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SILICON CHIP FEBRUARY 2008 PRINT POST APPROVED - PP255003/01272 8 $ 50* NZ $ 9 90 100mpg+ INC GST INC GST FROM A PRIUS – We show how! PLUS: Rev limiter Solar battery charger Long-range UHF remote mains switch PIR-triggered “anything” controller siliconchip.com.au February 2008  1 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents Vol.21, No.2; February 2008 SILICON CHIP www.siliconchip.com.au Features 10 How To Get More Than 100MPG From A Toyota Prius Adding a large lithium-ion battery lets you drive much further on battery power. Here’s how it was done – by Jim Fell 16 Review: ATTEN ADS7062CA Digital Storage Scope It packs many of the features found on expensive scopes, all for just over $1300 – by Mauro Grassi UHF-Remote-Controlled Mains Switch – Page 24. 78 PICAXE VSM: The PICAXE Circuit Simulator, Pt.2 Here’s how too use the new PICAXE VSM simulation software. It’s a great way for beginners to experiment as well – by Clive Seager Pro jects To Build 24 UHF Remote-Controlled Mains Switch Want to switch mains appliances on and off remotely? This unit can do it for you. It can operate as a standalone unit or can be teamed with the Water Tank Level Meter Base Station to control water pumps – by John Clarke 34 UHF Remote Mains Switch Transmitter It’s designed to control the UHF Remote Mains Switch, has a range of over 200 metres and is easy to build and get going – by John Clarke PIR-Triggered Mains Switch – Page 57. 57 A PIR-Triggered Mains Switch Build it and switch just about any plug-in mains-powered device when a passive infrared sensor detects a person approaching – by Jim Rowe 66 Shift Indicator & Rev Limiter For Cars This easy-to-build Shift Indicator lights one or more LEDs when it’s time to change gears. It also includes a rev limiter – by John Clarke 92 Mini Solar Battery Charger It uses an efficient step-up converter and teams with a compact 6V solar panel to charge 12V SLA or conventional car batteries – by Branko Justic Shift Indicator & Rev Limiter For Cars – Page 66. Special Columns 39 Serviceman’s Log Hopelessly devoted to you – by the TV Serviceman 44 Circuit Notebook (1) Using The Enhanced Voice Recorder In A Model Railway; (2) Rechargeable Cell Logger & Discharger; (3) Infrared Light Beam Relay; (4) Novel Neon Flasher With Low Current Drain Mini Solar Battery Charger – Page 92. 86 Vintage Radio DC-to-AC inverters from the valve era, Pt.2 – by Rodney Champness Departments   2 Publisher’s Letter   4 Mailbag   8 Order Form 77 Product Showcase siliconchip.com.au 97 Ask Silicon Chip 100 Notes & Errata 101 Market Centre February 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 Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Mauro Grassi, B.Sc.(Hons.) Photography Ross Tester Reader Services Ann Morris Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $89.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. Fax (02) 9939 2648. E-mail: silicon<at>siliconchip.com.au Publisher’s Letter Microcontroller projects can be simple and complex at the same time This month, we have two or three projects (depending on how you count them) which are based on PIC microcontrollers. They are the Shift Light Indicator and Rev Limiter, the UHF Remote Mains Switch (or Pump Controller) and the UHF Remote Transmitter. Last month (January), we had the PIC-Controlled Swimming Pool Alarm and the Water Tank Level Meter Base Station (again PIC-controlled). And then back in November 2007, we had four microcontroller projects of varying complexity, from the Playback Adaptor for CD-ROM Drives to a UV Light Box Timer. In fact, if you wanted to survey the last few years of SILICON CHIP projects, you would find a similar frequency of designs using Atmel, PIC or PICAXE microcontrollers. The main reason why so many microcontrollers are featured in our constructional projects these days is simply that they make it possible to bring these projects to fruition. Without them, these projects would be impossibly complex or just simply uneconomic. A good example of this is the CD-ROM Playback Adaptor. It simply would not be possible to produce this project without the powerful Atmel microcontroller and a lot of software to boot. It is also evident that microcontrollers also make the circuits seem quite simple while allowing very complex features to be incorporated. The Shift Light and Rev Limiter project in this month’s issue is a case in point. The PIC microcontroller allows very rapid measurements of engine RPM (necessary because engine RPM can vary over an extremely wide range with just a blip of the throttle) while performing two control functions: shift light indication and/or rev limiting. In fact, you could argue that we have made the control functions too complex and possibly we should have split the design into two separate projects. The reason I am canvassing this topic is that we would like to know what you, the readers, think of this general trend to microcontrollers. Do you accept that micros are the way to go for many of our projects or would you prefer, if it were possible, that SILICON CHIP’s projects not use a micro and instead use a more complex circuit with possibly a lot of conventional logic ICs? Or are our projects simply too complex, whether they use micros or conventional circuitry? We are also aware that we are devoting a lot of space to our electronic projects and they tend to incorporate a great deal of instructional detail so that novice readers have as few problems as possible. And of course, we also know that no matter how much detail we include, there will always be some questions unanswered for some readers. Or inevitably, there will always be some readers who want the project to provide for some other function which would have made the design more complicated. Finally, do we have too much emphasis on electronic projects and not enough on new developments in electronics? At the risk of unleashing a deluge of email, we would like to hear your opinions on these questions. And if you have suggestions for articles or projects, please let us know about those as well. Leo Simpson ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip siliconchip.com.au USB Mixed Signal Oscilloscope Analog + Digital Inventing the future requires a lot of test gear... ...or a BitScope Digital Storage Oscilloscope 9 Dual Channel Digital Scope with industry standard probes or POD connected analog inputs. Fully opto-isolated. Mixed Signal Oscilloscope 9 Capture and display analog and logic signals together with sophisticated cross-triggers for precise analog/logic timing. Multi-Band Spectrum Analyzer 9 Display analog waveforms and their spectra simultaneously. Base-band or RF displays with variable bandwidth control. Multi-Channel Logic Analyzer 9 Eight logic/trigger channels with event capture to 25nS. 9 Built-in flash programmable DSP based function generator. Operates concurrently with waveform and logic capture. DSP Waveform Generator BS100U Mixed Signal Storage Scope & Analyzer Innovations in modern electronics engineering are leading the new wave of inventions that promise clean and energy efficient technologies that will change the way we live. Mixed Signal Data Recorder It's a sophisticated world mixing digital logic, complex analog signals and high speed events. To make sense of it all you need to see exactly what's going on in real-time. User Programmable Tools and Drivers BS100U combines analog and digital capture and analysis in one cost effective test and measurement package to give you the tools you need to navigate this exciting new frontier. 9 Record to disk anything BitScope can capture. Supports on-screen waveform replay and export. 9 Use supplied drivers and interfaces to build custom test and measurement and data acquisition solutions. Standard 1M/20pF BNC inputs Smart POD Connector Opto-isolated USB 2.0 12VDC with low power modes BitScope DSO Software for Windows and Linux BS100U includes BitScope DSO the fast and intuitive multichannel test and measurement software for your PC or notebook. Capture deep buffer one-shots, display waveforms and spectra real-time or capture mixed signal data to disk. Comprehensive integration means you can view analog and logic signals in many different ways all at the click of a button. The software may also be used stand-alone to share data with colleagues, students or customers. Waveforms may be exported as portable image files or live captures replayed on another PC as if a BS100U was locally connected. BitScope Designs Ph: (02) 9436 2955 Fax: (02) 9436 3764 www.bitscope.com February 2008  3 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”. Recycling computers and printers Congratulations on your 20th year of successfully producing a truly world class electronics magazine. I have every copy except for No.1. I do wish you and your staff continued success for many years yet to come. The purpose of this letter is to draw attention to the situation regarding E-Waste and that our organisation is actually doing something about the problem. While councils and governments are scratching around like a bunch of sun-struck chooks, trying to work out what to do with unwanted computers, printers, monitors, plus a host of other items that make up E-Waste, Reverse Garbage (RG) at Marrickville in Sydney is turning the problem into the solution. RG collects and refurbishes unwanted PCs, which we then sell cheaply to the public. A lot of people may not want (or need) a brand new computer or can afford a newie. That is where RG excels. Reverse Garbage can sell a complete package for under $100 or a little more if we have to build it to a Electricity saving circuit is unsafe I read the article on the Electricity Saving Device in the November 2007 issue (pages 22-27) and I totally agree with the findings. However, the circuit for the device was published in the article. I don’t have a problem with this but there was no mention of any safety warnings about working with circuits connected directly to the 240VAC mains supply. Also, there was no mention of the type of capacitor suitable for connecting across the mains supply. If a reader was to construct this device (don’t for a minute think that no-one will!) and did not use a “X” type capacitor which has suitable charac- 4  Silicon Chip customer’s specs (some people prefer to build up their own computers or wish to upgrade cheaply). N. Bush, Canterbury, NSW. Reverse Garbage is at the Addison Road Community Centre, Building 8, 142 Addison Road, Marrickville, NSW 2204. Phone (02) 9569 3132. www.reversegarbage.org.au IR remote testers are not necessary This is a note to save people building circuits to test IR remote controls; such testers are not needed. All you need to do is look at the IR signal through an electronic camera. I used to have an old mono surveillance camera in my workshop and could check the signal strength and button functions by looking at a monitor. With so many people carrying camera phones, who would want to build an IR tester? Ray Banks, Wagga Wagga, NSW. Comment: you make a very good point. Virtually any digital or video camera teristics for this type of application, there may be severe consequences if an incorrect type of capacitor was used and it failed. I recommend that you publish errata or better still, write an article to describe the use of capacitors when mains voltages are concerned; eg, “X” and “Y” types. Rob Zanchetta, via email. Comment: we have published your letter but we cannot believe that anyone would be stupid enough to build such a circuit. Then again, perhaps someone would be. Incidentally, there is no labelling on the capacitor in the device concerned – the whole thing is dodgy. can be used to check if the IR LED on a remote is working. Dissent from Peter Seligman’s articles Editor’s comments: the following letter from Dave Waplington has been reproduced with Peter Seligman’s comments interspersed in italics. I am writing in response to your article “How To Cut Your Greenhouse Emissions”, by Peter Seligman (September 2007). How cynical and biased can an article get? Or was it just poorly researched? Here are the major points that I disagree with. I welcome this kind of response – it is what I was hoping to generate. Am I cynical and biased? Cynical? Yes – when I see “information” based on hype. Biased? Not intentionally. I do calculations based on the best information I can get hold of. I don’t have any particular barrow to push. I would just like to see our efforts go towards sensible use of energy, in the most effective way. Quote “. . . the pure electric vehicle which has the range, convenience and performance of a conventional car is still way off in the future”. Purely electric vehicle conversions that I have personal knowledge of have all the range, convenience and performance I need. Statistics tell us that the average daily drive is 28km. EVs easily travel 50-90km between charges. These same vehicles outperform their donor petrol engine counterparts and what can be more convenient than plugging it into your own power point when you get home? You start each day with a “full tank” and no more queues at a busy service station. No more oil changes, tuning, fan belts, fuel injection, radiator and exhaust problems – you get my drift? I am delighted to hear that purely electric conversions exist. Please let the readers know who does this and where they are available! That they siliconchip.com.au Problem with BT137 Triacs Whenever you feature a circuit containing a 240VAC interface you always put in large bold letters a precautionary note regarding the danger of working with high voltages. The need for this caution became blatantly apparent recently when I was working on a circuit containing a PIC microcontroller to control 240VAC lighting. In order to produce a circuit that was inherently safe, I elected to use a MOC3021M optocoupler to give optical isolation between the low and high voltage circuits and a BT137X Triac which has an isolated case. Having purchased the components from a well-known electronic component supplier, I downloaded the data sheet. According to this, the BT137 Triac has a maximum voltage of 1500V between any of the pins and the mounting tab. The circuit was duly made and trialled with no problems. Then just to be absolutely safe, this entire output circuit was encapsulated using epoxy resin into a 20mm square aluminium tube about 60mm long. The two low voltage wires came out one end of the tube and the two high voltage wires out the other end. The Triac was mounted to the wall of the tube using a small screw. I then used the multimeter to test the resistance between the VAC wires and the aluminium tube and found that there was a complete short circuit; ie, there would have been 240VAC on the aluminium tube! The BT137 was found to have an unisolated tab! have all the range “I need” or for the “average daily drive” makes them a suitable second vehicle but not the only vehicle in most households. And I totally agree with the statement about oil changes, etc. The article states that petrol burnt during a year’s motoring equates to 10,000kWh of energy. Petrol cars approach 25% efficiency but electric cars are between 80% and 90% efficient depending on their drive configuration, with AC being more efficient siliconchip.com.au I went back to the supplier (a different branch) and again the same Triac was presented to me. We tested the resistance between the case and the centre pin and it was a complete short circuit, not isolated as the data sheet stated. Being totally confused with this, I went onto the web again and found that there are at least three different types of BT137 Triac, all from Philips Semiconductors: (a) BT137 with its tab connected to the middle terminal (A2). There is absolutely NO electrical isolation on this pin (this is the component I was sold). (b) BT137F – this component looks exactly the same as the one above but it does have an electrically isolated metal tab. (c) BT137X – this component has a thick plastic tab which offers the best electrical isolation, however the thermal characteristics are somewhat worse than the ones above. To summarise: when dealing with high voltage, don’t always believe what seems to be obvious, Check, check and check again. Alfred Hirzel, Auckland, NZ. Comment: we contacted the retailer concerned in this matter and they have advised that all stocks of their BT137 Triacs have been withdrawn for checking. We advise anyone who has stocks of BT137 Triacs to check whether their tabs are isolated from the A2 terminal. If not, they must not be used in any application which requires a Triac with an isolated tab. than DC. This makes EVs almost four times more efficient than a petrol car. Dr Seligman suggests that EVs only require 3000kWh of energy to do the same running, which is three-tenths of the energy required by the petrol car. Now that’s not bad is it? If we do some sums, using his figures, this equates to 8kWh per day, which leads to the next point. The missing factor of 3 or 4 here is the efficiency of the power station. Black coal fired power stations have 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 February 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 Introducing the MT System A series of C programmable chips based on the latest generation of 8051, Atmel AVR or ARM core flash microcontrollers.  Onboard 16-bit run-time interpreter for fast program development  Multiple, selectable program storage  Free IDE includes text editor, compiler, simulator, test terminal and serial downloader (no programmer required)  Lots of sample programs  Demoboards available for quick and easy project development Prices & documentation available on website www.ozitronics.com A NOTE TO SILICON CHIP SUBSCRIBERS Your magazine address sheet shows when your current subscription expires. Check it out to see how many you still have. If your magazine has not turned up by the first week of the month, contact us at silchip<at>siliconchip.com.au 6  Silicon Chip Mailbag: continued an efficiency of about 33%. However, efficiency from station to the end user is about 92% giving an overall efficiency of about 30%. For brown coal, which powers most of Victoria, it is about 25%. I could have been more explicit about regional variations. New gas-fired power stations are better – see http://www.aie.org.au/melb/material/resource/pwr-eff.htm I recently bought a 2.1kW solar panel array. It cost $25,000 including inverter and installation and the federal government gave a rebate of $8000, which brought my cost down to a fraction of what Dr Seligman stated. I might just mention that today’s PV cells are 17% efficient, with laboratory units now approaching 40%. A 2kW array will generate 2kWh every hour under ideal conditions. After just four hours, my EV is fully charged. The rest of the time I sell the excess energy to my electricity supplier, as the article suggested but at the peak rate! I am delighted to hear that the price of installed PV power has come down so much. Let’s look at these figures. For Melbourne or Sydney the factor between peak and average power is about 7. So a 2.1kW array has a mean output of 300 watts. The inverter has an efficiency of about 90% and realistically, solar installations are de-rated at 90% because output drops with temperature. So that makes the effective output 243 watts or 2129kWh/year. At current Melbourne prices of 13 cents per kWh that’s $278 worth of electricity per year. Cost of installation after the rebate and credits is $16,000. To get that back, as a very crude guesstimate: 16,000/278 = 59 years. Now I admit that electricity will probably go up faster than inflation and indeed it should. The real point here is that electricity in Australia is ridiculously cheap – making renewable energy and conservation almost always not worth it. To put it another way, $16,000 invested at 6% returns about $960 year which means the electricity costs 960/2129 = $0.45 / kWh or 45 cents/kWh. Without the government rebates this would be 70 cents/kWh. Victoria has just commenced a new solar power station (see http://www. solarsystems.com.au/projects.html). This is a 154MW Heliostat plant which will cost $420 million. This gives a price of 7.9 cents/kWh. It is more sensible for us as a nation to put money into installations such as this rather than home-installed systems where the cost effectiveness is one-eighth of a large station. We need to spend our dollars effectively. With respect to carbon emissions, an EV charged from solar panels not only saves the 2.6 tonnes/year of CO2 that I would have generated (if I had used petrol) but also saves 4 tonnes/ year by not using coal. Let me just say something in support of the power companies, not all power is generated by coal. Gas turbine, combined cycle, hydro, wind and some small PV systems are used. No doubt the average CO2 emission from power generation is less than the figure quoted in the article. By the way, buying solar panels gave me carbon credits too; mine were worth $1000! You can’t have this both ways. Either you can charge your car from solar, saving 2.6 tonnes (over petrol) OR you can put the power into the grid saving 4 tonnes of CO2. But you can’t do both. My point was that, of the two options, putting the power into the grid wins. Now you may have a point re the CO2 produced from power generation. Victoria is the worst state in the (equal to USA) worst country for this. The figure of 1.3 kg/kWh is real and verifiable from many sources. But I accept that not all power utilities are that bad. For example, in the UK, the contribution is only 0.43kg/kWh, due to 40 % of gasfired power stations, 20% nuclear and 3.5% from renewables. For natural gas, the figure is 0.6kg/kWh. At that level, my argument breaks down. Then it becomes a choice between an LPG vehicle with an efficiency of 25% OR burning the gas in the power station at 33 % efficiency, reduced by 0.92 (transmission and maintenance), 0.9 (change discharge efficiency), 0.9 (electric motor efficiency) which gives an overall efficiency of about 25%. We won’t argue about the few persiliconchip.com.au Mobile phone towers are not a hazard While I share Brendan Falvey’s caution (Mailbag, November 2007) about mobile phone safety, I found it disappointing that his letter had characteristics and content similar to most phone tower protests. Contrary to Mr Falvey’s assertion that “very little detail of such tests is available”, journals such as Radiation Research (which I discovered with very little effort looking at the Australian Radiation Protection and Nuclear Safety Authority’s website a few years ago) can be accessed from more than 45 university and other libraries across Australia. This is a reputable scientific research journal which reports the full details of testing including frequency, intensity, duration and type of RF signals. ARPANSA’s website is at http://www.arpansa.gov.au/mobilephones/index.cfm. Another useful source is http://www.acma.gov.au/ WEB/STANDARD His view that “the risk was higher from base stations” seemed to contradict his discussion of the nearfield and far-field for handsets. In terms of safety and near-fields and far-fields, all base stations have to meet the ARPANSA safety limit. One base station in WA that was the subject of one of the largest protests in Perth was shown to have emissions thirty thousand times lower than the safety limit during low traffic cent my assumptions make. The point here is that you are back to where you started. Whether you burn the fuel in the car or the power station doesn’t make much difference. The real differences are practical. Electric cars are quiet, low maintenance and low pollution on the roads. The pollution is at the power station. Their range is limited to commuting type applications. On the other hand liquid, petrol or gas-powered cars have a lot of disadvantages but have enough range to go on a holiday. If you need two cars, one of each would be ideal. Dr Seligman could have said that converting a petrol car to an EV is the ultimate recycle job. How much CO2 siliconchip.com.au and still well below the safety limit during heaviest traffic. His view that “the risk was higher from base stations” is not supported by available evidence. In relation to the information available that is used by those working in the area, they do not “traditionally think in terms of far field radiation” but only measure the field that is there to be measured, and then with calibrated instruments. The relevant Australian standard (ARPANSA RPS 3) specifies measurement in terms of the E and H fields so it already takes into account both near and far fields. The ARPANSA web page at http:// www.arpansa.gov.au/mobilephones /index.cfm#6 contains this conclusion: “Users concerned about the possibility of health effects can minimise their exposure to the microwave emissions by: limiting the duration of mobile telephone calls, using a mobile telephone which does not have the antenna in the handset or using a ‘hands-free’ attachment. There is no clear evidence in the existing scientific literature that the use of mobile telephones poses a long-term public health hazard (although the possibility of a small risk cannot be ruled out).” I hope these sources will be helpful in providing more complete and accurate information. E. McAndrew, Cunderdin, WA. does that save? And let me finish with another saving – even if you do charge your EV from the grid, the running cost per km works out to about 2-4 cents, even cheaper if you charge off peak. What does petrol cost? $1.25 per litre (say) equals 12.5 cents per km in fuel costs alone (using Dr Seligman’s figures). Think again about EVs Dr Seligman. Dave Waplington, Karrinyup, WA. I agree that converting a petrol car to an EV is a great recycling job. Re the costs, look at it this way: say we compare a car run directly from LPG vs an electric car charged from electricity supplied by gas (LPG and natural gas We’re told we make the best speakers in the world… Now you can too “The best speakers I have ever heard” DVD Now “The best bass in the world” Rolling Stone Magazine “We have yet to hear another system that sounds as good” Best Buys Home Theatre Seven models from $769pr www.vaf.com.au FreeCall 1800 818 882 vaf<at>vaf.com.au February 2008  7 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 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, Australia 2097 02/08 Mailbag: continued are similar). LPG cost about 50 cents per litre or say 5 cents per km. I agree with your calculation of 4 cents (not 2) per km for charging. But can you legally get off-peak rates for electric vehicle charging? Finally on this pricing topic, I want to point out that if you use LPG or electricity for vehicles, you are not paying anything for road maintenance, in contrast to those who use petrol and diesel. So yes Dave, I have thought a lot about EVs. Do you still think my article was poorly researched? Thanks for the stimulating questions – I think this is the kind of discussion we need to have. Peter Seligman. EVs can cut greenhouse gas emissions I’m amongst the number of readers that are uncomfortable with the impression that Peter Seligman presented in his series of articles on “How to Cut Your Greenhouse Gas Emissions”. As an engineer with a passion for energy efficiency and renewable energy, I often have the overwhelming feeling that there is no solution available to our current energy consumption crisis. However, my rational side tells me that the best solution is to look at the big picture and to work in small steps towards a better solution. This is why I have a problem with the essence of Peter’s article on electric cars, as I believe they are an important step in improving our overall energy efficiency. Firstly, I believe that Peter Seligman’s number for the efficiency of petrol cars are incorrect and that Peter Kay’s numbers are closer to the mark, so at present your CO2 emissions are almost equivalent in an electric vehicle and a petrol vehicle. This isn’t the end the of the world; in fact, it’s a very good first step. I live in Brisbane and I pay ~15.5c/ kWh for electricity. Let’s say my electric car is 85% efficient. This means that it costs me 18.2c/kWh for the energy that the car uses. Using the approximate number of 10kW/l of petrol and the generous 25% efficiency for the petrol engine at a cost of $1.20/ litre, this costs me 48c/kWh to run the car. This is 2.6 times more then an equivalent-sized electric car. As the economics of scale work for electricity generation, so the most feasible way to generate renewable energy is in a large-scale grid-connected facility. As Peter Seligman finds, solar generation on a small scale is not currently economically viable. However, concentrated PV power currently costs approximately 2-3 times as much as coal power. So while at present, it is not cheaper to generate electricity from renewable energy sources, the renewable energy costs around the same as petrol. I see that you can look at this two ways: if you want to save money, buying an electric car and powering it from fossil fuel-generated electricity will save you ~60% on your fuel bill while having minimal effect on your CO2 emissions. Alternatively, if you want to save greenhouse gases, choose the “green energy” from your electricity supplier (currently AGL in Brisbane charges 5c/ kWh for the 100% green energy option or ~32% more) and you will save both on greenhouse gas emissions and your total energy bill! Apart from the immediate advantages, the main benefit is that electric cars are able to use energy generated by ANY source, so when we find a more economic renewable energy source, we will be able to realise the benefits to a greater extent then if we stick to fossil-fuelled cars and in the meantime, we can save some money. Chris Lister, SC Chermside West, Qld. “I’ll GO THE RIGOL ... UNBEATBLE FOR PRICE AND PERFORMANCE” Rigol DS5062MA 60MHz Rigol DS5102MA 100MHz Rigol DS1202CA 200MHz Rigol DS1302CA 300MHz 60MHz Bandwidth, 2 Ch 1GS/s Real Time Sampling 4k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 100MHz Bandwidth, 2 Ch 1GS/s Real Time Sampling 4k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 200MHz Bandwidth, 2 Ch 2GS/s Real Time Sampling 10k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty 300MHz Bandwidth, 2 Ch 2GS/s Real Time Sampling 10k Memory Per Channel Advanced Triggering Built-in USB 3 Year Warranty ONLY $799 Sydney ex GST Melbourne Tel 02 9519 3933 Tel 03 9889 0427 Fax 02 9550 1378 Fax 03 9889 0715 email testinst<at>emona.com.au siliconchip.com.au ONLY $1,099 Brisbane ex GST Tel 07 3275 2183 Fax 07 3275 2196 ONLY $2,036 Adelaide Tel 08 8363 5733 Fax 08 83635799 ex GST Perth Tel 08 9361 4200 Fax 08 9361 4300 web www.emona.com.au ONLY $2,620 ex GST EMONA February 2008  9 How to get more 100 MPG from a Toyota Prius By Jim Fell The Toyota Prius has been the most successful and popular hybrid car produced so far but it has one weakness – it cannot go very far on battery power alone. This article tells how a large Lithium-ion battery was added to a Prius, giving it the ability to drive much further on battery power, thereby greatly increasing fuel economy. I first converted a car to purely electric operation in 1999 and after several improvements, particularly to the battery pack, the car was moderately successful. I was generally able to travel about 80km on a charge and considerably more if care was taken. The car completed the London to Brighton Electric Vehicle (EV) Run in 2005 and 2006. Unfortunately the Achilles heel of any EV is still the battery pack. With low-cost lead-acid batteries the range is severely limited and a long crosscountry run must be planned like a military campaign. There must be charging points every 80km or so and you need to stop for a couple of hours at each to restore some charge. In 2005 I started looking at the hybrid cars that were available and the Toyota Prius in particular. The interesting thing about the Prius was that it could run for a limited period as an EV, however with the NiMh 10  Silicon Chip battery pack the electric motor can take the car only about 1.6km at less than 50km. I wanted to reduce the fuel consumption of the Prius from 60 to 100 MPG, a massive cost saving, by the addition of a large Li-ion batterypack. This article describes how I achieved this using E-blocks and Flowcode as a control system. How it works Fig.1 shows how the Toyota Prius works. Essentially it is a normal car Fig.1: a much simplified diagram of the Toyota Prius drivetrain – essentially a normal car with an electric motor/generator added. siliconchip.com.au than with the addition of an electric motor/ generator in the drive train. When the driver needs to slow down, the brake pedal puts the electric motor into generator mode which charges the battery up. Conversely, at low speeds the electric motor is used to assist the conventional petrol engine to decrease fuel consumption. When I started the project a few groups in the USA were experimenting with supplementary battery packs to increase the range of the Prius. The Toyota, along with most modern cars, has a very complex electronic control system. The part that deals with drive and battery management uses CAN bus. The operation of the drive amongst other things is based on the State Of Charge (SOC) of the battery pack. If the SOC is low, the management system will recharge when descending a hill, braking or use any surplus energy from the engine. If the SOC is high, then the battery pack will be used to drive the car at low speed or to supplement the engine when driving, climbing hills or overtaking. In practice, the SOC is varying continuously, dependent upon traffic and driving pattern. I saw two main problems in adding a large battery pack in parallel with the existing NiMH battery. The first was: what would the reaction be from the Toyota management system if the existing battery started receiving siliconchip.com.au charge from an outside source – the second battery? The second problem was how to control this external charging source. The control system needed to be such that the existing batteries’ SOC could be manipulated so that the Toyota management system “saw” a high SOC and used the battery instead of the engine wherever possible. The first problem was simple. I connected my external charger across the Toyota battery pack and charged the pack. The SOC increased up to fully charged (about 80% SOC). The battery manager took into account the pack temperature and voltage and computed the SOC quite happily. So solving the second problem – transferring energy to the Toyota’s battery – was the main area of work. Circuit details I was lucky enough to have acquired Fig.2: graphical representation of the display unit. February 2008  11 12  Silicon Chip siliconchip.com.au Fig.3: block diagram/circuit of the modified Toyota Prius. The DC/DC converter was required because the author’s Li-Ion battery pack was some 40V less than the NiMH pack standard in the Prius. A word of warning: these batteries do pack an enormous amount of energy at dangerous voltage. Getting across these can kill! The dashboard is standard Prius but it has the addition of the multiprogrammer and CAN unit (with LCD readout on the front) in the DIN space where a CD player, cassette, etc would normally be located. a set of 56 Thunder Sky Li-ion cells which I could use as a second battery. These are connected in series to give a around 210V DC and more than 50Ah (ie, 10.5kWh). The Toyota’s NiMh battery produces around 240V DC so I knew that I would need an inverter to allow the additional battery pack to charge the Toyota’s own battery. In addition, I wanted to be able to recharge the Li-ion batteries overnight so I needed a recharge circuit. I also needed a circuit to control the flow of charge into the Prius’s own battery. Fig.3 shows the block diagram of the system. The extra battery pack was con- nected to the existing pack was by using four single pole high voltage power contactors and a high power DC/DC converter. The DC-DC converter is actually a battery charger which has a bridge rectifier as the first component to convert the normal AC mains input to DC. The DC-DC onboard converter is used to charge the Li-ion battery if required but that’s another story. The converter had a 2-stage selectable output. In high the converter would try to lift the existing pack to a high voltage and thus a high SOC. In low this voltage was lower and allowed the existing pack to lose charge letting the SOC% to fall back. The output of the DC-DC converter is controlled by switching in one of two sets of points. When the battery is being charged overnight it is isolated from Toyota circuit by a second set of points. The NiMh to Li-ion battery contactors would be energised the whole time during vehicle operation, until the extra battery pack was fully discharged and no longer able to contribute – at which time the batteries were disconnected. Controlling this system meant hack- Before and after: the Toyota Prius with standard boot (left) and after the addition of the 200V Li-Ion battery pack. As you can see, a fair amount of boot space is sacrificed for the battery upgrade. At the extreme left (green box, almost hidden) is the inverter. siliconchip.com.au February 2008  13 The DC-DC inverter is actually a commercial battery charger with a two-stage selectable output. Because it has a bridge rectifier “up front”, it can also be pressed into service to charge the Li-Ion pack from the mains, if required. ing into the Toyota CAN bus. The car has many devices on the CAN bus and fortunately they all broadcast their data onto the bus. The devices that need the data read it and react accordingly. As far as I am aware, no device solicits information from another device. What was needed was a custom CAN bus device that could read parameters on the system and move charge into the existing battery pack at the right time. At this time I read an article in Elektor on Flowcode (February 2006).This referred to a CAN bus system consisting of two nodes of a network. From past experience with other bus systems it can take a long time to get a system up and running. I have some experience with Microchip PIC devices and there is a wealth of information on their website concerning CAN bus. The data sheet on the CAN interface chip (MCP2515) runs to 81 pages. I ordered the Flowcode CAN system and saw immediately that all the hard work of using the CAN bus had already been done. Setting up the parameters for the bus and reading specific messages is carried out by prewritten macro commands. Getting the communication between two points was very straightforward. In order to monitor SOC in the Prius, a Kvaser Light CAN to USB unit was used to look at the traffic on 14  Silicon Chip the CAN bus. There is a convenient OBDII connector with 12V power located just under the steering wheel in the Prius. There is some documentation regarding the messages on the bus on the internet. The format of the data varies and a bit of manipulation is needed to convert the data to a form which can be displayed on an LCD panel. With some idea of what I wanted initially from the bus, I set up a system in the workshop which mimicked the function of the CAN bus in the Prius: one of the E-blocks systems continuously transmitted an SOC message in the same format as the Toyota message while the other system showed the system parameters on an LCD. This was used in the development and commissioning phases of the project on the bench and fitted into the radio compartment of the car. The display shows Battery Current, Battery Voltage (charging/discharging), State of Charge %, Charge Current Limit, Discharge Current Limit, Max Battery Temperature and Min Battery Temperature. In this way the whole system could be built up and tested away from the car. The second stage of the program used only one of the items (SOC%) and gave one of two outputs, high or low, depending on the value of SOC. In order to maintain the existing battery SOC at around 70%, a pair of decision instructions in Flowcode put on the low output if SOC% >70 (and disconnected the Li-Ion cells from the charge circuit) and put on the high output if SOC%<65 (which switched the Li-ion cells into the circuit and charged the NiMh Prius battery). In each case the opposite output would be turned off. One additional output was used to drive a relay to then energise the four main contactors. This output Inside the E-blocks controller/CAN bus/display unit. These are commercial modules adapted as required for use in the Prius. siliconchip.com.au The Software The two packages used by the author in the development of the Prius and mentioned in this feature, “Flowcode 3” and C “for 16 Series PIC micro” are available from Matrix Multimedia Ltd in the UK. Here’s a close-up of the Prius electronic dash, with the consumption (99.9 MPG) highlighted. It’s actually better than that: 99.9 is as high as the Prius dash goes! would come on five seconds after the system powered up and would go off in response to the additional battery pack becoming discharged. There was no need for a display on the final controller and this now lives in an enclosure in the boot next to the extra batteries and power contactors. As noted above, the extra battery pack is a set of 56 Thunder Sky Li-ion cells. These cells are about two years old and vary in capacity, the worst being about 50Ah at 20°C when discharged at 25A. The worst cell defines the pack capacity so with the current limit set to 25A the car will run for two to three hours in assist mode until the battery pack switches off. The car then runs in normal hybrid mode as before. The drawback of the system is that these batteries are very expensive, and physically large and heavy. The batteries also take up much of the The E-blocks used are also available from Matrix Multimedia. Contact Matrix Multimedia via their website, www.matrixmultimedia. com boot space, as you can see in one of the photos. Conclusion In summer the car will return about 60 MPG (4.7l/100km) in normal hybrid mode and about 100 MPG (2.8l/100km) in battery boost mode. Unfortunately, the Prius’s readout only goes to 99.9 MPG so you cannot tell how well it’s really doing. Another job for Flowcode will be to read the instantaneous fuel flow from the bus along with the speed and compute the real fuel consumption. Further gains can also be made by reading the bus speed signal and pulsing a relay when the speed drops below 50km/h to force the car into EV mode. The relay would be pulsed again on the speed rising to 50km/h to take the car out of EV mode; that is SC another job for Flowcode. REFERENCES: A screen grab of various “Flowcode 3” flowcharts used. This software is designed for easy development of PICmicro-based systems (see above right). siliconchip.com.au Elektor February 2006 Easy CAN Microchip www.microchip. com Plug in Prius Wiki group at www.eaaphev.org/wiki/Main_Page Follow links to plug in hybrids then Prius. February 2008  15 Review by Mauro Grassi ATTEN ADS7062CA Digital Storage Oscilloscope The ADS7062CA Digital Storage Oscilloscope from ATTEN incorporates many features found only in dearer oscilloscopes. It represents very good value for money and its bandwidth is high enough for most applications, including video. T he ADS7062CA is a dual channel colour 60MHz DSO with real-time sampling up to 1GS/s. It is rare to find a comparable DSO at this price range that also boasts a colour screen. The display is a 5.7-inch quarterVGA colour LCD with adjustable contrast. Considering all the functions available, the front panel has a simple and easy-to-follow layout. The vertical attenuator and trace position knobs are colour-coded (yellow and cyan) to match the corresponding traces on the screen. All the knobs are digital by the way; there are no potentiometer controls, which means they should be durable and reliable. The vertical attenuator knobs work in two modes. The standard mode gives the usual 1:2:5 sequence from 20mV/div to 50V/div. Pressing the knob then provides a vernier function, to give much finer control, allowing you to shows the measured waveform using the full screen, for example. Three BNC inputs are accessible from the front, rated at 300V RMS, one for each channel and one for an external trigger. The scope does not have probe sensing but you would not expect that feature on a low-cost scope. Seven of the buttons are backlit, together with an indicator for the multi-purpose User Select knob which adjusts Fig 1: the yellow trace shows a PWM signal at around 3.48kHz. The cyan signal is the output at the drain of a Mosfet connected to a motor being switched by the PWM signal. Five measurements are shown at right. The large spikes in the back-EMF of the motor are visible and are measured to be as high as 65.6V. Fig 2: the same set-up as in Fig 1 but showing the vital statistics of channel 1 on the screen. The peak-peak voltage, frequency, period and average voltage are shown. The trigger level can be read at the bottom of the display, showing the trigger is a rising level above 6.4V on channel 1. 16  Silicon Chip siliconchip.com.au a range of functions. Auto Set & measurements Although most digital scopes incorporate some kind of AUTO set feature, the ADS7062CA is unusual because it Fig 3: the same set-up as in Fig 1, but showing more detail of the switching waveforms. Ringing in the output of the Mosfet is visible and the rise time is measured to be 110ns. Compare this with the fall time of 10ns measured on the gate of the MOSFET to the right. siliconchip.com.au gives the user four additional options after the AUTO set has been completed. These options are especially useful when viewing periodic waveforms. For example, one can choose to show only one complete cycle of a periodic waveform, or only the rising or falling parts. Fig 4: a PWM signal at approximately 3.48kHz. On screen cursors are used to measure the positive pulse width. The pulse width is shown to be 96ms in the window at top right. The values of the two horizontal cursors also appear in this window, relative to the trigger point at the centre of the screen. February 2008  17 The ADS7062CA can make all the common measurements, with up to five independent measurements displayed at any one time to the right of the main window. When using the AUTO set feature, the measurements are shown on the screen, at bottom. The measurements apply to one of the two channels and show peak-peak voltage, period, frequency and average voltage levels. The channel that is selected is the current triggering channel. Alternatively, all measurements can be displayed at once, in a semi-transparent window in the centre of the screen. An independent 6-digit frequency counter appears at the bottom right of the screen. Maths function The ADS7062CA has maths functions on a par with higher end oscilloscopes, including FFT. The two traces can be added, subtracted, multiplied and divided and the result shown as a separate red trace on the screen. Apart from arithmetic functions, the FFT (Fast Fourier Transform) can be used to analyse the frequency components of a waveform. At the fastest timebase setting, the scale goes up to 12.5GHz! However, the magnitude accuracy at frequencies near or above the bandwidth of 60MHz will be poor. The FFT implemented on the ADS7062CA is quite good and the only difference with FFTs on other oscilloscopes we have seen is that you cannot view the FFT and the waveform simultaneously on the screen. However, the ADS7062CA implements a FFT zoom feature that is often lacking in other oscilloscopes. It is particularly handy for examining the frequency components in closer detail, providing up to x10 magnification. A further way to make measurements is via the on-screen cursors. Two cursors are available in either vertical or horizontal mode and are adjusted by turning USER SELECT knob. The cursor values (eg, time, voltage) and the difference between them are shown in the top right-hand corner of the display. Interestingly, you can use the cursors on the MATH function or a previously stored waveform. Acquisition modes The ADS7062CA implements three acquisition modes. In normal sampling mode, the scope acquires samples (of 8-bit vertical resolution) at constant periods as set by the timebase setting. Peak detect mode is good for viewing waveforms that are rapidly changing relative to the chosen timebase period. It detects peaks of the waveform and is therefore well suited to viewing waveforms where there are very narrow peaks that can easily be missed in normal sampling mode. The trade-off is lower noise immunity. For improved noise immunity you can resort to the average sampling mode, in which up to 256 sweeps (selectable) of the waveform are averaged out. This mode is particularly good for seeing overall trends while ignoring unwanted noise. Triggering Featured triggering modes include edge, pulse and video triggering. The SET TO 50% button can be used to quickly set the trigger level halfway between the vertical range of the waveform. This is an easy way to stabilise a waveform on the display. From there, you can adjust the trigger level with a knob. Triggering can be AC or DC-coupled and filtered for better 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. 18  Silicon Chip BY INTERNET:^ siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information siliconchip.com.au noise immunity. Either high or low frequencies can be attenuated. The trigger source can be either channel, external source or from the 50Hz mains. Video triggering works with both PAL and NTSC and can synchronise on even or odd fields, or both. Windowing Mode The ADS7062CA incorporates a simple windowing mode, which can be considered a zoom feature. The limits of the window are set with a horizontal knob, while pressing a button makes the window fit the display. User Interface The user interface is typical of most digital oscilloscopes, being organised as a hierarchy of menus with each having sub-menus which are accessed by five “soft” buttons on the edge of the screen. An audible beep informs you when you have set a knob beyond its range, although the beeping can be disabled and a visible cue used instead. Save and recall Up to ten waveforms can be saved and recalled for later analysis. Saved traces are recalled to the screen in red and can be transferred to a PC. In addition, up to ten user settings can be saved to non-volatile memory and recalled later. The current settings are automatically saved three seconds after they are changed which ensures that the oscilloscope starts in the same mode next time you power it up. If you have many unwanted settings, you can always press the DEFAULT SETUP button and begin with the most common options. Connections The ADS7062CA has a USB device port and a standard GPIB port, both on the rear panel, to enable you to connect the scope to a PC. There is no USB host port, meaning that acquiring screenshots is only possible by connecting to a PC. This could be a problem if you are working in the field or away from a computer. The only way to save waveforms in that case would be to store them on the scope’s internal memory and transfer them later. Screen grabs can be saved with the supplied EasyScope software. Keep in mind that the resolution of the exported bit maps will only be quarter-VGA (320x240 pixels) which is the native resolution of the oscilloscope. You can also export data in CSV (comma separated values) format for importing into a spreadsheet. Conclusion This oscilloscope represents very good value for money. It is reasonably fast and responsive and has many features found only in more expensive oscilloscopes. The colour screen makes this DSO particularly attractive for its price. The biggest compromises are the limited resolution of the screen, limited memory depth (4K) and 8-bit vertical resolution. On the positive side, the scope is supplied with two probes, a USB cable, user manual and PC software. Where from, how much? Recommend retail price is $1195 excluding GST. It can be purchased from Trio Smartcal. For more information, contact: Trio Smartcal or visit www.triosmartcal.com.au SC siliconchip.com.au February 2008  19 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au Remote-Controlled Mains Switch Want to switch mains appliances on and off remotely? This UHF Remote Mains Switch can do it for you. It’s operated using a hand-held UHF transmitter or you can team it with the Water Tank Level Meter Base Station described last month to automatically control mains-operated water pumps. An in-built timer also enables the unit to turn off automatically after a preset period. By JOHN CLARKE T The transmitter has two buttons to turn the UHF Remote Mains Switch On and Off. It can control up to 10 switch units simply by changing the identity setting. 24  Silicon Chip HERE ARE MANY INSTANCES when it would be convenient to switch an appliance on or off remotely rather than switching it manually. Such circumstances include switching on pathway lights when you arrive home, switching garden and/or pool lighting on or off, and switching power to water pumps. Remote switching can also be very convenient for appliances that are difficult to access, eg, in a factory. This unit was originally designed to switch mains-powered water pumps on and off in response to signals transmitted by the Water Tank Level Meter Base Station described last month. However, we soon realised that by adding a separate handheld transmitter to control the unit, it could also be used as a stand-alone unit for lots of other applications. It’s quite simple really – if you want to team the unit with the Water Tank Level Meter Base Station, then you don’t need the handheld transmitter. That’s because a transmitter is built into the Base Station itself. Conversely, you do need the transmitter to use the unit in other applications – ie, without the Base Station. siliconchip.com.au The UHF Remote Mains Switch can switch loads of up to 1875W or 2500W – see text. By the way, commercial remote control mains operated switches are readily available for switching appliances rated up to 1000W. Typical of these is the Altronics Cat. A-0340 which can be used with up to five outlets and has a range of 20m. However, if you want to switch devices rated over 1000W or control water pumps, then you need the UHF Remote Mains Switch described here. It can switch devices rated at up to 2500W over a range of up to 200m. That’s 10 times the range typically available from the low-cost commercial units! Main features As previously indicated, the UHF Remote Mains Switch is controlled either via a Water Tank Level Meter Base Station or using a hand-held UHF transmitter. The latter has just two switches for power control, one to switch the appliance on and the other to switch it off. An indicator LED located just above the “On” switch lights briefly during each UHF transmission, to indicate that the signal has been sent. A feature of the transmitter unit siliconchip.com.au is that is can be set to one of 10 identities. This means that you can independently control up to 10 UHF Remote Mains Switches using a single transmitter. Let’s say, for example, that you have two UHF Remote Mains Switches. In this case, one of these can be set as identity “1” and the other as identity “2”. The UHF transmitter can then be set to control either UHF Remote Mains Switch by selecting the required transmitter identity number. In other words, when the transmitter is set to identity “1” it will control the UHF Remote Mains Switch with identity “1”. Similarly, when set to identity “2” it will control the UHF Remote Mains Switch with identity “2”. Note that a small screwdriver is required to change the transmitter’s identity. It’s just a matter of changing the setting of a BCD switch via an access hole in the front panel (below the “On” button). Similarly, the Water Tank Level Meter Base Station transmits the identity of the pump that’s to be controlled. This pump is then switched by the UHF Remote Mains Switch that’s set to the same identity. Note that you will require a separate UHF Remote Mains Switch for each pump you wish to control. Encode switch The transmission range is such that you can easily control a UHF Remote Mains Switch up to 200m away. This means that, in a suburban environment, you could easily end up controlling a neighbour’s UHF Remote Mains Switch or vice versa, unless special precautions are taken. In this unit, a 16-position encode switch is included to prevent this from happening. Basically, the encode setting on the UHF Remote Mains Switch must match the encode setting on the UHF transmitter before it will operate in response to the UHF signal. This means that if both you and a neighbour have UHF Remote Mains Switches set to identity 1, you can simply select a different encode value to prevent false triggering. Timer An inbuilt timer in the UHF Remote Mains Switch allows you set the unit to automatically turn off after a preset period. This period is set by a BCD February 2008  25 Main Features • • Switches loads of up to 1875W (or 2500W using 10A mains wiring). • • • 16 encoder selections. • • On and off switching via remote transmitter or local switch. • • • Brownout detection switching. Up to 10 units can be used with the one transmitter, each with a separate identity. Over 200m range. Unit is operated using a separate handheld UHF transmitter or via a Water Tank Level Meter Base Station. Timer operates from 1 minute to 4 hours in 15 ranges, plus a continuously on selection. Optional power-on variation. Not suitable for security applications. switch during construction and ranges from 1 minute through to 4 hours in 15 steps. Table 2 shows the full range of periods available. This automatic switch-off feature is useful if you are controlling pathway or garden lights. For example, you might want the unit to automatically switch the pathway lights off after a few minutes or switch the garden lights off after a couple of hours. Alternatively, the unit can be set to permanently remain on until an “off” signal is received from the transmitter (ie, either from the hand-held transmitter or from the Base Station transmitter). Brownout protection Another feature of the UHF Remote Mains Switch is “brownout” detection, with automatic switch-off should a brownout occur. Brownouts occur when the mains voltage drops to a lower than normal level, usually because of a fault in the supply. The lowered voltage not only dims house lights but can also cause motors to overheat and burn out. Basically, burn-out occurs because the current through a motor’s induction windings increases when it is not spinning at its correct speed (ie, when the supply voltage is low). In fact, in severe brownouts, the voltage can be so low that the motor will not turn at all. In that situation, the motor will quickly overheat and suffer permanent damage. By including brownout detection, 26  Silicon Chip the motor is protected by switching off the power if the supply voltage falls below a preset value. Brownout detection is vital when it comes to preventing burn-out of mains-powered water pumps. Presentation As shown in the photos, the UHF Remote Mains Switch is housed a plastic enclosure with a General Purpose Outlet (GPO) on the front panel. Also included on the front panel is a neon indicator to indicate when power is applied to the GPO, plus a pushbutton switch to manually switch the unit on and off. Power indication for the unit itself is provided a neon indicator within the mains switch. An internal relay is used to switch the power to the GPO. This relay is a high-current type that’s suited to withstanding the high start-up currents associated with motors. A heavier duty relay can be used if required to power motors rated up to 2500W. The transmitter is housed in a case measuring 135 x 70 x 24mm. It’s powered by a 9V battery and sends out a coded 433MHz signal. Circuit details Fig.1 shows the circuit details for the UHF Remote Mains Switch. It’s based on IC1, a PIC16F88-I/P microcontroller. This monitors the signals from a 433MHz receiver module and controls the GPO via a relay circuit accordingly. In operation, the 433MHz receiver picks up the transmitter signal and applies the resulting data to IC1’s RA5 (pin 4) input via a 1kW current-limiting resistor. This resistor is included because the RA5 input can cause IC1 to latch up if excessive current flows into or out of this pin. This could happen if the input goes above 5V or below the 0V supply rail. The data signal is read by IC1 by clocking it in at a rate set by the transmission locking pulse. It is then accepted by IC1 if the format is correct but will be rejected if its identity and encode values do not match the settings of BCD (binary coded decimal) switches S1 and S2. Switch S1 (identity) is arranged as a rotary switch with 10 settings ranging from 0-9. It connects the RB0, RB1, RB2 and RB3 inputs of IC1 to ground when its 2, 4, 1 & 8 switches are closed respectively. Conversely, the RB0-RB3 inputs are pulled to the +5V supply rail when their corresponding switches are open. That’s because each input has an internal pull-up resistor of about 20kW. In operation, the switch settings for S1 can be read by IC1 because a low voltage on one of the inputs means that its corresponding switch is closed while a high voltage means that the switch is open. BCD switches S2 (encode) & S3 (timer) are monitored in a similar way. However, these have six extra positions labelled A-F, giving a total of 16 positions. Note that the RA0, RA1, RA6 & RA7 inputs of IC1 that monitor S3’s setting are pulled to +5V via external 10kW resistors. These resistors are necessary because there are no internal pull-ups at the RA pins. Switching the relay IC1’s output at RA3 controls relaydriver transistor Q1 via a 330W resistor. When RA3 is high, Q1 switches on and so relay RLY1 also turns on and switches mains power to the GPO (ie, it switches the Active lead). Diode D5 clamps the back-EMF voltage that is produced when the relay coil switches off, to protect the transistor. S4 is used to manually switch the relay on or off with each consecutive pressing. This switch connects to IC1’s RA4 input and pulls this input to ground when closed. Conversely, a 1kW resistor pulls RA4 high when the switch is open. The 100nF capacitor siliconchip.com.au 8 4 2 1 8 4 2 1 11 13 12 10 9 7 6 8 4 5 RA6 RA1 RB7 RB5 RA7 RB6 RA3 RA0 Vss IC1 PIC16F88-I/P AN2 RA4 RB4 RB3 RB1 RB0 RB2 RA5 14 Vdd 15 18 16 17 2 1 3 TPG TP1 4x 10k 100nF 8 4 2 1 COM S3 330 10 F 16V TIMER (0–F) 1k 100nF 1k WARNING: WIRING IN THE SHADED AREA MAY POSE A RISK OF LETHAL SHOCK IF TOUCHED! UHF REMOTE MAINS SWITCH RECEIVER ENCODE (0–F) COM S2 1k F1 10A DATA IDENTITY (0–9) COM S1 GND 433MHz RX MODULE 100 F 16V B D5 A K E C Q1 BC337 RLY 1 +12V NEON LAMP 10 F 16V A K D1–D5: 1N4004 POWER S5 * NOT REQUIRED FOR HEAVY DUTY RELAY (SEE TEXT) 470 * 0.5W S4 ON/OFF A 240V E 100 F 16V 10 F 16V 6.3V B 0V 6.3V C BC337 E GPO T1 2851 IN N A A BROWNOUT LEVEL SET GND OUT REG2 7812 GND IN K 17V K 433MHz Rx MODULE A A GND K K D1–D4 VR1 10k 22k 470 F 25V +17V 100 F 25V +17V S1 78 ➡ 4 C 1 S2, S3 A ➡ BC DE 4 C 1 2 C 8 7805, 7812 OUT IN 2 C 8 Fig.1: the circuit for the UHF Remote Mains Switch is based on a 433MHz receiver module and a PIC16F88-I/P microcontroller (IC1). The microcontroller processes the data from the receiver and controls relay RLY1 which switches the power to the mains socket (GPO) accordingly. SC 2008 N MAINS E INPUT A ANT Vcc 100nF CERAMIC OUT REG1 7805 ANT GND GND Vcc 901 23 +5V 78 9 4 56 456 Vcc DATA DATA GND 23 siliconchip.com.au F0 1 February 2008  27 23 4 56 23 10k 10k 45 23 6 S2 Vcc GND GND ANT DATA Vcc GND DATA 901 1k 4 C 1 ➡ 100nF 100nF BC DE S1 78 9 A D5 4 C 1 ➡ 78 18020101 L ORT N O C P MUP K NAT RETAW ➡ S3 2 C 8 456 78 9 BC DE 330 4 C 1 470 * 100 F 1k CORD GRIP GROMMET 10k 1k TP1 Q1 170mm OF 1mm ENAMELLED COPPER WIRE 10 F 100nF 7.5A MAINS CABLE FOR LOADS UP TO 1875W, 10A CABLE FOR LOADS UP TO 2500W 10k D4 D1 240V PRIMARY LEADS 6.3V 0V 6.3V VR1 10 F A SPADE TERMINAL M4 SCREW RLY1 & NUT 100 F IC1 PIC16F88-I/P SWITCH 1 TPG 10 F 470 F 22k SWITCH 2 REG1 7805 REG2 7812 100 F S5 (N) 2851 NEON 3 (A) F0 1 HEATSHRINK SLEEVING (N) F0 1 F1 T1 (A) 2 C 8 AERA G NIRI W S NIA M 10A TERMINAL BLOCK 433MHz Rx MODULE * NOT NEEDED FOR HEAVY DUTY RELAY NEON LAMP NOTE 2: BEND TOPS OF SPADE CRIMP CONNECTORS ON RELAY OVER SLIGHTLY TO CLEAR CASE LID E A 4.5mm DIAM. NOTE 1: INSULATE TERMINALS OF FUSE F1 & THE NEON LAMP WITH HEATSHRINK SLEEVING N GPO 14 10.9 S4 RADIUS 16.75 NOTE 3: USE THE HEAVY DUTY RELAY FOR LOADS ABOVE 1875W -- SEE PARTS LIST 33.5 (BOX LID) DETAILS OF CUTOUT IN LID FOR GPO Fig.2: follow this parts layout and wiring diagram to build the UHF Remote Mains Switch. Note that all wiring must be run using 240VAC cable (see text) and this must be firmly secured using cable ties as shown in one of the photos. The cutout diagram for the GPO is shown at bottom right. bypasses any glitches that may otherwise cause false switching. Power supply Power for the UHF Remote Mains Switch comes from the mains via transformer T1. The transformer’s 12.6V secondary voltage is then fullwave rectified using diodes D1-D4 28  Silicon Chip and filtered using 470mF and 100mF electrolytic. The resulting 17V DC rail is then applied to 3-terminal regulators REG1 & REG2 to derive regulated +5V and +12V rails. The +5V rail is used to power IC1 and the 433MHz receiver module, while the +12V rail powers the relay. Note that the outputs of REG1 and REG2 are each bypassed using 10mF capacitors. In addition, a 100mF capacitor and two 100nF capacitors are used to further decouple the supply for IC1 and the 433MHz receiver module. Brownout IC1’s AN2 input is used for brownsiliconchip.com.au out detection. Basically, this input samples the 17V rail via a voltage divider consisting of a 22kW resistor and trimpot VR1. VR1’s wiper voltage is filtered using a 10mF capacitor (to smooth out 100Hz ripple and transients) and applied to the AN2 input via a 1kW resistor. During the set-up procedure, VR1 is adjusted so that the voltage at AN2 is +2.5V when the mains voltage is 250VAC. If a brownout subsequently occurs and the mains drops to below about 200VAC, the voltage applied to AN2 will fall below 2V. This is detected by microcontroller IC1 which then switches the relay off to disconnect power from the GPO. The relay subsequently switches on again when the mains supply returns to normal. One small problem with monitoring the 17V rail is that it varies with load. Relay RLY1 has a coil resistance of 160W and so there is an extra 75mA drawn from the 17V rail when the relay is on. As a result, this supply rail drops in level when the relay is on, so we have to take this into consideration. In practice, it’s just a matter of ensuring that trimpot VR1 is set when RLY1 is on and power is being applied to the GPO socket. By doing this, the brownout detection operates correctly when the mains voltage drops to 200VAC. Note also that we have included a 470W resistor across the 160W relay coil and this reduces the effective resistance to 120W. We have done this so that a heavy-duty relay that has a coil resistance of 120W can be used instead without affecting the brownout settings. The 470W resistor is not used with the 120W relay. Another possible problem is that when the relay switches off due to a brownout, the 17V rail immediately rises again due to the reduced load. This could cause the relay to immediately switch on again, only to then switch off again when the 17V rail drops. This cycle could thus go on indefinitely as the AN2 input repeatedly goes above and below 2V, thereby causing relay chatter. To circumvent this relay chatter, the microcontroller doesn’t switch the relay back on again following a brownout until its AN2 input rises above 2.5V, corresponding to a mains voltage of 220VAC. When the relay is switched on, the voltage at AN2 will then fall to 2.2V but this is still 200mV above the voltage required to switch off the relay and so the relay remains on You Need A Ratchet Type Crimping Tool One essential item that’s required to build this project is a ratchetdriven crimping tool, necessary for crimping the insulated quick-connect terminals to the leads. Suitable crimping tools include the Altronics Cat. T-1552, Dick Smith Electronics Cat T-3535 and the Jaycar TH-1829. These all feature doublejaws so that the bared wire end and the lead insu­lation are crimped in a single action. Don’t even think of using one of the cheap (non-ratchet) crimpers that are typically supplied in automotive crimp kits. They are not up to the job for a project like this, as the amount of pressure that’s applied to the crimp connectors will vary all over the place. This will result in unreliable and unsafe connections at the mains switch and relay terminals. By contrast, a ratchet-driven crimp­ i ng tool applies a preset amount of pressure to ensure consistent, reliable connections. If you don’t have a suitable crimping tool, then it will be necessary to solder the leads to the mains switch and relay and cover the connections with heatshrink sleeving. Construction Construction of the UHF Remote Mains Switch is straightforward, with most of the parts installed on a PC board coded 10102081 and measuring 160 x 110mm. The only off-board parts are the GPO socket, pushbutton switch S4, power switch S5, the neon lamp and the fuseholder. Fig.2 shows the parts layout on the PC board. Begin by carefully checking your board for any defects, such as shorted or open-circuit tracks. That done, check that the hole sizes are correct. In particular, the holes for the four corner mounting screws and for REG1 & REG2 must be 3mm in diameter, while the mounting holes for transformer T1 and the relay must be 4mm in diameter. You should also check that the main PC board is cut and shaped to size so that it fits into the box. If not, you can make the corner cut-outs using a hacksaw and a round file. Now for the board assembly. Install the resistors first, taking care to place each in its correct position. Table 1 shows the resistor colour codes but you should also use a digital multimeter to check each resistor before mounting it in position. Note that if you are using the 120W heavy duty relay, then the 470W resistor immediately to its right is not used. Once the resistors are in, install the wire link (it goes in between the two regulators), then install PC stakes for the antenna connection at bottom right and for TP1 and TP GND. In addition, you will need to install another three PC stakes to terminate the transform- Table 1: Resistor Colour Codes o o o o o o siliconchip.com.au No. 1 4 3 1 1 Value 22kW 10kW 1kW 470W 330W 4-Band Code (1%) red red orange brown brown black orange brown brown black red brown yellow violet brown brown orange orange brown brown 5-Band Code (1%) red red black red brown brown black black red brown brown black black brown brown yellow violet black black brown orange orange black black brown February 2008  29 Parts List 1 PC board, code 10102081, 160 x 110mm 1 IP65 ABS enclosure, 171 x 121 x 55mm 1 433MHz UHF data receiver (Jaycar ZW-3102 or equiv.) 1 2851 12.6V 2VA mains transformer 1 12V relay with 20A 220VAC contacts (Jaycar SY04042 or equivalent). Note: for loads above 1875W, use a 30A relay (Jaycar SY-4040 or equivalent) 1 2-way 10A mains terminal block 1 0-9 BCD DIL PC-mount switch (S1) 2 0-F BCD DIL PC-mount switches (S2,S3) 1 momentary push to close 250VAC panel-mount mains switch (S4) (Jaycar SP-0716, Altronics S-1080) 1 SPST mains rocker switch with Neon indicator (S5) (Jaycar SK-0976, Altronics S-3228) 1 panel-mount 240VAC Neon indicator 1 M205 or 3AG 250VAC 10A panel-mount safety fuseholder (Jaycar SZ-2028 or SZ-2025; Altronics S-5992) 1 M205 or 3AG 10A fast-blow fuse (to suit fuse holder) 1 7.5A mains cord and plug with earth (or 10A cord and plug for controlling appliances rated at up to 2500W) 1 10A mains panel socket with side wire entry (Jaycar PS4094; Altronics P-8241) 2 20°C/W TO-220 mini heatsinks, 19 x 19 x 10mm (Jaycar HH8502) 1 cordgrip grommet for 6.5mm OD mains cable 1 18-pin DIL IC socket 9 100mm cable ties 8 6.4mm insulated spade crimp connectors for 1mm2 wire 2 4.8mm insulated spade crimp connectors for 1mm2 wire 1 chassis-mount 6.4mm spade terminal 2 PC-mount 6.4mm spade terminals 4 M4 x 10mm screws 4 M4 nuts 4 M3 x 6mm screws 2 M3 x 10mm screws 1 M3 x 15mm screw 3 M3 nuts 1 200mm length of 7.5A blue mains wire (or 10A for up to 2500W) 1 200mm length of 7.5A brown mains wire (or 10A for up to 2500W) 1 100mm length of 10mm heatshrink tubing 1 50mm length of 4mm heatshrink tubing 1 170mm length of 1mm enamelled copper wire 1 25mm length of 0.8mm tinned copper wire 6 PC stakes 1 10kW top-adjust multi-turn trimpot (code 103) (VR1) er’s secondary leads (6.3V, 0V, 6.3V), plus another two to terminate switch S4’s leads. Diodes D1-D5 are next on the list. Make sure these are oriented correctly before soldering their leads. That done, install a socket for IC1, making sure its notched end matches the position shown on Fig.2. Do not install IC1 yet – that step comes later, after the power 30  Silicon Chip Semiconductors 1 PIC16F88-I/P microcontroller programmed with 1010208A. hex 1 7805 5V regulator (REG1) 1 7812 12V regulator (REG2) 1 BC337 NPN transistor (Q1) 5 1N4004 1A diodes (D1-D5) Capacitors 1 470mF 25V PC electrolytic 1 100mF 25V PC electrolytic 2 100mF 16V PC electrolytic 3 10mF 16V PC electrolytic 1 100nF MKT polyester (code 104 or 100n) 1 100nF ceramic (code 104 or 100n) Resistors (1/4W, 1%) 1 22kW 1 470W 0.5W 4 10kW 1 330W 3 1kW supply has been checked. Next on the list are the capacitors. Be sure to orient the electrolytics as shown and note that the 100nF ceramic capacitor goes in next to the 433MHz receiver module. The other two 100nF capacitors are MKT polyester types. One is just below one end of IC1, while the other is just above BCD switch S1. Regulators REG1 & REG2 are both mounted horizontally on the PC board. The first step is to bend their leads down through 90° so that they will go through their PC board holes. In each case, the regulator’s two outer leads are bent down 8mm from its body, while its centre lead is bent down 5mm from the body. That done, secure each regulator together with a U-shaped heatsink to the PC board using an M3 x 10mm machine screw and nut. Be careful not to get the regulators mixed up – the 7805 (REG1) mounts on the righthand side. Tighten each assembly down firmly before solder their leads and trimming them to length. Do not solder the regulator leads before tightening the mounting screws, as this could stress the soldered joints and fracture the board tracks. Next, install trimpot VR1, transistor Q1 and the three BCD switches. Be sure to use the correct BCD switch at each location (S1 is the 0-9 switch) and note that they must be oriented exactly as shown. Follow these parts with the 433MHz receiver module, again taking care to ensure it goes in the right way around. The pin designations are all clearly labelled on the back of the module and you can also match the orientation of the module against the photographs. The antenna is made using a 170mm length of 1mm enamelled copper wire. This is formed into a gentle spiral by winding it over a 10mm mandril (eg, a drill). As shown in Fig.2, it extends from the antenna PC stake to a hole in one corner of the PC board, immediately to the right of REG1. Be sure to scrape away the enamel insulation from the wire ends before soldering it in position. Note: for safety reasons, the antenna must be fully enclosed in the plastic case. Under no circumstances should it be mounted externally, nor should any part of the antenna protrude from the enclosure. The reason for this is siliconchip.com.au INSTALL CABLE TIES AT LOCATIONS INDICATED BY RED ARROWS This is the view inside the completed UHF Remote Mains Switch. Be sure to use insulated spade connectors for the connections to the mains switch and the relay and insulate all other connections with heatshrink sleeving to ensure safety. The wiring must be secured using cable ties at the positions indicated by the arrows. siliconchip.com.au February 2008  31 This close-up view shows how the antenna is mounted at one end of the PC board. It’s made by winding a 170mm length of 1mm enamelled copper wire onto a 10mm mandril (eg, a drill). that if a mains wire comes adrift inside the case, it may contact low-voltage circuitry and so the antenna may also become live (ie, at 240V AC) . The next step is to install two PCmount 6.4mm spade terminals immediately to the right of RLY1 (these are used to terminate the leads from the relay’s coil). That done, the relay and transformer can both be secured in position using M4 screws, nuts and star washers. Note the earth lug that’s fitted under one of the transformer mounting screws. Before fitting this, be sure to scrape away the enamel from the transformer mounting foot to ensure good contact. The board assembly can now be completed by mounting the mains terminal block. Secure it using an M3 x 15mm screw, nut and lockwasher. Final assembly The UHF Remote Mains Switch is housed in an ABS enclosure measur- ing 171 x 121 x 55mm. If you buy a kit, then the box will probably be supplied pre-punched and with screened lettering on the front panel (or an adhesive label). If not, then you will have to drill the holes yourself. Basically, you will have to drill and shape holes in one end of the case for the fuseholder, the mains switch and the cordgrip grommet. That done, you will have to drill holes in the lid for the GPO socket, the neon indicator and for pushbutton switch S4. The diagram for the GPO cutout is shown in the bottom righthand corner of Fig.2. The large cutout can be made by drilling a series of small holes around the inside perimeter, then knocking out the centre piece and filing the job to a smooth finish. Once the drilling is completed, install the PC board, safety fuseholder and power switch and check where the 2-way terminal block should be positioned. Mark and drill a mounting hole for this in the PC board, then Install the UHF receiver module with its crystal towards BCD switch S1 as shown here. 32  Silicon Chip secure it in position using an M3 x 15mm screw and nut. The PC board can then be secured inside the case using four M3 x 6mm screws. Note that you must use the correct safety fuseholder, as specified in the parts list. Do not substitute for this part, as other fuseholders may pose a shock hazard. It’s now simply a matter of completing the wiring as shown in Fig.2. All wiring must be run using mainsrated cable. You can use 7.5A cable throughout for powering appliances rated up to 1875W but be sure to use 10A cable where indicated if you want to power appliances that are rated up to 2500W. Note that the brown cable is used for the Active wiring while the blue cable is used for the Neutral leads. The green/yellow-striped wire is used for the earth wiring only and the Earth lead from the mains cord must go straight to the GPO. The connections to the mains switch (S5) and the relay are made via insulated crimp connectors. Be sure to use insulated connectors here as these terminals all operate at 240VAC. By the way, a proper ratchet-driven crimp tool (see panel) is an absolute necessity to attach the connectors to the leads. Low-cost automotive type crimpers are definitely not suitable here, as their use would result in unreliable and unsafe connections. The leads to fuseholder (F1) and the neon lamp are soldered to their respective terminals. Note that the Active lead from the mains cord goes to the terminal on the end of the fuseholder. Note also that all these connections should all be insulated with heatshrink sleeving – see photos. Similarly, use heatshrink sleeving to insulate switch S4’s terminals. The transformer secondary leads and the leads from S4 connect to adjacent PC stakes. Once again, these connections should all be insulated with heatshrink sleeving to ensure reliability. Take great care when making the connections to the mains socket (GPO). In particular, be sure to run the leads to their correct terminals (the GPO is clearly labelled) and do the screws up nice and tight so that the leads are held securely. Similarly, make sure that the leads to the mains terminal block are firmly secured. Once the wiring is complete, it siliconchip.com.au Table 2: Setting The Timeout Period Switch S3 Setting Timeout Period (Minutes) 0 1 2 3 4 5 6 7 8 9 A B C D E F No timeout 1 2.55 4.5 5.5 6.75 10 15.5 30 45 60 90 120 150 180 240 Follow this table to adjust BCD switch S3 to set the required timeout period (if required). A setting of “0” gives no timeout period – ie, the unit will only switch off in response to an “Off” signal from the transmitter or the Water Tank Level Meter Base Station. should be secured using cable ties. This is done so that if a mains wire does come loose, it cannot move and make contact with any low-voltage components on the PC board. One of the photographs clearly shows the locations of the cable ties. Note that the Active and Neutral leads are secured to the GPO using cable ties which pass through the holes in its moulding. Testing Before applying power, check your wiring carefully and make sure that all mains connections are covered in heatshrink tubing. That done, check that there is a 10A fuse inside the fuseholder and note that IC1 should be left out of its socket for the time being. When testing and making adjustments, the UHF Remote Mains Switch will be operated with the lid open. During this procedure, you must not touch any of the 240VAC wiring. This includes the transformer primary leads plus all wiring to the mains socket, neon lamp, switch S5, the fuseholder, the relay and the mains terminal block. Although all connections should be insulated, it’s wise to be careful. In particular, note that the relay’s wiper (COM) contact, the fuseholder’s siliconchip.com.au terminals and the switch wiper will all be at 240VAC if the device is plugged into the mains, even if switch S5 is off. If your house has a safety switch (earth leakage detection) installed then this can provide added protection. If not, then consider using a portable safety switch for this part of the test. Apply power and use your DMM to check that there is 5V (4.9-5.1V is acceptable) between pins 14 & 5 of IC1’s socket. If this is correct, switch off, disconnect the mains plug from the wall socket and install IC1. Take care to ensure that IC1 goes in the right way around – see Fig.2. Next, set the DMM to the 250VAC range, apply power again and carefully check the voltage between the Active and Neutral sides of the mains terminal block (ie, measure the mains voltage). That done, press switch S4 to turn on the relay, set your DMM to read volts DC and adjust multi-turn trimpot VR1 so the DC voltage between TP1 and TP GND is 1% of the mains voltage reading. For example, if the mains voltage is 250V AC then adjust VR1 for a reading at TP1 of 2.50VDC. Similarly, if the mains voltage is 230VAC, VR1 would be set for a reading of 2.30V at TP1. Note that for a European mains voltage of 220VAC, VR1 should be adjusted so that TP1 reads 2.5V when the mains voltage is 220VAC. In other words set VR1 so that the DC voltage at TP1 is 1.14% of the mains voltage. This will set the brownout cut-out to 192VAC. Setting the BCD switches If you intend using this unit with a Water Tank Level Meter Base Station, then you will have to set BCD switches S1 and S2 accordingly. It’s just a matter of setting S1 to the pump number and S2 to the encode value to match both the Water Tank Level Meter and the Base Station. BCD switch S3 sets the timer period – see Table 2. Usually, S3 is set to 0 for controlling pumps that deliver to a household water supply. If pumping between tanks, then the timer can act as a back-up to switch off the pump if the level meter fails. GPO power at power-up Another option is for the UHF Remote Mains Switch to apply power to the GPO at power-up. This feature is handy if you want the unit to automatically supply power to an appliance when power is restored after a blackout; eg, to a pump that supplies water to a house. To enable this option, all you have to do is press and hold down switch S4 when powering up the UHF Remote Mains Switch. Once enabled, exactly the same procedure is used to disable this option. Your UHF Remote Mains Switch is now complete. Be sure to disconnect the mains lead from the wall socket when fitting the lid and be careful not to pinch any of the leads to the mains socket. Provided you’ve dressed the leads correctly and secured them with cable ties, the leads should fold back neatly into the case when the lid is placed in position. Transmitter Now then, what about the optional transmitter unit for those who wish to use the UHF Remote Mains Switch in a stand-alone application? Well, that’s fully described in the followSC ing article. Check These Important Safety Points (1) Use the specified plastic case to house this project and note that the antenna must be fully enclosed inside the case. DO NOT use a metal case. (2) Use mains-rated cable for all wiring connections and insulate all soldered terminals with heatshrink tubing. Use insulated spade crimp connectors for all connections to the mains switch and relay and be sure to use a ratchet-driven crimping tool to properly secure the spade lugs to the leads. (3) Secure the mains wiring and all other wiring connections with cable ties (see photo), so that they cannot move if they come adrift. Make sure that the wiring to the GPO is correct and that it is properly secured. (4) All wiring to the mains switch, mains socket, neon indicator, relay contacts, the 2-way terminal block & the transformer primary operates at 240VAC (ie,mains potential). Do not touch any of this wiring or the connections to any of these these parts while this device is plugged into the mains. DO NOT attempt to build this device unless you know what you are doing and are familiar with high-voltage wiring. February 2008  33 UHF Remote Mains Switch Transmitter Designed to control the UHF Remote Mains Switch, this hand-held transmitter can operate over a 200m range. It’s based on a PIC micro and a pre-assembled transmitter module, making it easy to build and get going. By JOHN CLARKE I the UHF Remote Mains Switch in a standalone application, then you need to also build this UHF transmitter. As shown in the photos, it’s housed in a plastic case with two pushbutton switches for on/off switching. Press the On button and power is applied to the mains socket on the UHF Remote Mains Switch. Alternatively, press the Off button and the power turns off. What could be easier? The front panel also provides access to a small rotary switch. This selects one of 10 “identities” which means that the transmitter can control up to 10 separate UHF Remote Mains Switches. This rotary switch is adjusted using a small blade screwdriver. Immediately above the “On” button is a “transmit indicator” LED. This briefly lights each time a transmission is sent (ie, when ever the On or Off buttons are pressed). However, if there is an error, this LED will flash three times in a 1.5-second period. Typically, an error will be indicated if both switches are pressed simultaf you want to control 34  Silicon Chip neously or if a switch is pressed too briefly. In either case, it’s simply a matter of pressing the desired switch again to send the control signal. How it works Refer now to Fig.1 for the circuit details. As previously stated, it’s based on a PIC microcontroller (IC1) and a 433MHz transmitter module. Under normal conditions (ie, when no signal is being transmitted), no power is applied to the circuit. This means that battery usage is kept to an absolute minimum. Pressing either switch S1 (On) or switch S2 (Off) connects the battery’s positive terminal to regulator REG1 via diode D1 or D2. A 10W resistor is included between the battery and the switches to limit the initial charge current to the 10mF bypass capacitor at REG1’s input. This minimises wear on the switch contacts. As soon as power is applied to REG1’s input, its output delivers a +5V rail to pin 14 (Vdd) of IC1. As a result, the program within IC1 starts running. One of the first things it does is to check which switch was pressed and this happens after a short delay to ensure that the switch is fully closed. In operation, S1 is monitored via a 10kW resistor at the RA2 input, while S2 is monitored via a 10kW resistor at the RA4 input. The program first checks to see if S1 is closed and it does this as follows. Initially, RA2 (pin 1) is set as an output with this pin at 0V. RA2 is then set as an input and its voltage checked to see if it is still at 0V or if has been pulled to +5V. If it is at +5V, then S1 (On) is closed and the battery voltage is being applied to REG1 via diode D1. The 10kW resistor in series with RA2 is included to limit the current into this input when its internal clamping diode conducts. This diode prevents RA2 from going more than 0.6V above the +5V supply, thereby protecting this input from damage. Next, the program checks to see if S2 is closed. In this case, RA4 (pin 3) is initially held low (0V) as an output. siliconchip.com.au Q1 BC327 REG1 78L05 C E 10k D3 D1 A 10 RA1 10k 1 10k Q2 BC549 C 3 10k B 16 E 1 S3 S4 4 C 1 4 C 1 8 9A 67 BC D ➡ 23 34 5 2 C 8 012 901 ➡ COM EF 78 456 9V BATTERY 2 C 8 Vdd MCLR A S2 (OFF) 14 4 D2 S1 (ON) A 100 F 16V 100nF 10k 100nF K K K GND 10 F 16V B 1k OUT IN 2 4 8 S3 IDENTITY (0–9) 8 6 7 9 LED1 1k 18  K ANTENNA A Vcc RA2 RA0 RA4 17 DATA IC1 PIC16F88-I/P 433MHz TRANSMITTER MODULE RA7 ANT GND RB2 RB4 RB0 RB6 RB1 RB7 RB3 RB5 10 12 13 11 Vss 5 1 2 COM 4 433MHz Tx MODULE 8 ANT Vcc DATA GND S4 ENCODE (0-F) D1– D3: 1N4148 A SC  2008 LED K UHF REMOTE MAINS SWITCH TRANSMITTER 78L05 BC337, BC549 K COM B E A C IN OUT Fig.1: the transmitter circuit uses PIC microcontroller IC1 to generate a data signal whenever switch S1 (On) or S2 (Off) is pressed. This data is then fed via IC1’s RA0 output to a 433MHz transmitter module. BCD switches S3 & S4 set the identity and encode values & must be set to match settings in the UHF Remote Mains Switch. RA4 is then set as an input and its voltage checked. A high voltage means that S2 is closed and that voltage is being applied to REG1 via diode D2. Diodes D1 and D2 provide reverse polarity protection for REG1 if the battery is connected the wrong way around. They also isolate the switch actions, so that RA2 will only go high if S1 is pressed and RA4 will only go high if S2 is pressed. As well as detecting which switch was pressed, IC1’s firmware also detects whether both switches were pressed simultaneously (as indicated by a high at both RA2 & RA4). It also detects if neither switch is pressed. In the latter case, this would mean that one of the switches was pressed but then released before the program had a chance to check which switch it was. Next, the program sets RA7 (pin 16) of IC1 high and this drives the base of transistor Q2 via a 10kW resistor. As a result, Q2 turns on and supplies base current to Q1 which also turns on. As a result, supply current can now siliconchip.com.au flow through D3 and Q1 to REG1, which means that power to REG1 is maintained even if switch S1 or S2 is released. This supply latching is necessary to allow time for the on or off code to be transmitted in its entirety without supply interruption. Diode D3 is there simply to protect the circuit from reverse battery connection. RA1 (pin 18) is the transmit indicator output. This output goes low during code transmission and turns on LED1 via a 1kW resistor. However, if the program detects that both switches were pressed or if it detects that neither switch was pressed (ie, the press was too brief), the LED flashes three times to indicate an error. BCD switches Now let’s take a look at the two binary coded decimal (BCD) switches (S3 & S4) that are connected to the microcontroller. First, BCD switch S3 sets the identity. It’s connected to IC1’s RB0-RB3 inputs and individually connects these Main Features • Controls the UHF Remote Mains Switch • Up to 10 UHF Remote Mains Switch units can be controlled • • • • • • • 16 encoder selections 200m range On/off switching Handheld operation 9V battery supply Transmit indicator Transmit error indication inputs to ground when its 2, 4, 1 & 8 switches are closed respectively. Basically, S3 is arranged as a rotary switch with 10 settings ranging from 0-9. For the “0” setting, all switches are open, while and for the other numbers, different combinations of switches are open and closed. For February 2008  35 170mm OF 1mm ENAMELLED COPPER WIRE K 10 F 100 F 4148 10k ➡ BC DE 4 C 1 78 9 A 23 Q2 2 C 8 4 C 1 78 ➡ 2 C 8 456 100nF 10k 4148 45 23 6 10k D2 IC1 PIC16F88-I/P LIE ON SIDE S2 OFF 901 S4 S3 – 433MHz Tx MODULE 1k D1 10k 10k S1 ON F0 1 18020151 REG1 ANT Vcc LED1 A DATA GND RETTIMSNART WS SNIAM ETOMER 100nF + 4148 D3 10 Q1 1k 9V BATTERY CJ Fig.2: follow this diagram to install the parts on the PC board and complete the battery wiring. Note that BCD switch S3 is installed in a socket to raise it up off the PC board (see text), to make it easier to access. The view at right shows the completed PC board mounted inside the handheld case. example, a “1” position ties the RB2 input to ground. Conversely, the RB0-RB3 inputs are pulled to the +5V supply rail when their corresponding switch is open. That’s because each input has an internal pull-up resistor of about 20kW. In operation, S3’s settings can be read by microcontroller IC1 because a low voltage on one of the inputs means that its corresponding switch is closed while a high voltage means that the switch is open. BCD switch S4 sets the encode number and is monitored in a similar way. However, this switch has six extra positions labelled A-F, giving it a total of 16 positions. The settings for S3 & S4 are sent as part of the on/off code that’s fed from RA0 to the 433MHz transmitter module. Basically, the UHF transmitter transmits a modulated signal when data is applied to its data input. A ¼-wave dipole antenna is connected to the transmitter’s output. In practice, IC1’s RA0 output can generate on/off signals for up to 10 UHF Remote Mains Switches, depending on the setting of S3 (identity). Initially, a 50ms transmission is sent to set up the receiver so that it is ready to accept data. A 16ms locking signal is then sent, followed by 4-bit encode and 4-bit identity numbers. Next, an 8-bit on/off signal is sent – either a value of 162 for “On” or a value of 150 for “Off”. An 8-bit stop code with a value of 204 completes the data transmission. Once this data has been sent, IC1’s RA7 output is set low to switch off transistors Q2 & Q1. This ensures that the supply to REG1 turns off (assuming that switches S1 & S2 are both open). Resistor Colour Codes o o o o No. 4 2 1 36  Silicon Chip Value 10kW 1kW 10W 4-Band Code (1%) brown black orange brown brown black red brown brown black black brown 5-Band Code (1%) brown black black red brown brown black black brown brown brown black black gold brown siliconchip.com.au In addition, the RA1 output is taken to +5V to switch off LED1. Finally, note that there are several decoupling capacitors at the output of REG1. These filter the supply rails for IC1 and the 433MHz transmitter module. Construction The assembly is straightforward with all parts mounted on a PC board coded 10202081 and measuring 86 x 64mm. This is housed in a remote control case that measures 135 x 70 x 24mm. Fig.2 shows the parts layout. Begin by checking the PC board for any defects such as shorted tracks or breaks in the copper. That done, check the hole sizes. The four corner mounting holes should be 3mm in diameter, as should the two holes used to anchor the battery snap leads. Now for the assembly. Install the resistors first, taking care to place each in its correct position. Table 1 shows the resistor colour codes but it’s also a good idea to use a DMM to check each resistor before installing it on the board. Next, install PC stakes for the battery snap leads and for the antenna connection near the 433MHz transmitter module. That done, install diodes D1D3, REG1 and transistor Q1 & Q2. Be sure to orient the diodes and transistors correctly and don’t get Q1 & Q2 mixed up. They may look the same but Q1 is a BC337 PNP type while Q2 is a BC549 NPN transistor. The capacitors are next on the list. Note that the 100nF ceramic capacitor mounts between Q2 and the transmitter module, while the 100nF polyester capacitors is located just below IC1. In addition, the two electrolytic capacitors adjacent to REG1 need to lie on their side, to clear the lid of the case – see photo. Switches S1 & S2 can now go in. Be sure to mount these with their flat sides positioned as shown in Fig.2 (ie, towards the top edge of the PC board). That done, install an IC socket for IC1 (notched end towards REG1) but don’t install the IC at this stage. BCD switch S3 also mounts in an IC socket, so that it is raised off the board to make it easier to adjust from outside the case. One option here is to fit a cut-down DIP-8 socket, with three pins on each side. Alternatively, we’ve provided two extra holes on the PC siliconchip.com.au Parts List 1 PC board, code 10202081, 86 x 64mm 1 remote control case, 135 x 70 x 24mm 1 433MHz UHF data transmitter (Jaycar ZW-3100 or equivalent) 1 9V battery 1 18-pin DIL socket 1 6-pin DIL socket (or 8-pin) 2 click action momentary switches (S1,S2) 1 0-9 BCD DIL PC-mount switch (S3) 1 0-F BCD DIL PC-mount switch (S4) 4 M4 x 10mm screws 1 170mm length of 1mm enamelled copper wire 1 9V battery snap connector 3 PC stakes Semiconductors 1 PIC16F88-I/P microcontroller programmed with 1020208A. hex 1 BC327 PNP transistor (Q1) 1 BC549 NPN transistor (Q2) 1 78L05 5V regulator (REG1) 2 1N4148 diodes (D1-D3) 1 3mm red LED (LED1) Capacitors 1 100mF 16V PC electrolytic 1 10mF 16V PC electrolytic 1 100nF MKT polyester (code 104 or 100n) 1 100nF ceramic (code 104 or 100n) Resistors (0.25W, 1%) 5 10kW 1 10W 2 1kW board so that it will accept a standard 8-pin DIP socket. Once the socket is in place, install S3 with its orientation dot at bottom right – see Fig.2 and the photos. If you have fitted an 8-pin socket, be sure to plug S3 into the top six pins – the two pins nearest the battery terminals are unused. By contrast, BCD switch S4 mounts directly on the PC board. Once again, be sure to mount it with the correct orientation. The UHF transmitter can now be installed. This is done by first placing it in position, then bending it down so Helping to put you in Control Sensors We have a selection of sensors for monitoring your processes. Accelerometers Accelerometer Breakout boards range from +/-2G to +/10G. Available as 2 and 3 axis. From $39+GST Serial Accelerometer A 3 axis accelerometer up to +/-6g with a simple RS232 serial interface. Available as card or enclosed. From $105+GST Dual Axis Gyro This is the first dual-axis MEMs gyro available. The IDG-300 is a 3.3V IC with a smaller profile than other single axis gyros. $99+GST Proximity Switches Inductive Proximity switches in both square and tubular forms. Detection distances from 4 to 12mm. PNP and NPN outputs From $22.50+GST Photoelectric Switches These Photoelectric switches range from 0.4m to 15m. Available with PNP and NPN outputs From $44.50+GST Temperature and Humidity Industrial grade. Wall and Duct Mount. From $209+GST Pressure High quality Industrial Pressure Sensors. Range from 0-0.5 to 0 – 1500 Bar. 4-20mA Output. $399+GST Contact Ocean Controls Ph: 03 9782 5882 www.oceancontrols.com.au February 2008  37 SILICON CHIP + + On + Off + Identity UHF Remote Mains Switch Transmitter Fig.3: this full-size artwork can be used as a drilling template for the front panel. that its top edge is about 8mm above the top of the main PC board. That done, check that it is correctly oriented before soldering its pins. LED1 must be installed so that the top of its lens is 14mm above the PC board (ie, level with the switch top). Be sure to orient it with its anode lead (the longer of the two) to the left. The board assembly can now be completed by installing the antenna coil. This is made from a 170mm length of 1mm enamelled copper wire (ECW). First, cut the wire to length and scrape away about 3mm of insulation at each end, then shape the wire into a spiral by winding it around an 8mm mandril. Once that’s done, solder one end of the antenna coil to the antenna PC stake and the other end directly to the PC board. Final assembly The final assembly basically involves fitting the board inside the case. The first step is to feed the battery snap leads through from inside the battery compartment and then down through the two holes in the PC board – see Fig.2. That done, solder the leads to their respective PC stakes, taking care to ensure that the polarity is correct. Now connect the battery and check that the voltage between pins 14 & 5 of IC1’s socket is close to 5V when S1 is pressed. If this is correct, install IC1 with its notched end towards REG1. LED1 should now briefly light each time S1 or S2 is pressed. If it doesn’t, check the LED’s orientation. Assuming all is well, the PC board can now be fitted into the base. It’s secured to the four integral stand-offs using M3 x 6mm screws. That done, set the identity and encode switches to match those in the UHF Remote Mains Switch. Now check that the UHF transmitter controls the UHF Remote Mains Switch by pressing the On and Off buttons. The neon indicator below the mains socket should come on when the transmitter’s On button is pressed and go out when the Off button is pressed. If it doesn’t work, unplug the UHF Remote Mains Switch from the wall socket and check the identity and encode switch settings in the two units. If it still doesn’t work, go over the transmitter assembly carefully and check for errors. Note also that the transmitter will not operate the UHF Remote Mains Switch if they are too close to each other. The two units must be separated by at least one metre. Once everything is working, attach the lid to the transmitter case. If you are building the unit from a kit, the lid will be probably be supplied with all holes pre-punched and with a screenprinted label. If not, then you will have to drill the holes yourself. These holes can be drilled using the front panel label shown in Fig.3 as a template. You will need to drill two 10mm holes to clear the switch caps, a 3mm hole for the LED and a 9mm hole to give access to the Identity switch (note: the latter is not necessary if you intend using the transmitter with just one UHF Remote Mains Switch). By the way, it’s best to make the larger holes by first drilling small pilot holes which can then be further drilled out to about 5mm. These holes can then be carefully reamed out to their correct sizes. That done, the front-panel artwork can be downloaded from the SILICON CHIP website, printed onto photographic paper and attached to the lid using an even smear of clear silicone sealant. Alternatively, you can print a mirror image of the panel onto clear overhead projector film and attach this with the print side towards the panel, again using clear silicone sealant. That’s it – your UHF Remote Mains Switch Transmitter is now complete SC and ready for action. Looking for real performance? Completely NEW projects – the result of two years research • • • • 160 PAGES From the publ ishe rs of 23 CHAPTE Learn how engine management systems work RS Build projects to control nitrous, fuel injection and turbo boost systems Switch devices on and off on the basis of signal frequency, temperature and voltage Build test instruments to check fuel injector duty cycle, fuel mixture and brake and coolant temperatures 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. 38  Silicon Chip Intelligent turbo timer I SBN 09585 2294 9 780958 5229 -4 46 $19.80 (inc GST) NZ $22.00 (inc GST) TURBO BOOS T & nitrous fue l controllers How engin e management works siliconchip.com.au SERVICEMAN'S LOG Hopelessly devoted to you When is it time to retire an ageing TV set? Most people are only too happy to scrap a faulty set and go and buy the latest technology. Then there are those who are too devoted to their existing set to see it go – especially if they paid a lot of money for it. Loewe sets can be a problem when it comes to quoting. Invariably, their owners have parted with a motsa for what is undeniably a very good set and that’s where psychology comes in. The implication is that because they have spent top dollar, they have bought the very best and therefore it is not likely to break down. Or if it does, it won’t be serious (or so they think). Unfortunately, in reality, there is very little correlation between buying a complex high-tech set and reliability. In fact, you could argue that there is more to go wrong in a complex set. Anyway, a neighbour brought in his Loewe Concept 7000 which was dead. And for some reason (possibly to do with the foregoing), he was under the strong impression that it was either a fuse or a small adjustment and that it would cost very little to fix. I plugged it in and the red standby siliconchip.com.au LED immediately came on. Then, when I switched it on, I could momentarily hear a hiss as the EHT came up, after which the set reverted to standby mode. My next drama was identifying which chassis this was. Its “Art No.” was 52431 and it said it was a 110C93. Eventually, I determined that it was a 1993 C9003/93 chassis, which made the set 14 years old. Despite its age, the cabinet looked to be in mint condition. However, when I removed the back, I discovered that the chassis was badly corroded (it’s amazing what seaside salt-air does to electronic equipment). That by itself should also have condemned the set. In view of this, I told my neighbour that I thought the set wasn’t worth fixing. Even if I fixed the current problem, it would probably fail again within a very short time for other reasons. Items Covered This Month • Loewe Concept 7000 TV set (C9003/93 chassis) • Grundig Xentia 72 Digi100 M72-420/8/Dolby TV set (CUC1038 chassis). • Philips 43PP925/79 CRT rear projection TV set (A10PTV2.0 chassis). Unfortunately, he just kept looking at the smart front of the set while murmuring something about Loewe being the “Tiger Tank of German TVs”. In short, he wanted it fixed and I couldn’t persuade him that it really wasn’t worth it. In the end, I gave in and got on with it. First, I removed the chassis and checked for dry joints and for signs of overheating. That done, I cleaned the chassis and left a film of CRC 2-26 all over it to help protect against further corrosion. February 2008  39 Serviceman’s Log – continued good luck came to an end. A few days later, mother was vacuuming away and reversing herself and the machine without looking and backed right into the set. Oops! The vacuum cleaner cracked the screen on impact. It was an expensive non-warranty write-off. Unfortunately, that wasn’t to be the end of it. Next, the kids, bless them, in a bit of rough and tumble, knocked over the remaining set and oops again – then there were none! They had to bite the bullet and go out and buy two new sets. Switchmode supplies Because the EHT had initially come up, I suspected that the protection circuit had been activated by a faulty vertical output IC (I561). This IC is – or rather was – a TDA8175 which can be difficult to obtain these days. However, you can substitute a TDA8172 and change 10 other components around it. Fortunately, I managed to get one of the last ones in captivity but I was disappointed to find that this didn’t completely fix the fault symptom. Instead, the set was now coming on with sound and a very dull picture before cutting off again. When I first tried it, it cut off very rapidly but over time, it began taking longer and longer. The dull picture was due to a beam limiting problem and was caused by R546 (10kW) going open-circuit. This connects +U200V to the ABL circuit on the earth end of the EHT overwind. Replacing R546 (which was corroded) restored the picture, while resoldering a few dry joints on the CRT socket enabled the set to stay on permanently. Now that the set was more or less working properly, I found that there was no remote control. I removed the front control panel which is clipped in with its PC board upside down and 40  Silicon Chip was horrified at its condition. Some of the tracks on the board were almost completely gone in parts and others had already been repaired with wire jumpers. If the board had not been designed to fit in upside down, its tracks would not have been so badly affected. In the end, I cleaned it up as best I could and fitted additional jumpers over the corroded tracks. This restored all the remote functions and the set was now working satisfactorily – but for how long? When luck runs out Some people have all the luck (or lack of it), don’t they? A family went out and bought two Panasonic LCD TVs. The pictures were great and they performed excellently for a whole year and everyone was very happy. One day a violent storm passed overhead and one of the TVs was struck by lightning. It came into our workshop with a blown power regulator. The part was not available and so Panasonic replaced the entire set under warranty. You can’t get better than that can you? Well, it was about here that their Over the years, I have repaired many hundreds of switchmode power supplies, from the early Philips K9 to the multiple types we have today. When they blow up, it is almost always spectacular, with the pyrotechnics occurring on both sides of the PC board. Occasionally though, you get the sneaky ones that do not show any sign of failure except that the fuse has blown and there is still +350V sitting on the reservoir capacitor a fortnight later. If it doesn’t actually bite you, it might easily destroy other components if you unwittingly use solder wick. If you forget to discharge the capacitor and put your ohmmeter on it, you can be assured that an internal resistor will vaporise! And discharging it directly with a pair of pliers or a screwdriver will show you how much power is stored in “them thar” capacitors. In fact, I am always nervous about discharging these electros and I prefer to use a 240V 100W globe. Repairing these power supplies requires concentration because you almost always have to find all the faulty parts using an ohmmeter and you cannot afford to overlook anything or make a single mistake, otherwise it will all blow up again. Basically, you have to examine several stages separately. First, the switching FET/transistor will be short circuit and the fuse or resistor between the +350V rail and the switcher will be open-circuit (or the current limiting resistor could be between the emitter/ source and the negative rail). While you are furiously replacing these obviously blown parts you are constantly asking yourself why did this occur? Was it a short in the secondary? Was it a surge in the mains? Or was it the drive to the transistor/FET? siliconchip.com.au The base/gate is usually directly connected to the driver (IC) and this will usually be damaged as well. It will not be possible for you to check this completely and bearing in mind the price of the switching device, it is always best just to replace it at the same time. There will be people out there who will say why don’t you power it up slowly using a Variac and a limiting globe in series and measure the voltages as it comes up. Well, this can sometimes work and help with the diagnosis but most switchmode power supplies will turn fully on at about 90V and can still destroy themselves, even with a limiting globe. Right now, I am battling a Grundig power supply and I will use this as an example. This supply is for a 2001 Xentia 72 Digi100 M72-420/8/DOLBY TV set using a CUC1038 chassis. Initially, I went to the client’s house and saw immediately that fuse Si 60501 was open circuit. This fuse feeds +315V to a 2SK2699 switching FET (T60506). Because of the work involved, I took the chassis back to the workshop. First, I replaced the FET, checked its insulator and replaced the TDA16846 driver (IC60510). I then carefully removed and tested all the components around these parts but could find nothing wrong. Unfortunately, a fault was still present because when I subsequently powered it up, it took maybe 1-2 seconds before it blew up again. I replaced these parts again and also the two CN17F1 optocouplers siliconchip.com.au (OK60531) to the control IC, the 220pF 1.6kV capacitor (C60509), the 47mF electro (C60511) and the 10W resistor (R60000) between the IC and the FET. None of these parts measured faulty on my ohmmeter but then again an ohmmeter is not the “be-all and end-all” when it comes to test equipment. By that stage, there really were very few parts that I hadn’t thoroughly checked out of circuit. In fact, all the resistors and capacitors had been checked and that left only the chopper transformer (TR60500) and the secondary diodes. I could measure no shorts on any of the output rails and I was forced to conclude it was the transformer itself that had shorted turns. Unfortunately, I didn’t have access to another set and the cost of a new transformer was over $400 – if available. And that meant that the set was a write-off, even though I had spent a lot of time and used up a lot of expensive parts proving this. Either I have overlooked something or it really is the transformer but this cannot be proved one way or the other until an identical set comes in and I can swap parts. For that reason, I won’t be scrapping it just yet – just in case! Another example was a 2002 Philips 43PP925/79 CRT rear projection TV using an A10PTV2.0 chassis. This set was hit during a storm and was now completely dead with not even the standby LED coming on. A quick check showed there were no blown fuses and in fact I had +130V all the way to the line output transistor’s collector. However, I soon found that I had no 5V or 3.3V standby voltages, though there was no sign of any component damage in the switchmode power supply. A few quick checks revealed that R3216 (10W) was open-circuit, while IC7211 (TOP221P) was short-circuit. This latter device is part of the TOP switch-II family of 3-terminal PWM switches. Replacing these restored the standby voltages and the set worked again. Antenna installations Commercial antenna installations are a steady source of income for those who know what they are doing. We have long since moved on from blocks of units that were fitted out with ribbon cable or “Concordia” coaxial cable by untrained electricians or part time telecommunications technicians (Concordia was a cheap air-cored coax cable introduced from the UK in the 1970s, with only a 40% copper braid sheath). Today’s antenna contractor has to be familiar with both analog and digital reception and has to be tooled up with expensive digital field strength meters, not to mention all the ladders and safety gear. Investment and commitment is now the name of the game and if you are at the cutting edge, then you are also in high demand. A heavy storm can render dozens of home unit installations inoperative all over the city. Those body corporates wanting multiple quotes can find themselves facing long delays and complaints from individual unit owners. The pressure on the body corpo- February 2008  41 STIC FANTAIDEA GIFT UDENTS FOR SFT ALL O S! AGE THEAMATEUR SCIENTIST An incredible CD with over 1000 classic projects from the pages of Scientific American, covering every field of science... THE LATEST VERSION 4 – WITH EVEN MORE FEATURES! Arguably THE most IMPORTANT collection of scientific projects ever put together! This is version 4, Super Science Fair Edition from the pages of Scientific American. As well as specific project material, the CDs contain hints and tips by experienced amateur scientists, details on building science apparatus, a large database of chemicals and so much more. ONLY 62 $ 00 PLUS $10 Pack and Post within Australia NZ P&P: $AU12.00, Elsewhere: $AU18.00 “A must for every science student, science teacher, science lab . . . or simply for those with an enquiring mind . . .” Just a tiny selection of the incredible range of projects: ! Build a seismograph to study earthquakes ! Make soap bubbles that last for months ! Monitor the health of local streams ! Preserve biological specimens ! Build a carbon dioxide laser ! Grow bacteria cultures safely at home ! Build a ripple tank to study wave phenomena ! Discover how plants grow in low gravity ! Do strange experiments with sound ! Use a hot wire to study the crystal structure of steel ! Extract and purify DNA in your kitchen !Create a laser hologram ! Study variable stars like a pro ! Investigate vortexes in water ! Cultivate slime moulds ! Study the flight efficiency of soaring birds ! How to make an Electret ! Construct fluid lenses ! Raise butterflies as experimental animals ! Study the physics of spinning tops ! Build an apparatus for studying chaotic systems ! Detect metals in air, liquids, or solids ! Photograph an ant's brain and nervous system ! Use magnets to make fluids into solids ! Measure the metabolism of an insect . . . ! and many, many more (a thousand more, in fact!) See the V2 review in SILICON CHIP, October 2004. . . or read on line at siliconchip.com.au This is the ALL-NEW Version 4 . . . it’s even BETTER! HERE’S HOW TO ORDER YOUR COPY: BY PHONE:* (02) 9939 3295 9-5 Mon-Fri BY FAX:# <at> (02) 9939 2648 24 Hours 7 Days BY EMAIL:# silicon<at>siliconchip.com.au 24 Hours 7 Days BY MAIL:# BY PAYPAL:# PO Box 139, Collaroy NSW 2097 silicon<at>siliconchip.com.au 24 Hours 7 Days * Please have your credit card handy! # Don’t forget to include your name, address, phone no and credit card details. BY INTERNET:^ siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information There’s also a handy order form inside this issue. Exclusive in SILICON Australia to: CHIP siliconchip.com.au 42  Silicon Chip siliconchip.com.au Serviceman’s Log – continued rate to get a failed antenna system fixed ASAP can be enormous – especially if a sports final is not far away. Experienced contractors have seen it all before and are just not interested in recalcitrant corporate bodies or unit owners. If you want to take on an antenna contractor, you will quickly find yourself outside the loop. There are many instances when a crew has been called in to fix the antenna system in a high-rise block of units, only to find at least one unit owner who is un-cooperative when it comes to accessing that particular unit. The contractor’s response is straightforward – troublemakers are simply siliconchip.com.au wired out of the system altogether and end up paying triple the cost to be reconnected much, much later. Recently there was a high-rise block of 20 units that lost all reception in half the units. The first contractor called and on seeing that the oldish block was wired with Concordia cable, quoted $49,000 to rewire the lot with RG6 Quadshield and would not contemplate just doing a repair. A younger contractor did a quick survey and found out that there was plenty of signal at the top head-end (105dB) but nearly nothing (48dB) on the trunk and just stray pick-up at all the wall sockets (9-60dB) on all the floors below. He recognised that there had to be a break or a short somewhere between the distribution amplifier and the top floor. He quoted $1600 to repair and replace all the old fashioned wall plates as well and the job was accepted, providing it was effective. The clients really wanted a low-cost repair as opposed to a costly upgrade, which would have required a levy. Sooner or later, of course, the full job will have to be done properly. And that means wiring it in a star formation instead of the loop installation that’s currently in place. In this case, the contractor was exceptionally lucky in finding that the output plug of the splitter had been wired with Concordia cable and a single strand of copper wire was shorting the core lead to the shield. When this was cleared, each wallplate on all the floors now had 60-80dB with CSI (Channel Status Info) of 25% on analog and a bit error greater than -E7 on digital as per the Australian Standard. This was quite surprising considering the quality of cable being used. In fact, the technician was delighted to find 70dB of good signal on the ground floor. What’s more, the entire job was finished in less than a day. On another note, these days the antenna installation is coordinated with the architect and the antenna contractor. An electrician usually installs the cabling and the final commissioning is done by the contractor. Most large installations are divided into separate channels using digital amplifiers. These are often integrated with computerised 2-way AV systems. However, the actual antenna is still probably the weakest link and is often taken out along with its preamplifier during electrical storms. This particularly applies to high-rise blocks. Some blocks in city centres rely on satellite reception because there are no adequate off-air signals. In this case, the digital picture information is encoded on an analog subcarrier and decoded using a COFDM to PAL processor; eg, Channel 6 is converted to a PAL Channel 7 RF signal. This type of system costs in excess of $12,000. Builders who have gone bankrupt or are just bad payers can also cause problems for contractors. Another problem is that installations are sometimes contracted out to untrained and incompetent part-time amateurs. This can cause huge problems for new unit owners, as no-one knows who did the job or the circuit and layout used. A contractor who’s subsequently called in to solve the problems then has to guess his way around the installation to track down the faults and make the necessary modifications. Apparently, there have even been instances of sabotage, usually by a disgruntled creditor. Unfortunately, by attempting to re­ pair dodgy installations, a reputable contractor can have his own reputation unfairly tarnished. According to one industry source, sometimes it’s better not to even quote for these SC “stuff-ups”. February 2008  43 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. Using the Enhanced Voice Recorder in a model railway Since publication of the Enhanced 45-Second Voice Recorder in the December 2007 issue of SILICON CHIP, we’ve had requests for more information on using the recorder module in a model railway layout. Presumably this is for providing station announcements, loco whistle sounds etc, whenever a train passes over reed switch sensors placed under the track in various places. This circuit (Fig.1) shows how this can be done. The basic idea is to connect the reed switch sensors (as shown in the diagram on page 70 of the December 2007 issue), so that each one pulls one of the module’s MSG-bar lines down to ground, whenever the magnet on a train loco passes overhead. It’s a good idea to connect a 4.7mF tantalum or electrolytic capacitor across each reed switch as well, to ensure that even if the loco magnet passes over the switch very briefly, the module input line is still effectively pulled down to logic low (0V) for long enough to trigger message playback. This works because even a brief reed switch closure discharges the capacitor across it but when the switch opens the capacitor must recharge (through the 22kW pull-up resistor inside the module) before the voltage across that input rises to logic high level again. So the effective logic low/switch closure time is extended long enough to ensure reliable message triggering. The rest of this new circuit is provided to show you how the replayed announcements or sounds from the recorder module (fed through a small audio amplifier) can be switched automatically to any of eight different speakers, using the same reed switch closures. This should give greater realism, because the sounds concerned will emanate from the specific location of the train rather than from a single centralised speaker. The way the circuit works is by using eight D-type flipflops (in IC4 & IC5) to store the status of all eight message trigger lines, whenever any one of the trigger lines is pulled low by a closure of its reed switch. The storage is produced by a positivegoing edge produced by 8-input gate IC3, used here as a negative input logic OR gate. Eight of the inverters in IC1 and IC2 are used to invert the message trigger line levels, so only the line which has been pulled low will be stored as a ‘1’ (the rest, being high, will be stored as a ‘0’). The eight outputs from the storage flipflops inside IC4 & IC5 are connected to eight relay driver circuits using transistors Q1-Q8. As a result, the relay (RLY1 - RLY8) corresponding to the message line which was pulled down by its reed switch will be energised, switching the output of the audio amplifier through to that particular speaker. For example, if reed switch 8 was closed, a ‘1’ will be stored in flipflop 5 of IC4 and O5 (pin 15) of IC4 will go high, causing Q8 to be turned on and energising RLY8 to switch the audio through to speaker 8. Whichever speaker is turned on to replay the sound at that location also needs to be turned off again, when the replayed sound or message ends. This automatic turn-off is achieved by the simple circuitry involving diode D1 and inverter IC1f, which senses the BUSY-bar logic signal available from pin 10 of the HK828 recorder chip inside the recorder module. This logic signal goes low during playback (or recording) of any of the messages and returns high only when the message ends. The ‘return to high’ edge of the signal is differentiated by a 100nF capacitor and 100kW resistor and clipped by diode D1 at the input of IC1f, to produce a brief positivegoing pulse. IC1f inverts this pulse to produce a brief active-low reset pulse for both IC4 & IC5. As a result, all the storage flipflops are reset at the end of any message playback, turning off all relays at the same time. The relays used in this circuit are not critical but should be capable of operating from 12V with a coil current of no more than about 30-40mA. The low cost SY-4066 relays sold by Jaycar would be quite suitable. Jim Rowe, SILICON CHIP. C h o o s e Yo u r P r i z e There are now five great reasons to send in your circuit idea for publication in SILICON CHIP. We pay for each item published or better still, the best item in “Circuit Notebook” each month will entitle the author to choose one of four prizes: (1) an LCR40 LCR meter, (2) a DCA55 Semiconductor Component Analyser, (3) an ESR60 Equivalent Series Resistance Analyser or (4) an SCR100 Thyristor & Triac Analyser, with the compliments of 44  Silicon Chip Peak Electronic Design Ltd. See their website at www.peakelec.co.uk So now you have even more reasons to send that brilliant circuit in. Send it to SILICON CHIP and you could be a winner. You can either email your idea to silchip<at>siliconchip.com.au or post it to PO Box 139, Collaroy, NSW 2097. siliconchip.com.au siliconchip.com.au February 2008  45 REED SWITCH 1 M1 M2 M3 M4 M5 M6 M7 4.7 F REED SWITCH 8 CLOSE FOR RECORDING IC2c IC2b IC2a 7 12 11 6 5 4 3 2 1 IC1e 4.7 F 11 5 3 1 14 10 9 6 5 4 3 2 1 14 7 +5V 8 6 4 2 +5V 8 D1 1N4148 100nF IC3: 74HC30 IC1d IC1c IC1b IC1a 14 IC1,IC2: 74HC14 A K 3 4 6 11 13 14 3 4 6 11 13 14 D5 IC5 16 8 O3 O4 O5 O0 MR 1 D0 CP 9 D1 7 IC1f 12 8 12 15 +5V 2 5 7 10 12 15 +5V 2 5 END OF MESSAGE O0 MR 1 O1 D2 74HC174 O2 D3 D4 9 D0 CP O2 O1 D1 100k 13 O4 O5 10 IC4 O3 74HC174 7 16 D2 D3 D4 D5 REED SWITCH CLOSED AUDIO AMP 13 11 9 IC2f IC2e IC2d 3.9k 3.9k 12 10 8 D2 D9 A K A K B B E C E C D1 K A K D2–D9: 1N4004 A PN100 C B E Q1 PN100 RLY1 Q8 PN100 RLY8 +12V SPEAKER 1 SPEAKER 8 Fig.1: the circuit uses reed switch sensors to pull the voice recorder module’s MSG-bar lines to ground whenever the magnet on a train loco passes overhead. The module then outputs the appropriate audio message. In addition, the reed switches pull down the inputs of inverters IC1a-IC1e & IC2a-IC2c and also the inputs of 8-input gate IC3. These in turn control eight D-type flipflops in IC4 & IC5. The flipflops then drive transistors Q1-Q8 and relays RLY1-RLY8 to switch the announcements to the appropriate loudspeaker. MESSAGE BEING PLAYED PIN 10 (BUSY) OF IC1 MULTI-MESSAGE VOICE RECORDER MODULE M8 RE AUDIO OUT GND GND +12V Circuit Notebook – Continued Rechargeable cell logger & discharger This PICAXE-controlled circuit will discharge and log the discharge characteristics of up to four rechargeable cells (NiMH, Nicad, etc). The logging function allows comparisons to be made between batteries and the assembling of cells with similar discharge characteristics. It also helps in identifying suspect cells. The PICAXE (see Fig.1) drives four relays via a ULN2803A Darlington transistor array. Only four transistors in the array are used. It includes internal diodes to clip back-EMF spikes when the relays are turned off. A LED indicates when each relay is energised. Each relay switches a 1.5W 5W resistor across a rechargeable cell to provide a nominal discharge current of around 800mA. The cells are then discharged to a level of 0.9V whereupon the discharge load is disconnected. The discharge end-point can be set in the software. Relays were chosen because they are cheap and provide low resistance switching. This is important since the cell voltages are quite low and any residual resistance in the discharge circuit needs to be minimised for the logging function to be accurate. For the same reason, the cell holders must be carefully selected as they sometimes make poor connections. The 5V supply to the logger needs to be regulated to ensure the reliability of the reference for the voltages measured. An LCD display by Revolution Education was used. While both the in and out lines were connected, only the input to the LCD may be needed. Other serial LCD displays can be used but note that some program changes may be necessary. The main power switch is DPDT with centre off. The power is on in either position away from centre and the other pole pair is used for selecting the logging function or transfer of data to the PC. Discharging is shut off at 900mV. 46  Silicon Chip This is set in the ‘testbatt1’, ‘testbatt2’, etc, parts of the program. To use the Discharger, move power switch S1 to “log”, put the cells in and press reset button S2. The logger records the initial cell voltage before discharging is started. Press start button S3 to initiate discharging. The unit will log the cell voltage every minute while also monitoring the voltage and when the cell voltage falls below the set point (in testbatt1: w3 >900), the relay is turned off and the discharge of that particular cell is complete. The final voltage before the relay turns off is recorded as is the voltage after the it is off. The discharge current is about 600mA. When all cells have been discharged and the final logging has taken place, the EEPROM location of the final data byte is recorded. This gives the end point for the transfer of data to the PC if that is to take place. Logging will also be terminated when 254 minutes has elapsed. If it is desired to work with longer times then a word value is needed instead of byte or the logging period needs to be changed. For example, instead of every minute, go for every 2 or 5 minutes. This can be changed through manipulation of the value b2 is compared with in control: if b2 =60 and the pause value in final: pause 1000 Making both parameters greater will give a longer logging period. Alternatively, if the logging time is found to be too short, two runs could be performed and the results of the second run appended to the first. When logging is terminated automatically the time to discharge for each cell is given. The EEPROM is a 24LC256 which has a capacity of 34k bytes, much more than needed here but a 2500 limit is put on logging in case it tries to go further. It has the capacity to be expanded to accommodate much more data using a word to count the minutes logged. More data may not be needed and also more data means more to transfer and wade through. Excel can have problems with too much. So avoid data overload! When the unit is switched off for a few seconds and then on to the transfer function, pressing the start button and holding it for 3s will bring up the discharge times for the last operation. Pressing it again for a couple of seconds or an initial brief press will initiate the transfer of data to the PC. Be sure to have the terminal window opened in the PICAXE programmer software or a terminal program like HyperTerminal open (set to 4800 no parity 8 bits, 1 stop bit). In the PICAXE software, only the speed needs to be set. Each data word transferred to the PC is followed by a comma and each set of four words is followed by a carriage return or line feed. This facilitates the delimiting of the data, which is necessary for it to be imported into Excel. Download will stop when all data is sent. No error detection or correction has been used to keep it simple! Once the data has been transferred, the most reliable way to get it into Excel for graphing is to copy the input buffer (easy in PICAXE terminal) and paste it to Notebook. Save and then open it with Excel. On attempting to open it, Excel will determine that the data is delimited. On the first panel click next and the second one will offer you the choice as to how the data is delimited. Select comma and click next. You should then see your data in four columns. Select finish and your data will then be imported into the standard Excel format. The first row can be deleted – it has a single character that was first sent to initialise the transfer. The second row has the final times to discharge and the remainder of the data is the times recorded every minute. You can then graph these: select the spread of data you are interested in and highlight. Click the graphing icon on the toolbar, select the line graph format, then the first line sub type and then next. You should be presented with a graph of your data with four lines. You can tidy up the legends, etc, as for normal graphing and click finish. Peter Shooter, Fremantle, WA. Note: the software (Cell logger.bas) can be downloaded from the SILICON CHIP website. siliconchip.com.au Fig:1: the cells are monitored using PICAXE microcontroller IC1 and this drives four relays (RLY1-RLY4) via a ULN2803A Darlington transistor array (IC4). When activated, each relay switches a 1.5W 5W resistor across its corresponding cell to provide a nominal discharge current of around 800mA. Discharging ceases once the cell voltage reaches 0.9V. Peter S h is this m ooter onth’s winne Peak At r of a las Instrum Test ent siliconchip.com.au February 2008  47 Circuit Notebook – Continued Infrared light beam relay This circuit projects an infrared beam across a doorway or path to enable passing traffic to be monitored. The beam is switched at 20kHz using an LM567 phase lock loop, IC1. This drives transistor Q1, a BD140, which in turn drives infrared LED1. The infrared beam is reflected back by any passer-by and sensed by optotransistor Q2, connected in Darlington mode with Q3. In standby state, with no IR being sensed by Q2, IC1’s pin 8 output is high and transistor Q4 is biased on by a 10kW resistor. This pulls down the trigger input of 555 timer IC2 which is wired here as a simple inverter to drive relay relay RLY1. LED2 is a standby indicator. Novel neon flasher has low current drain This circuit was developed to revive a now obsolete novelty, the neon flasher. However, while past neon flashers have been relaxation oscillators with the neon being the “relaxation” element, this circuit uses a CMOS oscillator to drive a Mosfet and transformer to flash a neon at around 1Hz. The current drain is low, at around 200mA (depending on brightness) from a 9V supply. IC1a is a 1Hz oscillator with a long duty cycle, by virtue of diode D1 in series with the 1kW resistor and VR1. IC1b inverts the pulse signal and feeds it to Mosfet Q1 which thus has a very short duty cycle. Q1 drives a 12V relay coil or similar inductor (L1) to develop a train of large positive pulses. This pulse train is then fed to the neon lamp and a parallel 48  Silicon Chip 8 9 12 When the infrared beam is reflected by a passer-by, it is sensed by phototransistor Q2 and IC1’s output at pin 8 goes low and turns off Q4. This causes IC2’s output at pin 3 to go low and turn on the relay. This condition is maintained as long as the reflected IR signal is being received. T. K. Hareendran, Kerala, India. ($40) IC1c D BUZ71 10 L1 D2 47k IC1d G 11 D 13 1 9–12V BATTERY D1 220 F 16V 2 A K 14 3 IC1a 1k 6.8M 5 VR1 100k Q1 BUZ71 S 6 IC1b 4 1k G 7 IC1: 4093B A K D S NEON LAMP 100nF 400V 470nF D1: 1N4148 A K 100nF capacitor via diode D2. Interestingly, there is no diode across L1 which would normally be there to protect Q1 against the large positive spikes. In this circuit, we do not want any clipping. Instead the peak voltage at the drain of Q1 is ultimately limited by the neon D2: 1N4007 A K itself, to a voltage between 60V and 90V, depending on the on-time set by VR1. Hence, Q1 must be able to withstand relatively high voltages, which is why a BUZ71 or similar high voltage Mosfet is specified. Thomas Scarborough, Cape Town, South Africa. ($50) siliconchip.com.au BACK TO SCHOOL BACK TO WORK WATER MANAGEMENT KITS PIC Based Water Tank Level Meter Kit Ref Silicon Chip November 2007 This PIC-based unit uses a pressure sensor to monitor water level and will display tank level at the press of a button. The kit can be expanded to include an optional wireless remote display panel that can monitor up to ten separate tanks (KC-5461) or you can add a wireless remote controlled mains power switch (KC-5462) to control remote water pumps. Kit includes Cat. KC-5460 electronic components, case, screen $99.95 printed PCB, and pressure sensor. Telemetry Base Station for Water Tank Level Meter Ref Silicon Chip January 2008 This Base Station is intended for use with the telemetry version of the KC-5460 water tank level meter. It has an inbuilt 433MHz wireless receiver and can handle data transmissions from up to 10 level meters and display the results on a 2-line 32Cat. KC-5461 character LCD module. Kit includes electronic components, case, $79.95 screen printed PCB and RF module. UHF Remote Controlled Mains Switch Ref Silicon Chip February 2008 Commercial remote control mains switches are available but these are generally limited to a range of less than 20m. This UHF system will operate up to 200m and is perfect for remote power control systems etc. The switch can be activated using the included hand held controller or our KC-5460 water tank level sensor base station. Kit supplied with case, screen printed PCB, RF modules and all electronic components. Cat. KC-5462 $99.95 PIR Controlled Mains Power Switch Ref Silicon Chip February 2008 You’ve seen those lights fitted with PIR detectors that turn on when someone approaches. Well now you can do the same thing with just about any mains powered device you like including security systems, decorative lighting, fountain pumps or even commercial advertising etc. The system uses a standard PIR to safely turn on 240VAC mains device(s) for an adjustable pre-set period. Kit supplied with case, screen printed PCB, and all electronic components. Cat. KC-5455 $79.95 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 Low Cost DMM This is a full featured meter with plug-in 4mm probes AND transistor tester. It is an ideal first multimeter and will give years of faithful service. Specifications: DC Voltage: 200mV to 1000V c Fantaseti DC Amps: 200uA to 10A Pric AC Volts: 200V to 750V Cat. QM-1500 Resistance: 200 ohm to 2M ohms $7.95 Size: 125(H) x 68(W) x 23(D)mm Temperature Controlled Soldering Station An effective yet simple soldering station that features a ceramic heating element to provide precise temperature control. The soldering iron weighs just 45g which makes it Cat. TS-1560 ideal for comfortable long term use. $99.00 General Specifications: Temperature Range 200 - 480°C Power consumption 60W Operating voltage 240VAC Control unit 140mm long Voice Reductions These compact recorders are packed with features to suit students, real estate agents and executives. Both supplied with driver, editing software and USB interface lead. 8hr Digital Voice Recorder with USB interface SAVE $30.00 • 8 hours recording time • Requires 2 x AAA batteries • Built in flash memory Cat. XC-0255 Was $99.95 $69.95 18hr Digital Voice Recorder • 9hrs in high quality mode and 18hrs in short play mode SAVE • ‘Plug & play' technology $50.00 • 8 folders to organise your recorded messages Cat. XC-0256 • MP3/WMA player • USB storage device $149.95 • Requires 2 x AAA batteries Was $199.95 7" LCD In-Car TV with Remote Featuring a motorised 7" TFT LCD screen, this unit fits into a standard automotive DIN opening and takes two extra video inputs and an input for a reversing camera. It also has composite video and audio output. Ideal for the caravan, motor home, or yacht. • Screen size: 7" • Display format: 16 x 9 • Resolution: 480 x 234 pixels • Includes Cat. QM-3782 analogue tuner for free-to-air TV $299.00 Uninterruptible Power Supply Guard your computer and peripherals from the shortfalls of mains power and interuptions. This UPS protects against low/over voltage, surges, short circuits and power overloads. The battery power, load, input/output voltage is displayed on an easy to read orange backlit LCD. • 3 mains sockets • Microprocessor control for high reliability • Telephone/Fax/Modem protection • Dimensions: 324(L) x 155(H) x 95(D)mm • 650VA NEW MP-5206 1500VA version also available $319.00 Cat. MP-5204 $149.00 Our Newcastle store has moved to bigger & better premises at: 230 Maitland Road Newcastle West 2302 Ph 4965-3799 Come along and check it out. AWESOME Subwoofer This new Response Precision subwoofer truly sound as good as it looks! Ideal for reverse installation with the basket displayed. • Size: 10" • Power Handling: 250WRMS • Impedance: 4 Ohms • SPL <at> 1Watt: 84dB For full specs, see website. 12” version also available CS-2354 $249.00 Cat. CS-2352 $199.00 Better. More Technical INTERNET> www.jaycar.com.au 1 CLEARANCE 100mm (4") LED Wall Clock iRecorder - iPod® Voice Recorder Adaptor Turn your iPod® into a personal digital voice recorder. Ideal for memos, lectures, interviews, or conversations. Simply plug this recorder to your iPod®. You can even copy recordings to your desktop or notebook. • Supports iPod® Generation 1, 2, 3, and 4 Cat. XC-0253 SAVE Was $49.95 $29.95 iPod® not included. This incredibly flat and light QWERTY keyboard includes wakeup, sleep and power functions so you can power down your computer from the touch of a key. Change the inclination with the two stands that are discreetly tucked away on the sides. NEW Cat. AR-2069 SAVE $7.00 iPod® not included. Cat. XC-5146 $9.95 iPod Shuffle or MP3 Player Active Tripod Speaker ® Run Your Laptop Computer from Your Car's Battery Delivers stereo sound and runs for 10 hours on one battery. • Folds away to a tiny 30 x 140mm cylinder • Requires 1 x AAA battery Was $39.95 Cat. XC-5159 SAVE $20.00 $19.95 Secret Spy Message Pen & Shredder Set Arrange clandestine meetings or just pass secret messages to your buddies at school. This intriguing set includes an invisible ink pen, a normal pen, mini shredder, and a special lamp to reveal your hidden instructions. • Batteries included. Was $16.95 Cat. ST-3105 SAVE $7.00 $9.95 Electronic Dictionary Knows 50,000, words and will help you understand practically any word you are likely to read. Features: • Flexible keyboard SAVE • Ten digit calculator $10.00 • Alarm clock • Lists the words you have looked up • Size 75(W) x 135(H) x 12(D)mm • Keyboard thickness is just 1mm Cat. XC-0185 • Uses 1 x CR2032 Was $29.95 $19.95 Solar Powered Calculator with 3 Port USB Hub A combination of a full-featured calculator, numeric keypad for laptops and a 3 port USB 2.0 hub. Requires Windows ME or later. Cat. XC-4846 Was $29.95 2 $99.00 Black QWERTY USB Keyboard Fit your iPod® Nano into this compact, lightweight holder, hang it round your neck and plug-in the neatly stored headphones for true hands free sound. Was $19.95 $19.95 A terrific introduction to the microscopic world of nature. This excellent microscope works with your computer and displays the camera output on your computer monitor. Up to 130 x magnification. USB powered. Approx. 150mm tall. Cat. QC-3244 $20.00 iPod® Nano Neck Strap with Earphones $12.95 A wall-mounted clock that can easily be seen across the room, day or night. It comes with a remote control to adjust the time after the clock has been wall mounted. It can be powered with the supplied plugpack or with 6 x AA batteries (use SB-2425). Cat. AR-1785 • Dimensions: 334(W) x 188(H) x $49.95 44(D)mm USB Digital Microscope Camera System with 130 x Magnification SAVE $10.00 This compact laptop computer power supply will deliver up to 6A <at> 20VDC and is supplied with a range of adaptors to suit most Cat. MP-3467 computers. It is $57.95 ideal for running laptops in cars or trucks or anywhere there is a 12V car cigarette lighter socket. Unwired Wireless Modem Antenna Booster This high-gain antenna replaces the existing 'rabbit ear' on your Unwired Cat. AR-3274 broadband modem and boosts the signal to $119.95 improve coverage. It can also improve performance in difficult areas. Simple and effective. Computer and modem not included. USB DVD Maker Turn your VHS video tapes into exciting video productions or record live video straight to your DVD or CD burner. Editing software lets you add effects as well as sound tracks and Cat. XC-4809 titles to your work. • Requires PC with suitable burner. $99.00 D.I.Y. KITS Audio Playback Adaptor for CD-ROM Drives Refer Silicon Chip Magazine November 2007 Put those old CD-ROM drives to good use as CD players using this nifty adaptor kit. The adaptor accepts signals from common TV remote controls and operates the audio functions of the drive as easily as you would control a normal CD player. Kit features a double sided PCB, Cat. KC-5459 pre-programmed micro controller, and $64.95 IDC connectors for the display panel. USB Experimenter's Interface Kit Interface your computer to the real world. There are five digital and two variable Cat. KV-3600 gain analogue inputs. Eight digital and $69.95 two analogue outputs are available. Supplied with all components, silk screened PCB, assembly manual, and software. Miniature Digital Video Cameras Spoil yourself with these fantastic digital video cameras that fit into the palm of your hand. Sensational value. QC-3230 3.1MP • 3.1 mega pixel software resolution for stills • 32MB built in memory. SAVE • 1.5" LCD Colour Flip-out Screen $90.00 • 4 x Digital Zoom for still photo capture • Playback on TV • Built-in speaker • Self Timer • SD/MMC memory expansion • Requires 2 x AA batteries Cat. QC-3230 Was $179.00 $89.00 Better. More Technical QC-3234 6.6MP • 16MB internal memory • Accepts SD / MMC cards • 1.5" colour TFT rotatable screen • Video recording with sound • Still shots • PC camera • MP3 player • Requires 4 x AAA batteries Cat. QC-3234 Was $299.00 SAVE $150.00 $149.00 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au THANKS FOR THE MEMORIES These are 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. 7" Video Picture Frame with AV input 10" Electronic Photo Frame 10.4" Wooden Frame Bluetooth Enabled • QM-3768 Black acrylic Specifications: • Resolution: 480 x 234 pixels • Supports SM, SD, XD, MS & MMC card formats • Supports MPEG1, SAVE MPEG2, MPEG4, JPEG $50.00 • Power supply: 12VDC Was $299.00 • White Acrylic • Power adaptor included Specifications: • Resolution: 480 x 234 pixels • Supports SM, SD, XD, MS & MMC card formats • Supports MPEG1, MPEG2, MPEG4, JPEG • Power supply: 12VDC NEW 12.1" Black Acrylic • Resolution: 640 x 480 • Accepts CF, SD, XD, MMC and MS cards • Supports JPEG, MBP, AVI, motionJPEG, MPEG1, MPEG4, MP3, & WMA • Calendar and clock functions • Resolution: 640 x 480 • Supports SM, SD, XD, MS & MMC cards • Supports: MPEG1, MPEG2, JPEG, MPEG4, MP3, WMA, Divx/Xvid Cat. QM-3774 $349.95 Cat. QM-3767 $349.00 Cat. QM-3768 $249.00 Cat. QM-3765 $179.00 USB Hub Traffic Light with Recorder In addition to being a 4-port USB 2.0 hub, this little gizmo also records and plays back up to 10 seconds of speech to store a short reminder. Turn your traffic lights to red when you want to be left alone, green when you feel sociable, or amber when you want to procrastinate. Cat. GE-4099 • Base 65 x 65mm • 125mm high $14.95 Relaxing, tension relieving massage for your back! Just attach to a high backed chair and let one of the 3 programmable settings soothe away those aches and pains. Comes with PSU Cat. GH-1762 and control pad. Exercise within safe limits and monitor your work out with this handy heart rate monitor. It has normal watch functions plus a heart rate monitor that logs current, average and maximum heart rate. • Time & date • Alarm • Back light Cat. XC-0269 • Stopwatch • 30m water resistant $39.95 Desk Mounted Magnifier Light Cat. QM-3525 $99.95 Internet Radio with Clock This Internet radio works via your existing broadband connection to give you world wide access to the streaming audio being broadcast by radio stations across the globe. The radio works in conjunction with the Reciva web site and lets you pick and choose what is sent to your radio and when. Cat. YN-8079 • 200mm wide $269.95 $119.00 Pulse Sonic® Heart Rate Monitor Watch High quality all metal frame construction with a magnifying lens and weighted base. Perfect for office or hobby use. • Includes a 22 watt circular light • 240 volt mains adaptor Shiatsu Massaging Cushion NEW NEW Mobile iPod® & MP3 Player Speakers SAVE $10.00 This nifty little unit is compatible to iPods®, MP3, players, portable CD players, laptops and PC's etc. It folds into a compact 90mm x 65mm x 60m box and weighs only 177g. Was $29.95 Colour Weather Station with Digital Photo Viewer Cat. XC-5186 iPod not included ® $19.95 Home Theatre Power Board Comprehensive protection for your home theatre system! Mains power surge protection and filtering is provided on all mains outlets. Overload protection via the in-built circuit breaker. The power board also includes protection for telephone, network data connection, satellite/cable TV video and TV aerials connections. Cat. MS-4024 One display shows up to 50 photos or a simple weather image while the other shows indoor/outdoor temperatures, humidity, barometric pressure on colourful bargraphs as well as clock, calendar and moon phase functions. • Single image or slideshow • Unit measures 70(L) x 55(W) x 200(H)mm • Mains adaptor included or can stand alone using 3 x AAA batteries • Wireless RF transmitter: 75m range $59.95 Cat. XC-0344 $129.95 NEW BLUETOOTH CAPABILITY Tiny Bluetooth Adaptor Don't be fooled by its tiny size. Has all the functions of larger adaptors but will sit almost unnoticed in your notebook's USB Cat. XC-4892 port. Just 23mm long, including the USB $39.95 connector. Bluetooth Boom Box Play your MP3s wirelessly on this excellent powered speaker system. Can also be used with wired audio devices. • Function range: 10m • Dimensions: 380(L) x 160(H) x 190(D)mm FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Stereo Bluetooth Adaptor Cat. AR-1856 $149.95 Add Bluetooth capability to virtually any audio output device. Just connect your iPod®, mobile phone, CD player, etc. to the Bluetooth adaptor and you can transmit stereo audio signals wirelessly. Cat. AR-1854 • Functional range up to 10 metres Better. More Technical $69.95 3 18W Soldering Iron This iron is perfect for precise soldering of delicate components. It offers rapid heat up, instant recovery, a stainless steel barrel and iron clad chrome plated long life interchangeable tip. Cat. TS-1551 $34.95 45 Watt Goot Soldering Iron This is a quality Japanese made temperature controlled iron. It has a ceramic heating element to provide excellent heat recovery. Also features a silicon covered power cable. Cat. TS-1430 $59.95 Cat. HB-6352 Here at Jaycar Electronics we are firmly committed to supporting young people and helping them achieve their goal of following a electrical trade or engineering career. The joint Australian Federal Government and the Australian Apprenticeship initiative also supports this and provides an allowance of up to $800 (including GST) for qualified participants to purchase 'Tools for your Trade'. $49.00 4.8 Volt Cordless Screwdriver Cat II Autoranging DMM The driver has a comfortable pistol grip that gives you maximum control and allows your fingers to fall naturally on the forward/reverse control switch. The driver also has a bright LED lamp, a magnetic bit holder, and a handy security strap. There is even a Cat. TD-2498 handy LED battery level. $19.95 • Voltage: 4.8V This Cat II DMM is suitable for voltages up to 600VAC and has 15mm high digits for easy measurement. Features include overload protection, 10A AC & DC current, diode check, data hold,& backlit display. 50W Temperature Controlled Soldering Station Temperature adjustable up to 450° with tip cleaner and lightweight 50W iron. Tools for Aluminium Attaché Case A high quality aluminium case supplied with tool pallet which can be removed if not required. Lid includes a document holder and the padded case includes 5 dividers that can be rearranged or removed. Lockable and includes two keys. • 450(W) x 320(D) x 145(H)mm Cat. QM-1524 $19.95 Auto Ranging RS-232 DMM Solder Paste 80g Syringe Ideal for surface mount work and rework, solder paste provides a quick and easy soldering solution. Supplied in a syringe for easy application. Eliminates the need for clumsy resin core solder with fine circuits. Cat. TS-1620 $49.95 SMD Soldering Iron These surface mount soldering tweezers will allow easy soldering and desoldering of all surface mount components from small resistors to large 'flat pack' IC's. The iron is mains powered and features rapid heat recovery. It is supplied with 2 x 2mm tips and a metal stand with sponge. SAA Cat. TS-1700 Approved. Larger tips to 20mm are available. $99.95 Cat. NS-3037 $29.95 Attractive double moulded case design with handy probe holders. Features a blue backlit screen and an optical RS-232 computer interface to store measurements on your computer for later analysis. • Please see our website or catalogue for full specifications. Cat. QM-1538 • Contains lead $49.95 Aluminium Desolder Tool This metal desolder tool has the strongest suction we've ever seen in this type of tool. Features include: • One hand operation Cat. TH-1862 • Automatic cleaning $15.75 • Total length - 195mm Soldering Iron Tip Cleaner Keep your iron tip clean and healthy. No wet sponge, and a rubber base to keep it where you need it. • Static safe • Suitable for lead-free solders • Supplied with spare insert • Measures 60(dia) x 58(H)mm Cat. TS-1510 Lead Free Solder Works just as well as ordinary solder but contains no harmful lead. Supplied on a 45gm roll with handy cover and available in two sizes. NS-3082: 0.8mm dia. NS-3084: 1.0mm dia. Multifunction ESD Safe Soldering Station Features a soldering pencil and a hot blower for rework applications. Both have adjustable temperature and air flow is adjustable. $12.95 Goot Desolder Braid High quality Goot brand "Gootwick", made in Japan. Contains wash-free RMA flux and conforms to MIL-F-14256F. • Supplied in plastic reels. • 1.5 metres long • Three widths available 1.5mm, 2.0mm, 3.0mm. Cat. TS-1570 $299.00 Cat. NS-3082 $15.95 4 Cat. NS-3084 $15.95 Cat. NS-3026 See our website for full details. Better. More Technical $4.95 Cat. NS-3027 $4.95 Cat. NS-3028 $4.95 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Your Trade The employer of eligible Australian Apprentices receives a voucher to the value of $800 which can be presented to any Jaycar store. Bring your voucher in and our staff will be happy to help you find the best tools for your trade. For more information visit www.toolsforyourtrade.com.au Precision Screwdriver Set This precision screwdriver set consists of 3 Flathead and 3 Phillips head drivers, and is supplied with a handy stand to house your investment. Cat. TD-2017 $11.50 IP67 Rated DMM for Harsh Environments This DMM can be taken places where the others can't go. IP67 rated, it can survive harsh environments and will resist the ingress of fines everywhere from the dusty, dirty outback to any filthy warehouse in the big smoke. • See website or catalogue for full specifications. 7 Piece Screwdriver Set 1000 Volt Rated High quality, bright red drivers you can find easily. Insulated right to the tip and rated to 1000V. Includes Phillips and slotted drivers. Cat. TD-2022 $19.95 Autoranging DMM With USB Datalogging Interface The USB interface is much simpler than older RS-232 serial connections and offers plug & play setup and reliable data logging capability. You still get the vast array of features you expect from a high end DMM including large, easy to read display and temperature readings for both ambient temperature and the probe temperature Cat. QM-1462 reading. $139.95 100 pc Driver Bit Set This must be the ultimate driver bit set. It includes just about every type of bit you could imagine - even one for wing nuts! 110mm Precision Side Cutters These cutters are precision ground and are perfect for cutting super fine wire as well as for general workshop use. The insulated handles are spring loaded for effortless use. • 110mm long • Blade hardness: Cat. TH-2332 Rockwell C Scale 57~61 $24.95 • Soft grip handle 110mm Precision Long Nose Pliers These are the perfect companion for our TH-2332 precision side cutters and are made to the same exacting specifications. They also feature sturdy box joint construction and will last for many years. The insulated handles are spring loaded for effortless Cat. TH-2334 use. $24.95 Automatic Wire Stripper A great way to strip all sorts of cable without damaging the conductors. • Automatically adjusts to insulation diameter • One hand operation • Spring return New h it Model Gwuard Finger Cat. TH-1824 Cat. QM-1541 $18.95 Cat. TD-2038 $99.95 $16.95 10 MHz Single Trace Cathode Ray Oscilloscope (CRO) This entry-level oscilloscope is ideal for the tradesman or advanced hobbyist who is working with audio equipment or other low frequency applications. PVC Insulation Tape High quality insulation tape for general electrical use. Available in white, red, blue, black, grey, or yellow/green on a 20m roll • Self-Extinguished within 2 seconds • Voltage breakdown: 8.0kV Cat. NM-2852 $1.25 Cat. QC-1920 $155.00 PCB Etching Kit An ideal kit for anyone needing to etch a circuit board - complete with an assortment of double-sided copper boards, etchant, working bath and tweezers. It also includes a positive acting photosensitive PCB and developer. See web site for full list of inclusions. Adjustable Holesaws An excellent cutter designed to cut plaster board and ceiling tiles. Features calibrated hole size adjustment. Two sizes available 62 to 177mm and 158 to 264mm (TD-2522). Cat. TD-2520 $69.95 $24.95 Drill not included FOR INFORMATION AND ORDERING INTERNET> www.jaycar.com.au Adel Nibbling Tool The best hand nibbler going around. Ideal for chassis-bashing and all sorts of hobby applications. Cut, notch or trim simple or complex shaped holes in plastics, laminates, leather or metal. • Capacity: • Mild steel: 1.2mm Cat. TH-1765 • Aluminium: 1.6mm $59.95 • Plastics: 2mm • Punch to suit sold separately TH-1767 $44.95 Component Lead Forming Tool This handy forming tool provides uniform hole spacing from 10 to 38mm. Made in USA from engineering plastic. • 138mm long Cat. TH-1810 Cat. HG-9990 TELEPHONE> 1800 022 888 Fujiya Precision Tools $6.95 Better. More Technical 5 SECURITY SAVINGS Digital Video Recorder with Dome and Waterproof IR Cameras This system turns any standard TV or monitor into a 4 channel multiplexer. It can display a single camera view, or multiple combinations of different camera views including one or two picture-inpicture or automatic sequencing. The cameras are waterproof and have infrared illumination so they can see in the dark. Adjustable brightness, contrast, hue, saturation and sharpness The system includes: 1 x Quad video processor 4 x QC-3096 CMOS colour I/R bullet cameras 4 x 20m camera connecting cables (video & power) Cat. QV-3083 $1190.00 2.4GHz Baby Monitor with LCD Screen & IR Colour Camera Has a specially designed indoor colour CMOS camera and hand-held LCD monitor, that enables you to monitor your home, children or elderly residents even when it gets dark. Link the monitor to a VCR to record what the camera captures or link it to a TV that has the 'Picture-in-Picture’ feature to keep an eye on the baby while you watch your favourite TV show. • 2.4 inch colour TFT-LCD screen • Can work with up to 4 cameras • 10 IR LED illuminator • Hi-Res colour CMOS camera • 4 channel selection • Low power consumption • 2 x PSU included • Monitor measures 65(L) x110(H)x 23(W)mm • Spare camera QC-3259 $99.95 NEW Cat. QC-3258 $199.00 Pro 8 Channel MPEG-4 DVR with GPRS Support A complete professional surveillance installation with sophisticated monitoring and recording functions. • Including network connect, DVD burner, MPEG4 compression, and 250GB HDD. Crystal clear image clarity with minimal disk consumption. • 432mm wide. Was $1399.00 Includes SAVE $100.00 Cat. QV-3088 250GB HDD $1299.00 See website for full specifications and range. Cat. QC-3492 $149.00 SAVE $50.00 Emergency 12V Lighting Controller Refer Silicon Chip Magazine January 2008 Automatically supplies power for 12V emergency lighting during a blackout. The system has its own 7.5Ah SLA battery which is maintained via an external smart charger. Includes manual override and over-discharge protection for the battery. Kit supplied with all electronic components, screen printed PCB, front panel and case. Charger and SLA battery available separately. NEW This camera is housed in a robust aluminum case and carries an IP57 rating. The Sony® Super HAD sensor and the camera's 102 infrared LEDs enable the system to 'see' up to 50 metres in total darkness. Features include: • 1/3" Super HAD CCD sensor • 480 TV line resolution • 12mm lens Was $499.00 SAVE Cat. QC-3381 $449.00 6 $50.00 ALARM BELLS 116db Car Alarm Siren This in-car siren is so loud that intruders will have difficulty staying inside your car while the alarm is sounding. • 12VDC <at> 200mA. Piezo Siren Black in colour, supplied with mounting bracket and connecting cable. • Size 100mm H (from mounting bracket to top) • Resonant freq: 3kHz • Sound output: 120dB • Current drain: 300mA Cat. LA-5258 $29.95 5" Round Horn Speaker Fully weatherproof. Unique voice coil construction ensures high dependability on full drive. • Suitable for PA, intercom, security systems etc • 8 ohm • 10 Watt Cat. AS-3180 IR Door or Perimeter Entrance Alert The perfect electronic door alert device. • Infrared beam with 20m range • High/ Medium /Low sound levels • Wide angle operation • Requires 2 x 9V batteries Cat. LA-5184 IP57 Pro Outdoor Colour Camera with Sony Super HAD CCD Sensor NEW $17.50 $69.95 A water resistance rating to IP57 makes this camera ideal for exposed outdoor applications and immersion in water up to 1m for 30 minutes. 120mm long. Operates down to 0-lux with 12 infrared LEDs. • 330 line resolution • Infrared night vision Was $199.00 Cordon off hazardous areas or create an unmistakable marker with this heavy duty PVC tape. The vivid red and white colouring will draw anyone's attention to the barrier. Cat. NM-2864 • Width: 50mm • Thickness: 0.18mm $12.95 • 33m roll • Raw material: PVC film, rubber-based adhesive • Colour: Red/White Cat. LA-5255 Cat. KC-5456 Day/Night Colour CCD Camera (IP57 Rated) Heavy-duty PVC Tape $14.95 Wireless Solar Bellbox with Siren and Strobe This siren/strobe combination includes an integrated solar panel to charge a 6V SLA battery and uses wireless RF technology to communicate with an ordinary alarm panel. Wireless receiver included. SLA battery available separately. Cat. LA-5307 $199.00 $39.95 External Alarm Strobe Light - Blue Designed to be mounted on siren covers or other exposed locations to provide a visible indication of the alarm condition. Red or amber versions also available. Cat. LA-5302 $24.50 Better. More Technical Surveillance System Consisting of a 5” B&W monitor, two operating and two dummy cameras, the system is quick and easy to install. The monitor also houses an automatic switcher with adjustable dwell time. Cat. QC-3446 $149.00 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au IT’S NOT ALL ABOUT WORK... SHOCKING SAVINGS Electric Shock Reaction Game This is the ultimate test in speed and concentration. You don't want to be the "last man" standing when you play this game or you'll cop a mild electric shock. • Suitable for ages 14+ Was $34.95 As seen on TV Cat. GH-1095 SAVE $10.00 $24.95 Shocking Alarm Clock This will get you out of bed of a morning. Risk a mild electric shock when you turn the alarm off. Requires 2 x AA batteries. SAVE • Suitable for $5.00 ages 14yrs+ • Measures 90(dia) x 50(D)mm Cat. GH-1109 Was $19.95 REMOTE CONTROL ENTHUSIASTS Mobile Missile Launcher Remote controlled battle tanks that fire foam missiles with a range of about 4 metres, and can even fire full automatic. Charger and 10 foam rockets included. Two models available so you can fight your friends. Approx 320mm long. SAVE • GT-3220: 27MHz $10.00 • GT-3222: 40MHz Each • Suitable for ages 8+ $ 59.95 Was $69.95 Remote Control Ferraris $14.95 Shocking Autopsy Game SAVE Remove the various weapons $10.00 from the body without touching the injury area. Make a slip and you get a mild shock. Turn the shock function off and he'll just scream instead. • 1 - 4 players • Suitable for ages 14+ • Requires 3 x AAA batteries Cat. GH-1108 Was $29.95 $19.95 Drive a Ferrari Today! These 1/10 scale factory endorsed Ferrari replicas will amaze you. The detail is fantastic. They have operating (LED) headlights and tail lights and independent front and rear suspension. The best finished model cars we have ever seen. • Remotes included • Supplied with rechargeable battery pack and mains charger • Suitable for ages 10yrs+ • 4 models available GT-3210 GT-3211 While stocks last. All models GT-3212 not available all stores. GT-3214 Was $69.95 Factor Endorsey d Each $59.95 NEW Cat. GT-3213 $24.95 A series of do-it-yourself experiments to acquire the basic knowledge of solar energy. • Includes Solar cell module, musical unit, plastic lamp, motor accessories and plastic adaptors. $24.95 USB Roll-up Drum Kit • Dimensions: 340(W) x 250(H)mm Cat. GE-4092 $49.95 153 Experiments in Electricity and Magnetism Kit Learn all the basic principles behind electricity. 153 different experiments require only a 9V battery or no power at all. • Ages 9+ • Requires 9V battery: SB-2423 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 SAVE $10.00 IR Remote Control Horse Racing Game Run your own Melbourne Cup. Playing cash is also included. Pick a horse and try to win. Track measures 1200(L) x 600(W)mm. Spare horses available separately. • Horses & remotes require 2 x AA batteries each Was $99.95 No Hors Flu Heree Cat. GT-3240 $79.95 SAVE $20.00 KITS FOR KIDS Deluxe Solar Educational Kit Cat. KJ-6694 Eight different drum sounds from African to jazz and dozens of different rhythm patterns. You can also record and play back your grooves for later playback. We have two fantastic licensed 1:18 scale models to race with. The inside wheel locks up when you execute a turn to enable a skid and the full function remote control has sound effects. Each car comes with a rechargeable Ni-Cd battery pack and plugpack charger. • Suitable for ages 12+ Each • Two models available: $59.95 • GT-3250 Mazda RX-8 27MHz • GT-3252 Subaru Impreza WRX 40MHz • Remote control requires 3 X AA batteries Was $69.95 SAVE $10.00 Desktop F430 Ferrari This 1/64th scale F430 Ferrari has rear wheel drive and adjustable steering bias to ensure a straight and smooth ride. It's finished in Ferrari red and is sure to be a conversation starter. • Remote control 100(L) x 25(W) x 53(H)mm • Requires 6 x AA batteries • Recharges from display base Drift RC Rechargeable Cars INTERNET> www.jaycar.com.au Cat. KJ-8835 $39.95 Antworks Ant Farm with Illuminated Base This combined ant farm and illuminated base will keep you fascinated for hours. The special gel is full of nutrients especially formulated to promote healthy growth in your ant colony. • Tank approx 165mm wide • Mains adaptor included Cat. GH-1231 $49.95 H-Racer Hydrogen Car with Solar Refuelling Station See the future today! All you need is water and sunshine. This palm-sized car has an on-board hydrogen storage tank, a fuel cell system connected to the car's electric motor, and a hydrogen refueling system linking the car's storage tank to the solar-powered T e Magazim ine To refueling station. o f th e Ye y Cat. KT-2529 • Dimensions: 165(L) x -2006 ar $179.95 70(W)mm Better. More Technical 7 AUTOMOTIVE SIGHT & SOUND Variable Boost Kit for Turbochargers It's a very simple circuit with only a few components to modify the factory boost levels. It works by intercepting the boost signal from the car's engine management computer and modifying the duty cycle of the solenoid signal. Kit supplied in short Cat. KC-5438 form with PCB and overlay, and all $19.95 specified electronic components. SHADOW 3-Point Engine Immobilising Car Alarm Wireless MP3 Modulator $199.00 Cat. GE-4030 $34.95 NEW This versatile monitor connects to any of our rear view cameras and will help make reversing safer for you and your family by giving you an unobstructed view of the area behind your vehicle. The monitor can also act as a hands free unit for your Bluetooth enabled phone or it can be connected to in-car DVD or other Cat. QM-3763 entertainment systems. $299.00 • 2 composite video inputs • Built-in caller id • Remote control included NEW Hassle-free sharing of audio and video signals all over the house without the inconvenience and cost of running wires. This powerful 5.8GHz SAVE $50.00 sender will ensure crystal clear reception. • Not ACA approved • 5.8GHz operation • Extra receivers available Cat. AR-1840 Was $249.00 $119.00 Bluetooth Rear Vision Mirror LCD Monitor Catch local digital TV broadcasts with crystal clear reception and audio quality. Rechargeable battery, plugpack, headphones, car adaptor and AV lead included. • Resolution: 480 x 234 pixels • A/V decoding: MPEG2 Cat. QM-3775 • Dimensions: 135(L) x 85(H) x $299.00 30(D)mm Watch Foxtel All Over The House This high quality fully featured engine immobilising car alarm is made to and has passed the latest Australian and New Zealand Standards. Includes code hopping remotes. Cat. LA-8970 Use any ordinary USB flash drive to store your favourite MP3 files and play them through your car's FM radio. TFT 3.5" Portable LCD Digital TV A PA system in a box. 3 channels with balanced and unbalanced inputs, RCA inputs for an auxiliary source. The ideal small PA for schools, sports organisations, churches, weddings, conferences or solo acts. Cat. CS-2517 • 12" speaker $399.00 • 2 channel equaliser • Line level RCA inputs • Tough moulded enclosure • Balanced and unbalanced line outs • 200WRMS power output • Dimensions: 600(H) x 410(W) x 325(D)mm This simple amplifier features a stripline-type high-gain RF transistor and provides up to 15dB gain over the bandwidth of 50-1000MHz. This covers all T.V., FM, marine and aircraft VHF as well as Police, mobile phone etc. Kit includes screen printed PCB and all electronic components • Operates on 6-18V. Keep a spare or replace a broken garage door remote with this latest version of the most common transmitter in use in Australia/New Zealand today. • Operates on 27MHz Cat. KG-9002 Cat. LR-8827 $19.95 $59.95 YOUR LOCAL JAYCAR STORE Australia Freecall Orders: Ph 1800 022 888 NEW SOUTH WALES Albury Ph (02) Alexandria Ph (02) Bankstown Ph (02) Blacktown Ph (02) Bondi Junction Ph (02) Brookvale Ph (02) Campbelltown Ph (02) Erina Ph (02) Gore Hill Ph (02) Hornsby Ph (02) Newcastle Ph (02) Parramatta Ph (02) Penrith Ph (02) Silverwater Ph (02) 8 6021 9699 9709 9678 9369 9905 4620 4365 9439 9476 4965 9683 4721 9741 6788 4699 2822 9669 3899 4130 7155 3433 4799 6221 3799 3377 8337 8557 Sydney City Taren Point Tweed Heads Wollongong VICTORIA Coburg Frankston Geelong Melbourne Ringwood Springvale Sunshine Thomastown QUEENSLAND Aspley Cairns Ipswich Better. More Technical Prices valid until February 29th 2008 150W Inverter with USB Outlet Ph Ph Ph Ph (02) (02) (07) (02) 9267 9531 5524 4226 1614 7033 6566 7089 Ph Ph Ph Ph Ph Ph Ph Ph (03) (03) (03) (03) (03) (03) (03) (03) 9384 9781 5221 9663 9870 9547 9310 9465 1811 4100 5800 2030 9053 1022 8066 3333 Ph (07) 3863 0099 Ph (07) 4041 6747 Ph (07) 3282 5800 ORDER FREE CALL> USB Activated 6 Way Powerboard This powerboard connects to your computer's USB port and once your computer powers on, it applies the mains power to the 6 SAVE $30.00 way powerboard without you needing to flick a switch. Perfect for powered speakers, powered USB hubs, scanners, and powered docking stations. Cat. MS-4032 • SAA Approved. $39.95 Was $69.95 15VDC 1.5A Switchmode Power Supply Regulated 15VDC output voltage. Supplied with 7 different plugs. Includes LED power indicator. Was $34.95 Cat. MP-3423 $24.95 SAVE $10.00 Mains Power Meter The meter can tell you how much an appliance is costing to run and tracks the actual power being used. It can also display the instantaneous voltage or current being drawn as well as peak levels etc. Cat. MS-6115 10A max rating. $39.95 12VDC & 240VAC Battery Charger with USB Power Ni-Cd & Ni-MH Charge your batteries almost anywhere. This universal battery charger runs SAVE from mains power, your car's $15.00 cigarette lighter socket, or your computer's USB socket. Very handy. Cat. MB-3539 Was $39.95 $24.95 Cat. SB-1752 Long Life Pre-Charged Rechargeable Batteries 4 Pack $14.95 These are ultra-low self-discharge Cat. SB-1750 batteries and can be used immediately after purchase. Even after a full year, they $24.95 will still retain up to 85% of their original charge. Storage case included. • SB-1752 AAA 1.2V 800mAh • SB-1750 AA 1.2V 2000mAh Maroochydore Ph (07) 5479 3511 Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 Woolloongabba Ph (07) 3393 0777 AUSTRALIAN CAPITAL TERRITORY Belconnen Ph (02) 6253 5700 Fyshwick Ph (02) 6239 1801 TASMANIA Hobart Ph (03) 6272 9955 SOUTH AUSTRALIA Adelaide Ph (08) 8231 7355 Clovelly Park Ph (08) 8276 6901 Gepps Cross Ph (08) 8262 3200 WESTERN AUSTRALIA Maddington Ph (08) 9493 4300 Northbridge Ph (08) 9328 8252 1800 022 888 SAVE $20.00 This compact (150mm long) inverter plugs directly into your vehicle's cigarette lighter socket to deliver 230VAC at 150 watts. The modified sine wave unit comes with a USB port to charge or power your MP3 Cat. MI-5125 player or other USB operated device. $59.95 Was $79.95 200W PA Combo Amp/Speaker RF Preamplifier Kit Garage Door Remote Control POWER INTERNET> NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Christchurch Ph (03) 379 1662 Dunedin Ph (03) 471 7934 Glenfield Ph (09) 444 4628 Hamilton Ph (07) 846 0177 Manukau Ph (09) 263 6241 Newmarket Ph (09) 377 6421 Palmerston Nth Ph (06) 353 8246 Wellington Ph (04) 801 9005 Freecall Orders Ph 0800 452 9227 www.jaycar.com.au Switch just about any plug-in mains-powered device when a passive infrared sensor detects a person approaching. It’s easy with this low-cost and easy-to-build project. By JIM ROWE PIR-Triggered Mains Switch Y ou’ve seen those lights fitted with PIR detectors which turn on when someone approaches. But what if you want to switch on something else that’s mains powered? Perhaps it’s other security lighting? Possibly an AV recording or playback system? Maybe a fountain pump? Or just about anything else that can plug into a standard power point? Think outside the square: what about a commercial display which you’d like to spring into action when there’s an audience close by? If so, this project is for you. We take a bog-standard (and cheap!) passive infrared detector, as used in millions of burglar alarms and use it to safely turn on 240VAC mains device(s) for an adjustable pre-set period – and siliconchip.com.au that period is set by you. It’s compact and easy to build but at the same time it’ll cost you much less than commercial PIR-triggered switches with similar features. Talking of features, how are these? First, it will accept trigger signals from virtually any standard low cost PIR detector which can be located up to 20m away, if that’s what you need. The two are connected together via a length of two-pair telephone cable – and the Switch Unit also provides 12V power for the PIR detector, via the same cable. Next, the switch unit uses a heavyduty mains-rated relay to switch the power to twin 240VAC outlets. The relay contacts are rated for 20A, so the unit is quite capable of switching power for any likely load combination, up to the normal 10A limit of a standard power point. Once triggered by the PIR detector, the unit can keep the power switched on for a preset period of time, which you can set to any of 10 different periods, ranging from about just a few seconds to 128 minutes (over two hours). This should make the unit suitable for many different applications, especially as it is also provided with a manual override button which can be used to switch off the mains power to the loads at any time regardless of the hold-on time setting. Finally, the Switch Unit fits in a UB2 sized jiffy box, with all of the low voltage circuitry on a small PC board for easy assembly. In fact, the Switch Unit could itself February 2008  57 +12V PIR DETECTOR R1 S N/C RELAY DRIVER Q S-R FLIPFLOP + SET HOLD ON TIME S1 MANUAL TURN OFF R2 N E O14 C1 S2 A Q R – 240V OUTLETS MAINS RATED RELAY O6 O5 O4 A MR MULTISTAGE BINARY COUNTER N E CLK E TIMING CLOCK +17V +12V 0V POWER SUPPLY A A N N 240V POWER Fig.1: the block diagram of the PIR-triggered mains switch. It can switch up to 10A from the two outlets (the limitation of a standard power point). be battery operated and switch low voltage devices if you like (it needs about 12V <at> 80ma). In addition the ‘live’ mains wiring is all off the PC board, in the interests of safety. Before we explain how it works, you should know that development of the project has been sponsored by Jaycar Electronics. As a result, kits for it will only be available from Jaycar stores and dealers. How it works As you can see from the block diagram of Fig.1, the project is quite straightforward. At lower right is the built-in power supply, which provides regulated 12V DC to power both the remote PIR detector and its own internal circuitry, plus an unregulated ~17V DC to power the relay. The output of virtually all PIR detec- tors is a set of relay contacts, which are normally closed and open when the detector senses movement. It is this set of contacts which we use to trigger the mains switching unit, by connecting them between the input of a CMOS inverter and ground. The inverter input is also connected to the +12V line with resistor R1, so that whenever the detector contacts open the inverter’s input is pulled high by R1 and its output will switch low. This action is used to ‘set’ a set/reset flipflop which is normally resting in its reset state. When the flipflop switches into the set state its Q output switches high. This is used to activate a driver circuit and energise the relay. Power is thus switched to the two 240VAC outlets and the loads. At the same time as the S-R flipflop switches to its set state, its Q-bar output switches low. This output is connected This shot shows the IEC connector and PIR input on the left end of the Jiffy box. 58  Silicon Chip to the master reset (MR) input of a multi-stage binary counter. So when the flipflop sets, this removes the reset from the counter and allows it to begin counting. It counts the pulses from a simple clock oscillator which runs at 0.9375Hz (the reason for this rather odd frequency will become clear in a moment). The binary counter has 14 stages but makes available only the outputs from internal flipflops 4-10 (O4-O10) and 12-14 (012-O14). We use rotary switch S2 to select one of these 10 outputs, so the rotor of S2 is kept low until the selected counter output switches high. This happens as soon as the counter has received the appropriate number of clock pulses: eight pulses in the case of O4, 16 for O5, 32 for O6, 64 for O7 and so on right up to O14, which only switches high after 8192 pulses have been counted. Whenever the selected counter output does switch high, this low-to-high transition is coupled via capacitor C1 into the input of a second inverter, which is normally held low by resistor R2. So the inverter’s input is taken high briefly, as C1 charges up via R2. But this is long enough for the inverter’s output to switch low, applying a triggering pulse to the reset input of the S-R flopflop. As a result the flipflop switches back to its reset state, turning off the relay and removing 240VAC power from the loads. So as you can see, this combination of a flipflop and a multistage binary counter allows us to automatically turn the relay off again after an approprisiliconchip.com.au PIR DET CON1 +12V 1 2 3 4 5 6 100nF 10k 1 14 3 13 2 IC1d IC1: 4093B 5 16 4 12 10k +12V 1M IN 0V 680nF LEDS +12V GND IC1c A 10 10 9 MR O9 O8 Rs O7 Rtc O6 O5 Ctc O4 OUT K 9 13 4m 14 2m 6 1m 4 30s E 5 15s +17V 7 68  5W S2 SET HOLD ON TIME 1k D6 E N CAUTION: CAUTION: Area within Area withinredred dotted at at dottedline lineis is 240V 240V potential potential K TRIGGERED LED2 15k  A K 240VAC OUTLET No.1 A T1 B 0V K A K A K 6V K Q1 BD139 N A E +17V A A C E D2–D5 6V 240V RLY 1 K A 10k A B C 22nF GND 240V AC INPUT BD139 BD13 7.5s 9 D1 POWER  LED1 15 8m MANUAL TURN OFF S1 8 7 IN 11 O10 Vss 8 K 7812 A IC2 4060B IC1b 6 1k Vdd 3 128m O14 2 64m O13 1 32m O12 11 12 IC1a 100nF (RJ12) OR 3-WAY PCB TERMINAL BLOCK 100nF REG1 7812 IN 2200 F 25V +12V OUT 240VAC OUTLET No.2 GND 22 F N A E MAINS EARTH SC  2008 PIR SENSOR TRIGGERED MAINS SWITCH D1: 1N4148 A D2–D6: 1N4004 K A K Fig.2: the circuit diagram shows how simple the PIR Mains Switch is. Note that this project switches mains and great care must be taken with mains wiring. It is definitely not a project for beginners! ate number of clock pulses have been counted – as selected by S2. For example, if S2 is set to O4 of the counter, the relay will be turned off after eight pulses have been counted; if it’s set to O5, the turnoff will be after 16 pulses; to O6 and it will be after 32 pulses and so on. 0.9375Hz? The reason for that apparently odd frequency of 0.9375Hz for the counter’s clock oscillator is due to the binary relationship between all of the counter outputs. The counter’s O6 output goes high after 64 pulses have been counted but by making the clock frequency 0.9375Hz we ensure that this corresponds to 60 siliconchip.com.au seconds or one minute. (That’s because 60/64 = 0.9375.) The same clock frequency makes the switch-off times corresponding to the higher counter outputs also correspond to reasonably convenient multiples of minutes: two minutes for O8, four minutes for O9, eight minutes for O10, 32 minutes for O12, 64 minutes for 013 and 128 minutes for O14. The lower outputs also give reasonably convenient shorter times: 30 seconds for O6, 15 seconds for O5 and 7.5 seconds for O4. But what if you have set the project to hold the power on for, say, 64 minutes after triggering and then want to switch it off immediately? That’s easily fixed, because we have also provided normally open pushbutton S1, which pulls the inverter input high and causes it to reset the S-R flipflop straight away. All you have to do to turn off the load power at any time is press S1 briefly. By the way, whenever the S-R flipflop is reset (and for whatever reason), this doesn’t just turn off the relay and power to the load. It also re-applies a logic high to the MR input of the counter, resetting it and preventing it from counting. So the whole circuit is reset, ready to await the next trigger pulse from the PIR detector. Circuit details The schematic diagram of Fig.2 provides all of the circuit details. The February 2008  59 240V MAINS INPUT RELAY (RLY1) CABLE TIES T1 2851 A E HEATSHRINK SLEEVING OVER JOINTS 0V S1 MANUAL TURNOFF 7002 C 17011101 4004 4004 4004 D4 D5 + 4004 D3 HS2 Q1 BD139 1k 4004 22 F D6 BD135 EJ 680nF 10 10k 1M S2 10k 1 2 22nF IC1 4093B IC2 4060B HOLD ON TIME 15k 10k 100nF D1 4148 + DNG RELAY COIL 68 /5W 2200 F 100nF REG1 7812 1k (OPTIONAL RJ12 SOCKET OR 3-WAY TERMINAL BLOCK) PIR DET LED2 TRIG’D D2 91217002 5545CK 3728CE NI HS1 PWR HCTIWS SNIAM GIRT RIP +V 12V AC IN 100nF LED1 CON1 6V 6V N HEATSHRINK SLEEVES OVER ALL QUICK CONNECTORS 6 CABLE FROM PIR DETECTOR PLUGS IN HERE Fig.3: combined component overlay and wiring diagram. Follow this diagram exactly – you cannot take chances when mains is involved! Note the comments in the text about the RJ12 socket or 3-way terminal block (PIR input) options. S1 (ON FRONT PANEL) SUITABLE LENGTH OF 2-PAIR CABLE E A N E A N RJ11 4-PIN MODULAR PLUG (TOP VIEW) ALARM (NC) (2) (3) (4) (5) – + REAR OF MAINS OUTLET 2 REAR OF MAINS OUTLET 1 NOTE LINK TAMPER (NC) “PRESSPAHN” OR OTHER SUITABLE INSULATION COVERING OUTLETS TERMINAL BLOCK INSIDE PIR DETECTOR Fig.4: detail of the cable connecting a typical PIR detector and the Switch Unit, assuming the RJ12 socket is used on the PC board. PIR detector connects to the circuit via CON1, a ‘modular’ telephone-type connector. It receives 12V power via pins 2 and 5 of CON1, while its output (switching) contacts are connected to pins 4 and 3. Pin 4 connects to the two inputs of Schmitt gate IC1a, tied together so that it forms the input inverter. As you can see the input pins are connected to +12V via a 10kW resistor 60  Silicon Chip (the equivalent of R1 in Fig.1), while they are also connected to ground via a 100nF capacitor to bypass any RF signals which may be picked up by the cable from the PIR detector. (Once upon a time all we had to worry about was radio stations. Now there’s TV, mobile phones, cordless phones, WiFi, Bluetooth, video/audio senders and even wireless doorbells to cause problems on long cables). Cross-coupled gates IC1d and IC1b form the S-R flipflop, with the output of IC1d (pin 11) forming its Q output and that from IC1b (pin 4) forming the Q-bar output. IC2 is a 4060B device, which not only provides our 14-stage binary counter but also its clock oscillator as well. The two resistors and 680nF capacitor connected between pins 9, 10 siliconchip.com.au Same-size photo clearly shows component placement on the PC board. and 11 of IC2 set the clock frequency to 0.9375Hz. In reality, it will not be anywhere near as precise. As explained earlier, the S-R flipflop’s Q-bar output (pin 4 of IC1) is used to control the counter’s operation by pulling the MR input of IC2 (pin 12) high to prevent counting, or pulling it low to allow it to count. The remaining gate of IC1 (IC1c) is used to form the inverter for the S-R flipflop’s reset input. One input of this gate is tied to +12V, while the other input (pin 8) is pulled down to earth by a 15kW resistor (equivalent to R2 in Fig.1) and coupled to the rotor of switch S2 via a 22nF capacitor which corresponds to C1 in Fig.1. Manual turnoff switch S1 also connects between pin 8 and +12V. The Q output of IC1 (pin 11) is also connected to the base of transistor Q1, via a 10kW series resistor. Q1 is the relay driver, which energises relay RLY1 when it conducts. The relay coil is connected to +17V via a 68W 5W resistor for current limiting. Diode D6 is also connected across the relay coil to protect Q1 from damage due to the inductive ‘spike’ when the relay de-energises. LED2 and its 1kW series resistor are also connected across the relay coil, to indicate when the relay – and therefore load power – is ‘ON’. The project’s power supply uses a small (2VA) power transformer T1 driving a four-diode bridge rectifier to produce the unregulated output (about 17V) which operates the relay. Regulator REG1 then derives a regulated 12V line from the rectifier output to provide power for the rest of the circuit and siliconchip.com.au the PIR detector. LED1 and its series 1kW resistor are connected across the 12V supply to indicate when power is applied to the switch unit and PIR detector. Construction There are two parts to this circuit – the low voltage side (which mounts on a small PC board) and the mains wiring. It all fits inside a standard UB2 size (197 x 113 x 63mm) jiffy box, with room left for the off-board (mains) components: the IEC mains input plug, power transformer T1, relay RLY1, the two flush-mount mains outlet sockets and manual turnoff switch S1. In our prototype, the IEC mains input connector is mounted in the left-hand end of the box. However, we have been informed that production kits from Jaycar will probably have the IEC connector mounted on the front panel (the jiffy box lid) adjacent to the mains output sockets. The wiring is the same but take the changed position into account. Transformer T1 and the mains relay (RLY1) are bolted into the bottom of the box alongside the PC board, while the two mains outlet sockets and manual turn-off switch (S1) are mounted in the lid of the box (which forms the front panel). Rotary switch S2 actually mounts on the PC board, but its control shaft is left at its full length so that it protrudes through a matching hole in the lid, to be fitted with a small pointer knob. The overlay/wiring diagram of Fig.3 shows not only where all components go on the PC board (and their orienta- tion) but also how the wiring is made connecting the offboard components. It also shows which joints need to be provided with heatshrink sleeves, to prevent accidental contact when the box is opened. So if you follow all aspects of this diagram carefully, you should be able to build up the unit both safely and successfully. Note that there are six wire links (all 0.4” long) to be fitted to the PC board, preferably before any of the components are fitted because this is the easiest time to do so. After the links are fitted it’s a good idea to fit the seven PC pins, three of which are used to make the connections from the secondary of T1, two are for the relay coil connections while the remaining two pins are used for the wires connecting S1. Next fit the DIL sockets for IC1 and IC2, making sure you fit them with their ‘notch’ end towards the left so they’ll guide you later in fitting the ICs with the correct orientation. Then fit CON1, the RJ12 modular connector which fits at the left hand end of the board. A note here: the PC board pattern will also accommodate a 4-way PC-mounting terminal block, if you would rather “hard wire” the PIR to the PC board. After this, fit rotary switch S2, noting that it needs to be orientated with its indexing spigot in the ‘north-east’ position. After mounting it you need to remove its nut, star lockwasher and position stop plate, then refit these in reverse order after making sure the stop plate’s locating pin is entering the slotted hole between the ‘10’ and ‘11’ numerals moulded into the top of the switch body. This is to ensure that the switch is set for 10 positions. Once S2 is in place and set correctly, fit the various resistors and smaller unpolarised capacitors. Follow these with the 22mF and 2200mF electrolytics, which are of course polarised – so fit these carefully according to the overlay diagram. Then fit signal diode D1 and the five power diodes D2-D6, followed by transFebruary 2008  61 Opened-out view of the completed project. Note the heatshrink covering any exposed mains and the Presspahn shield over the mains outlet sockets. This photo is of the first prototype which used a DIN PIR input socket – now changed to either an RJ12 phone-type socket or a 3-way PC board terminal block. istor Q1 and regulator REG1. Note that both Q1 and REG1 are mounted horizontally and each device is fitted with (or on) a small U-shaped TO-220 type heatsink, with a 6mm long M3 machine screw and nut used to clamp them in place on the top of the board. The next components to fit to the board are LED1 and LED2. These need to have their leads extended using 25mm lengths of hookup wire, so that the body of each LED will protrude through the matching holes in the box lid when this is fitted. Use hookup wire with red insulation to extend the longer LED anode leads, and wire with black insulation to extend the cathode leads. Then you shouldn’t have any trouble fitting the extended leads to the board correctly – the red anode leads go towards the rear of the board, and the black cathode leads towards the front. Wiring Your PC board assembly is now just 62  Silicon Chip on complete, so place it aside while you fit the IEC mains input plug into the end of the box. It’s fastened into the matching hole via a pair of 10mm long countersink-head M3 machine screws, fitted with star lockwashers and nuts on the inside. Then mount the power transformer T1 in the bottom of the box, using another pair of M3 countersink-head 10mm long screws with flat washers, star lockwashers and nuts. Once it’s in position, fit another star lockwasher to the mounting screw nearer the IEC mains plug, and then slip on a solder lug followed by a further lockwasher and finally a second nut. Tighten this last nut firmly with a nut driver or tube spanner so there’s no chance of the solder lug coming loose. (The lug is used to connect the transformer core and frame to mains earth, for safety.) Now relay RLY1 can be bolted into the bottom of the box in much the same way, except that its plastic case needs no earthing. So in this case just use a pair of 10mm x M3 countersink head screws with flat washers, star lockwashers and nuts. Next is a 50mm length of mainsrated figure-8 wire, used to connect S1 to the board just before the box lid is fitted. Solder one end of these to the PC pins marked “S1” on the PC board and leave the other end for the moment. We specify mains-rated cable here due to the fact that inside the box is mains wiring which (while the chance is very remote), could possibly come loose and move around. The figure-8 itself only carries low voltage but its insulation is mains rated to prevent any possible contact. At this stage you can mount the PC board assembly into the box using four 15mm long M3 tapped spacers, with four 10mm long x M3 countersink head Nylon machine screws to attach the spacers to the bottom of the box and four 6mm long pan head M3 screws to attach the board to the top of the spacers. Again, Nylon screws are specified “just in case” – these screws pass from the inside of the case, where there is mains wiring, to the outside. Then you can make the connections between the secondary winding of T1 and the three PC pins on the board just near T1. Do this by cutting all three leads to about 50mm long, removing about 6mm of insulation from the end of each wire and then soldering them to the terminal pins. The two wires with yellow insulation connect to the outer pins, while the wire with white insulation connects to the centre pin. After this prepare two 60mm lengths of mains-rated insulated hookup wire by baring about 5mm of wire at each end, and then fitting a female ‘quick connect’ spade connector to one end of each wire. Then slip a 25mm length of 6mm diameter heatshrink sleeving over each connector, and use a hot air gun or the barrel of your soldering iron to shrink the sleeves down snugly around each connector. After this, tin the other end of each wire and finally, solder them to the PC board terminal pins just to the left of the heatsink for Q1. These wires are used to connect between the board and the coil lugs of RLY1 - which are the two closer-spaced lugs on its left (assuming you’ve fitted it the correct way around). So once the wires have been soldered to the PC board pins, siliconchip.com.au Parts List – PIR-Triggered Mains Switch 1 1 2 1 1 1 1 Here’s a close-up view of the Presspahn insulation over the mains outlet sockets just before it was secured in place. push their quick connector ends down firmly over the relay lugs as far as they’ll go. Next fit the two flush mounting mains outlets to the lid of the box, and also fit pushbutton switch S1 into its hole in the lid near the other end. Then if you turn the lid and place it near the right-hand end of the box, you should be able to add all of the remaining off-board mains wiring between the IEC mains plug, the primary winding of T1, the switching contacts of RLY1 and the mains outlets. Do this by carefully following the overlay/wiring diagram, which shows all of the wiring fairly clearly. How do you know if the insulation on the cable you want to use is mains-rated? A good source of “guaranteed” mains-rated cable is from a length of discarded mains lead. It’s always handy to keep some in the junk box for purposes such as this! Each of the three terminals (A, N and E) on the IEC mains input connector has two wires connected to it First the earth: a short length of green/yellow mainsrated wire is used to make the connection between the IEC connector’s centre earth lug and the solder lug fitted to the left-hand end of T1, while another much longer piece of the same wire (~160mm) is used to connect to the earth connection of each mains outlet. Both wires should be soldered to the IEC plug’s centre lug together, to ensure a good reliable connection for them both. The mains (Active and Neutral) wires don’t solder to the lugs on the IEC socket but to quick-connect female spade connectors. Each of these connectors has a 25mm length of heatshrink insulation fitted after soldering so they are completely covered. Cut two 25mm lengths of heatshrink, pass the two wires through and slide the heatshrink well up before soldering. Otherwise they may shrink from the heat of soldering before you get them over the quick-connect spade terminals. The “A” terminal of the IEC connector has the brown (Active) wire from the transformer primary, along with a 160mm-long mains-rated wire with brown (or red) insulation which goes to one of the switching terminals of the relay, again via a quick-connect female spade connector. Another, similar, length of the same wire (also fitted with an insulated spade connector) goes from the other switching terminal of the relay with its opposite end going to both the “A” screw terminals of the mains sockets. The second primary wire from the transformer (with blue siliconchip.com.au PC board, code EC8273, 147 x 69mm UB2 jiffy box, 197 x 113 x 63mm Heatsinks, 19mm square TO-220 type Pushbutton switch, SPST (S1) Rotary switch, 1 pole 12 position (S2) Pointer knob with removable pointer inset 6-pin RJ12 socket, PC board mtg (CON1) OR 3-way PC board mounting terminal block (see text) 1 14-pin DIL IC socket (for IC1) 1 16-pin DIL IC socket (for IC2) 1 Power transformer, 12.6V/2VA, 2851 type 1 20A mains rated relay, chassis mtg (RLY1) 1 IEC mains plug, panel mounting 2 Mains sockets, flush mounting panel type 4 15mm long M3 tapped spacer 10 Nylon M3 machine screws, 10mm long CSK head 6 M3 machine screws, 6mm long pan head 8 M3 nuts with flat and star lockwashers 1 Solder lug 8 Nylon cable ties, 100mm long 6 Quick connectors, female spade type 6 25mm lengths of 6mm diameter heatshrink tubing 7 PC board terminal pins, 1mm diameter 1 90 x 104mm piece “Presspahn” or similar insulation Semiconductors 1 4093B quad Schmitt NAND (IC1) 1 4060B binary counter (IC2) 1 7812 12V regulator (REG1) 1 BD139 NPN transistor (Q1) 1 5mm LED, green (LED1) 1 5mm LED, red (LED2) 1 1 N4148 silicon diode (D1) 5 1N4004 1A power diode (D2-D6) Capacitors 1 2200mF 25V RB electrolytic 1 22mF 16V RB electrolytic 1 680nF MKT metallised polyester 3 100nF MKT metallised polyester 1 22nF MKT metallised polyester Resistors (0.25W 1% unless specified) 1 1MW 1 15kW 3 10kW 2 1kW 1   68W/5W wirewound The design of this kit and PC board are Copyright (C) 2007 to Jaycar Electronics. Kits (cat no KC5455) will be available from Jaycar Electronics stores and resellers shortly after this issue goes on sale. insulation) attaches via an insulated female spade terminal to the “N” terminal of the IEC connector, along with an even longer wire (about 300mm) whose opposite end screws into both the “N” terminals of the mains output sockets. When you have soldered all wires to their female spade connectors, slide the lengths of heatshrink back down the wires so that the connectors are fully covered, then shrink February 2008  63 with a heat gun. When you push the female spade connectors onto their appropriate male spade terminals, there should be no exposed mains wiring or metalwork visible. Once you’ve completed the mains wiring, it’s a good idea to tidy it all up using about six small cable ties as shown in the overlay diagram. This doesn’t just make the wiring look tidier; it also helps ensure that in the unlikely event of a live wire breaking off anywhere, it can’t ‘wander’ far enough to make contact with any of the low voltage wiring. With the cable ties fitted, the next step is to swing the box lid around so it’s just in front of the box, so you can solder the two wires coming from the PC board pins (just to the left of the socket for IC1) to the lugs on the rear of pushbutton S1. We also covered these joins in heatshrink – just in case. You will note from our photographs that we also shielded the two mains outlet sockets with an insulating material – again, just in case. In the past, the most usual material to use was a product called “Presspahn” but that is becoming rather difficult to get these days (at least in small quantities). We used a piece of cardboard which has a PVC insulation on one side. Other ideas that spring to mind are thin plastic or perhaps a sheet of plastic laminated paper. The U-shaped shield, the dimension of which are shown in Fig.5, is fixed to the case by slightly undoing the mains socket mounting screws and “sandwiching” the insulation between the back of the mains socket and the case (tightening the screws again to keep it in place). After this the final assembly step is to plug the two ICs into their sockets, making sure you fit them with their ‘notch’ ends towards the left in each case. The internal wiring of your PIR Triggered Mains Switch will now be complete and you can swing the box lid up and lower it in position, carefully making sure that the control spindle BEND DOWN 90 o 25mm 7mm BEND DOWN 90 o 40mm BEND DOWN 90 o 25mm 7mm BEND UP 90 o 90mm Fig.5: the detail for the insulating shield over the mains outlet sockets. It secures under the outlet backs. of S2 and the two LEDs pass through their corresponding holes and that no internal wiring is pinched between box and lid. You should then be able to fit the pointer knob to S2’s spindle, and also screw the lid down using the four small self-tapping screws provided. If you find the pointer on the knob doesn’t point to the right place, the knob specified has a small inset plate at the top which can be prised off and rotated to get the pointer in the correct position. PIR Wiring There is no testing or adjustment procedure required for this project; it should operate as soon as power is applied. However you will no doubt have to make up a cable to connect the project to the PIR detector unit you have chosen to use with it. Needless to say the cable will need to be long enough to run for the distance between them. It should be very easy to make up the cable, because we’ve made the connector for the Switch end an RJ12 modular socket and used only the four centre pins of it. As a result you can make the cable easily by ‘converting’ a standard low cost modular telephone extension lead, sold in Jaycar stores (and many others as well) in lengths up to at least 15m. These leads are fitted with an RJ12 (6P/4C) plug at each end, so all you need to do is cut off the RJ12 plug at one end, and then remove the outer sleeve at that end to reveal the four wires which will be used to connect to the PIR Detector’s terminals. The PC board also has provision for a standard 3-way terminal block if you prefer to wire the PIR detector in that way. Both inputs are shown on the overlay diagram. The way to make the connections at the PIR Detector end of the cable is shown in Fig.4. As you can see it’s quite straightforward: the 12V power wires from pins 2 and 5 of the RJ12 plug connect to the positive and negative power terminals, while the wires from pins 3 and 4 of the plug connect to the two end terminals of the four provided for connections to the normally closed ‘detect’ contacts and the ‘tamper’ (or box opening) sensor switch. Then the two centre terminals are linked by a short length of wire as shown, to connect the two pairs of normally closed contacts in series. That’s about it. When you connect up the PIR Detector to your completed Switch Unit and also connect a 240V IEC power lead to the Switch Unit’s IEC input plug, on power-up you should find that the green power LED (LED1) on the Switch Unit will turn on to show that the circuit is active. As soon as the PIR Detector senses any movement, the Switch Unit’s red LED2 should also turn on to indicate that the mains switch has been triggered on. It should continue glowing for whatever period of time corresponds to the setting of switch S2 – anywhere between 7.5 seconds and 128 minutes. And if you plug some lights etc into one of the Switch Unit’s mains outlets, they should also receive power for the same period of time following a trigger event. Check that the timing period is correct (see comment above about moving the pointer on the knob) and also check that pushbutton S1 turns off the load power (and LED2) when pressed. SC Capacitor Codes Resistor Colour Codes No. o   2 o   1 o   2 o   6 Value 1MW 15kW 10kW 1kW 64  Silicon Chip 4-Band Code (1%) brown black green brown brown green orange brown brown black orange brown brown black red brown 5-Band Code (1%) brown black black yellow brown brown green black red brown brown black black red brown brown black black brown brown Value 680nF 100nF 22nF mF Code IEC Code EIA Code 0.68mF 680n 684 0.1mF 100n 104 .022mF 22n 223 siliconchip.com.au 100W SOLAR PANEL ARRAY WITH FREE REGULATOR KIT NEW 300W WIND GENERATORS Power: 300W Peak: 500W Voltage: 12 or 24VDC Current: 12A Start Speed: 2.5m/S Cut-in Speed: 3m/S Rated Speed: 12m/S Rated RPM 450 Blade span 1.5m Weight: 18kg Protection Level: IP54 AL DE E G KA AC P L A ECI SP LY N O 69 $5 This 100W solar array includes 5 X 20W – 12V polycrystalline solar panels, a 12V/24V regulator kit + weatherproof kit box. Why 5 X 12V/20W panels and not 1 X 100W panel?...Loss of output due to damage or obstruction of a panel will result in a 20% loss in output, not 100% loss. Air gaps between panels increase cooling and thus increases panel efficiency. Much cheaper and less fragile to post. The wiring can be changed for different voltages. Aluminum angle, rivets or wire not inc, all worth around $15. Specifications For each Panel: Peak Power: 20W, Open Circuit Voltage: 21V, Short Circuit Current: 1.3A, Voltage At Max. Power: 17.5V, Current At Max. Power: 1.1A, Dim: 610 x 290 x 25mm. 5 X 12V/20W panels +regulator kit + weatherproof This modern lightweight box (ARRAY) $690.00 generator including it's packaging weighs 18KG's!!: Cheap to Ship by Australia Post. Has a built in rectifier/regulator and sliprings. It is made from good quality new materials. Available in 12V (AW12) and 24V (AW24). More info. on our website: Note: Mast and mast fittings not supplied. Very bright 4W LED lamp NEW 8X10mm LED LAMP KIT kit, employs 8 X 1/2W White LEDs driven by an efficient switched mode power supply: Consumes a constant 4W at 9-30V DC. Can also fit inside a common salsa / dip jar to make a watertight housing for a very bright Prawning light!: Kit inc. PCB, LEDs & all onboard parts. (K263A) E RY O CT IC PR 4 2 $ U D RO INT NEW 0.5W10mm LEDs Amazing new bright LEDs. More light for your money and more light from the same space than regular LEDs. Unlike LUXEON style LEDs these LEDs do not require any additional heatsinking. White $2.40 L10W Water clear lens. 25 Lumens <at> 150mA / 80,000 mcd <at> 20mA. Red $2.40 L10R Water clear lens. 20 Lumens <at> 150ma / 65,000 mcd <at> 20mA. Blue $2.40 L10B Water clear lens. 15 Lumens <at> 150mA / 40,000 mcd <at> 20mA. Green $2.40 L10G Water clear lens. 20 Lumens <at> 150mA / 80,000 mcd <at> 20mA. CODE HOPPING 4 CH UP/DOWN INVERTER LED DRIVER KIT VIRTUALLY PRE-BUILT REMOTE CONTROL Receiver: This kit is almost identical in its function to our very popular K180 kit but is pre-built (requires soldering of 2 wires). Has individual limit/reset input for each channel. Combined with our TX8 Transmitter, this kit can control any combination of four output relays in either momentary (on while the button is held) or latching (push on push of) operation. Features inc. range of up to 50m, 240VAC 7A relays, indicator LEDs, & screw terminals for ease of use. (K239) Receiver $30 Transmitter: This small key fob transmitter is used in conjunction with the K239. Uses a pre-built and pre-aligned 433MHz UHF code hopping transmitter module. Includes transmitter module, battery clips, battery and key-fob case. (TX8) Transmitter $15 This kit is designed to step up or step down a wide range of voltages to power a different strings of series or series / parallel LEDs. Parts of the PCB can be snapped of and wired to suit many different applications for cars, boats, trucks and more. More info on our website. Kit includes PCB and all onboard components. (K207A) $9.90. Can be configured to drive... 5mm/20mA, 0.5W and 1W LED's. This kit could also drive a 3W LED in some configurations but we did not try them. See our website for more details. 12VDC GEARED MOTOR & SPEED CONTROLLER COMBO The speed controller kit is designed to produce a Pulse Width Modulated (PWM) output to vary the speed of DC motors. Use it with the PCB mounted trimpot supplied or your own external 5K Pot. 10VDC - 36VDC 20A+. These motors are brand new and the worm drive makes them very powerful. They were intended for car electric windows. Starts turning at 0.9V, 0.9V <at> 0.7A - 4rpm, 6V <at> 1.2A - 60rpm, 12V <at> 1.7A - 120rpm, 15V <at> 1.9A - 150rpm. Motor plus speed controller kit (K252M) only $27 Check out the range of large DC motors, controllers, wheels, chains and sprockets for electric scooter, buggy, robot or other electro/mechanical projects. All at oatleyelectronics.com GEARED MOTOR AND CONTROLLER FOR JUST $27 Don't forget to check out the many other kits on our website www.oatleyelectronics.com Suppliers of kits and surplus electronics to hobbyists, experimenters, industry & professionals. siliconchip.com.au February 2008  65 Orders: Ph ( 02 ) 9584 3563, Fax 9584 3561, sales<at>oatleyelectronics.com, PO Box 89 Oatley NSW 2223 major credit cards accepted Post & Pack typically $7 for up to 0.5kg Prices subject to change without notice ACN 068 740 081 ABN18068 740 081 SC_DEC_07 By JOHN CLARKE Shift Indicator & Rev Limiter For Cars If you drive your car for optimum performance, you will want this Shift Light Indicator to indicate just when to change gears. As a bonus, it incorporates a Rev Limiter which throttles back the fuel injectors. I F YOU ARE INTERESTED in driving your car for best acceleration or fuel economy, you will know that an engine’s torque peaks at a lower RPM than the peak power. You will also know that when driving for maximum fuel economy, it is wise to keep engine revs reasonably low and to get into the The gear shift and rev limit points are indicated by four LEDs. The LDR at far left is part of the dimming circuit. 66  Silicon Chip highest gear as soon as possible. But whether driving for best acceleration or economy, you don’t want to be watching the tacho to judge each gear change. That would distract your attention from the road. Having a Shift Light Indicator is the way to go. You will see LEDs light up without having to divert your eyes from the road. Our Shift Light Indicator has three LEDs to indicate shift points and a fourth LED for the Rev Limiter. How you set the individual LED RPM values is up to you. For example, you could set the three LEDs to give a ‘ready’, ‘set’ and ‘go’ indication for each gear change. Rev limiting can be hard or soft. Hard limiting simply switches off power to the fuel injectors and the engine immediately “dies”; power does not came back until the RPM falls below a threshold value. Soft limiting reduces the fuel injector duty cycle in stages so that the power is not killed abruptly. Either way, the engine is protected from damage due to over-revving. Note that many cars these days already have inbuilt rev limiting, so you may choose not to implement this feature. Connections The Shift Light Indicator (SLI) can either connect to the tachometer signal from the car’s ECU (engine control unit) or to the ignition coil where there is no ECU. We have catered for just about every conceivable engine configuration: 1 to 12-cylinder 4-stroke, 1 to 6-cylinder 2-strokes and 2 & 3-cylinder asymmetrical 4-strokes. Other connections required are +12V power, 0V (chassis), ground and to the fuel injectors. siliconchip.com.au Measuring engine revs We measure engine revs in RPM (revolutions per minute) by monitoring the tachometer signal from the car’s ECU. This delivers one pulse for every cylinder firing (ie, each spark plug firing). We also need to know the engine FULL SOFT LIMITING LIMIT LED4 ON (HARD LIMIT ON) LIMIT LED4 OFF (HARD LIMIT OFF) SHIFT3 LED OFF SHIFT3 LED ON SHIFT2 LED OFF SHIFT2 LED ON HYSTERESIS SHIFT1 START OF SOFT LIMITING Each shift point can be set and operates independently from the others. While the software has them labelled as Shift1, Shift2 and Shift3, they can each be set anywhere between 0 and about 12,500 RPM, in 25 RPM steps. Setting shift points is easy and is done with a trimpot that produces a voltage directly proportional to RPM. So if a shift point is required at 5500 RPM, you set the trimpot wiper to 0.55V. You then press a switch to store the value. The Shift LEDs light to indicate RPM at and above the stored values, as shown in Fig.1. An adjustment is provided to prevent them from flickering on and off when the RPM is hovering around the shift point. This adjustment causes the Shift LEDs to go out at an RPM lower than the shift setting. The difference in the thresholds is called the “hysteresis”. HYSTERESIS SHIFT2 SHIFT1 LED OFF Shift points HYSTERESIS SHIFT3 SHIFT1 LED ON The SLI unit can be located in a convenient location under the car’s dashboard while the separate display involving four high brightness LEDs can be mounted on the dashboard. The shift LEDs have automatic dimming so that they will not be too bright when driving at night but the Rev Limiter does not have dimming – when it comes on, you will be fully alerted! RPM HYSTERESIS (LIMITING) Fig.1: this diagram shows how the shift LEDs light to indicate RPM at and above the stored values. Note that a degree of hysteresis is built into each shift point, to prevent LED flicker at the critical values. type (2 or 4-stroke) and the number of cylinders in order to calculate engine RPM. For example, a 4-cylinder 4-stroke engine has two cylinder firings per revolution, a 6-cylinder has three firings, a V8 has four firings per rev and so on. A particular problem in measuring engine RPM is that we cannot just count pulses over a one minute or even 10-second period. That would mean that the SLI just would not react fast enough. Instead, we could use a 300ms period which gives a count of 10 for a 4-cylinder 4-stroke engine running at 1000 RPM. But even this period is too long when you consider how fast engine RPM could change – it could easily go from 1000 RPM to 6000 RPM or more, in that short time. In addition, a counting period of just 300ms means that the RPM cannot be measured accurately. That previous count of 10 pules might mean the RPM is 900 or 1100 RPM, a 200-RPM uncertainty – not very good. There is a better way, as shown in Fig.2, the block diagram of the cir­cuit. Here the RPM signal from the engine is filtered to prevent triggering on transient signals and then instead of counting the pulses, we measure How Rev Limiting Is Achieved T HIS PROJECT achieves rev limit­ ing by cutting power to the fuel injectors and this involves switching the injector positive (+12V) supply rail. This can be done using one of two methods – either by using a relay to switch the supply for hard limiting or by pulse width modulating power Mosfets to give soft limiting – ie, a gradual reduction in engine power. Fig.7(a) shows the standard fuel injector setup. As can be seen, the positive terminals of the fuel injectors are all connected to a common +12V supply rail. The engine management siliconchip.com.au computer (ECU) switches the negative side of each injector. Hard limiting is achieved by wiring the relay in series between the positive terminals of the fuel injectors and the +12V injector supply rail. This relay, which is controlled by the limiter circuit, switches off the injectors (by opening its contacts) when the rev limit is reached and this immediately cuts engine power. Fig.7(b) shows this scheme. Alternatively, soft limiting is achieved by wiring two parallel power Mosfets in series between the fuel injectors and the +12V injector supply rail. These Mosfets are then pulse width modulated (PWM) by the limiter circuit when the rev limit is reached, which means that the injector supply rail is also pulse width modulated. The higher the revs go, the lower the PWM duty cycle. As a result, the engine power is gradually reduced when the rev limit is reached. Fig.7(c) shows this scheme. Why do we also include the relay in the soft limiting circuit? It’s there for added reliability, as explained in another panel. February 2008  67 SHIFT1 (LED1) COMPARE IC1 PIC 16F88-I/P RPM SIGNAL FILTERING RB0 CAPTURED COUNTER VALUE COUNTER SHIFT 1 SETTING RA6 SHIFT 2 SETTING SHIFT2 (LED2)  RA7 COMPARE RPM SHIFT3 (LED3) SHIFT3 SETTING 2MHz SIGNAL RPM FACTOR RA0 HARD/SOFT LIMITING RB4 RB1 RB3 RB2 LIMIT (LED4) COMPARE 8 4 2  COMPARE AVERAGE S3 BCD SWITCH ENGINE FORMAT  1 LIMIT SETTING COM  RA1/ RA2 Fig.2: block diagram of the Shift Indicator & Rev Limiter. It measures RPM by using the tacho signal to gate a 2MHz signal into a counter. The counter value is then divided into the RPM factor as set by BCD switch S3 to give engine RPM. the time between them, using a 2MHz signal. What happens is that each firing pulse gates the 2MHz signal to a counter. The next pulse places the count in memory and clears the counter which then proceeds to count again. For example, if the RPM signal is 33.333Hz, the counter will reach 60,000 between pulses. This value is divided into the RPM factor which for a 4-cylinder 4-stroke engine is 60 million. So in this case, the result of the division is 1000 RPM. Each RPM calculation takes 888ms; well before a new count is available. This RPM value is then compared against the settings for shift1, shift2 and shift3. ECU (LO). The ignition coil signal is filtered using one or two 47nF capacitors (LK1 adds the second capacitor) and then AC-coupled via a 2.2mF capacitor to the next stage comprising a 100kW resistor and 16V zener diode clamp (ZD2). Diodes D5 and D6 clamp the signal between +5.6V and -0.6V before it is fed to the RB0 input at pin 6 of IC1. The inputs that connect to the BCD switch and to the Select (S1) and Set (S2) switches are normally pulled to +5V via internal resistors. When the respective switch is closed, its input is pulled low. Switches S1 and S2 are continuously monitored by IC1. Circuit description Engine selection The full circuit is shown in Fig.3. It is based on IC1, a PIC16F88-I/P microcontroller which monitors the RPM signal. It then makes the RPM calculations and comparisons with the set shift and limit levels and drives the associated LEDs and limiting circuitry. IC1 operates at 8MHz and is powered from a 5V supply derived from 3-terminal regulator REG1. Two RPM signal input options are provided: either from the ignition coil negative terminal (HI) via a 22kW resistor or the nominal 5V signal from the BCD switch S3 selects the engine type. This has four switches (at RB4, RB3, RB1 & RB2) and provides 16 possible combinations, ranging from all switches open to all closed. The settings for S3 are checked by IC1 when it is first powered up; this sets the required engine type for RPM calculations. VR1 provides the RPM values for the shift and limit settings. The series 30kW and 10kW resistors connected to the trimpot’s wiper reduce the maximum voltage at TP1 to 1.25V. 68  Silicon Chip In practice, VR1 is adjusted to provide the desired RPM voltage at TP1 and 1V is equivalent to 10,000 RPM. So to set the RPM to 5500 RPM, VR1 is adjusted so that the voltage at TP1 is 0.55V. Trimpot VR2 sets the hysteresis range for each shift and limit setting. A 5V setting at TP2 provides 500-RPM hysteresis and 1V gives 100-RPM hysteresis. Trimpot VR3 sets the ambient light threshold for dimming the LEDs. The LEDs are bright enough to be easily seen in daytime driving and therefore need to be dimmed for night-time driving. The ambient light is monitored by a Light Dependent Resistor (LDR1) and it is connected in series with a 10kW resistor and trimpot VR3 to provide a voltage at IC1’s AN5 input. The 10mF capacitor at the AN5 input averages out changes in ambient light. This prevents the display rapidly changing in brightness if passing along a street lit area at night. Dimming is achieved by driving the LEDs with a duty cycle that can be varied from 1.56% through to 100% (full brightness) in 63 steps. Microcontroller outputs Apart from the three shift LED outputs at pins 15, 16 & 17, there are siliconchip.com.au siliconchip.com.au February 2008  69 Fig.3: the circuit is based on PIC16F88-I/P microcontroller IC1. This stores the shift and limit settings and compares these against the incoming RPM signal that’s fed to its RB0 input at pin 6. IC1 then drives shift LEDs1-3 at its RA6, RA7 & RA0 outputs accordingly. The RA1 output drives the soft limiting circuitry (Q1, Q3, Q5 & Q5), while RA2 drives relay RLY1 via Q2 to provide the hard limiting option. Fig.4: install the parts on the PC board as shown on this parts layout diagram. You can either mount LEDs1-4 & the LDR on the main board as shown, or you can mount these parts on a separate display PC board (shown at bottom right). The two boards are connected together via a 16-way ribbon cable fitted with IDC line plugs. two rev limiting outputs at pins 18 & 1 (RA1 & RA2). Pin 1 (RA2) drives transistor Q2 and this in turn drives an external relay (RLY1) for the hard limiting function. Diode D2 clamps any back-EMF spikes produced by the relay’s coil when the transistor is switched off. Pin 18 (RA1) drives transistor Q1 and this then drives the gates of Pchannel Mosfets Q4 & Q5 for the softlimiting function. Q4 & Q5 control the positive supply to the motor’s fuel injectors and this can be progressively reduced by varying the duty cycle of the pulse width modulation drive. In operation, P-channel Mosfets Q4 & Q5 provide “high side” switching of the injector supply rail. Normally, the RA1 output at pin is set high to turn on transistors Q1, Q4 & Q5 so that the injectors are fully powered. Above the set RPM limit, IC1’s RA1 output (pin 18) will switch Mosfets Q4 & Q5 with a duty cycle which is reduced gradually until there is no injector drive once the motor is over the set limit. The pulse frequency to the injectors is 30.5Hz. Mosfets Q4 & Q5 are driven in the following way: when Q1 is switched off, the base of transistor Q3 is pulled high via a 2.2kW resistor to +12V. This turns on Q3 and so its emitter pulls the gates of Q4 & Q5 towards the +12V supply and switches them off. However, when Q1 is switched on, Q3 is switched off and its emitter is pulled down to 0V via diode D3. This pulls the gates of Q4 & Q5 low and switches them on. Diode D4 is included to protect Q4 & Q5 from the back-EMF spikes produced by the injectors when they turn off. Power supply Power for the circuit is derived from the vehicle’s +12V rail via diode D1. This provides protection if the supply Table 2: Capacitor Codes Value 47nF 10nF mF Code IEC Code EIA Code 0.047mF 47n 473 0.01mF 10n 103 Table 1: Resistor Colour Codes o o o o o o o o o o No. 1 1 1 5 2 2 5 2 1 70  Silicon Chip Value 100kW 30kW 22kW 10kW 2.2kW 1kW 220W 100W 47W 1W 5% 4-Band Code (1%) brown black yellow brown orange black orange brown red red orange brown brown black orange brown red red red brown brown black red brown red red brown brown brown black brown brown yellow violet black gold 5-Band Code (1%) brown black black orange brown orange black black red brown red red black red brown brown black black red brown red red black brown brown brown black black brown brown red red black black brown brown black black black brown not applicable siliconchip.com.au Fig.5: the mounting details for REG1 & Mosfets Q4 & Q5. Each device is electrically isolated from the case using an insulating washer and bush (see photo). Make sure that all polarised parts are correctly oriented when installing them on the board. The locating slot in the IDC header goes towards the bottom edge. Don’t install the IC until the supply has been tested. is connected the wrong way around. A 16V zener diode (ZD1) clamps any spike voltages which may occur on the battery supply and further filtering is provided by the 100mF capacitor for the supply to REG1, a 7805 5V regulator. The 5V rail from REG1 is used to power IC1. Construction The Shift Light Indicator is built on a PC board coded 05102081 (101 x 81mm), while a separate display board coded 05102082 (42 x 19mm) carries the display LEDs. Alternatively, the LEDs can be mounted on the main board. If you do elect to use the separate display board, it’s connected back to the main board via a 16-way ribbon cable fitted with IDC headers (Fig.6). As usual, begin construction by checking the PC board for any defects such as shorted tracks and breaks in the copper. That done, check that the hole sizes are correct. The holes for the four corner mounting screws need to be 3mm in diameter, while the holes for the screw terminal blocks need to be 1.2mm. Check also that the PC board fits into the box. If it doesn’t fit, use a small file to round the corners until is does. Fig.4 shows the parts layout on siliconchip.com.au the PC board. Start the assembly by installing the wire links, followed by the resistors. Table 1 shows the resistor colour codes but you should also check each one using a digital multimeter before installing, as some colours can be hard to read. Next, install the PC stakes for test points TP GND, TP1 & TP2. That done, install the 2-way header for LK1. Follow these with the diodes and zener diodes, taking care to install each with the correct orientation. Once these parts are in, install a socket for IC1 with its notched end towards Q2. Don’t install the IC yet – that step comes later. The capacitors can go in next, again taking care to ensure that the electrolytics are correctly oriented. That DISPLAY BOARD CONNECTOR 16-WAY IDC CABLE done, install transistors Q1-Q5 and regulator REG1. Note that REG1, Q4 & Q5 mount with their leads protruding through the bottom of the PC board by about 1mm. This will leave sufficient lead length to allow the devices to be later fastened to the side of the box. Now install trimpots VR1-VR3 and the BCD switch. The correct orientation for S3 is with its corner dot to the lower left – see Fig.4. Switches S1 & S2 can then be inserted. These two switches will only fit on the PC board with the correct orientation. The next step is to mount the two 6.8mm PC spade terminals, the 16way IDC cable socket and the screw terminal blocks. Note that the 4-way terminal block consists of two 2-way blocks which are joined by sliding their moulded dovetails together. Display board assembly Fig.4 also shows the display board assembly. It should only take a few minutes to assemble. There are a couple of options here MAIN BOARD CONNECTOR GROMMET PIN 1 LOCATING SPIGOT SIDE OF BOX LOCATING SPIGOT Fig.6: here’s how to make up the IDC cable that connects the display board to the main board. The header plugs can be clamped together using a small vice. Note the positions of the locating spigots on the plugs. February 2008  71 Features & Specifications Features • Three independent shift indicator LEDs • One RPM limit LED • Adjustable hysteresis for each shift setting and at the limit • Relay switching of injectors at limit (hard limiting) • Alternative soft limiting using pulse width modulation (PWM) • Suits most petrol engines, including asymmetrical cylinder types • Automatic dimming of shift LEDs & adjustable minimum brightness • Easy adjustment of shift and RPM limit settings • Easy engine selection – suits all engine types from 1-12 cylinders • Easy adjustment of soft limiting effect Specifications RPM accuracy: typically <2% at 25°C with a 5.0V supply. Maximum shift & limit settings: 12,500 RPM for 1 to 12-cylinder 4-stroke engines (1 to 6-cylinder 2-stroke). Shift & limit RPM adjustment: 0 to >12,500 RPM in 25 RPM steps. Adjustment for RPM using VR1: 1V = 10,000 RPM, 0.5V = 5000 RPM (5.0V supply). Hysteresis adjustment: 0-500 RPM in 2-RPM steps Adjustment for hysteresis using VR2: 1V = 100 RPM, 5V = 500 RPM (5.0V supply). Shift and limiting response: RPM dependent (see Table 3). PWM limiting response is slowed using effects. Soft limiting PWM: 100% to 0% with a maximum of 250 steps over the hysteresis RPM range at a 30.5Hz rate. Soft limiting effects: PWM update after 1-16 PWM cycles, RPM measurement averaging over 1-64 RPM values. Dimming of shift LEDs: full range of 63 dimming steps from 1.5625% to 100% using PWM at 122Hz. The 0% PWM is not included. Minimum dimming can be adjusted to any one of the 63 settings. when it comes to mounting the LEDs and the LDR. One option is to bend the LED leads at right angles about 8mm from their bodies and install them so that they sit at right angles to the PC board as shown in the photo. Similarly, the LDR’s leads can be bent at right angles about 11mm from its body before installing it on the board. A 7mm-wide cardboard spacer can be used to ensure that these parts all sit the same distance above the board. Alternatively, you can push the parts right down onto the board so that the leads touch the board surface. Another option is to mount the LEDs and the LDR on the back of the 72  Silicon Chip PC board. It all depends on how you intend to ultimately mount the display board on the dashboard. Which ever option you choose though, be sure to install each LED with the correct orientation – the anode lead is always the longer of the two. The LDR can go in either way around. Once these parts are in, install the IDC socket. The other option is to install the LEDs and the LDR on the main PC board. In that case, you will have to later drill matching holes in the side of the case. Final assembly A metal diecast case measuring 111 x 60 x 54mm is used to house the main board. This makes for a rugged assembly and provides heatsinking for regulator REG1 and the two power Mosfets (Q4 & Q5). The first step here is to drill the four mounting holes in the base for the PC board. That done, fit four 10mm spacers to the case, then mount the board in position and secure it using M3 x 6mm screws and nuts. Having secured the board, bend the leads for REG1, Q4 and Q5 so that their metal tabs sit flat against the sides of the case. Carefully mark out their tab mounting holes, then remove the PC board and drill these holes to 3mm. Be sure to de-burr each hole using an oversize drill, to give a clean, flat surface (this is important to prevent punch-through of the insulating washers when the devices are secured to the case). In addition, you will have to drill three 9.5mm holes in the side of the case to provide external wiring access. These holes should be opposite (and slightly above) the 2-way and 4-way terminal blocks and the IDC header. Use a small pilot drill to start these holes, then ream them to size and de-burr them before fitting the rubber grommets. Note: the hole opposite the IDC header is not required if the LEDs and LDR are mounted on the main board. You will, however, have to drill five holes to accept the LED bodies and to allow light through to the LDR. The PC board can now be reinstalled and REG1, Q4 and Q5 secured to the sides of the case. Note that their metal tabs must be electrically isolated from the case using TO-220 insulating washers and mounting bushes – see Fig.5. Each device is secured using an M3 x 10mm screw and nut. Once these devices have been secured, use a multimeter to confirm that their metal tabs are indeed isolated from the case. The IDC cable can now be installed. This is done by first rolling up the cable and feeding it through the hole opposite the IDC socket. The IDC plug can then be attached, making sure that the orientation is correct (see Fig.6). Use a small vice to clamp the header plugs together to secure the cable. Testing the PC board The first step in the test procedure is to apply power to the +12V & 0V siliconchip.com.au terminals on the 4-way terminal block. That done, check the voltage between pins 14 & 5 on the IC socket. This should be close to 5V (a range of 4.8V and 5.2V is acceptable). If the voltage is below 4.8V, check for a short on the PC board. If there is no voltage, check that diode D1 is the right way around. Assuming that everything is correct, switch off and install IC1 in its socket. It must be installed with its notched end towards transistor Q2, Next, apply power and adjust trimpot VR3 fully clockwise. Now press switch S1 and check that LED1 lights. Repeated pressings should now cause LED2, LED3 and LED4 to light in sequence, with only one LED on at a time. These correspond to the settings mode for Shift1, Shift2, Shift3 and Limit respectively. If S1 is now pressed again, LED 4 (Limit) should remain on while LEDs1-3 should light up in sequence at a relatively fast rate. This is the soft limiting setting mode for the rev limiting feature. Pressing S1 yet again should turn on just LED1, LED2 & LED3. This is the selection for setting the minimum dimming level. Finally, pressing S1 again should switch all the LEDs off. This returns the unit to its normal mode, whereby each LED lights when the incoming RPM signal reaches its respective threshold. Threshold adjustments As noted already, trimpots VR1 & VR2 are used to set the Shift and Limit thresholds and hysteresis values. The first step it to set these values for Shift1. The procedure is as follows: Step 1: press switch S1 so that LED1 lights. Step 2: attach a multimeter between TP1 & TP GND and adjust VR1 to set the desired RPM threshold. Note that the voltage on TP1 is directly related to the RPM setting, where 1V represents 10,000 RPM. To set a 4000 RPM threshold, for example, adjust VR1 for a reading of 0.4V (400mV). Note also that, due to trimpot resolution, you may not be able to adjust the voltage to better than within 5mV (equivalent to 50 RPM) of the desired value. Step 3: connect a multimeter between TP2 & TP GND. Step 4: adjust VR2 to set the RPM siliconchip.com.au The PC board is mounted inside the case on 10mm spacers and secured using M3 x 6mm screws. REG1, Q4 & Q5 are then bolted to the case – see Fig.5. Note that the wiring to the fuel injectors is not required if you opt for hard limiting. hysteresis value. This can be adjusted from 0-500 RPM. Note that 5V at TP2 sets the hysteresis to 500 RPM, 4V gives 400 RPM and so on. Step 5: press Set switch S2 to program the RPM threshold and hysteresis adjustments for Shift1 into IC1. LED1 will now flash five times to indicate that these settings have been saved. Note: if you require the highest possible accuracy, you will have to scale the adjustment voltages to compensate for REG’s output (ie, if this is not exactly +5V). In practice, it’s just a matter of multiplying the threshold RPM required by the measured supply voltage and dividing the result by 5V. For example, let’s say that you want to set the RPM threshold to 4000 RPM and that the supply voltage is 4.95V. In that case, the calculation is 4000 x 4.95V/5V or 3960. So to adjust for 4000 RPM when the supply is 4.95V, you must set VR1 to give 0.396V at TP1. Step 6: press S1 so that LED2 lights and repeat the above steps (through to Step 5) to set the threshold and hysteresis values for Shift2. Repeat this procedure to set the values for Shift3, making sure each time that the correct LED is selected. Don’t forget to press S2 to save the changes each time you adjust VR1 & VR2 for each Shift setting. This must be done before moving on to the next Shift light, otherwise the settings will not be saved. Rev limit adjustments Now for the rev limit adjustments. Just follow these steps: Step 1: press S1 after the Shift3 settings have been saved. This turns LED4 (Limit) on, while all the other LEDs are off. Step 2: monitor the voltage at TP1 and adjust VR1 to set the rev limit. As before, 1V is equivalent to 10,000 RPM so to set a limit of 6000 RPM, for example, set VR1 for a reading of 0.6V. Step 3: monitor TP2 and adjust VR2 to set the rev limit hysteresis. In this case, 1V is equivalent to 100 RPM. If you intend using PWM limiting so that the engine power drops off gradually, use an initial value of 500 RPM (5V at TP2). Alternatively, if you intend using relay limiting, set the value to 200 RPM (2V at TP2). Step 4: press S2 to save these settings. Step 5: press S1 to bring up the soft February 2008  73 RLY1 (a) STANDARD INJECTOR WIRING INJECTOR 4 INJECTOR 3 INJECTOR 2 INJECTOR 1 INJECTOR 4 INJECTOR 3 INJECTOR 2 INJECTOR 1 ECU ECU (b) WIRING FOR HARD LIMITING 87(NO) B RLY1 C(30) SHIFT INDICATOR & REV LIMITER 87a(NC) INJECTOR 4 C(30) 87a(NC) EXISTING +12V INJECTOR SUPPLY RAIL A NEW INJECTOR SUPPLY RAIL INJECTOR 3 87(NO) INJECTOR 2 EXISTING +12V INJECTOR SUPPLY RAIL INJECTOR 1 EXISTING +12V INJECTOR SUPPLY RAIL ECU (c) WIRING FOR SOFT LIMITING Fig.7: these diagrams shows the standard fuel injector setup (a) plus the modifications required to wire in the limiter circuit for hard limiting (b) or soft limiting (c). Be sure to use a relay with 30A contacts, as specified in the parts list. Note that the relay (RLY1) is used in both the hard limiting and soft limiting circuits – see panel. limiting adjustment mode – ie, LED4 lit and LEDs1-3 lighting in sequence. Trimpot VR1 now adjusts the number of RPM calculations that are used in averaging the RPM reading while VR2 adjusts the rate at which the PWM (pulse width modulation) that provides the soft limiting changes. Setting VR1 fully clockwise gives an average of 64 RPM calculations, while setting VR2 fully clockwise gives 16 PWM cycles before changes occur. Conversely, fully anticlockwise settings for VR1 and VR2 give no averaging and a PWM that can change with each cycle. Setting both VR1 & VR2 to mid-way would provide a suitable soft limiting effect for most engines. However, if the soft limiting subsequently proves to be too soft, so that the engine RPM overshoots the desired limit by a large margin, then the trimpots should be adjusted further anticlockwise. Note that VR1 has an effect on both the soft limiting smoothness and the response time when it comes to limiting the engine RPM. VR2 only affects the RPM limiting response speed. Step 6: press S2 to save the soft limiting settings. Dimming adjustments Pressing S1 again brings up the Surround the base & leads of diode D4 with neutral cure silicone This view shows how power Mosfets Q4 & Q5 are bolted to the case and their tabs isolated using insulating washers and bushes. REG1 mounts in similar fashion – see also Fig.5. Note that diode D4’s leads should be surrounded with neutral-cure silicone, to prevent them from vibrating and breaking. 74  Silicon Chip dimming adjustment mode (LEDs1-3 all lit, LED 4 off). It’s now just a matter of covering the LDR sufficiently (both front and back) to bring the LED brightness down to the minimum level you require and then pressing the Set switch (S2) to save the setting. The three LEDs will then flash five times to indicate that this has now been stored. Note that the above procedure is best carried out in a room with a low ambient light level (but not dark). That done, adjust VR3 to set the ambient light level threshold at which dimming begins (this may take some trial and error). By the way, changing the 10mF capacitor at pin 12 of IC1 to 1mF will increase the rate at which the LEDs dim or become brighter in response to ambient light changes. Installation The unit is relatively straightforward to install and requires only a limited amount of external wiring. This involves wiring for the +12V and ground (0V) connections, the rev signal input and the connections to the fuel injectors. The +12V supply can be obtained from the fusebox and must be switched on (or off) by the ignition. Note, however, that this supply rail must remain on when the engine is being cranked (ie, when the starter motor is running). The 0V rail can be connected to vehicle siliconchip.com.au Parts List 1 main PC board, code 05102081, 101 x 81mm 1 display PC board coded 05102082, 42 x 19mm 1 diecast case, 111 x 60 x 54mm 1 SPDT 30A horn relay 1 relay base to suit horn relay (optional) 3 2-way PC-mount screw terminals (5.08mm spacing) 1 PC-mount 0-F BCD DIL switch (S3) 2 SPST micro tactile switches (S1,S2) 2 16-way IDC PC-mount headers 2 16-way IDC line plugs 2 6.8mm PC-mount spade terminals 2 6.8mm insulated spade crimp connectors 3 rubber grommets for 6mm cable diameter 3 TO-220 silicone insulating washers 3 3mm insulating bushes 4 M3 x 10mm tapped Nylon standoffs 8 M3 x 6mm screws 3 M3 x 10mm screws 3 M3 nuts chassis. These supply connections can be run using medium-duty automotive hook-up wire. The rev signal can be from derived from the coil’s negative terminal and this wire connects to the HI input. Alternatively, in a multi-coil car, you can use the ECU tachometer signal and this should go to the LO input. Injector wiring Fig.7(a) shows the basic set-up for standard injector wiring. Note that the engine management system (ECU) switches the negative side of the fuel injectors. The first step is to disconnect the injectors from their existing common positive supply rail. After that, it depends on whether you are opting for hard limiting or soft limiting. If you are opting for hard limiting, it’s simply a matter of wiring in the relay as shown in Fig.7(b). This involves first connecting the vehicle’s existing +12V injector supply rail to the relay’s common (C) contact. The normally siliconchip.com.au 1 2-way header with 2.54mm spacing (LK1) 1 jumper plug (for LK1) 3 PC stakes 1 1m length of 16-way IDC cable 1 160mm length of 0.8mm tinned copper wire 1 1m length of figure-8 20A automotive wire 1 1m length of red medium-duty automotive wire 1 1m length of black mediumduty automotive wire Trimpots & LDR 2 1kW horizontal mount trimpots (VR1,VR2) 1 500W horizontal mount trimpot (VR3) 1 LDR (50kW light & 10MW dark resistance) (LDR1) Semiconductors 1 PIC16F88-I/P microcontroller programmed with 0510208A. hex (IC1) 1 7805 3-terminal regulator (REG1) 2 IRF9540 P-channel Mosfets (Q4,Q5) 3 BC337 NPN transistors (Q1-Q3) 2 1N4004 diodes (D1,D2) 1 UF4003 ultrafast diode (D3) 1 BY229 fast diode (D4) 2 1N4148 diodes (D5,D6) 2 16V 1W zener diodes (ZD1,ZD2) 2 18V 1W zener diodes (ZD3,ZD4) 1 5mm high-intensity green LED (LED1) 1 5mm high-intensity yellow LED (LED2) 2 5mm high-intensity red LEDs (LED3,LED4) Capacitors 3 100mF 16V PC electrolytic 2 10mF 16V PC electrolytic 1 2.2mF 63V PC electrolytic 2 47nF MKT polyester 1 10nF MKT polyester Resistors (0.25W, 1%) 1 100kW 2 1kW 1 30kW 5 220W 1 22kW 0.5W 2 100W 5 10kW 1 47W 1W 2 2.2kW Why Use The Relay With Soft Limiting? Strictly speaking, if you elect to use soft rev limiting, the relay shown in Fig.7(c) is optional. However, we still recommend wiring it into circuit for a couple of reasons. First, by using the relay as shown, its NC contacts take the load off the soft limiting Mosfets (Q4 & Q5) during normal engine operation. However, if the rev limit is reached, the relay quickly opens and the Mosfets then take over to provide the soft limiting function – ie, they pulse width modulate the new injector supply rail. Second, the relay’s contacts ensure that the injectors are still supplied with power during normal running if the Mosfets become faulty or if a fault develops in the unit which switches them off. For this reason, we strongly recommend that you include the relay as shown in Fig.7(c) – it’s a worthwhile safety and reliability feature. closed (NC) contact is then connected to the positive injector terminals. Note that all wiring to the relay contacts and to the injectors should be run using 20A automotive cable. Note also that, for hard limiting, no connections are made to points A & B on the circuit board. Alternatively, if you are opting for soft limiting, then you need to wire the injectors as shown in Fig.7(c). In this case, the vehicle’s existing injector positive supply rail is connected to point A on the main PC board. Point B on the circuit board then becomes the new injector positive supply rail. February 2008  75 Table 3: BCD Switch Settings & Details For Various Engine Types Frequency/ 1000 RPM Shift light Response <at> 1000 RPM Shift light Response <at> 2000 RPM Between each pulse 8.33Hz 120ms 60ms Between each pulse 16.66Hz 60ms 30ms Between each pulse 25Hz 40ms 20ms Between each pulse 33.33Hz 30ms 15ms 2.5 Between each pulse 41.66Hz 24ms 12ms 50Hz 20ms 10ms BCD Switch Setting (S3) Cylinders (4-stroke) Cylinders (2-stroke) Pulses per RPM RPM Counter 1 1 – 0.5 2 2 1 1 3 3 – 1.5 4 4 2 2 5 5 – 6 6 3 3 Between each fourth pulse 8 8 4 4 Between each fourth pulse 66.66Hz 15ms 7.5ms 9 Asymmetric 3-cylinder – 3 over 2 RPM Between each fourth pulse 25Hz 80ms 40ms A 10 5 5 Between each fourth pulse 83.33Hz 12ms 6ms B Asymmetric 2-cylinder – 2 over 2 RPM Between each fourth pulse 16.66Hz 120ms 60ms C 12 6 6 Between each fourth pulse 100Hz 10ms 5ms The relay is also wired into circuit as before. Once again, be sure to use 20A automotive cable for the wiring to the injectors, the relay contacts and to points A & B on the PC board. Note that this wiring is run to the main board by feeding it through the adjacent rubber grommet and terminating it with spade crimp connectors. These connectors are then plugged into the A & B terminals. Make sure that the crimp connections are nice and tight to ensure reliability and be sure to plug each into its correct terminal. A ratchet-driving crimping tool is a necessity here. It’s vital that all wiring be installed in a professional manner, to ensure reliability. That means using proper automotive connectors to terminate the wiring and securing the wiring with tape and cable ties. Testing Once the wiring is complete, set the BCD switch to the number that suits your engine – see Table 3. That done, start the engine and rev it to check that the shift & limit LEDs light at their correct RPM values. If Determining The Shift Points How do you determine the best shift points to program into the Shift Indicator & Rev Limiter? In most cases, it’s just a matter of driving the car and noting down a sensible RPM value for each gear change. The values can then be programmed into the unit, after which it’s simply a matter of monitoring the LEDs to pick the gear-change points. Alternatively, as mentioned in the text, you could set the three LEDs to give a ‘ready’, ‘set’ and ‘go’ indication for each gear change. The rev limit can simply be set to just under the tacho’s redline value. Note, however, that many modern cars include rev limiting as part of their engine management system. In that case, you won’t need the rev limiting feature provided by this unit and it’s just a matter of leaving out the wiring between this unit and the fuel injectors (you can also leave out the relay, power Mosfets Q4 & Q5 and transistors Q1-Q3). If you are modifying a car for racetrack use, then the shift points would be set much more aggressively – typically at those points that provide maximum acceleration. In some cases, you might want to set the shift points at close to engine redline. In other cases, it may be a matter of picking the maximum engine power points. 76  Silicon Chip you haven’t yet programmed the unit, the initial settings are 1000 RPM for shift1, 2000 RPM for shift2, 3000 RPM for shift 3 and 4000 RPM for the limit. The hysteresis is 200 RPM for shift1 and 500 RPM for the other thresholds. If the shift points are incorrect and you are using the HI input, try installing link LK1 to change the input filtering. Alternatively, if you are using the LO input, LK1 has no effect and no adjustments to the input filtering should be necessary. If the LEDs do not light at all, check that the RPM input signal is correctly connected. Peak hold injectors Finally, note that the soft limiting option is not suitable for injectors that operate with a so-called peak hold drive. This is where an initial high current is used to close the injector but then the current is reduced by rapidly switching the injector signal on and off (this keeps the injector open but with reduced power to the injector solenoid). Note, however, that you can use the hard limiting option, provided that the relay contacts can handle the peak currents that drive this type of injector. How do you know whether you have peak hold injectors? They will typically have a solenoid coil resistance of less than 1W (normal injectors have SC a resistance of 4-5W). siliconchip.com.au PRODUCT SHOWCASE Microgram’s new hand-held Digital Microscope range Digital FM Stereo Encoder from RF Power MicroGram Computers have a new range of Digital Microscopes for education, industry and even advanced hobbyists. With magnification up to 500 times, they provide high quality microscopy video interfacing to a PC through USB 2.0, allowing easy installation and operation. Magnification and focus are simple to control, while maintaining clear and steady images. The images seen through the microscope’s eyepiece can be shown on the computer’s monitor and saved on the hard drive as an image (jpg) or as video (avi). In education, many students can view the same subject at the same time. Students can use these saved images for assignments or later study. There are several digital microscopes Contact: in the range, along MicroGram Computers with accessories PO Box 8202, Tumbi Umbi, NSW 2261 such as stands and Tel: (02) 4389 8444 Fax: (02) 4389 8388 eyepieces. Website: www.microgram.com.au RF Power have introduced a high-performance stereo encoder to their range of FM transmitters. The encoder uses digital signal processing (DSP) to accurately generate the entire composite stereo signal. The DSP produces very high quality audio and channel separation without the audio phase shifts and other artifacts present in analog encoders. The encoder accepts AES/EBU or 3ID (BNC) digital inputs as well as analog balanced audio. An effective feed forward digital limiter limiter operating on the final composite signal ensures the transmitted signal remains within the licenced FM channel. A user-selectable audio processor is Contact: also included which RF Power is especially useful 24 Filip Way, West Swan Phone WA 6055 in remote and satel- Tel: (08) 94481995 Fax: (08) 94488140 lite re-transmission Website: www.rfpower.com.au applications. February is Amateur Radio Field Day Season This month sees two of the country’s largest and best-known amateur radio/ communications field days. First, on Sunday 10 February, is the Centre Victoria RadioFest, which will be held at the Kyneton Racecourse, Campaspe Pl, Kyneton – about 50 minutes from Melbourne. This Field Day will feature the Australian launch of Icom’s D-STAR digital voice and data mode, including D-STAR in action and expert presentations of this revolution in amateur radio. Entry tickets (at $10 each) will go into a draw for a D-STAR radio and other prizes. Children 12 and under are admitted free. Of course, there will be the obligatory second-hand market and car boot sales alley, along with numerous commercial and radio special interest group displays. Further details from www.radiofest. amateurradio.com.au One week later (Sunday 17 February) is the southern hemisphere’s largest, the Central Coast Field Day, held at Wyong Race Course, Howarth St, Wyong – about siliconchip.com.au 90 minutes north of Sydney (and right next door to Wyong railway station). The Central Coast Field Day, established in 1957, has grown to become a “must visit” event for amateurs and those interested in radio, communications and electronics over much of the eastern seaboard. Among other features will be • Truckloads of preloved equipment at giveaway prices in the flea market area. • All major radio and electronic equipment suppliers together under one roof with many dealers showing the latest offerings and great bargains. • Interesting technical lectures, seminars and workshops Packet Radio Computerised Communications Displays Scanning and Dx Listening displays and information. • Vintage and historical radio exhibits • Radio fox hunts • Amateur television transmission demonstrations Admission is also $10 per person with children under 12 free. Information (much more!) is available at www. ccarc.org.au ANTRIM TRANSFORMERS manufactured in Australia by Harbuch Electronics Pty Ltd harbuch<at>optusnet.com.au Toroidal – Conventional Transformers Power – Audio – Valve – ‘Specials’ Medical – Isolated – Stepup/down Encased Power Supplies Toroidal General Construction OUTER INSULATION OUTER WINDING WINDING INSULATION INNER WINDING CORE CORE INSULATION Comprehensive data available: www.harbuch.com.au Harbuch Electronics Pty Ltd 9/40 Leighton Pl, HORNSBY 2077 Ph (02) 9476 5854 Fax (02) 9476 3231 February 2008  77 PICAXE VSM: Getting It Going! In this second part of our mini-series, Clive Seager talks us through using the new PICAXE VSM simulation software. L ast month we introduced the new PICAXE VSM software, which will allow you to simulate PICAXE designs on the computer to see if they (or your software!) will do what you intended to do! As well as a serious design tool, PICAXE VSM is also a great way for beginners to experiment with PICAXEs – without any risk of letting the smoke out! What’s more, PICAXE VSM will help you with the circuit so that you can actually build your PICAXE project. Installation To install the PICAXE VSM software download the demo installation package (18MB) from www.picaxevsm.com If you are on dial-up and prefer a CD your local PICAXE distributor should be able to oblige. The software is designed for Windows 2000, XP, and Vista. 95, 98 and ME are not officially supported, however many users have reported that the software does actually run on these older Windows versions. The software will run in restricted ‘demo’mode until you purchase a licence key (you can still use the Rudolph simulation sample described below in demo mode). Registration is also carried out online, again at www. picaxevsm.com, via secure credit card transaction, you Overview Window Object Selector Design Area Animation Control Panel 78  Silicon Chip siliconchip.com.au Fig.1: you not only get the simulation, you can also see the program stepping through line-byline AND see the variables in another window. will receive an email with your key shortly after purchase (VSM costs UK ₤49.99 (~AU$118 at press time). Use the PICAXE VSM ‘Licence Manager’ utility to install your key and ‘unlock’ the full version. Let’s Begin! PICAXE VSM is a powerful piece of software and so will naturally take a little while to learn. To get started the most important thing is to be sitting comfortably with one hand on the mouse and the other on the keyboard! As with most graphics packages, the software uses keyboard shortcuts as well as the mouse. These take a little while to get used to but you should very quickly learn the shortcuts and appreciate how they speed up use of the software. So to learn basic navigation lets start by opening the existing ‘AXE107 Rudolph.dsn’ example from the / samples/(Demo Version Samples)/PICAXE folder. Then move the mouse over the design and press the <Z> zoom, <U> unzoom and <P> pan keyboard keys as you move the mouse around the design – see how you can zoom in and out very quickly by using keyboard and mouse at the same time! If you are already familiar with a different graphics/ PCB application that uses different shortcut keys, you can easily customise ‘PICAXE VSM’ to your preferred shortcut keys. To do this use the ‘System>Set Keyboard Mapping’ menu. Object Selector While the sample design is open, let’s look at the different parts of the screen. The main editing window is obviously where you draw and edit your designs. To the left of this is the ‘Object Selector’ list, that lists all objects (components) currently used in the design. Above the ‘Object Selector’ is the ‘Overview’ window, which we will look at later. At the top and left of the screen are menu bars, and at the bottom of the screen is the ‘animation control panel’. This looks like the buttons on a traditional tape recorder (remember the days before CDs and MP3s?) – Play, Forward, Pause and Stop. Simulation Click on the ‘Play’ button at the bottom left of the screen and the Rudolph simulation will compile and start. When you click on the animated pushbutton switch, a tune will siliconchip.com.au play on the piezo sounder (simulated via the computer’s speaker) and the LEDs will flash. The actual tune played will be decided by the resistance of the LDR – varying light levels are simulated via the up and down buttons beside the LDR (you may wish to zoom in using the <Z> key). While the simulation is playing click the pause button at the bottom of the screen. This will pause the simulation and open up a number of other ‘debug’ windows, which show, for instance, the variable values and the PICAXE program. (Tip - you can select which PICAXE windows are automatically displayed by checking them in the ‘Debug’ menu while the program is paused). If so desired you can now also step through the PICAXE program line by line, by clicking on the ‘Step into Source’ button on the Program window. You can also run at full speed again by selecting the ‘Run’ button. While the Program window is open, practice setting ‘break points’ by clicking at the left hand side of any program line – a red circle will appear. This means the program will run until this particular point and then stop – ideal for debugging those problem programs. Try it out! One final tip for simulation, if you want to step through a program line-by-line right from the start, simply click ‘pause’ (rather than ‘play’) to start the simulation. This will start the simulation and automatically break on the first program line. Our first circuit! Now click File>New Design menu and select the default template layout (this gives you a blank A4 paper size layout). It is good practice to give your design a title, so use the ‘Design>Edit Design Properties’ menu to enter a title, version number and your name. Also save the file now, and remember to keep saving every so often as you work through creating your masterpiece! Now we need to build the design. To start with we will February 2008  79 Fig.3: this is the list of components you will require for the Rudolph project. Fig.2: use the ‘Design>Edit Design Properties’ menu to enter a title, revision number and your name. Also save the file now and remember to keep saving every so often as you work through creating your masterpiece! just create a straight copy of the existing Rudolph design from scratch – you may find it useful to print it out to copy. The first thing is to add parts to our ‘Object Selector’. To do this click on the small ‘P’ at the top of the ‘Object Selector’ (which is a shortcut for the ‘Library>Pick Device’ menu). We now have a list of 10,000+ components to search through. This could be daunting but fortunately a very powerful search facility and special ‘PICAXE’ category enables us to quickly locate the parts you want! Start by typing in ‘LED’, and then click on the ‘PICAXE’ category. You will then have a much smaller list to choose from! Double click on LED-RED and LED-GREEN. This will add then to the Object Selector. Delete the ‘LED’ text and change to ‘resistor’, then click on the PICAXE category again. Double click on the 330W, 10kW and 22kW resistors. Fig.4: there are two ways to display the PICAXE chip -– the choice is yours (depending on which one you’re used to). Then repeat this process for all the parts in Fig.3. Note there are two options for the PICAXE chip, either ‘traditional’ schematic format (which has the power pins hidden) or ‘IC’ layout. Choose whichever you prefer, then close the ‘Pick Devices’ window. Let’s draw! First job is to drop the parts onto the screen, copying the Rudolph design layout already used. Leave plenty of space between components to start with, you can always ‘tidy up’ later. To select the first part to drop, click on it in the ‘Object Selector’. A preview of the item will be shown in the ‘Overview’ window. Then move over the design and click to drop it in place. You can then drop another of the same component straight away, or select a different component from the Object Selector. When all the components are placed click on the ‘Selection Mode’ arrow (top of the left hand toolbar) to move out of ‘Component Mode’ If required components can be rotated and mirrored to make a neater schematic. To do this right click over the component and select the appropriate menu option. Fig.5: a very powerful search facility and special ‘PICAXE’ category enables us to quickly locate the wanted parts! 80  Silicon Chip siliconchip.com.au Your components names (R1, R2, R3 etc) should automatically be added as the components are dropped. If you just get ‘R?’ instead of a number make sure that ‘Tools>Real Time Annotation’ menu is enabled. If necessary ‘R?’ can be changed to a number simply by double clicking the label and editing. You will also need to add a couple of ‘Ground’ and ‘Power’ terminals. To do this right click the mouse and select P l a c e > Te r m i n a l > Ground and then P l a c e > Te r m i n a l > Power. The default powFig.6: components can be rotated er rail is always and mirrored to make a neater 5V, if you want to schematic. To do this, right-click change this (e.g. to over the component and select the appropriate popup menu option. 4.5V to simulate 3xAA cells) use the ‘Design>Configure Power Rails’ menu. Wiring Finally we need to wire the components together. Make sure no part is currently selected (a useful tip is just to click on a blank part of the screen to clear any selection) and then move the mouse over a component pin. The mouse cursor will change to the ‘pencil’ shape and you can then click to start the wire. Move the cursor to draw the wire, clicking wherever you want to fix a corner. Finish the wire by clicking over the second component pin (or on to another wire). You cannot draw wires over labels or components, so always leave plenty of room between parts. The wires will automatically move if you later drag a connected component, so it is easy tidy up designs at a later point. To delete a wire simply right click and select delete. Segments of wires can also be individually dragged when the wire is highlighted. Note that you must specifically wire all parts together. Two components pins placed ‘overlapping’ each other will not be ‘electrically’ connected within the design. PICAXE Program Before the simulation can run we need to allocate a PICAXE program to the PICAXE-08M component. This is done via the ‘Source>Add/Remove Source File’ menu but first you have to type in and save the PICAXE BASIC file! This can be carried out using the normal PICAXE Programming Editor software, or the simple ‘Source Editor’ siliconchip.com.au Fig.7: type in this test program and save it as a .bas BASIC file in the same folder as your .dsn design file. Fig.8: make sure the PICAXE chip (eg, U1) is highlighted as the target processor. Then click ‘New’, select your file and then click OK. application provided with PICAXE VSM. Type in the test program shown in Fig.7 and save it as a .bas BASIC file in the same folder as your .dsn design file. I recommend that you always use the same filename stem to avoid confusion. Back within PICAXE VSM select the ‘Source>Add/Remove Source File’ menu and make sure the PICAXE chip (e.g. U1) is highlighted as the target processor. Then click ‘New’, select your file and then click OK. If you now go back to the ‘Source’ menu you will see your program file is now listed within the menu. If you click on the filename it will now open within the ‘Source Editor’. This is a very useful shortcut if you want to tweak and save modifications to your BASIC program while simulating and testing. Run Your First Program. Click ‘Play’ and if all is well your two Rudolph eye LEDs should now start flashing every second! Congratulations, that is your first PICAXE VSM design created and simulated. To have a play with the LDR, switch and piezo have a look at the example BASIC file provided within the ‘AXE107 Rudolph.dsn’ sample design file. We’ve run out of space for this month. Next month we will look at a couple more complex designs and learn how to use some of the virtual instruments – voltmeter, oscilloscope and even an I2C debugger! SC February 2008  81 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/ Vintage Radio By RODNEY CHAMPNESS, VK3UG More DC-to-AC Inverters From The Valve Era DC-to-AC inverters were essential in many rural areas for powering mains equipment from 32V DC lighting plants. Here we take a look at the AWA VB-32 transistorised inverter and the Ferris vibrator inverter, the latter often used to power car radios. M These two views show the internal construction of the AWA VB-32 inverter (photos taken after restoration). The germanium power transistors were mounted on the finned heatsink. 86  Silicon Chip ANY RADIOS DESIGNED for rural areas ran off batteries during the valve era, since a mains supply was often not available. Often, this involved using separate batteries to power the filament, bias and hightension (HT) circuits. By contrast, those sets designed to work from a 6V wet battery used a vibrator power supply to derive a 90V or 135V HT rail for the plate supply. The filament wiring of the valves was arranged so that they could run from the 6V battery. Other valve radios were designed to work off 12V, 32V, 50V, 110V and 240V DC supplies (eg, from home lighting supplies and small town power plants). In fact, 32V DC home lighting plants were common in farming communities and other areas remote from the reticulated 240V AC mains. Unfortunately, not many appliances were designed to work off 32V. As a result, several manufacturers built 32V DC to 240V AC inverters to power mains devices, such as radiograms and later on, TV receivers. To my know­ ledge, only Ferris radio produced a 32V DC-operated TV receiver, this siliconchip.com.au Fig.1: the AWA VB-32 used four germanium transistors to provide push-pull drive to an output transformer. Q1, ZD1 and their associated parts form a protection circuit which switches off the inverter if the input voltage exceeds 36V. being back in the valve black and white era. Vibrator inverters In the June 2007 issue, we described two vibrator type DC-to-AC inverters. The larger of these – a Van Ruyten 200W unit – was designed to power a TV receiver from a 32V supply. Ferris Radio also produced a small 30W vibrator unit that could power AC/ battery portables (or other small low drain devices) from 6, 12 or 32V DC AWA VB-32 inverter The development of high-power germanium transistors during the early 1960s saw the demise of vibrator inverters. Transistorised 200W inverters were quickly released by a number of manufacturers, the AWA VB-32 being just one example. The VB-32 probably came onto the market in the early 1960s and used four germanium power output transistors in a flipflop-type oscillator circuit. It produced nominally 60-65Hz 240V AC at up to 180W from a supply of 32V DC. The model I have is the VB-32 whereas the information I have is for a VB-32QA, which is a later version. siliconchip.com.au The only difference between them seems to be some minor changes to component values plus the use of a different transistor type for Q1. Fig.1 shows the circuit details of the unit. We’ll describe how it works shortly. Boning up on VB-32 Before commencing restoration of the VB-32, I sat down and carefully read the Technical Information and Service Data booklet for this device. From the content, it was obvious that AWA thought that the servicemen of that era needed some tuition on how transistors worked. This was probably a wise move, as transistors were relatively new at that time and servicemen were often not very conversant with transistor theory and practice. This particularly applied to country servicemen, as they did not have much access to training seminars and courses. Instead, most (if not all) of their training was through books and correspondence courses – and there was probably a lot of trial and error learning as well. At that time, transistors were almost exclusively germanium PNP types. With valves, the chassis was generally more negative than the plate circuits, which had positive HT applied to them. By contrast, transistors were current-operated devices. Those early circuits usually had the positive rail connected to chassis, operated from quite low voltages, did not like short circuits or heat and, of course, had to be biased “on” to operate. It was quite an education to read the literature on the device. It gives a blow-by-blow description of how transistors work, describes the circuit functions, sets out the adjustment procedure for the over and undervoltage settings, and describes how to do measurements around the circuit. It even describes how the transistors are mounted to prevent them from being damaged. Protection circuitry It’s also worth noting that the design includes features to ensure that the transistors are not damaged by reverse polarity or over-voltage. In addition, there’s no on-off switch on the device, to minimise voltage losses in the supply circuit. Continuing the latter point, the manual includes notes specifying the size of cable necessary between the 32V February 2008  87 This is the AWA VB-32 inverter following restoration. It produced nominally 60-65Hz 240V AC at up to 180W from a supply of 32V DC. This was also the reason for the overvoltage cut-out circuit in the inverter. Together with the reverse voltage cutout circuit, this served to protect the transistors from catastrophic failure. High-power transistors were not cheap in the 1950s and 1960s. There are a couple of additional features that are worth noting. First, inductor L1 and its parallel 100nF capacitor are broadly resonant at the output frequency. This helps modify the output waveform so that it is not so much a square-wave but a waveform that more nearly approaches a sinewave. Second, thermistor TH3 in the output line provides a “soft” start feature, so that the supply voltage builds up to maximum over a short period of time. This is not only kinder to the TV receiver it is powering but also kinder to the inverter itself. Restoring the VB-32 battery bank and the inverter. If the 32V is connected back-to-front, no damage occurs as the MR2 protection diode does not conduct. As a result, no voltage is applied to Q1 and relay RLY1 can not operate to supply power to the inverter circuitry. The main purpose of the control circuit at the left of Fig.1 is to turn the inverter off if the input voltage exceeds 36V. In operation, zener diode MR1 sets the reference voltage, while trimpot VR1 sets the trip voltage. When the input voltage exceeds 36V, the relay switches off and removes power from the inverter circuit. In addition, the relay turns off if the voltage goes below about 26V. This protects the 32V battery bank from damage due to deep discharge. When the relay is off, its NC contacts apply power to an indicator light on the front of the unit to indicate high or low supply voltage. Bad practice In the manual, AWA suggests that the inverter could be tapped down the battery bank if the supply voltage was too high. However, this would mean that most of the battery bank would be discharged by the inverter but a cell or two would remain at full charge, as they were not part of the circuit. As a result, these cells would be regularly overcharged which is bad practice. Of course, this would be only likely to occur if the 32V lighting system was in fact set up as a 34V or 36V system. This was sometimes done to overcome voltage losses over long supply cables. These paper capacitors from the AWA VB-32 inverter all failed highvoltage leakage tests and were replaced with modern polyester types. 88  Silicon Chip I had hoped to restore my VB-32 inverter some time ago but had been unable to find the technical notes or a circuit until recently. When these items were finally obtained, I set to work and removed the top cover which also exposes the sides of the unit. Two iron-cored transformers and a choke are the most noticeable components, along with several wirewound resistors and capacitors (including some paper types). No horrible smells greeted me and nothing looked the worse for wear. The plastic insulation around the two electrolytic capacitors had shrunk but they subsequently proved to be in good working order. Based on previous experience, I was particularly interested in the condition of all the paper capacitors. This was heightened by that fact that when restoring a Van Ruyten inverter some time ago, I found several paper capacitors with their insides on the outside. Anyway, I tested them all on my high-voltage leakage meter and none of them passed the test. It’s interesting to note that one of these capacitors was rated at 1600V and another at 1000V. I would have thought that these two at least wouldn’t have had much leakage but they did. In the end, the low-voltage units were replaced with polyester types with the same ratings. However, I couldn’t do this with the two highvoltage types, so I used two capacitors siliconchip.com.au L1 CHOKE + S1 22  0.5W BATTERY C1 1nF C2 500nF 200V C3 500nF 200V – R1 VIBRATOR C4 100nF C5 100nF 22  0.5W R2 T1 C6 250nF 400V OUTPUT GPO C7 250nF 400V FERRIS VIBRATOR TYPE INVERTER UNIT Fig.2: the Ferris inverter used a vibrator to drive the output transformer. This basic circuit could be made to operate from 6V, 12V or 32V DC simply by changing the transformer, the vibrator itself and one or two small components. in series in each case (both double the original value) to obtain the required voltage rating. By the way, a 10nF 1600V capacitor isn’t shown on the circuit diagram. It’s wired between the active 240V output terminal and the chassis of the inverter. Next, I checked the over-voltage relay RLY1 and found that one set of contacts had badly tarnished. In fact, they were so bad that my multimeter indicated an open circuit between them when they were closed. They were cleaned by holding the contacts closed while rubbing fine wet and dry paper between them. Having fixed the relay, I then dusted out the cabinet with a small paintbrush, after which I cleaned all the surfaces using household kerosene on a rag. This works well and leaves the metalwork with a slightly bright appearance, although there are a few obvious “wear and tear” marks in various places. Having done all that, it was time for the smoke test (well hopefully, there wouldn’t be any smoke). There is a fuse in the positive line in the inverter and as my 32V power supply is only capable of supplying around 3A, I wasn’t expecting any problems. I connected the supply, switched on and the inverter immediately produced a low-frequency buzz, indicating that it was working. What’s more, it immediately lit a 25W globe that was plugged into the outlet socket. In short then, this inverter is solidly made, with the circuitry well protected against over and under-voltage as well as reversed polarity. However, the control circuitry could have been made easier to get at, as there is plenty of room in the case. siliconchip.com.au In addition, the technical notes that were supplied by AWA are a real bonus. They are quite extensive and would have been very helpful to any serviceman who was unfamiliar with transistor equipment at that time. On the downside, the wiring could have been tidier but it must be remembered that this unit was built at the start of the transistor era. The VB-32 may not be for every collector but for those who specialise in 32V equipment, it’s well worth having. The Ferris inverter unit The next inverter that I want to describe was made by Ferris Radio. Ferris, for some reason best known to themselves, did not give this unit a model number, however. It’s worth noting that Ferris came up with a number of niche market devices over the years and this inverter from around 1954 is one of them. The circuit was basically designed to operate off 6V, 12V or 32V DC simply by changing the transformer, the vibrator itself and one or two small components. The unit’s purpose was to power small 240V AC devices with a maximum power rating of 30W. However, unlike the Bland Radio inverter described in the June 2007 issue, the Ferris unit was designed to minimise radio (RF) interference, being fitted with a reasonable amount of filtering. As a result, it could be used on lowdrain AC radios such as AC/battery valve portables. In fixed installations, the Ferris Fig.2: this photo shows the Ferris inverter after restoration. It was designed to power small appliances rated up to about 30W. February 2008  89 output socket. From there, the supply goes to the vibrator transformer and the vibrator. The resistors and capacitors across the primary and secondary of the transformer act as both buffer capacitors and interference suppressors. The AC output of the unit has a frequency of about 100Hz, this being the vibrator frequency. Cleaning up the case This is the view inside the Ferris inverter, from the top. The vibrator unit is located at bottom centre, immediately to the right of the transformer. The case of my unit had been mounted on a car firewall and carried quite a few marks. Most of these marks came off when it was given a rub-down using a cloth moistened with household kerosene. That done, a kitchen scouring-pad was used to remove some of the more stubborn marks while taking care not to damage the paint. I did consider repainting the case but in the end decided that it wasn’t sufficiently marked to warrant the trouble. The 240V power point was given a rub over with car cut and polish and it came up looking almost like new. Overhauling the electronics The original paper capacitors in the Ferris inverter were all leaky and were replaced. The two resistors were also changed. This view shows underside of the Ferris inverter after restoration. The paper capacitors were replaced with polyester units. inverter could be mounted in a farmhouse and supplied with 32V from the lighting plant. Alternatively, for powering a car radio, a 12V version could be mounted on the firewall of the vehicle. The circuit of the Ferris inverter is relatively simple – see Fig.2. Power is applied to the unit via a shielded cable, 90  Silicon Chip which has a metal-cased fuseholder in series. This shielded cable is designed to assist with filtering any interference on the power input line. Inside the case, the supply is further filtered using three capacitors and an RF choke arranged in a “pi” network. Following the filter, the supply input then goes to the switch on the AC The case of the Ferris unit is opened by removing four screws in both the top and bottom covers. This showed that the internal assembly was still in quite reasonable condition. Once again, after my experience with the Van Ruyten inverter, I looked closely at the buffer capacitors. I tested C4, C5, C6 & C7 and found that they were all leaky so they were replaced with new polyester capacitors. Resistors give very little trouble usually but when I tested the 22W two resistors (R1 & R2) in this unit, I found that one measured 30W and the other varied between 30W and 500kW. As a result, they were both replaced. Because the resistors were faulty, it was also quite possible that the vibrator itself had been damaged. To check this, I dismantled the vibrator and this revealed that there had been severe sparking at the points. Initially, I attempted to clean the contacts by sliding a small piece of fine wet and dry paper between them, while applying light pressure with my fingers to keep the points together, Unfortunately though, after cleaning them, I was unable to get continuity across the points. I suspect that the points themselves siliconchip.com.au were OK but were not making electrical contact where they were attached to the vibrating assembly. In the end, I gave up trying to get the original vibrator to work and substituted a new one from my parts collection. Next, I checked the fuse and although this was intact, its rating (15A) was too high. In fact, the unit should draw no more than about 4A. I replaced the fuse with a 5A unit so that the device would be protected if a severe short were to occur. Photo Gallery: 1949 Astor Model GJ Testing the Ferris unit Before applying power, I checked for shorts between the input and the case. These checks proved to be OK so I connected the supply and switched on. The result? – nothing happened! Initially, I thought that there might be a problem which had blown the fuse but this was found to be OK. I then checked further and found that the inner power lead was continuous but there was a break somewhere in the outer braid. I cut the terminals off the end of the cable and slid the fabric cover off. The braid was extremely corroded and in one spot it was just a bunch of oxidised strands with no conductivity across them. As a result, I completely replaced the cable – it was just too badly corroded to salvage. I used some shielded hook-up wire to replace the original cable but slipped the fabric cover back over this new cable so that it looked like the original. Once this was done, I reconnected power to the inverter and it quite happily supplied power to a 25W 240V globe. I then tried a portable radio near the inverter and found that the weak stations were drowned out by the interference. However, the stronger stations suffered very little interference. In practice, the interference along the 12V line was low but was quite THE FIRST AUSTRALIAN RADIO IN A BAKELITE case was the AWA C87, launched in 1932. It was a 3-valve set and the valve line-up was as follows: 35 RF amplifier, regenerative 24 detector and 47 audio amplifier. This set is now one of the most sought-after by vintage radio collectors. Photo: Kevin Poulter, for the Historical Radio Society of Australia. pronounced near the 240V AC output. Perhaps if Ferris had paid as much attention to filtering of the output as they did to the input, this unit would have been able to power portable radios with virtually no interference. In summary, the little Ferris inverter is quite a good performer and is a much better unit that the Bland Radio unit described in June 2007. It has a better vibrator buffer system and better RF SC filtering. Looking for real performance? • • • • Learn how engine management systems work 160 PAGES 23 CHAPTE Build projects to control nitrous, fuel injection and turbo boost systems RS Switch devices on and off on the basis of signal frequency, temperature and voltage 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. siliconchip.com.au From the publis hers of Intelligent turbo timer I SBN 095852 294 -4 TURBO BO OST & nitrous fuel con 9 78095 8 5229 46 $19.80 (inc GST) NZ $22.00 (inc GST) trollers How engin e management works February 2008  91 This solar battery charger uses a compact 6V solar panel to charge 12V sealed lead acid or conventional car batteries. That sounds a little odd but the circuit employs a voltage step-up to extract good efficiency from the panel. Design by Branko Justic* MINI SOLAR BAT T here is any number of applications where this Mini Solar Battery Charger could be put to work. For example, if you have a seldom-used boat which is stored out in the open, whether on a trailer or swinging on a mooring, this solar panel and charger could keep the battery permanently topped up so that it would not risk sulphation. Maybe you have a caravan which spends most of its time unattended? The same comments apply. Or you might use the panel in conjunction with a sealed lead acid (SLA) battery to provide permanent power for a device which is not close to mains power. Why a 6V solar panel for a 12V battery? You might wonder why the circuit uses a 6V panel with voltage step-up rather than a more conventional approach of a 12V panel and a simpler regulator circuit. The reason is that solar panels have their maximum power output at somewhat higher than their nominal voltage. For example, a typical 12V solar panel will deliver its maximum output at around 16V or thereabouts when it is fully illuminated by the Sun. That means that to get the maximum charging efficiency at all times, a fairly complex boost/buck switchmode charging circuit must be used when charging 12V batteries. For similar reasons, a 6V panel will deliver its maximum output at around 8V and it makes sense to double its output to charge a 12V SLA battery. Then if the battery is up 92  Silicon Chip to full charge (say 13.6V), the inclusion of a simple shunt regulator will prevent over-charging. The 6V panel used for this project comes in a sturdy aluminium frame and measures 395 x 160mm, although the active cell area is less than this, at 314 x 123mm. In the photo opposite (where the ratings panel is highlighted), it shows the output is rated at 4W, with a Vmp of 8.5V and Imp of 0.47A. The panel’s open-circuit voltage (Voc) is 10.6V and its short-circuit current (Isc) is 0.5A. So those are the voltage and current parameters we are working with. The panel is coupled to the charger circuit of Fig.1. This circuit is divided into two parts, the DC-DC Converter (voltage step-up) and the Shunt Regulator. The DC-DC Converter comprises a 4093 CMOS quad NAND Schmitt Trigger gate package (IC1), two Mosfets (Q1 & Q2) and five diodes (D1 – D5). IC1b is connected as a square wave oscillator running at around 4kHz, as determined by the 120kW resistor and 2.2nF capacitor. Its output is fed to gates IC1a & IC1c which drive Mosfets Q1 & Q2 in complementary fashion, ie, when Q1 is on, Q2 is off and vice versa. Both gates IC1a & IC1c have RC networks at their inputs to delay the clock pulses from IC1b while diodes D1 & D2 are included to insure that the respective Mosfets are switched off quickly. The inclusion of the RC network components assures that the two Mosfets can never be on at the same time, no siliconchip.com.au TTERY CHARGER matter how short the time may be: This would effectively place a short circuit across the supply and could blow the Mosfets. The output from the complementary Mosfets is used to drive a cascade voltage doubler, also known as a “diode pump” consisting of Schottky diodes D4 & D5 and the two 100mF 35V capacitors, C1 & C2. The voltage developed across C2 would exceed 14V DC but is ultimately limited by the following shunt regulator circuit involving Darlington transistor Q3 and its associated components. The rate of charge depends on the battery under charge but with the 4W solar panel supplied for this design, the charging rate is around 250mA or thereabouts. Shunt regulator The shunt regulator circuit consists of Q3 (the already mentioned TIP117 Darlington transistor), zener diode ZD1 (12V) and diode D6. Nothing happens in the shunt regula- Here’s the back of the solar panel used in this project, with the specifications panel highlighted. Maximum opencircuit voltage is 10.6V while the short-circuit current is 0.5A. siliconchip.com.au February 2008  93 DC-DC CONVERTER SECTION + D4 A D3 1N5817-8-9 100 F 16V SHUNT REGULATOR D5 K A 1N5817-8-9 A D7 A K 1N5817-8-9 K + 1N5817-8-9 K D1 1N4148 120k 5 FROM SOLAR PANEL IC1b 10 F 16V A K 2 6 2.2nF A 3 S G IC1a 12 IC1: 4093 D2 1N4148 2.2nF 14 1 12k 4 C1 100 F 35V D IC1d Q1 2SJ607 600 8 B A 11 13 9 1N4148 10 G S 7 2.2nF C D6 TO BATTERY K Q2 2SK3812 OR SDP85N03L D IC1c Q3 TIP117 10k C2 100 F 35V K 12k E K ZD1 12V A – – 1N4148 A ZD1 1N5817-8-9 K A A K K SOLAR POWER REGULATOR SC 2008 Q1, Q2 G C TIP117 D B S C E Fig.1: the circuit diagram. We’ve broken it into two sections for ease of understanding – most of the work is done by the DC-DC converter while the shunt regulator only operates when the battery is charged. tor circuit until the voltage across the zener diode is high enough for it to conduct. For that to happen, diode D6 and the base-emitter junction of Q3 also must be forward biased. For that to happen, the total voltage across that string must therefore be 12V + 0.6V + 1.2V = 13.8V. When the voltage across Q3 rises to this level, it effectively becomes a high power zener diode and conducts heavily to prevent any further voltage rise. In other words, Q3 “regulates” the voltage by “shunting off” the excess. Finally, the Schottky diode D7 further drops the voltage being fed to the battery to about 13.6V, by dint of its forward voltage drop of around 0.2V. Diode D7 also serves as an isolating diode and prevents the shunt from operating if 74 HEATSINK CUT FROM 1.3mm ALUMINIUM SHEET 50 24 70 38 Q3 G TIP117 D (UNDER BOARD) 12V + ZD1 100 F 100 F D5 SOLAR PANEL D7 – + S D4 BATTERY IN5819 94  Silicon Chip A152K – + + 100 F G Q1 Q2 (UNDER D BOARD) + D6 10 F + S 4148 12k 2.2nF 4093 D2 31 IC1 D1 2.2nF 2.2nF 4148 12k 120k MOC.SCINORTCELEYELTAO C D3 Fig.2 (left): the component overlay with its aluminium heatsink attached. The photo at right shows exactly the same thing for comparison. siliconchip.com.au PARTS LIST – Mini Solar Battery Charger 1 PC board,74 x 54mm, coded OE-K251A 1 plastic case to suit PC board 1 14-pin IC socket 2 2-way screw terminals with 5mm spacing 2 6mm self-tapping screws 1 3mm diam. 10mm long screw with nut and washer Semiconductors 1 4093 quad Schmitt NAND gate (IC1) 1 2SJ607 P-channel Mosfet (Q1) 1 2SK3812 N-channel Mosfet (Q2) 1 TIP117 Darlington PNP Transistor (Q3) 3 1N4148 signal diodes (D1,D2,D6) 4 IN5817 Schottky diodes (D3-D5,D7) 1 12V 400mW zener diode (ZD1) Capacitors 2 100mF 35V PC electrolytic (C1,C2) 1 100mF 16V PC electrolytic 1 10mF 16V PC electrolytic 3 2.2nF MKT polyester or disc ceramic the battery voltage rises to above 13.8V while it is being charged by other means: alternator, charger etc. Note that shunt regulators are inherently inefficient and in fact, in this circuit, once the battery has come up to full voltage, Q3 dissipates 100% of the boost circuit’s output, ie, is 0% efficient. This also means that Q3 will dissipate about 3 watts and it will need a heatsink. The heatsink is the one “component” not supplied in the kit. You’ll need to find a small piece of aluminium about 75mm or so square and cut it to shape to suit the PC board. While 1.3mm aluminium is specified, if you have slightly thicker, use it. In fact, thicker will make a better heatsink. We wouldn’t go any thinner though. The dimensions are shown on the component overlay. It also needs a hole for the bolt – the quickest way to get its position is to bring the heatsink and PC board together and mark the bolt hole position from the hole in the PC board. At least that way you’ll know they’ll match! Resistors (0.25W 5%) 1 120kW 2 12kW This project was designed by Oatley Electronics, who hold the copyright on the project and PC board pattern. A complete kit for this project, which includes the solar panel, PC board, components, case and 12V 7Ah battery is available from Oatley Electronics for $79.00. Individual components are also available: The solar panel – $36.00; Electronics kit – $18.00; and 12V 7Ah battery – $25.00 Contact: Oatley Electronics Pty Ltd. PO BOX 89, OATLEY, NSW 2223, AUSTRALIA Phone: 02 9584 3563 website: www.oatleyelectronics.com * Oatley Electronics Pty Ltd not you use an IC socket) make sure its notch points to the right, as shown on the component overlay. Otherwise you’ll almost certainly let its smoke out and as we all know, to work projects need the smoke to stay inside. The TIP117 Darlington transistor also requires special mention. Two of its leads, the emitter and base, solder to the PC board in the normal way but its collector connects to the copper via the small bolt and nut which holds it and the heatsink in position. The easiest way to make sure that the hole in the transistor lines up with the hole in the PC board is to mount it, with its heatsink underneath, onto the PC board with its Board assembly All the components for this project are mounted on a PC board measuring 74 x 54mm and coded OE-K251A. The major point of interest about the PC board is that the two Mosfets (Q1 & Q2) are surface-mount devices which have their bodies soldered directly to the underside. This is the first step in the assembly. You can do this by first tinning the leads with solder. Then hold the Mosfets in place with a clothes peg or similar spring clamp. They’re pretty small so you must make sure you get them into the right spot before soldering and that they don’t move during soldering. You might need to apply a little extra solder to ensure the leads are actually soldered to the PC board. Once these are done, proceed as you would for any project: solder the lowest components such as the 1N4148 diodes and work your way up to the tallest capacitors. Leave the 4093 IC until last just to make sure you don’t damage it. When you’re ready to solder it (and whether or siliconchip.com.au This oscilloscope screen shot illustrates the operation of the DC-DC converter section of the circuit. The top trace (yellow) is the oscillator output from pin 4 of IC1, running at 7.6kHz. Traces 2 & 3 (magenta and cyan) show the delayed gate drive signals to the complementary Mosfets, Q1 & Q2. Finally, the green trace shows the waveform at the commoned drains of Q1 & Q2 and this drives the diode pump circuit involving D4 & D5. February 2008  95 The regulator with its heatsink mounted inside the plastic case supplied with the kit (left). Above the same case is shown in its closed position. Provision is made for cables to emerge from the bottom of the case (handy when used outdoors!). bolt and nut. You only need to do the nut up finger-tight just now. Bend the base and emitter leads down at the appropriate point so they will go through their holes in the PC board. If you have a brass bolt and nut, it’s a good idea to solder the nut to the PC board copper to make absolutely sure it’s making good contact. The same can be done for steel nuts but usually these have a nickel coating which makes them difficult to solder. (Don’t know if you have a steel or brass nut? Try a magnet – if it picks up it’s steel!) Mounting in the case If you are building the project from the complete Oatley kit, it will come with a small case (as shown above) which is a perfect fit for the PC board and heatsink (you’d almost think they were designed that way . . .). Even the two mounting holes on the bottom of the PC board line up with mounting pillars inside the case. Using it If everything has been assembled correctly, it should work properly first up. There are no adjustments or controls to worry about. Connect the solar panel and battery with polarity-marked cable – polarised figure 8 is ideal – to the appropriate terminal blocks (again, watch the polarity – make sure + goes to + and - goes to -). Measure the voltage in from the solar panel and compare it to the voltage out across C2 (if you measure the output terminals you’re likely to be reading the battery voltage). If the panel voltage is ~6-8V and the voltage out is >12V, the circuit is working correctly. After a full day’s charge in the sun you should find the heatsink gets quite warm, indicating that the shunt regulator section is also working correctly. SC Expertise From SILICON CHIP 160 PAGES 23 CHAPTE RS Completely NEW projects – the result of two years research & development • Learn how engine management systems work • Build projects to control nitrous, fuel injection and turbo boost systems • Switch devices on and off on the basis of signal frequency, temperature and voltage • Build test instruments to check fuel injector duty cycle, fuel mixtures and brake & temperature Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas $A26.00 via airmail. Order by phoning (02) 9979 5644 & quoting your credit card number; or fax the details to (02) 9979 6503; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 96  Silicon Chip From the publishers of Intelligent turbo timer I SBN 095852294 - 4 9 780958 522946 $19.80 (inc GST) NZ $22.00 (inc GST) TURBO BOOST & nitrous fuel controllers How engine management works 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 Connecting an MP3 player to a hifi system A common problem my teenage son has is that the output of his MP3 player is not enough to drive the amplifier input of hifi and not so hifi systems, such as in cars or standalone systems. The result is a flat battery and poor audio because the volume needs to be on full. Can anything be done to match the output of an MP3 player to the input of a stereo system? R. K., Armidale, NSW). • Most MP3 players will deliver a nominal 770mV or even 1V RMS to drive the headphones and this is suitable for connection to a power amplifier without any need to boost the signal. The actual level used should not have much effect on the MP3 player’s battery life. The problem you might have is that the MP3 player’s output may require a load that is a lower resistance than the nominal 47kW input impedance of a typical power amplifier. The load is required to set up the MP3 amplifier’s DC conditions. With some MP3 players, the audio will not be available (or will be distorted) until a suitable load is connected. In practice, you may need to add a load resistor between each of the left and right channel outputs and ground before the MP3 player can be used successfully with a power amplifier. 100W resistors should be adequate although you may need to go as low as 47W or 39W. Open circuit inputs to mixer I recently completed the Versatile 4-Input Mixer featured in the June 2007 issue of SILICON CHIP. I encountered no problems during the construction and when I went through all of the suggested checks at the end of the article, all readings were right on the button. The headphone check also performed as stated in the text. However, when tested with a guitar and microphone, I get no output except a loud hiss when the input levels and volume are up. There is not even a small output from the guitar and mic to be heard under the hiss. As stated above, the unit checks out perfectly on the testbench. Any ideas on this would be greatly appreciated. (G. G., Wollongong, NSW). • Assuming that you have the correct voltages on the pins of IC1 and IC2, the fault must be an open-circuit in the respective input stages. If you are getting plenty of hiss when you wind up the respective gain controls, there must be open-circuit components or tracks in the inputs to the op amps. Using a Crane optical trigger I have installed a High-Energy Ignition Module (Jaycar KC5247) and using points to the trigger module works OK. Could I use a Crane optical sensor with trigger wheel to trigger the ignition module and what modifications would be needed? Also, can the optical sensor replace the Hall effect unit and use the Hall effect circuit layout? The optical sensor has three wires: +12V, 0V and a Proposed Layout Changes To Class-A Amplifier I am currently purchasing your new Class-A amplifier modules from Altronics. All the parts seem to be available except for the case and the nearest in the catalog is 65mm less in depth at 360mm. As I intend not to include your preamp (I built the separate earlier one), I should have room to move things about. What do I need to keep well spaced? I will keep the general layout as per your article. Can I move the left and right power amplifiers off-centre on the heatsinks, closer to the front panel, thus allowing other bits to be moved forward in relation? Can the speaker protector board be moved close to the amplifiers without risk of noise induction? Can the bridge rectifier be siliconchip.com.au moved? All I know for sure is that the power transformer needs to be spaced as much as possible. I could alternatively mount the transformer in a separate box. In that case do you have the rectifier in the same box with a DC output or is AC best? I assume the main power board would go in the main amplifier case. (P. G., Orient Point, NSW). • While we may seem pedantic, even quite small differences in layout will have a significant effect on the signal-to-noise ratio. For example, just moving the Loudspeaker Protector board out from its location in the corner of the chassis can degrade the signal-tonoise ratio by 10dB or more. Doing the other changes that you propose would make it worse – such changes NEVER improve things. The wiring layout we produced for that amplifier was produced after a great deal of trial and error. Believe us, there were times when we were very frustrated in attempting to get the very best performance. So unless you are prepared to accept quite significant degrading of the performance, do not make any changes to the layout. If you really must change the layout, then perhaps better results may be obtained by putting the power supply in a separate steel box – ie, with the transformer, bridge rectifier and power PC board. By the way, a complete kit is available from Altronics. February 2008  97 Programmable Ignition System Problems I have just finished building the Programmable Electronic Ignition System, the Hand Controller and the coil drivers (SILICON CHIP, March, April & May 2007). Unfortunately, it is not working. I get 5.1V with the microcontroller test and can adjust the voltage out of VR1 as suggested but when I connect the Hand Controller, the display is very faint (even with VR1 fully clockwise) and the display just shows dots in the top line of the display. I have checked my soldering and while it’s not that pretty, I can’t see any dry joints or bridges and I’m not sure if it’s safe to test for these with a multimeter. What would be really handy would be able to plug my Hand Controller and ignition controller into working versions of each other and determine which is at fault. signal wire which goes to ground when the sensor light is blocked. Any help regarding this issue would be appreciated. (C.W., via email). • We showed how to use an ignition module with the Crane optical trigger in the December 2005 High Energy Ignition article and the March 2007 Programmable Ignition System article. The KC5427 is an older design but the same connections apply. Temperature sensor may be open-circuit I have a question regarding the Fridge/Freezer Temperature Controller in the June 2005 issue. I have built the kit and find that the unit is permanently on. I’ve double-checked the construction (I bet everyone says that) and can’t find anything wrong. What I am getting is 8.9V at pin 3 of the comparator chip and if I measure the resistance of the LM335 over a range of 2-20°C it only varies from 35.7kW to around 36.5kW. I’m guessing that this small change isn’t enough to give a 2-3V drop across pin 3; in fact, the voltage stays at 8.9V. If I remove the LM335 and replace it with say a 2.2kW resistor, the LED goes out. My question is where could my 98  Silicon Chip Can you offer any suggestions that would narrow down the search for the fault? On another point, I found it quite difficult to work out the numbering on the IC. In the circuit diagram in the article, the shape of the IC in relation to the terminals does not match the real thing. A few numbers on the board layout diagrams would have helped a novice like me out a lot. (D. P., via email). • Pin 1 is adjacent to the dot on the IC. Numbering is then counted anticlockwise around the IC. The lack of display would indicate that there is no connection between pins 8,7,13,12,11 & 10 of the IC and pins 4,6,14,13,12 & 11, respectively, at the LCD module. Check that the lead you are using makes connections between the DB25 connector at one end and at the other. circuit be wrong or is there some instruction missing and should I be adding some extra resistance to the LM335 part of the circuit to help with the voltage drop? (J. P., via email). • If you are getting a voltage of 8.9V more or less permanently on pin 3 of IC1, this suggests that the connections to your temperature sensor are either open-circuit or perhaps reversed. Measuring the resistance of the LM335 is not meaningful because it’s very non-linear. In fact, it behaves very much like a zener diode, whose reverse breakdown voltage varies in direct proportion to the absolute temperature in Kelvin. And at any particular temperature the dynamic resistance is very low, so that the voltage drop hardly changes over a fairly wide range in current (100mA to say 5mA). Filtering for Voltage Switch kit I built a Voltage Switch kit from your book “Performance Electronics for Cars” to switch the radiator fans I added to a 1971 Mustang. It works fine when bench-tested. The problem is that the voltage reading at the temperature sender oscillates enough to have the unit switching rapidly on and off, ie, like the indicators. I think the gauges in these cars run at around 5V and the regulator, being “vintage”, oscillates the voltage relatively slowly which doesn’t effect a slow-acting gauge but does effect the voltage switch. Is there something I can add (eg, a capacitor) or make to dampen the signal voltage to the voltage switch? (R. A., via email). • The signal can be filtered by increasing the value of the capacitor connected across ZD2. This is currently specified as 100nF and is located just to the left of ZD2 on the PC board. You can increase this to 1mF (or more) by replacing it with an electrolytic capacitor. Note that the plus side of the capacitor should connect to the (K) cathode side of ZD2. The size of the capacitor will affect the response to voltage changes. A large value (10mF or 100mF) will delay the switching by several seconds. Fuel flow sensor circuit wanted I wonder if it would be simple to design a circuit which would give an indication of the duty cycle of fuel injectors? While not giving complete info, it could be of help in refining one’s driving technique as related to fuel economy. If the duty cycle varied between cylinders, that would require a little further thinking. (A. B., North Mackay, Qld). • We published a fuel injector monitor in the August 1995 issue. PIC-Based Water Level Meter I have a question regarding the PICBased Water Level Meter (SILICON CHIP, November 2007). I was wondering if it is possible to increase the wireless telemetry to a 1km range? If so, could you please explain how to do it? • The ultimate range will depend on the terrain and the antenna used for the Water Tank Level Meter and the Base Station. Better range can be obtained by using ¼-wavelength whip antennas cut for 433MHz. These whips would replace the wire antenna inside the units. You need to couple to the antennas using 50W coaxial cable. For greater range (up to 1km), you would need to use a directional ansiliconchip.com.au tenna such as a 433MHz Yagi and point the transmitter’s antenna towards the receiver antenna. ¼-wave whips are available from RS Components (Cat 451-0747 and 451-0753). A 433MHz Yagi is also available (Cat 532-4480) – see http:// www.rsaustralia.com. ¼-wave whips are also available from Farnell – see www.farnellinone.com.au. Transistor failures in the SC480 I built the TO-126 version of the SC480 amplifier (SILICON CHIP, January & February 2003) and I am impressed with its performance. It goes very well except at odd times when powered up or turned on, the output transistors fail. This has now happened three times and my confidence in the unit is now going. Not all the transistors go together but just one or two and the PNPs go first followed by the NPNs. After failure the transistors have shorts between the base, collector and emitter. As this fault is unpredictable, it makes it hard to locate. I am just hoping that you have experienced this fault before. (W. T., via email). • The most likely cause of this problem is an intermittent open-circuit in the Vbe multiplier transistor (Q7), in trimpot VR1 or the associated 100W resistor. If any of these components goes open-circuit, the output stage transistors are turned fully on and they will quickly self-destruct. Check the soldering around these components very carefully. One other possible cause is that the output transistors are not in intimate contact with the heatsink. Question on honeycomb chokes I was wondering if the modern miniature RFCs are equivalent in electrical performance to the older honeycomb wound types because I have a regenerative radio circuit (from the “Electronics Australia” publication “Basic Electronics”) that requires a 2.5mH choke. I have been able to obtain some miniature ones but the project is very unstable using these. Do you think it would be worth increasing my effort to try and obtain the older ones as used in the EA project which has a 2N5459 as a regenerative siliconchip.com.au Subwoofer Controller Is Too Noisy With regards to the Subwoofer Controller (SILICON CHIP, August 2007), I was wondering why you used the outdated TL074 op amp in the parametric circuit rather than using a higher performance operational amplifier? Secondly, can you recommend a replacement for the TL074 op amp, to provide a higher signal-to-noise ratio because -80dB is on the low side. Many commercial parametric equalisers have signal-to-noise ratios above -100dB. Thirdly, what alterations are nec­ essary to increase the maximum output signal from 2.4V RMS to 6V RMS? (M. T., Albury, NSW). • It is likely that most of the noise in the circuit originates in the first two stage op amps (LM833) rather than the TL074. It may be possible to improve the S/N ratio by changing the LM833 op amp to the detector? All I seem to get is uncontrollable feedback. (N. S., via email). • We are unable to tell you whether modern miniature RF chokes are equivalent to honeycomb chokes. However, it is unlikely that they would be, given that the honeycomb method is specifically used to reduce inter-turn capacitance. Having said that, the circuit you refer to in “Basic Electronics” does not call for a honeycomb choke. Given its position in the circuit, the choke should not be a critical component. In fact, you could probably use a resistor of around 470W instead. Finally, note that regenerative circuits can be frustrating at the best of times! Interference to 2.4GHZ A/V senders Can anything be done to stop interference on an audio-video sender? I had been using one for a long time with no interference but these days, with all the wireless routers, cordless phones and the rest, which all operate in the 2.4GHZ range, it has been impossible to use it lately. It seems that my next-door neighbour must have got a wireless router much higher performance LF4562 op amps and also changing all the resistors in these stages (and the input 47kW resistors) to metal film types. However, be aware that inverting op amp stages (as used for IC1b) are always noisier than non-inverting stages. However, before you do any changes, it probably is not a problem since most of the noise is hiss and will not be readily apparent with the very limited high-frequency response of typical subwoofers. The output signal is limited by the 12V supply of the Subwoofer Controller. We used this low supply because many users would want to use the unit in a car. If you wanted a 6V RMS output capability, the supply would need to be increased to around 24V. Note that ZD1 would also need to change, together with the circuit for IC4. and it’s interfering with my AV sender, 24 hours a day. I have tried all four different channels but it made no difference. Also, repositioning the sender and the receiver makes no change. I know there are new ones which operate in the 5.8GHz range but I’m not willing to spend $170 dollars. (P. T., via email). • We suggest that you try getting your neighbour to change channels and that you try using better antennas for the sender and receiver. Higher temperature setting for fan control I am enquiring about the Thermostatic Switch for Radiator Fans in your “Electronic Projects for Cars, Volume 1”. I’ve built the project successfully but I can’t get the fan to run at a lower temperature, despite VR1 being turned fully clockwise. I suspect that the problem is with the sensor which measured around 560W at 25°C. I need to run the engine at around 75°C where currently it runs at 82°C. I was planning to replace the 100W resistor in parallel with VR1 with a lower resistance (around 47W maybe) hoping it will give extra bottom end. February 2008  99 Landing Aid For A Paraglider Since retiring, I have taken up the sport of paragliding. At 66 years of age, I have now lost the sight in my left eye and when I try to land in vast featureless sandy spaces, I have difficulty judging the height above ground in the range one to four metres. This is quite important, as this is final approach height for landing with my legs down. While I can accomplish landing with great difficulty on sand, I would like to use a simple electronic aid to ensure my ultimate safety. Can you suggest a person or firm which can take a standard laser or ultrasonic tape and equip it with a vibrator to alert me when I reach 4m, 3m & 2m above ground? The unit would be attached to one leg by Velcro straps, pointing towards the ground. Landing speed is not a problem, as I can control this down to a virtual stall. Altimeters and GPS devices are Or do you have better alternative? (D. K., Bandung, Indonesia). • The 100W resistor in series with VR1 could be reduced in value to get your fan running at a higher temperature. Problems with PIC Testbed I am having a lot of trouble with the PIC Testbed kit featured in the January 2001 issue. I have downloaded MPLAB IDE and built the board and serial lead correctly but am unable not suitable, as the landing zone is in a sand blow more than 300 feet above sea level. The terrain constantly varies from day to day, as does the landing site. I would appreciate your assistance in finding someone to modify an existing device, or design and build a new one. Any laser would be very low power and not a problem for people under the flight path. (C. P., Point Vernon, Qld). • In principle, it should be possible to modify an ultrasonic tape to do what you want. Unfortunately, we are unable to suggest someone to do it. As an alternative, you may want to consider using or modifying an ultrasonic parking sensor for cars. These do have an audible alarm. Have a look at the Jaycar LR8869 (page 322 of the current Jaycar catalog). This will give audible indications from 2m and less. to program the PIC16F84. I want to load the DEMO & TESTBED programs into the PIC but the software will not recognise the hardware. I have also tried to use ICPROG & PICPROG but these also didn’t work correctly. How do I solve the problem? (C. S., Ararat, Vic). • First, make sure that all the jumpers for JP10, JP11 & JP12 are out. That done, check that power is being applied to the PIC (IC2). Next, in the communication settings for the RS232 COM port, select the one that is for your computer; eg, Notes & Errata Multi-Message Voice Recorder, December 2007: the resistor from pin 7 of the HK828 should be a 47kW. The parts list should show one 10kW and nine 47kW resistors. COM1. The computer’s RS232 port must be able to produce 12V for the VPP programming voltage. The best program to use for programming the PIC is WINPIC. The interface is set to JDM (2) for serial port. The program also has functions to test the hardware by setting the lines high and low manually. WINPIC is available at http://freenethomepage.de/dl4yhf/winpicpr.html Query on ASK coding I have recently purchased a 433MHz TX/RX module from Jaycar. It requires ASK coding and I am unable to find any circuits to make the modules work. Could you help? (D. H., via email). • ASK encoding is amplitude shift keying. So all you need to do is apply a 5V square-wave with a frequency between 300Hz and 5kHz to the transmitter input for the same signal to be received and decoded at the receiver output. In practice, instead of a square wave, the signal can be encoded as a data stream such as RS232 or similar, as long as the bit rate does not go outside the 300 to 5K baud rate. Stan Swan in his “433 Revisited” article from December 2005 discussed SC the use of these modules. 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. GST) for up to 20 words plus 85 cents for each additional word. Display ads: $54.50 (incl. GST) per column centimetre (max. 10cm). Closing date: 5 weeks prior to month of sale. To book your classified ad, email the text to silicon<at>siliconchip.com.au and include your credit card details, or fax (02) 9939 2648, or post to Silicon Chip Classifieds, PO Box 139, Collaroy, NSW, Australia 2097. Enclosed is my cheque/money order for $­__________ or please debit my o Visa Card   o Master Card Card No. Signature­­­­___­­­­­­­­__________________________ Card expiry date______/______ Name _________________________________________________________ Street _________________________________________________________ Suburb/town ______________________________ Postcode______________ Phone:______________ Fax:______________ Email:___________________ FOR SALE LEDs! I NOW HAVE good stocks of Nichia superbright oval LEDs, as well as 5mm Agilent (HP) LEDs. These are fantastic, bright brand-name quality LEDs at Chinese LED prices! Also Osram surface mount range and other NOS standard and superbright brand name LEDs from just a few cents each. Also Cree X-Lamps, 5 and 10 watt power LEDs, LED drivers, kits and all sorts of other stuff. www.ledsales.com.au RCS RADIO/DESIGN is at 41 Arlewis St, Chester Hill 2162, NSW Australia and has all the published PC boards from SC, EA, ETI, HE, AEM & others. Ph (02) 9738 0330. sales<at>rcsradio.com. au, www.rcsradio.com.au MicroByte Electronics: PIC Micros – Development Board – Development Issues Getting Dog-Eared? Keep your copies safe with these handy binders Available Aust. only. Price: $A13.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. Buy five and get them postage free! siliconchip.com.au REAL VALUE AT $13.95 PLUS P&P tools & Components. Phone: (03) 9378 4288. info<at>microbyte.com.au; www. microbyte.com.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 9593 1025. sesame<at>sesame.com.au www.sesame.com.au 1997-2005 SILICON CHIP in 9 folders for sale. 10 issues missing. $150 ONO. Pick-up only. Details mathewharper<at> gmail.com COMING EVENTS CENTRAL COAST FIELD DAY: Wyong. Feb 17th 2008 Wyong Race Course, only 1 hour north of Sydney. It’s on again! The biggest and the best Amateur (Ham) Radio Field Day in Australia. All the big Amateur Radio traders and Electronics dealers will be in attendance. Other attractions are Radio Club displays, CB radio groups, Seminars and Workshops, Flea Market, Raffles, Foxhunts, Volunteer communications organisations and YL activities,. There is also a Field Day dinner on Sat night 16th February 7pm, bookings required. Access to the racecourse for hot food, free parking, Flea Market setup, etc will be from 6:30am. The exhibitors area will open for trading from 9:30am. All the latest details at www.ccarc.org.au. Phone (02) 4340 2500. Email fieldday<at>ccarc.org.au continued page 103 February 2008  101 VIDEO - AUDIO - PC High quality Realistic prices Free software updates Large range of adaptors Windows 95/98/Me/NT/2k/XP distribution amps - splitters digital standards converters - tbc's switchers - cables - adaptors genlockers - scan converters bulk vga cable - wallplates CLEVERSCOPE USB OSCILLOSCOPES DVS5c & DVS5s High Performance Video / S-Video and Audio Splitters 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 MD12 Media Distribution Amplifier QUEST ® Quest AV® IMAGECRAFT C COMPILERS ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 VGA Splitter VGS2 HQ VGA Cables GRANTRONICS PTY LTD www.grantronics.com.au 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 fax (02) 4341 2795 phone (02) 4343 1970 email: questav<at>questronix.com.au www.dontronics.com has 300 selected hardware and software products available from over 40 world wide manufacturers, and authors. Olimex Development Boards & Tools: ARM, AVR, MAXQ, MSP430 and PIC. Atmel Programmers And Compilers: STK500, Codevision C, Bascom AVR, FED AVIDICY Pro, MikroElektronika Basic and Pascal, Flash File support, and boot loaders. PICmicro Programmers And Compilers: microEngineering Labs USB programmers, adapters, and Basic Compilers, DIY (Kitsrus) USB programmers, MikroElektronika Basic, Pascal, DSpic Pascal Compilers, CCS C, FED C, Hi-Tech C, MikroElektronika C, disassembler and hex tools. CAN: Lawicell CANUSB, CAN232 FTDI: USB Family of IC ‘s. FT232RL, FT2452RL, also BL and others. 4DSystems LCD/Graphics: Add VGA monitor, or OLED LCD to your micro. Simple Serial I/F. Heaps And Heaps Of USB Products: TTL, RS-232, RS-485, modules, cables, analyzers, CRO’s. Popular Easysync USB To RS-232 Cable: Works when the others fail. Only one recommended by CBUS. Money back guarantee. www.dontronics-shop.com 102  Silicon Chip ELNEC IC PROGRAMMERS Satellite TV Reception International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au C O N T R O L S MS120 The world’s lowest cost controller with inbuilt operator interface  12 digital I/O  2 line LCD  5 push buttons  Expandable  Easy to program 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 $164 Developer’s Kit $197 includes programming cable & software Made in Australia - used world-wide splat-sc.com Do you have wireless problems? Telelink has wireless solutions! Telelink Communications www.telelink.com.au e-mail Jack Chomley – jack<at>telelink.com.au or call (07) 4934 0413 or 0428 199 551 Circuit & Design 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. siliconchip.com.au Do You Eat, Breathe and Sleep TECHNOLOGY? Opportunities for full-time and part-time positions all over Australia & New Zealand Jaycar Electronics is a rapidly growing, Australian owned, international retailer with more than 39 stores in Australia and New Zealand. Our aggressive expansion programme has resulted in the need for dedicated individuals to join our team to assist us in achieving our goals. We pride ourselves on the technical knowledge of our staff. Do you think that the following statements describe you? Please put a tick in the boxes that do: Knowledge of electronics, particularly at component level. Assemble projects or kits yourself for car, computer, audio, etc. Have empathy with others who have the same interest as you. May have worked in some retail already (not obligatory). Have energy, enthusiasm and a personality that enjoys helping people. Appreciates an opportunity for future advancement. Have an eye for detail. Why not do something you love and get paid for it? Please write or email us with your details, along with your C.V. and any qualifications you may have. We pay a competitive salary, sales commissions and have great benefits like a liberal staff purchase policy. Send to: Retail Operations Manager - Jaycar Electronics Pty Ltd P.O. Box 6424 Silverwater NSW 1811 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Advertising Index Altronics.................................. 82-85 Amateur Scientist CDs................. 42 Av-Comm................................... 102 BitScope Designs........................... 3 Central Coast Amateur Radio.... 101 Computronics............................. 101 Dick Smith Electronics............ 20-23 Dontronics.................................. 102 Ecowatch.................................... 102 Emona Instruments........................ 9 Front Panel Express....................... 6 Grantronics................................. 102 Harbuch Electronics..................... 77 Instant PCBs.............................. 103 Jaycar........................ IFC,49-56,103 JED Microprocessors..................... 5 Keith Rippon............................... 103 LED Sales.................................. 101 Microbyte Electronics................. 101 Ocean Controls............................ 37 SPK360 3/5/06 1:10 PM Page 1 Oatley Electronics........................ 65 Ozitronics....................................... 6 DOWNLOAD OUR CATALOG at 20 years experience! www.iinet.net.au/~worcom HI-FISPEAKER REPAIRS WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au YOUR EXPERT SPEAKER REPAIR SPECIALISTS Radio, TV & Hobbies DVD............ 18 RCS Radio................................. 101 RF Modules................................ 103 Sesame Electronics................... 101 Silicon Chip Binders................... 101 Silicon Chip Bookshop........ 104,IBC SC Perf. Elect. For Cars.......... 38,91 SPK360 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! Quest Electronics....................... 102 tel: 03 9647 7000 www.speakerbits.com Silicon Chip Subscriptions............. 8 KIT ASSEMBLY Speakerbits................................ 103 KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand * Small production runs. Phone Keith 0409 662 794. keith.rippon<at>gmail.com WANTED WANTED: ONE (1) HEWLETT-PACKARD SCIENTIFIC CALCULATOR model 15-C plus its matching Owner/User’s Manual. Preference will be given to units in good usable condition. Please phone (08) 8337 6887 A/H (reverse charges) or siliconchip.com.au Soundlabs Group......................... 43 write to: Eugenio Muratore, 695 Lower North East Road, PARADISE 5075. Splat Controls............................. 102 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 Tenrod Australia........................... 19 WANTED: ANY NUMBER of 2.5mH radio frequency chokes, the old honeycomb-wound coil type, single pile, not the modern miniature type. Will pay top money. nsamuels1<at>bigpond.com Telelink....................................... 102 Truscotts Electronic World.......... 103 Vaf Research.................................. 7 Wagner Electronics..............OBC,41 Worldwide Elect. Components... 103 PC Boards Printed circuit boards for SILICON CHIP designs can be obtained from RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. February 2008  103 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* by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. 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. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. 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 Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* 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 To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. 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. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. 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 Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* 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 To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST