D., via email). • No modifications are required to the speed controller to drive a serieswound motor. In the case of a shunt motor, you will find it has four connections, two for the armature and two for the field windings. To run it, you connect the armature winding to the speed controller while the field winding is connected to the full DC supply which also feeds the speed controller. However, you would then need a 2-pole DC contactor to switch the DC supply to the speed controller and the shunt field windings. Headphone socket for the Class-A amplifier I would like to put a headphone socket on the 20W Class-A Stereo Amplifier (SILICON CHIP, May & June 2007). Where is the best place to put it, PWM Causes Heating In Model Locomotive Motors Does SILICON CHIP have any comment on the matter of PWM controllers causing motors to heat up during slow speed running? I would like to post an answer to a railway modellers’ forum in defence of PWM controllers, as these guys seem to prefer using 2N3055s or similar (switched by a BC158, etc) and with little else except a 12V supply, bridge rectifier and a potentiometer! One “design” offered by one of the group doesn’t even have any filter capacitors. I doubt that such a controller would give very good slow siliconchip.com.au speed running? (P. C., via email). • It is true that PWM (pulse width modulation) will cause more heating in the motor than constant DC. However, there would not be a significant difference between PWM and the unsmoothed DC from basic train controllers. Even so, the heating involved is still less than would occur if the motor was being used at high-speed settings. Any basic train controller using pure or unsmoothed DC will give very inferior low speed operation compared to our PWM designs. Another point is that DCC (Digital Command Control) systems automatically feed PWM to the locomotive motors so any currently available locomotive which is sold with an inbuilt DCC decoder or as “DCC-ready” will have no problems. However, PWM should not be used with coreless motors as made by Portescap. They should only be used with smooth DC controllers but again, unless the track and loco pickups are kept scrupulously clean, low speed operation will tend to be poor. October 2008  97 Trouble With The Subwoofer Controller I purchased a Subwoofer Controller kit (SILICON CHIP, August 2007) from Jaycar and after correcting a diode which I fitted around the wrong way the kit fired up and was exactly what I had been looking for. I run two subwoofers using two separate amplifiers, with the signal split by a single male to twin female RCA fitting, at the back of the surround amplifier. I use one direct from the surround amplifier and one through the sub controller to boost the very lowest frequencies. The surround amplifier has no low-pass filter for the sub, so it booms instead of thumping. Everything has been running fine, except that the power controller for the amplifiers has never worked; the power to the amplifiers is on all the time, regardless of whether there is a signal or not and even if I disconnect the power to the controller, the circuit still allows power to the amplifiers. I have replaced all the ICs to no avail. I can live with this problem but now things have got worse. The controller processes the signal coming in, the level control knob works fine but there is no real volume coming through. For a while it seemed to take a while, then suddenly it would go but now there is no real signal at all. With the amplifier turned right up, there is only the faintest noise coming out of the subwoofer. I switched before the speaker protector or after? I know I may have some hum problems but I like headphones. It’s a pity you did not factor this into the design as many people may desire this. (F. B., via email). • If you want a headphone connector it would probably be best to connect it after the Loudspeaker Protector. Use a 270W 1W resistor in series with each side of headphones. However, there are two reasons why we did not do it. First, the extra wiring does present a problem in attempting to keep buzz from the transformer out of the audio. Second, it does seem quite wasteful to run an amplifier consuming over 100W to drive a couple 98  Silicon Chip amplifiers and subwoofer to no avail; the problem remains the same. I had a friend who is a retired technician check it out but he could not get a grasp of it all. Jaycar had a look but could only suggest replacing all the ICs, which I did. The thing is still not putting any real power out. Can you help me please? (S. G., via email). • Well, it isn’t working now and it probably wasn’t working in the first place. The first point is that if the controller supplies power to the amplifier even when its own power is off, either the SSR (solid state relay) is faulty or there is a short across it in the wiring on the PC board. As far as the rest of the circuit is concerned, the only way you can find the fault is to trace the signal right through the circuit. In general, replacing all the ICs in a project in an attempt to find a fault is usually fruitless and you never have the satisfaction of finding out what the fault really was, if you do happen to succeed in fixing the problem in this way. The way to proceed is as follows: connect an audio signal to the input and then use a small amplifier and connect its input to the output of every op amp in the signal chain. This should give you a clue as to where the problem lies. Our bet is that it is a poor or missed solder joint on the PC board. It’s rare for new ICs to be faulty. of flea-power headphones. As an alternative, you could build the Deluxe Headphone Adaptor described in the April 2008 issue of SILICON CHIP or the much-simplified version published in the Circuit Notebook pages of the June 2008 issue. PC-Controlled Burglar Alarm I’ve built the PC-Controlled Burglar Alarm (SILICON CHIP, February & March 2006). All the testing checks out until you get to the point you have to connect a sensor. The only sensors I have at the moment are reed switches. These don’t have a tamper circuit and obvi- ously don’t have power – just the alarm loop, ie, a wire in and out to form an in-series loop for a given zone. I saw a response to a question on this a while back. The magazine stated that most sensors had four connectors – two for power and two others providing NC or NO. The response suggested you just needed to connect one of the NC or NO connectors to the appropriate zone, ie, one lead to one zone connector for any sensor that didn’t have power. I can’t see how this can work because there is no earth connector for a voltage signal and there is no way of the alarm board checking continuity (which is how reed switches work). I tried connecting one connection to a GND for the sensor’s terminal and the other to a zone but no joy. What should I do? (P. G., Hook, UK). • The zone inputs from 1-8 on the PCControlled Burglar Alarm are normally pulled to +5V via 100kW resistors. A zone input is pulled to ground when its input is connected to the GND terminal. A reed switch can be connected between a zone input and ground to form this connection to ground when the contact is closed. Some reed switches do provide both NO (normally open) and NC (normally closed) contacts and a common. The zone input connects, for example, to the common and the NO or NC contact connects to the GND. When using more than one reed switch per zone, the switches are connected in series when you use the NC contacts and in parallel when using the NO contacts. Power is only required for sensors that require it, such as infrared movement detectors. The NO, NC and common connections connect in the same way as reed switches as described above – ie, to the zone and GND terminals on the alarm. The PC-Controlled Burglar Alarm needs to be set up for the sensors used before the system will work correctly. This is described on page 33 of the March 2006 issue. High-quality power supply wanted I need to build a high-quality regulated power supply (not switchmode) to power a mixer. I require 36V at around 2.5A. Do you know of such a circuit that siliconchip.com.au Incompatibility Between Smart Charger & Digital Inverter Generator I have a problem of compatibility between a smart battery charger and a portable digital inverter generator that is proving very frustrating. We have a trailer/sailer yacht on which we go for extended cruises of four weeks or so in isolated areas away from shore power. In order to provide sufficient power to keep the fridge, etc, operational we have two 120Ah deep-cycle batteries on board which are sufficient for about four days without the need to recharge. As we prefer to sail rather than motor, which is the present method for charging, we decided to invest in a portable generator and a 30A smart charger. This means we need to run the generator for approx four hours per week to satisfy our needs. This is now common practice with our fellow trailer/sailer friends. As a result, I recently purchased a YK2000i true sinewave digital inverter generator from a dealer in Melbourne and an iFonix iB-1230 smart charger from a dealer in Brisbane. The smart charger works perfectly on mains power and the generator also handles various power tools with no problem but when I connect the charger to the generator, the latter immediately drops out, showing an overload indication on the panel. This happens without the charger even being connected to a battery! I have tried connecting the charger to a different inverter type generator brand, eg, a Honda20i, with no problems. Therefore, it would appear that the YK generator is either unsuitable or faulty. While connected to the mains supply, I measured the charger’s AC current draw with a clamp-type ammeter. The measurement when switched on without connection to a battery was too small to register on that particular ammeter, while the draw when connected to a perhaps may be part of an amplifier design in SILICON CHIP or any other source? (K. C., via email). • We have not produced a 36V 2.5A power supply that specifically suits your needs. A supply could be made using a 30VAC 100VA transformer siliconchip.com.au partly-charged battery showed 2A. Therefore, no significant inrush current was detected. No checks were carried out using an oscilloscope, however. I have been in touch with both suppliers regarding the problem. The smart charger supplier was very helpful and placed me in contact with the manufacturers in Hong Kong. They were unable to advise what the cause of the incompatibility was likely to be but suggested that I start the generator with the charger already plugged in to see whether that helped. When this is done, the generator does not immediately drop out but does so after a few seconds. I know that a particular inverter we use on the boat (12V DC-to-240V AC) needs to be switched on and off at times to get it to work properly. This fact is, however, mentioned in the operations manual. The generator supplier unfortunately has only mechanical expertise and understands nothing about electronics. He could only offer to send my query to China to see what they suggested. However, I am not that optimistic about receiving an adequate reply or a solution. He does not possess a wiring diagram or modus operandi of the inverter protection monitoring so as to assist others with their troubleshooting. I have not been able to find a similar generator unit locally to check whether it displays the same problem with the charger. Here in Port Macquarie we have limited access to anyone with an electronic capability and I have had no luck to date in finding anyone who even vaguely has any meaningful explanation. As a result, I am approaching you in the hope that you can assist me to ascertain what the problem may be or to suggest someone that may be able to help. driving a bridge rectifier and filtered by three 4700mF 50V electrolytic capacitors. You could then use a variation of the Low Voltage Adjustable Regulator described in the May 2008 issue to regulate to 36V. Note that all capacitors would need (M. A., Port Macquarie, NSW). • Apparently, this problem of in­ compatibility between cheap generators and switchmode chargers is fairly common and difficult to solve. It is likely that the smart charger is taking power from the inverter in large gulps, ie, in pulse mode. An oscilloscope would be needed to confirm this. Without knowing the details of the circuit of the inverter/generator or charger, it is not possible to suggest a modification to the charger to reduce its pulse draw (if that’s what is actually happening). However, it may be possible to get the units to work together if you put a suitable limiting resistor in the output of the inverter/generator to enable it to work with the charger. For example, if the inverter/generator is rated for 2000 watts, we know it can supply at least 8A and probably more if it works OK with power tools. Therefore, we would be inclined to try the effect of a 10ohm 10W wirewound resistor in series with the charger input. Such a resistor may get quite hot but if it works you will be some way towards a solution. Note that this resistor will float at the 240VAC potential of the inverter and should be installed so as to avoid a shock hazard, eg, inside the charger case. We think the fault probably lies with the generator rather than the charger because the Honda generator worked OK. Possibly, you might be able to trade up to a Honda. In general, we would advise prospective purchasers to buy a generator and smart charger from the same supplier (in the same city!), with the stipulation that both units must work together. Otherwise the two suppliers are likely to blame each other’s piece of equipment. to be rated at 50V and the LM317 regulator should be an LM317HV type to cope with the higher input voltage. A 1N4004 diode should be placed between the output and input of the regulator (anode to output) and another 1N4004 diode between the October 2008  99 Incompatibility Between TV & Set-Top Box I recently purchased an inexpensive 68cm CRT TV (Rank Arena ex Target) which has RCA inputs at the rear of the set marked Y, C, & Cr which are selected as YUV-IN on the remote. I purchased a Tevion TEV8200 set-top box and used the Green Blue Red (Y Pb Pr) connectors. But cycling the various Component Video resolutions selected on the remote, I can only produce a full colour scrambled picture, in numerous unstable columns. I can use the TV AV inputs but I assume these will be of lower definition than one using the YUV-in. Internet information about the Y, Pb & Pr and Y, Cb & Cr signals suggests that “Y/Pb/Pr is used for analog applications while Y/Cb/Cr is used for digital applications. For Y/Pb/ Pr, all three components have the same voltage spread of about 714 millivolts RMS (or about 1.0 volts peak-to-peak) including the black pedestal (for NTSC broadcasts black adjust and output terminals (anode to adjust). The resistance between the adjust and ground for 36V would be 3.3kW 1W. A large heatsink would be required if 2.5A was drawn continuously. Ceramic filters for Jupiter receiver I am having a problem with the acquisition of two Murata 5.5MHz ceramic filters for the Planet Jupiter Receiver (SILICON CHIP, August 2008). I now learn that this description is er- is slightly above zero) but not counting the negative going sync pulse.” “For Y/Cb/Cr in an 8 bit system, the Y typically has a digital value spread from 16 to 235 which is slightly less than for Cb and Cr which each have a digital spread from 16 to 240. Component video comes in different non-interchangeable formats (scan rate formats) for regular TV or HDTV, for example: Interlaced or 480i from a standard NTSC DVD player, 480p from a progressive scan NTSC DVD player, 1080i or 720p HDTV. Also in PAL formats.” “Unfortunately there is a hodgepodge of standards for the exact definitions of Y, Pb and Pr. Picture quality loss occurs if a different formula is used to recreate RGB at the receiving end compared with what was used during video source production.” A friend who has recently purchased a CRT TV (Audiosonic ex Kmart), which has an unused Y/Cb/ roneous as they are properly described as “ceramic resonators! Looking for “ceramic filters” resulted in a lot of useless internet searching. I can only find a possibility of acquiring 100 or so of the correct units from the manufacturer. I would appreciate it if you can nominate a source of two only of the units anywhere worldwide. I have had no luck so far. (F. A., via email). • As far as we are aware, Murata themselves refer to the said devices as filters rather than as resonators. Having said that, there does not appear to be Cr input, is also thinking of purchasing a HD set-top box. I have looked through the back issues of SILICON CHIP in the hopes of finding a Y/ Pb/Pr to Y/Cb/Cr converter, without success. Any help will be appreciated. (T. F., Chinderah, NSW). • One of our staff members also has a Tevion TEV8200 set-top box and he uses its component video outputs to drive a Panasonic LCD projector, without problems. Provided your TV is set to PAL and the set-top box is set to minimum resolution, you should not have problems. Make sure your TV set is not set to NTSC; it must be set to PAL. You might also try the STB with your friend’s TV set, to determine if there is a problem with the STB itself. By the way, in a typical low-cost TV set, there will not be much difference in picture quality between normal A/V (ie, composite video) and component video. any outlet where you could easily buy just two filters. However, it seems possible that you could use a 3-pin resonator instead of a filter in this application, since the receiver is not critical as far as IF bandwidth concerned. We note that Futurlec can supply 6MHz 3-pin ceramic resonators and we think these could be made to work in the circuit with no mods required – see http:// www.futurlec.com/ICCrystalsResonators.shtml We should note that Altronics has a kit for this project, Cat K-1127. SC WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 100  Silicon Chip siliconchip.com.au 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. 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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:___________________ siliconchip.com.au 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 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 FACTORY OUTLET: flexible neon wire. Sheet (Backlight cuttable) flower. LGP Backlight. EL products. Phone 041 771 8607 Fax (07) 3397 5787. Email: cjappliance<at>gmail.com continued page 103 October 2008  101 ELNEC IC PROGRAMMERS 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 Degen 1103 Pocket Receiver Range 100kHz - 29,999kHz, direct entry, digital display. Listen to SSB, amateur radio, marine weather, HF aircraft, shortwave and many more. Supplied with rechargeable AA batteries, approved charger, 10m longwire, carry case and earphones. $159.00 + P/H. Contact Av-Comm Pty Ltd Tel: (02) 9939 4377; www.avcomm.com.au IMAGECRAFT C COMPILERS ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 GRANTRONICS PTY LTD www.grantronics.com.au C O N T R O L S You get results faster with the world’s easiest controllers! best v alue! MS120OEM216 $149 1-off Quality batteries to suit SONY BPL90 V LOCK & ANTON BAUER DIONIC Portable charger for mains or 12V vehicle supply also available C A L L PREMIER BATTERIES PTY LTD (02) 9755 1845 email: malcolmw<at>premierbatteries.com.au web: www.premierbatteries.com.au VIDEO - AUDIO - PC distribution amps - splitters digital standards converters - tbc's switchers - cables - adaptors genlockers - scan converters bulk vga cable - wallplates Developer’s Kit $193 includes programming cable & software DVS5c & DVS5s High Performance Video / S-Video and Audio Splitters Made in Australia - enthusiastic users world-wide splat-sc.com Surplus Electronic Components ABN: 38 445 311 223 www.excesselectronics.com.au Excess Electronic Components SMD Led (Pk-100) siliconchip.com.au PO Box 2417 AB687 Rowville Vic 3178 Tel: 041 567 7761 $ 3.00 Fax: 03 9755 8280 On-line Shopping FREE MONTHLY MAILER Range Of Excess Please Enquire Electronic Parts sales<at> excesselectronics.com.au 30mcd Dark Blue FREE FREIGHT FOR ORDER OVER $100 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! 01010101 Telelink Communications www.telelink.com.au e-mail Jack Chomley – jack<at>telelink.com.au or call (07) 4934 0413 or 0428 199 551 102  Silicon Chip Silicon Chip QUEST ® Quest AV® VGA Splitter VGS2 HQ VGA Cables AWP1 A-V Wallplate Come to the specialists... ® Quest Electronics® Pty Limited abn 83 003 501 282 t/a Questronix Products, Specials & Pricelist at www.questronix.com.au phonePM (02) 4343 1970 1:10 Page 1 email: questav<at>questronix.com.au fax (02) 43413/5/06 2795 SPK360 Circuit Ideas Wanted 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. 20 years experience! HI-FISPEAKER REPAIRS YOUR EXPERT SPEAKER REPAIR SPECIALISTS Specialising in UK, US and Danish brands. Speakerbits are your vintage, rare and collectable speaker repair experts. Foam surrounds, voice coils, complete recone kits and more. Original OEM parts for Scan-Speak, Dynaudio, Tannoy, JBL, ElectroVoice and others! SPK360 Do you have wireless problems? Telelink has wireless solutions! MD12 Media Distribution Amplifier tel: 03 9647 7000 www.speakerbits.com siliconchip.com.au Do You Eat, Breathe and Sleep TECHNOLOGY? Opportunities for full-time and part-time positions all over Australia & New Zealand Jaycar Electronics is a rapidly growing, Australian owned, international retailer with more than 50 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. RFMA 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 PO Box 107, Rydalmere, NSW 2116 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. 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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 Place104  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 October 2008  105 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