July 2006 - Silicon Chip Online

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Contents
Publisher's Letter: Nuclear power debate should look at the whole picture
Feature: MoTeC Race Car Data Logging by Julian Edgar
Feature: Television: The Elusive Goal; Pt.2 by Kevin Poulter
Project: Mini Theremin Mk.2; Pt.1 by John Clarke
Project: Programmable Analog On-Off Controller by Greg Radion
Project: Studio Series Stereo Preamplifier by Peter Smith
Salvage It: There Are Lots Of Good Bits Inside Junked Photocopiers by Julian Edgar
Project: PC Controlled Mains Switch Mk.2 by Trent Jackson
Project: Stop Those Zaps From Double-Insulated Equipment by John Clarke
Vintage Radio: AWA B33: the ultimate Australian-made transistor portable by Rodney Champness
Book Store
Advertising Index
Outer Back Cover

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SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents Vol.19, No.7; July 2006 FEATURES 8 MoTeC Race Car Data Logging Want to monitor racing car performance data in real time? This innovative system from MoTeC delivers the goods – by Julian Edgar SILICON CHIP www.siliconchip.com.au Mini Theremin Mk.2 – Page 24. 14 Television: The Elusive Goal; Pt.2 The introduction of television 50 years ago captured the imagination of the nation. It wasn’t without its problems, however – by Kevin Poulter PROJECTS TO BUILD 24 Mini Theremin Mk.2; Pt.1 It’s our best Theremin yet and is easy to build. Just move your fingers near the antennas to create your own electronic music – by John Clarke 40 Programmable Analog On-Off Controller Want to fill or empty a water tank automatically or control some other device based on an analog input signal? This easy-to-build controller has an LCD panel and two independently programmable relay outputs – by Greg Radion 64 Studio Series Stereo Preamplifier At last! . . . here’s how to assemble your high-performance Studio Series preamplifier modules into a professional-quality case. The result is superb hifi sound reproduction – by Peter Smith 80 PC Controlled Mains Switch Mk.2 It connects to your PC’s parallel port and lets you independently control two mains sockets (GPO) using Windows based software – by Tent Jackson 92 Stop Those Zaps From Double-Insulated Equipment Ever experienced mild shocks from double-insulated equipment, such as DVD players? If so, you need the “Tingle Terminator” – by John Clarke SPECIAL COLUMNS Programmable Analog On-Off Controller – Page 40. 48 Serviceman’s Log Looks like a duck, quacks like a duck – by the TV Serviceman 73 Salvage It! There are lots of good bits inside junked photocopiers – by Julian Edgar 97 Vintage Radio AWA B33: the ultimate Australian-made transistor portable – by Rodney Champness 102 Circuit Notebook (1) Mains Frequency Monitor; (2) RC Phase-Shift Oscillator; (3) How To Add Tick’n’Tock To A Quartz Clock; (4) Judging System For Photography Clubs DEPARTMENTS 2 4 61 62 Publisher’s Letter Mailbag Order Form Product Showcase siliconchip.com.au 105 107 110 112 Ask Silicon Chip Notes & Errata Market Centre Ad Index Studio Series Stereo Preamplifier – Page 64. July 2006 1 SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor Peter Smith Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Glyn Smith Phone (02) 9979 5644 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed, Grad.Dip.Jnl Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $83.00 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silicon<at>siliconchip.com.au Publisher’s Letter Nuclear power debate should look at the whole picture Back in the January 2006 issue, we advocated that Australia should build nuclear power stations and now surprise, surprise, Prime Minister John Howard has launched a national debate on the subject. Good. But already a number of prominent people have started making hysterical statements and you wonder whether the ensuing debate is likely to be logical and carefully considered. It is not enough to consider nuclear power in isolation. We should also be reviewing all existing methods of power generation: coal, gas-fired, bargasse, wind, hydro, solar and so on. For example, if we want more wind power, the existing base load power stations must be able to cope with the vagaries of this form of generation. In addition, coal-fired stations and carbon dioxide sequestration should be considered. The cost and complexity of this system, if it even works, must be carefully considered in making future power decisions. As well, Australia’s needs for desalination and water resources in general should also be part of the picture. Australians are woefully ignorant of how much energy is required to bring water to them and then to take it away in the form of sewage. The New South Wales government’s recent decision to cancel the Kurnell desalination plant and to concentrate in future on water recycling just shows the extent of the problem; water recycling for sewage is almost as energy intensive as desalination! In fact, some years ago we editorialised that when Australians drink water, they are effectively eating coal! Another prime example of general ignorance about water and electricity resources was the decision by the States and Federal government to sell the Snowy Hydro scheme, now fortunately cancelled. I would not have minded so much if the Snowy had been sold, if the price had not been so incredibly cheap, compared with its cost of replacement! We need to consider the total costs of every form of power generation, from the initial method of extraction and transport (for coal, gas, uranium or whatever), the cost of power generation itself and the eventual cost of plant decommissioning, restoration of open-cut mines, carbon trading and so on. Ultimately, the decision should come down to cold hard economics. In the final result, I suspect that the best and cheapest course will be for Australia to use its vast natural gas resources for all future base load power stations. Gas is clean burning, does not spew radioactive particles into the atmosphere as happens with burning coal and is potentially more efficient than coal-fired stations. It also costs less to transport and there is no gaping open-cut mine to restore at the end of it all. Rather than exporting all our natural gas overseas, we should be using some of it here to meet our energy needs, for both electricity and transport. Leo Simpson ISSN 1030-2662 * Recommended and maximum price only. 2 Silicon Chip siliconchip.com.au                                         MAILBAG Mobile phone health hazard may be long-term I have read with interest your editorial in the June 2006 issue of SILICON CHIP, dealing with possible health hazards associated with the use of mobile phones. I strongly agree with your comments and would like to suggest that perhaps the magazine should take the matter much further. I worked for many years on environmental problems in the nickel industry and in particular was concerned with the carcinogenic effects produced by some particular types of nickel fumes in the atmosphere. This material was the cause of many cases of lung cancer in the industry in several countries around the world and the overall story was very similar to the situation with cigarette smoke and asbestos. Radio frequency radiation has also been recognised as the possible cause of similar cancer problems, with high voltage power lines and radar transmitters being among the prime suspects. In this case, the main variables are the frequency and the intensity of the electromagnetic field. The mobile phone is, of course, only a low-powered device but the inverse-square law and the fact that the phone is usually located only a few centimetres away from the brain suggests that it may possibly pose a significant hazard. I think that one of the most important aspects of the three separate cases mentioned above, which involved dusts, was that the health problems usually only appeared 20 to 30 years after the initial exposure to the hazard. If the Winch controller could be simplified The winch controller published in the January 2006 Circuit Notebook is indeed a credit worthy design but the inputs to a PICAXE chip are Schmitt triggers. Therefore all of the circuitry that de-glitches the inputs (IC2, IC3, IC5 and all associated components) is not needed. The debounce function of this extra circuitry can be done in software. 4 Silicon Chip mobile phone does in fact present a similar hazard, this fact is therefore not likely to become apparent for perhaps another 10 to 20 years or so. In the meantime, it appears to me that it would be prudent to conduct a strong publicity campaign to minimise the use of these phones as far as possible. It is only if no major effect becomes apparent in the next 20 years that we can say that no real hazard exists. The fact that no health problems have yet appeared does not prove that none exists. In the meantime, it is only the phone companies who have anything to lose if we play it smart and reduce our own health risk by minimising the use of these instruments as far as is practical. Bert Hollebon, Cloverdale, WA. Australian TV tests at Brisbane I thoroughly enjoyed the article in the June 2006 issue but you didn’t mention that the tests at the Old Mill in Brisbane continued up to the outbreak of WW2 when they had reached 240 lines. There was also a demonstration in a house in Brighton (Vic) in 1949, as was reported in “Radio and Hobbies” magazine. Also, when Alfred Zworykin visited Melbourne in 1951/2, he demonstrated his latest invention, the Vidicon camera. It’s also worth noting that in 1960 it was realised that some of the original 10 channels planned would not be available in time to start the country stations. This led to a new 13-channel Removing all these components will make the unit much cheaper and a lot smaller. Jeff Monegal, Via email. Comment: you’re quite correct but both design concepts (ie, the hard ware and the software approach to switch debouncing) are valid. The way we see it, Circuit Notebook is not necessarily about the cheapest, simplest way to achieve a result. plan. What is now 5A was originally 5, with 4 just below. Channel 0 did not exist in the 10-channel plan and 1, 2 and 3 stayed below the FM band. 10 was moved down slightly so 11 could be added. 1 and 2 moved up to allow 0 and 3 joined 4 and 5 in the FM band. This was detailed in “Radio Television and Hobbies” in 1960 (August, I think). The FM band was occupied from 1949 to 1960 by FM tests in Brisbane, Sydney, Melbourne and Adelaide. Wenlock Burton, VK3YWB, Darley, Vic. June 2006 cover credits I have just picked up the June 2006 issue from my local newsagent. As usual, it is an interesting read, particularly the history of television in Australia. Your cover photograph shows a TV set and lounge chair which is very reminiscent of that era when TV first came into our homes. However, I thought it was customary for magazines to include a short synopsis of the front cover photograph or at least an acknowledgment or identification of any people included therein. I cannot find any such mention in the magazine of the very beautiful lady on your June cover and I think she deserves that recognition. The photograph with the model is just so ‘spot on’ for authenticity so I think we readers should know who she is and somehow “Ms June” just doesn’t seem fitting. Bob Howie, via email. Comment: glad you liked the issue and the cover. The lady is Julie, daughter of Kevin Poulter, who wrote the TV series. Julie has a keen interest in 50s and 60s decor, fashions and memorabilia. siliconchip.com.au It occurred to us that you might want to know other details as well, since they are all authentic to the period, including the house itself. The alu minium venetian blinds were probably made by Luxaflex while the polished floor is Australian cypress pine (very popular at that time). The AWA Deep Image TV is in working condition al though the Channel 9 TV pattern was dropped in electronically by Kevin Poulter (who also took the photo). Other props include the TV chair with wool boucle cushions (probably made by Parker Furniture) and the anodised aluminium TV lamp. Julie Poulter is wearing a 1950s cotton halter dress with atomic starburst print, 1950s “Curvees” suede high heels and 1950s “Weiss” Lucite and rhinestone jewellery. Early TV experiments in Australia Thanks for your article on television in Australia, in the June 2006 issue but the Australian connection is much more important than you portrayed. In writing this I am working from memory so some details may be wrong but I believe it was a Mr Saunders from Ballarat who used the telegraph lines to send the signals and modulated the light of a kerosene lamp with a Kerr cell to show the 1896 or 1898 Melbourne Cup in Ballarat. He realised that the telegraph system did not have enough bandwidth and he had no amplifiers so he stopped development. The Melbourne museum some years ago had his apparatus set up for display. Unfortunately, his work has generally been forgotten. Rod Cripps, Parkdale, Vic. Fire sensor for sprinkler system I am writing with regard to the reader’s request for a fire sensor in the “Ask SILICON CHIP” pages of the May 2006 issue. Several years ago, I worked for an organisation (Cerberus) in a technical support role with respect to fire detection systems. In their range of products was a flame detector but the price today would be prohibitive for the “private” user (around $700 per unit) wanting to provide protection for an unoccupied property. As a guide, siliconchip.com.au Acid-free resin flux paste I saw the request for acid-free flux paste in the Ask SILICON CHIP pages of the April 2006 issue. There is a very easy way to make your own resin flux. Go to a music store and buy a block of resin (it is used on bow strings). Crush it up very finely and mix it with a small amount of methylated spirits to make a paste. Spread it on the clean copper, solder and you don’t have to clean it up after. Arthur Prince, Via email. Comment: thanks Arthur. That is a good way to make a mild solder flux. However, an analysis is likely to reveal that it is not completely acid free. It will have a number of organic acids related to the tree species from which it originated. the device was capable of detecting a methyl alcohol flame (little to no visible signs) in a tea-candle container at about five metres. The general philosophy of any fire detection system is that it only has to work long enough for the occupants to evacuate the premises and that it should be “out of sight, out of mind” until it is required. With respect to unattended systems and approaching bushfires, the smoke density (obscuration) will be likely to be at alarm levels at a significant time before the fire front arrives and temperatures will be at elevated levels because of radiant heat from the fire, making ordinary smoke type and heat type detectors ineffective. Factors such as environmental temperature, wind speed and direction, humidity, fuel load and neighbouring vegetation all affect the speed and intensity of the fire front. Pre-wetting is a good idea in that it interrupts the fire triangle (fuel, heat and oxygen) by reducing heat through evaporation but delaying the wetting down reduces its effectiveness, and starting it too early just wastes water. If one assumes that there is a bushfire, then there are no guarantees regarding reliability of electricity supply or water supply, meaning that alternative 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 July 2006 5 Mailbag: continued supplies (pools and tanks) must be utilised and mechanical pumps used to pressurise the spray system. The amount of R&D that had gone into the aforementioned flame detector was significant – especially with regard to flame flicker frequencies and other flame behaviours. Without being negative, it might be a little optimistic for someone to design (and get right first time) a fire-front detector that can break out the fire pump, put the foot in the pool/tank/dam, prime the pump, divert the pre-wet system and mop up without human intervention. All of the above points pretty pessimistically to the fact that a human must be at “ground zero” with enough intelligence to make certain decisions about the situation. Another way to consider it might be like this: if you can’t afford to lose the asset, you can’t afford to be uninsured. 0 00 $10 I Z E P R OL! PO Furthermore, if it really is valuable, why is it remote and unattended? Mike Frede, Albury, NSW. Nuclear fusion will be worth the wait As you probably know, the world’s first nuclear fusion plant is to be built at Cadarache in Southern France at a cost of 10 billion euros. It has been estimated that if this process can be successfully harnessed, then there is enough fuel available to supply the planet’s energy needs for at least 1000 years. It would also go a long way toward solving the effects of global warming created by the continued burning of fossil fuels. In a news item in the May issue of IET there is a report of a study into safety with respect to these new generation nuclear power plants and the authors have concluded that a severe environmental impact would be “impossible” and that even the “most severe” accident would not require public evacuation. Because of the technical difficulties that still have yet to be resolved, this plant is not expected to be commissioned before 2045-50. My hope is that we will see a result well before this. Countries such as New Zealand and Australia should have a watching brief on these developments rather than moving into generating plants using nuclear fission. John Rogers, via email. Comment: there is no certainty that nuclear fusion will ever be safely harnessed for power generation. If it is successful, the world will never have an energy shortage. However, Australia cannot afford to wait for 30 years or more for the possible outcome of nuclear fusion research. It is highly likely that we will have many nuclear fission power plants by that time. SC 2006 SILICON CHIP Excellence in Education Technology Awards NOW OPEN SILICON CHIP magazine aims to promote the education, development and application of electronic technology in all fields throughout Australia. As part of that aim, we are announcing the SILICON CHIP Excellence in Education Technology awards, with a prize pool of $10,000. Separate awards will be made to students of secondary schools throughout Australia and to students of universities and TAFE colleges throughout Australia. AWARD FOR EXCELLENCE The secondary school awards will have three categories: (a) Best final year assignment of an individual student involving electronics technology (b) An award to the school sponsoring the winning individual student (c) Best school project involving electronics technology The university and TAFE college awards will have three categories: (a) Best project from a student as part completion of a degree, diploma or certificate in electronics or a related field (ie, mechatronics) (b) Best research project from a post-graduate student working in an area of applied electronics (c) An award to the university faculty or school sponsoring the best research project. Entries and judging The awards will be judged by the editorial staff of SILICON CHIP, convened as a judges panel. The decisions of the judges will be final. Entries for the 2006 awards are now open, with final submissions to be made by September 30th, 2006. All submissions will be confidential, until the winners are announced, in the December 2006 issue of SILICON CHIP. Each award will take the form of a cash prize and a commemorative plaque. All enquiries about these awards should be directed to the editor via email to: awards<at>siliconchip.com.au 6 Silicon Chip siliconchip.com.au Innovative • Unique • Interesting • Hard to find products PCMCIA to Serial Pentium 4 with ISA Now supports LGA 775 CPUs! This industrial motherboard is based on the Intel i915G chipset. It supports LGA 775 Pentium & Celeron processors. Cat 17096-7 $699 RAID Server Temperature Logger Sharp Cash Register A basic cash register that is suitable for small retail outlets. Cat 1008129-7 $289 Add two serial ports to your notebook. Cat 2726-7 $269 Great for servers this RAID device takes two IDE drives and mirrors them. If one drive fails it will work from Digital I/O to Extend USB the other until the faulty one is replaced and then rebuild "on the fly" to minimize Ethernet 50m downtime. This unit allows the user Use inexpensive network Cat 2874-7 $569 to remotely control 7 cable (not included) to Digital I/O ports and 1 extend any USB 1.1 Mini Portable Barcode RS232/422/485 port device up to 50m Scanner (MPBS) over LAN or WAN. from a PC. Cat 15157-7 $329 Cat 11666-7 $99 Stores up to 1000 barcodes With it's vibration alert this new silent scanner is perfect for use in loud environments (eg warehouses), quiet environments (eg libraries) or for people with disabilities. Normally after a "good-read" a barcode scanner will beep, this unit vibrates instead. Cat 9355-7 $179 You can use multiple tags with the one reader. The tags themselves have a similar face size to a credit card. They can log temperatures from -40 to +85 and store up to 8000 readings. The logging interval can be changed from 1min to several hours. Cat 18211-7 Reader + Software $175 Cat 18210-7 Tags $69 USB to PCMCIA Adapter for 3G Cards Take your 3G wireless internet access anywhere! These USB adapters allow the use of a wide number of high speed datacards via a USB port. This enables these PC cards to be used with a desktop or laptop without a CardBus slot. Cat 6884-7 (16 bit) $279 Cat 6885-7 (32 bit) $339 ExpressCards For Notebooks ExpressCard is the new standard in notebook addon card replacing the older PC Card (PCMCIA) standard. Our current range of ExpressCards include USB 2.0, SATA II, Gigabit, Firewire 800, Serial & Parallel. Cat 2449-7 Call for pricing Dual ADSL Router The MPBS offers a portable scanning solution that includes the functionality of larger, bulkier units. The MPBS features a 64 character LCD, Serial Interface and rechargeable batteries. Cat 9286-7 $399 Silent Barcode Scanner What’s New? Cash Drawer A robust cash drawer that is compatible with all major receipt printers and POS software. Cat 8897-7 $179 Serial over Bluetooth 12v Mini PC VGA Extender Extend VGA up to 130m over inexpensive STP cable. Cat 3441-7 $399 Enhance reliability and double your ADSL capacity by using two different ISP's. Cat 10145-7 $199 • Normally delivered next day • Not sure what product you require? Call us for friendly advice! Digital I/O Card Console Sharer A PCI card that provides 48 digital I/O lines and three 16bit counters with a maximum count rate of 10MHz. Cat 17053-7 $249 Allows two workstations to operate the one PC. Supports PS/2 keyboard and mouse with VGA monitor. Cat 11667-7 $139 USB DVR Surveillance System High Definition Video Switch Box ask<at>mgram.com.au USB VGA Adapter Plugs into a USB 2.0 port and allows the user to extend their desktop over two screens (or three screens if already using a dual head video card). Cat 15156-7 $179 1800 625 777 Ideal for home/office/shop security, users can setup their own security system with easy 3 in, 1 out. Component Video with Stereo and Optical Audio. installation. Cat 23032-7 $99 Cat 3575-7 $179 www.mgram.com.au USB to IDE PCI to PCMCIA Cable with Adapter Power This PCI card allows the use of PCMCIA and PC Card devices designed for notebooks in a standard desktop PC. Cat 6539-7 $69 Connect any IDE drives to your PC using a highspeed USB 2.0 port. An external power adapter for drives is included. Cat 6857-7 $48 SMS I/O Controller 16 Way KVM Switch Switch any electrical device on or off using SMS from any mobile phone. Cat 17087-7 $979 This rack-mountable switch allows one console to control up to 16 PC's. Cat 11657-7 $799 EPROM Programmer This programmer connects to the LPT port and has a 32 pin ZIF socket. It will program from 16k to 8M. Cat 3159-7 $479 Reseller inquiries welcome siliconchip.com.au 1800 625 777 ask<at>mgram.com.au www.mgram.com.au All prices subject to change without notice. For current pricing visit our website. Pictures are indicative only. July 2006 7 SHORE AD/MGRM0806 This mini barebones PC is based on the VIA Eden 800Mhz processor and motherboard. It can operate on 12v or 240v making it ideal for use in boats or cars. Cat 1167-7 $750 This unique unit will allow a serial device to operate wirelessly using Bluetooth. Cat 11920-7 $459 Part 1: by Julian Edgar Race Car Data Logging More information than you’d believe! O ptimising the engine and suspension of racing cars has always been a technologically intensive pursuit but the ability to log and then later analyse data has taken the sport to a new level. Australian motorsport specialist MoTeC is at the forefront of racing car electronics, producing digital dashboards, engine management systems and data analysis software. This month we’ll look at how racing car data is collected and then next month, examine MoTeC’s i2 data 8 Silicon Chip analysis software. So what sort of data is collected from a racing car? Engine Collecting data on the engine status is made simpler because the engine management system’s Electronic Control Unit (ECU) already uses many sensors. The outputs of these sensors can be used not only by the engine management system but also logged and then expressed in engineering units. In addition, the ECU has available internally calculated data, such as injector duty cycle. Engine Load On naturally-aspirated race cars, load is normally calculated by the engine management ECU looking at engine speed and throttle position. (This is in contrast to road cars that most often use an airflow meter to directly measure the mass of ingested air.) Forced aspirated racing cars (that is, those with turbo or supercharged • siliconchip.com.au or at the airfilter. Air/fuel ratio Previously, the air/fuel ratio was measured by a zirconia oxygen sensor such as the Bosch “four wire” design. Based very much on the technology of the oxygen sensors used in normal passenger cars, this device outputs a voltage of 0-1V, depending on mixture strength. However, the voltage is non-linear with respect to air/fuel ratio, with a sudden change in output around 450 – 550mV (corresponding to the air/fuel ratio passing through stoichiometric) and also varies with temperature. The Bosch unit has a slightly flatter response than garden variety oxygen sensors but still has severe limitations in accuracy, especially at the rich end of the automotive scale. Linearising it requires accurate temperature and voltage compensation. Replacing the Bosch “four wire” unit is the Bosch LSU probe. This probe works on a completely different principle and requires its own control circuit. In short, a zirconiumdioxide/ceramic measuring cell is used comprising a Nernst concentration cell and an oxygen pump cell, with a small diffusion gap positioned between them. Two porous platinum electrodes are placed within this gap – a Nernst measuring electrode and an oxygen pump electrode. The gap is connected to the exhaust gas via a small passage. On the other side, the Nernst cell is connected to the atmosphere by a reference air passage. By applying a pump voltage across the electrodes, oxygen is pumped from the exhaust gas into or out of the diffusion gap. • Fully configurable digital electronic dashboards are used to display sensed data and log it for later analysis. In addition, output alarms can be set when certain combinations of parameters are met. Data can also be scrolled through by the driver pushing a button. engines) use a Manifold Absolute Pressure (MAP) sensor that measures manifold pressure. When this is combined with measurement of engine speed, the ECU can again work out load. So when engine load is logged, the data is in the form of either throttle position and engine speed, or manifold pressure and engine speed. While it might first appear that this is a complex way of logging engine load, in fact in racing car applications it is advantageous. This is the case because engine load is most often used in conjunction with the logged air/fuel ratio to work out where in the load range the engine is running richer or leaner than desired. Since the fuel injector outputs are determined from an ECU map of throttle angle (or MAP) versus engine speed, having available throttle position and rpm (or MAP and rpm) allows the engineer to quickly find the load site at which the problem is and then make the appropriate tuning change. MAP sensors are calibrated in absolute pressure and are most commonly available in 1 Bar (suitable for naturally aspirated engines), 2 Bar (ie suitable for 1 Bar of boost) and 3 Bar (suitable for 2 Bar of boost) versions. Interestingly enough, there is also available a 1.05 Bar version which takes into account the aerodynamic air pressure build-up possible in the airbox of a fast-moving car. Most often used are Delco MAP sensors which start at $80. These conditioned sensors have a nominal siliconchip.com.au 0-5V output and are widely used in production cars. Coolant , Oil and Intake Air Temperature Coolant and oil temperatures are measured by NTC thermistors. The Bosch 023 and 026 sensors are commonly used – at $17 they are cheap, use a near universal 12 x 1.5mm thread and are 2-wire designs (ie, no chassis ground return) that use a standard fuel injector plug. Intake air temperature sensors comprise a similar design but with the thermistor exposed to the passing airflow. Intake air sensors can be used to sense air temperature in an intake runner just prior to entry into the engine (so measuring the temperature rise caused by the air compression of a supercharger or turbo, and intake manifold heat soak) • MoTeC’s dashboard display and logger uses surfacemount components, a military spec connector and heavy-duty aluminium construction. July 2006 9 (Left): an infrared receiver placed in the car watches for the output of a suitably coded trackside infrared transmitter. In this way, accurate lap times can be logged and also displayed on the in-car digital dash. (Right): these expansion units allow a greater number of inputs to be logged by the digital dash or the engine management ECU. The E816 has an additional 18 analog voltage inputs and eight PWM outputs, while the E888 has eight analog voltage inputs, eight K-type compensated thermocouple inputs, four digital inputs and eight PWM outputs. The sensor controller varies this voltage so that the composition of the gas in the diffusion gap remains at stoichiometric. If the exhaust gas is lean, the pump cell pumps the oxygen to the outside (positive pump current). If the exhaust gas is rich, the oxygen is pumped from the exhaust gas into the diffusion gap (negative pump current). The pump current therefore reflects the actual air/fuel ratio. Again, linearising is required. Other than the most recent M400/600/800 series MoTeC engine management systems and the PLM air/fuel ratio meter, no MoTeC logging device can accept a signal directly from the LSU sensor. Instead they read the data from the ECU or PLM via a CAN bus communication, while the PLM also has a configurable analog Manifold Absolute Pressure (MAP) sensors made by Delco are used in conjunction with RPM and intake air temperature to measure load. These sensors are available in 1, 1.05, 2, 3 and 4 Bar versions. 10 Silicon Chip output voltage that can be read by the data logger. Exhaust Gas Temperature Exhaust gas temperature is measured with K-type thermocouples. Again, an interface device is needed, this time to amplify and cold junction compensate the signal. One example of such an interface is the $1045 MoTeC E888 input/output expander. Amongst other inputs and outputs, this unit can accept eight K-type thermocouple inputs and then communicate this data to the engine management ECU or digital dash logger by means of a CAN bus connection. Exhaust gas temperature is most often measured at individual exhaust outlets near the engine, so explaining the requirement for eight probes in many race car applications. These give • Individual cylinder exhaust gas temperatures are often measured and logged to indicate cylinder-tocylinder mixture consistency. a guide to cylinder-to-cylinder mixture consistency and are most commonly used in drag racing. Oil, Brake and Fuel Pressures Two types of sensor are used in these applications. The first is the traditional Bourdon tube based potentiometer, as exemplified by the large canister VDO units used as oil gauge pressure sensors on countless road cars. However, the accuracy of these sensors in race car applications is suspect: when tested on the bench, a light finger tap can sometimes change the measured output by 5 psi! Replacing these are Texas Instruments sensors that use a load cell backed by a diaphragm. Available up to 2000 psi maximum pressures, these sensors have a conditioned 0-5V output and are available in gauge and • Bosch LSU sensors are used to sense the oxygen concentration of the exhaust gas and from this, work out the actual air/fuel ratio. These new sensors replace the older zirconia design and are faster and have higher accuracy over a wider measuring range. siliconchip.com.au absolute pressure configurations. Throttle Position Throttle position sensors comprise rotary potentiometers mounted on the throttle shaft. They are available in a wide range of physical designs to match various shafts but a common one accepts a D-shaped shaft. As we will see next month, knowing what the driver is doing with the throttle is a vital component in race car data analysis. Engine Speed Engine speed is sensed from the crankshaft position sensor. This normally comprises an inductive sensor mounted on flywheel, although in engines not specifically built for racing but instead adapted from road cars, the sensor can alternatively be optical or use a Hall Effect device. Other sensors that are sometimes uses on the engine include infrared thermometers measuring block temperature and pressure sensors in the coolant system, the latter used primarily to sense a catastrophic loss of coolant. • • Fully programmable engine management units like this MoTeC design incorporate memory for data logging. Engine sensor data is already available to the unit and suspension data can be communicated to it from the digital dashboard by CAN bus. Suspension data requires the installation of specific sensors. Where the behaviour of individual wheels needs to be monitored, this involves four sets of sensors. Damper Movement Damper movement is sensed by linear potentiometers. These are available with different stroke lengths (for example: 75, 100, 125, 150 and 200mm) and are mounted such that they move over as much of their range as possible as the suspension moves from full bump to full droop. These sensors cost about $400 each but they are fully rebuildable, something often required as their vulnerable positioning results in frequent damage in racing incidents. Finding space for the sensors and mounting them so that no bending loads are placed on them can be difficult; however, the logging software can be easily configured to show actual suspension deflection even when the sensor is angled from the vertical or is subjected to a non-linear motion ratio. Damper Temperature The temperature of the oil within the dampers is sensed indirectly, either by the use of stick-on thermocouples or, less commonly, by infra-red temperature sensors. Lateral , Longitudinal and Vertical Acceleration One, two and three axis accelerometers are used to sense accelerations. These sensors are conditioned with a 0-5V linear output and can be specified to have maximum acceleration of 10g. (In Top Fuel drag cars the previous 4g maxima were being exceeded in longitudinal acceleration!) However, in circuit racing cars, two-axis accelerometers with a maximum acceleration of 4g are more normally used. Cost varies from $360 for a single axis 4g accelerometer to $688 for a 3-axis 4g sensor. As we will cover next month, the outputs of this sensor can be used by the data analysis software to automatically construct a track map. The accelerometer is normally mounted at the roll and pitch centre of the car. However, two accelerometers can be individually mounted on the front and rear axle lines and when their outputs are compared to steering angle, be used to assess the magnitude of oversteer and understeer. Yaw Yaw is sensed by a Bosch yaw sensor, as normally fitted to the Subaru STi model WRX that uses an active Linear potentiometers are used to sense damper movement. Data interpretation software allows damper speeds to be calculated from this displacement data, allowing optimal bump and rebound settings of the dampers to be set. Hall Effect sensors are used to sense engine speed, a parameter used by the engine management ECU and also logged for later analysis. Load-cellbased pressure sensors are used to measure oil, brake and fuel pressures. In some cars, even the coolant pressure is measured! Chassis and Suspension • siliconchip.com.au • • • July 2006 11 mounted receiver. A configurable frequency signal is emitted by the beacon and the car’s system is programmed to respond to only this signal. Lap times are logged and also displayed to the driver in terms of laps to go or lap number. In addition, split times can be gained by the use of extra trackside beacons programmed appropriately. A dual axis accelerometer is used in most data-logged racing cars to sense lateral and longitudinal acceleration. The unit is designed to work up to 4g and outputs a conditioned 0-5V signal. centre differential as part of its four wheel drive system. In addition to a yaw rate signal output, this sensor also contains a lateral accelerometer. Cost is $1014. Tyre and Brake Temperatures Tyre and brake temperatures are monitored by infrared thermometers aimed appropriately. In the case of Le Mans racing cars, no less than three infrared sensors are used per tyre – quite a cost at $480 each sensor! Tyre temperatures are amongst the most useful of data in setting-up a car for optimal lap times as the temperature distribution shows how hard each tyre – and each part of the tyre – is working. The infrared thermometers have a conditioned 0-5V output and are available in 100°, 200° and 1000° Celsius ranges – the latter being used to measure brake temps. Steering Angle Steering angle is normally sensed by a multi-turn rotary potentiometer driven by a toothed rubber belt from a pulley mounted on the steering shaft. Road Speed In road cars adapted for racing, the ABS system is usually disconnected. In these cases, one of the inductive wheel speed sensors can then be used for measuring road speed. The logging software is configured for the AC voltage levels of the sensor and the frequency/speed relationship. In purpose-built race cars, a new inductive sensor is fitted behind a wheel. • • • Lap Time Car racing is about going faster than anyone else and so lap speed is a critically important parameter. MoTeC use a trackside mounted infrared transmitting beacon and a car 12 Silicon Chip Logging and Displaying the Data Given the number of channels and the frequency at which many are collected, most teams choose to use in-car logging rather than real time telemetry. (Telemetry is still used but for slowchanging factors like fuel levels and monitoring engine health.) It is useful if the device that stores the data can also display some of it for the driver and so a common approach is to use a customisable digital dashboard that can perform both functions. MoTeC’s Advanced Data Logger (ADL2) is such a unit. The ADL2 can read 28 analog voltage inputs, 12 digital inputs and two Bosch ‘four wire’ air/fuel ratio sensor inputs. And if even more logging capability is required, another 22 inputs can be added by means of an expansion unit! The unit will also accept data communicated to it in RS232 (eg, from a GPS unit) and CAN formats. A 16Mb internal memory is incorporated and the microprocessor is 32-bit. The fully configurable backlit LCD can display any of these inputs, shown in userselectable engineering units. Conclusion As we’ve seen, literally anything that can be sensed on a race car is capable of being logged. However, all the information in the world is of little use if no sense can be made of it. Next month, we’ll take a look at the MoTeC i2 data analysis software which has mind-boggling capabilities – not only can it display the data in many different forms but it can also make mathematical calculations based on that data and then display those calculations in relation to the SC collected data! Contact: MoTeC Pty Ltd 03 9761 5050 www.motec.com siliconchip.com.au USB Oscilloscope & Logic Analyzer The new generation Scope for the age of microelectronics. 8 Channel 40MS/s Logic Analyzer Capture digital signals down to 25nS with arbitrary trigger patterns. 3 Input 100MHz Analog DSO Classic Analog Scope using a standard x1/x10 BNC probe. Additional inputs on the POD for dual channel operation. 8 + 1 Mixed Signal Scope True MSO to capture an analog waveform time-synchronized with an 8 channel logic pattern triggered from any source. Real-Time Spectrum Analyzer See the spectrum and waveform of analog signals simultaneously and in real-time Waveform Generator Load up to 32K arbitrary waveform and replay via the onboard DAC (10MS/s) or a digital pattern from the POD (40MS/s) Standard 1M/20pF BNC Input 200uV-20V/div with x10 probe S/W select AC/DC coupling S/W select 50ohm termination Arbitrary Waveform Generator Turn your PC or NoteBook into a powerful Scope and Logic Analyzer! See inside your circuit in the analog and digital domains at the same time to make tracking down those elusive real-time bugs much easier. Pocket Analyzer combines a high speed sample-synchronized storage scope and logic analyzer with a programmable waveform and logic pattern generator. Also included is an integrated real-time spectrum analyzer and powered "Smart POD" expansion interface so you've got all bases covered! About the same size and weight as a Pocket PC, this USB powered BitScope needs no bulky accessories. It's the perfect low cost "go anywhere" test and debug solution. BitScope "Smart POD" Connector 8 logic channels, 2 analog channels Dual channel capture from POD A/B Async serial I/O for external control Logic Pattern generator 32K 40MS/s BUS Powered USB 2.0 Device Single USB cable to your PC Compressed data transmission Simple ASCII control protocol BitScope Scripting Language External/Passthru Power Supply Auto senses an external supply removes power load from USB for use with unpowered hubs. Supplies up to 500mA via POD BitScope and your PC provide an array of Virtual Instruments • R&D • Education • Robotics • Lab Scope • Fast DAQ • Service • Debug BitScope Pocket Analyzer uses highly integrated Surface Mount technology to provide functionality you would expect from scopes many times the size and price. Its programmable Virtual Machine architecture means new functionality can be added via software. For custom Data Acquisition, export directly to your spreadsheet. BitScope DSO 1.2 software for Windows and Linux siliconchip.com.au BitScope Designs Ph: (02) 9436 2955 www.bitscope.com July 2006 13 Fax: (02) 9436 3764 Television: let the game b Part 2 New and exciting, television was here – with euphoria reaching almost fever-pitch, capturing the imagination of an entertainment-starved nation. T his amazing new electronic medium – television – made an immense impact on society in the late fifties. Today, with dozens of TV channels, it’s hard to imagine the incredible anticipation and excitement of television at the time. TV performers became huge stars and technicians were respected as the people householders could rely on, to keep every home ‘on air’. After WW2 Astor, like AWA, sent technicians overseas, visiting top manufacturers to absorb their knowledge and experience, then commenced building experimental receivers. During 1949, Astor sent their televisions to be paraded in halls in capital cities and main provincial towns around Australia. Before TV started, Ron Blaskett, a ventriloquist with his 14 Silicon Chip wooden doll Gerry Gee, was asked to perform in Channel 9 closed circuit demonstrations at Melbourne’s Royal Agricultural Shows. Similar demonstrations were made at the Sydney show. As 1956 progressed, anticipation was so frenetic, people were purchasing Astor receivers as early as June 1956, to watch test broadcasts and the test pattern. The price of a good console was about the same as a second-hand car. An Astor, for example, was 250 pounds (with the 1956 average annual wage about £1100) plus 25 pounds for ‘installation’ and another 25 pounds for the antenna to be fixed on the roof. Many consumers believed the controls were for technicians only, so they endured a poor picture until help arrived. siliconchip.com.au : At left: the Govenor of Victoria, Sir Dallas Brooks, makes the grand entrance to the GTV9 Studio, Melbourne, to officially open the fourmonth-old station on January 19, 1957. Below: Astor’s 1956 television range. Manufacturers (wrongly) believed that the 17-inch models would be the most popular but as it turned out, Australian TV viewers wanted bigger! begin Part 2 – By Kevin Poulter GTV9 used ventriloquist Ron Blaskett and his sidekick Gerry Gee to introduce consumers to television. siliconchip.com.au July 2006 15 Just as much items of furniture as TV sets, these three Astor sets from the late 1950s show the style of the day. They called the larger cabinetstyle sets either “consoles” or “consolettes” – the one on the left was merely described as “special”. Friends you didn’t know you had . . . Any household that purchased a TV suddenly became popular with long-lost friends and neighbours. Television antennas were installed on the chimney or inside the roof, often according to whether the owner wanted neighbours to know a TV was installed or not. Some householders installed an outside TV antenna only, just to ‘keep up with the Joneses’. Others installed the antenna inside the roof to keep the house-proud mother happy or even to avoid paying the government radio and TV licence fee. The dreaded “RI’s”, or Radio Inspectors could legally enter homes but to people who could barely afford the set, the risk was relatively low. Stories circulated of owners being ‘nicked’ after detection by special vans that could locate noise from oscillators in the TV. It was a long time before this universally-disliked tax system (ostensibly to pay for the government-owned ABC) was abolished. Melbourne embraced television more than any other state, probably due to the climate, interest in theatre and lack of club activity. Certainly contributing factors were that no theatres or shops were allowed to open on Sundays and hotels had to close at 6pm. TV ownership at the time as a percentage of population was Sydney 1% and Melbourne 5%. TCN9 Sydney, though, transmitted the Pelaco Golf Tournament – the first live telecast of a sporting event and the Victorian Cricket Association sold the rights to televise the cricket to the ABC – for 25 pounds! Big investments The electronic manufacturers were certain of the future of television and invested heavily. More shots from the opening night at GTV Channel 9, Melbourne. At left is the camera boom with seated cameraman, made especially for high shots. Note the dress of the cameraman and grip: suits and ties, what! The team is Geoff Hiscock, Ron Davis on camera and Tom O’Donohue. Above right is the then Governor of Victoria, Sir Dallas Brooks, taking a peek through camera 1, with cameraman Ernie Carroll driving! 16 Silicon Chip siliconchip.com.au Wireless Data Networks Long Range Antennas 900 MHz 2.4 GHz 3.5 GHz A giant STC Commander 3-in-one. This all-valve monster, which includes a full-screen Polaroid filter, is probably the only one in captivity. Inspired by the scale of US manufacturers, Astor’s parent company, Electronic Industries, purchased 25 acres of land in Clayton (Vic) to build an electronics city, at a cost of 4.5 million pounds. Electronic Industries’ CEO Sir Arthur Warner’s grand vision was a massive cluster of suppliers and research facilities close by, like modern car manufacturers. His assemblage of Astor/Electronic Industries factories grew huge, with internal roads and communications networks. Soon they were joined by Gainsborough furniture (makers of fine home furniture, radiogram and TV cabinets) and PYE Telecommunications, relegated to the distant south-eastern corner of the electronics city. However, no other related brands or suppliers ever came to fill the remaining farm countryside. AWA erected a new 92,000 square-foot factory at Rydalmere, near Parramatta in Sydney’s west and the first production was 17-inch picture tubes. At the same time, AWA’s Radiola No 1 factory at the inner-western Sydney suburb of Ashfield (where the famous Radiola and Radiolettes were made from 1931) was quickly transformed into an automated carousel moving-conveyor productionline facility. The factory handled the large, heavy “Deep Image” television chassis, which were all hand-wired at that time. Chassis, tuners speakers and cabinets came together assembled and tested with AWA’s own purpose-built on-site transmitter and rolled along the conveyors to the warehouse. Brands like Astor, Admiral, Healing and others were also highly in motion. Astor’s cathode ray tubes were manufactured in 1956 by Anodeon, in nearby Huntingdale (Victoria). 5.8 GHz Omidirectional Sector + Mobile Hills distributes smartBridges outside wireless network point to point & multipoint products. airPoint - 2.4GHz Nexus - 5.8GHz Discover more: Phone: +61 2 9717 5275 Email: rolf.roelfsema<at>hills.com.au www.wireless.hillsantenna.com.au or with side-mount speakers, speakers in front on one side, or both sides of the tube and many quality furniture variations. Economy televisions were tabletop models with cabinets not much larger than the picture tube, with or without long legs. The first AWA television receivers were the 200 series, commencing with model 201T. ‘T’ denoted a 17-inch 70° picture tube table model, with a 23-valve deluxe chassis. These sets rolled off the production line pre-broadcasting, in July 1956, at a retail price of 209 guineas. Shortly after, the model 202c console version was produced, priced at 229 guineas. As televisions first appeared in stores, large crowds, often Built to last Early TVs were well-built (like a tank), as manufacturers hadn’t devised cost-cutting cheaper production techniques like printed circuit boards. The most common wiring was across tag-strips. Superb cabinets were made by furniture companies, with beautiful quality, gloss wood finishes to match furniture in even the finest homes. A single chassis would be the basis of a large range of sets – on legs, upright consoles with a large speaker below, siliconchip.com.au Telecine technicians controlling the quality of film converted to video. July 2006 17 The Siemens transmitter room at GTV9 at opening night. The meters at top show that the transmitter is operating – with all those fingers perilously close to the HT! The meter at left, by the way, reads output power as 10kW. These days GTV9 is licensed for just a tad more power! three to four deep or more, gathered to watch through the store windows at night. This became entertainment for many, like the Harrisons, a typical Aussie family. Every Friday night, the children were excited to go to town, to watch test broadcasts of ‘tele’ from the street. People bought deck-chairs and applauded – even the commercials. Some stores installed speakers under their veranda, so the crowd could hear the television too. Stores went the extra mile, with free in-home demonstrations, even loaning a television set or two for weeks, while the householder decided. In 1956, the Harrison family purchased a Ferris TV, a budget model with a compact metal case finished in iridescent blue, just the size of the screen. Rabbit-ears on top gave excellent metro reception. They weren’t the only ears – Mickey Mouse ears were worn by thousands of excited children during the Mickey Mouse Club. Just 11 days after TCN9 Sydney, GTV9 made Melbourne’s first live transmission on September 27, 1956, hosted by Geoff Corke and broadcast from the staff kitchen at the Mt. Dandenong transmitter. Prolonged Olympic Games negotiations finally reached agreement in November 1956, at the last minute. Channels 2, 7 and 9 televised the Olympics but only at sold-out events. Videotape recorders were a long way off, so broadcasting was live, plus a vast number of 16mm cameras filming, for replay later. Sydneysiders and overseas audiences only saw delayed footage, from 16mm film. Television transmitters for Melbourne were installed in a group on Mt. Dandenong, 35km from the city, with GTV9 employing a Siemens transmitter and PYE cameras. ATN Sydney built a 500-foot mast at Gore Hill. Their 72-foot aerial array and most studio equipment was Marconi of UK, supplied by AWA. Two 3-inch copper lines fed the two halves of the antenna, under a few pounds of pressure, to keep out moisture. 18 Silicon Chip Marconi orthicon camera tube. A sensor (top right) enclosed a tiny ball, which fell into a one-way tube if inverted in transit. This resulted in a return to the factory, as dust would show in the image. Over the years before official broadcasts, various Governments had pushed their ideology, from Labor decreeing television was to be all government-owned, to the Liberals reversing that to allow commercial television as well. By transmission time, the government was still fully in charge of all transmitters, through the “PMG” (Post Master General’s Department). This meant commercial TV stations mixed and converged their studio’s output into a large cable – the final feed leaving the station. From this point on, the PMG had absolute control, including getting the signal to the transmitters and towers. In the event of signal loss or quality problems after this exit point, the station engineer would telephone the PMG It all looks rather primitive by today’s standards . . . but at the time it was state-of-the-art! Do you recognise a rather young “King” of Television? Graham Kennedy was later to become one of the best-known faces on Australian TV. siliconchip.com.au engineer to report “all was well their end and could they please get back on air soon”. Australian TV stations lacked production experience, so they copied overseas ideas, telecasting live shows identical to stage presentations, or broadcasting overseas programs. TCN-9 transmitted just three hours each night in 1956, trying entertainment like Frank Ifield yodelling and other stage-style presentations. Their three 15-minute music shows could not compete with American drama and ceased within three months. “We may not be the first, but we are the best” TV stations who revelled in the one-upmanship of being first to start regular transmissions were soon torpedoed when Channel Nine Melbourne officially started in January 1957. GTV9 was immediately the envy of other networks with an enormous one million pounds worth of facilities, unofficially titled ‘Studio City’. As well as being the high-profile leader of Electronic Industries, Sir Arthur Warner was chairman of GTV9. He explained his decision to delay until they were the best. ‘It would be crazy and the stupidest thing to put on low grade programs in the early stages. This is a new adventure for the Australian public, and it wouldn’t be good to open with a colossal number of hours.’ The strategy paid off, as soon GTV9 was filming ratings-leading productions. Channel GTV9 Melbourne commenced official programs on January 19, 1957. Terry Dear was the presenter, with the Governor, Sir Dallas Brooks, making a grand entrance into the massive studio in his black limousine, led by motorcycle police. In front of an audience of 400 people, he declared the station open. Viewers far and wide reported excellent picture definition and sound from the channel 9 opening broadcast, including Bairnsdale, 280 kilometres from Melbourne and other distant locations, like Ararat, Mansfield, Yea, Bendigo, Traralgon and Ballarat. Channel Nine had an imposing camera boom, for rising above scenes, shooting with the cameraman seated – just like in the movies. Not to be left out, Seven went to great lengths to produce a devious but similar effect in a liveshow. Their stills photographer photographed a singer during rehearsals with arms outstretched, from a high angle. In the live performance, as the performer opened arms, a second camera faded to the photo enlargement of an overhead view! ATN-7 built their television complex at Epping in Sydney, with a main studio soon proclaimed as the biggest in the country. “In Sydney Tonight” started in the first week of transmission, with ex-radio host, Keith Walshe. Keith’s quick wit and the polished production soon made the show a ratings leader. On May 6, 1957, Norm Spencer launched “In Melbourne Tonight”, hosted by a young Graham Kennedy. Graham had a ‘naughty boy’ reputation on radio and attracted the housewife set. Overwhelming demand results in rationing. After the launch of television transmissions, the industry had difficulty in meeting consumer demand. Dealers were obliged to start an allocation system, which led to an influx of imported receivers but many imports ceased after local production began to cope with supply. siliconchip.com.au Marconi MkIV camera, used from the late 60s to 70s. This one still works – after an hour or so to warm up. Stations were known to leave cameras on all night to avoid warm up and stabilisation. Television was an expensive item, yet John Williamson, a television serviceman at the time, remembers clusters of television antennas were initially more prevalent in low-income worker’s areas. Families, who were already paying off many items, added new television sets to their hire-purchase. Government legislation required households to have a licence for their television, so the PMG figures give a reasonable indicator of sets sold. In the first month of regular broadcasting, 10,000 sets were licensed. By February 1957, Victoria had 8,000 licences and NSW 4,000. This initial boom in Victoria was attributed to interest in the Olympic Games but as 1957 progressed, Melbourne July 2006 19 The top show for adults was ‘I Love Lucy’ and for children, ‘The Mickey Mouse Club’. Along with their own brand, AWA produced Westinghouse badged receivers in their factory. Re-badging was common in television, like electronics manufacturers today. Large stores including Maples and Myers also sold house re-badged brands, like the ‘Maple Leaf’, manufactured by Astor. The power of advertising. A Camera Control unit for the Marconi on previous page. continued to lead television receiver sales. Bob Dyer’s quiz show “Pick a Box” started on ATN-7 and was simulcast on radio. A big “Pick a Box” winner was Barry Jones, who later became a federal member of parliament and Labor Science Minister. Barry Jones not only answered questions in considerable extra detail, he argued with some of the show’s answers – and usually won. During 1957, GTV-9 connected Melbourne with Sydney for the first time, via five mountain-top microwave links in an exercise called ‘Operation Kangaroo’. Australian content included ‘The Happy Show’ with Happy Hammond, broadcast from the Myer store window, though an OB van in the basement. Five hundred people watched the first show from the street. Then every evening at 5.30, crowds gathered for the show, made under the brilliant illumination of three banks of arc-lighting. Strong lighting was needed to compensate for the relatively low sensitivity of television cameras and white shirts were avoided, due to the image blooming and smearing of the camera tubes. Titles and drawings were filmed from flip-cards. Cameramen were dressed in suits or dust-coats and communicated to the director through throat microphones, headphones and hand signals. In April 1957, the Tarax Drinks Managing Director wrote to channel 9 to advise their sponsorship of the Tarax Happy Show had been so successful, they were continuing their sponsorship at a higher level and immediately allocating one hundred thousand pounds for plant and equipment to cope with increased sales. AWA models included the 17-inch 203T and the first This DIY TV design was described in the May, June and July 1957 issues of “Radio, TV and Hobbies”. 20 Silicon Chip siliconchip.com.au a ‘matter of life and death’ to the consumer, servicemen could work 15 hours, 7 days! They butcher on Sunday, we fix properly on Monday Inside a Marconi MkIV camera. Note the large blower and cathode ray tube for the camerman’s viewfinder. 21-inch 90° tube models, the 204T table, 205C console lowboy and 206C console with doors. These also featured the deluxe chassis, but with 24 valves. Additional 5AS4 rectifiers (two in parallel) handled the extra load. Later, in November 1957, AWA’s standard 17-valve chassis was introduced, the 209C 17-inch followed by the 21-inch 212C in December. The television industry originally predicted 17-inch receivers would dominate demand – the best compromise between screen size, clarity and cost. In fact, 21-inch models quickly became top sellers, as the 625-line transmission system gave excellent picture definition, without obtrusive raster lines being evident. Soon giant 23-inch sets were also available. Department stores established in-store radio and TV service departments. In addition to offering best service to customers, people with sets needing repair would pass the furniture and store’s products on display, potentially attracting more sales. Two things concerned the public about television ownership – the high purchase price and fears the expensive picture tube would fail. This was not helped by early guesstimates that picture tubes only lasted about three years. Invariably, as servicemen arrived at a home for a TV repair, they were met by a worried owner, sure the problem was the tube. This was capitalised on, with companies offering service contracts or insurance. Unfortunately, the need for TV service also attracted ‘cowboys’ and unscrupulous operators. Of course, tube life was far better than this, including cases of sets still performing well beyond 15 years. Thomas Tubes’ Melbourne manager said the emission life was largely determined by the number of sweeps of the cathodes by the spray gun operator. RCA Raytheon and Sylvania seemed to be particularly generous. Large service companies began, with ‘radio controlled’ service. Separate sections handled antennas, workshop pick-up and delivery plus spare parts feeder vans. Technicians started from home and averaged eight calls per eight hour day (more with overtime), finishing at home around 5-10pm. Once a week the technicians would visit their base for restock and technical updates. In the early years when a TV receiver breakdown was siliconchip.com.au Generally extreme hours were only offered by the crooks in the trade, like the one listed in the yellow pages under every alphabetical letter. Their itemised accounts for a workshop repair were deceptive, like ‘adjustment of horizontal drive’, a five second job – for fifteen pounds! The crook was featured prominently in the ‘reveal all’ Truth newspaper, lived in Melbourne’s most expensive suburb, Toorak, sent his kids to the best schools and ran his own debt collection agency. He even had the front to appear on an ABV2 interview and wondered what all the fuss was about. An employee said he was a capable technician but he would assign an apprentice or slower person work on the repair for a long time. When it was evident they would not get anywhere, he would take over and find the fault quite quickly – but the customer would be billed for the total time. He had the greatest assemblage of test equipment ever seen in one place. It completely covered one wall from bench height to the ceiling. This myriad of red indicators and blinking numbers could be seen by customers through the shop front window. Very impressive – but not used, especially when no staff were there late at night. Independent radio repairmen in 1956 without retailer connections were at a disadvantage by not having many television sets, installations and faults to learn on. War- “MERLIN” Safe External Switchmode Power Supply Practical and Versatile Mini Broadcast Audio Mixer Broadcast Quality with Operational Features and Technical Performance identical to full sized Radio Station Mixing Panels Permanent Installation is not required, the “Merlin” is as easy as a Stereo System to “Set Up”,all connections via Plugs and Sockets The “Merlin” originally designed for Media Training use in High Schools and Colleges is a remarkably versatile Audio Mixer Applications: Media Training - Basic Audio Production - News Room Mixer - Outside Broadcasts - Radio Program Pre Recording On-Air Mixer in small Radio Stations - “Disco Mixer” The “Merlin” is an Affordable Professional Audio Product Buy one for your School, College, Community Radio Station, Ethnic Radio Broadcast Association or for yourself For Details and Price, please contact us at ELAN Phone 08 9277 3500 AUDIO Fax 08 9478 2266 2 Steel Court. South Guildford email sales<at>elan.com.au www.elan.com.au Western Australia 6055 July 2006 21 For programming with tight deadlines, like news and sports, it was not uncommon for 16mm film to be sent to telecine still damp from processing! Given no inexpensive recording options, most entertainment was broadcast live, ‘warts and all’, with memorable moments, due to no editing possibilities. These include Rover the dog starring on In Melbourne Tonight, doing what a dog needs to do – a puddle on the floor – plus performers occasionally exclaiming adjectives not in more genteel vocabularies. 1959 was a big year “We’re testing it now Mr. Jones. Looks like you need a new picture tube.” A topical cartoon from the August 1959 issue of Radio, TV and Hobbies – itself from an earlier edition of “Radio Electronics.” Unfortunately this was often too close to the truth . . . ranties and insurance policies meant that any service was closely tied to the retailer for quite a while. Occasionally there were disputes between a TV technician and the antenna installer/repairer, whether a snowy picture was due to an antenna fault or the receiver (two-storey building and no portable on hand). This was a good reason for always using folded dipoles, rather than the open ended fan type, so a feeder continuity reading was possible. Service technician John Williamson recalls receiving a service call to a rural area with no house numbers. Armed with a description of the house, he travelled the dirt road until he saw a farmhouse. Nobody was home, but the door was unlocked – not unusual in those days –- so he soon found the TV. Sure enough, it had faults, which John fixed and then proceeded down the road. To his consternation, a little further down there was a house that better fitted the description. He had repaired the wrong TV! There was no option but to repair the right one and wonder what the lucky neighbour thought of the set mysteriously fixing itself. Video tape recording Ampex USA was the leading force in VTRs and in 1955 began to see usable images on recorders. The challenge was to fit massively greater information on tape than sound. On November 30th 1956, Ampex made the first American video recorder, an impressive recorder with four (quad) spinning heads, rotating at 14,400 rpm. Thirty-two passes of the heads composed one picture frame. Still, Australian television was not to have access to video recorders until 1959, so our only recording option was ‘telerecording’, using a kinescope. This involved simply pointing a 16mm film camera at a monitor – which explains why some historical footage is low quality. 16mm film was the only alternative. This was expensive and delayed the broadcast but was top quality. With news and overseas programming only on 16mm film, TV stations had state-of-the-art 16mm projection telecines, 16mm cameras (field and studio) and even in-house movie film processing labs. 22 Silicon Chip New South Wales began to lead in TV ownership, overtaking Victoria’s early 2 to 1 lead. Now NSW boasted 350,536 licences, compared to Victoria’s 301,138. Tasmania trailed with just 87 licences. QTQ9 Brisbane began test transmissions but Darwin had to wait many more years for TV. ATN-7 was the first Australian station with a videotape recorder. The Ampex recorder was a huge quadruplex reelto-reel unit with massive 2-inch tapes – so bulky, each tape case included a carry handle! Due to their expense, tapes were wiped and re-used, until too many drop-outs appeared, so many classic TV moments were lost. Other stations purchased recorders soon after, at a jawdropping thirty thousand pounds each! The quality was very good at the time, so the quad format was in use until the late 70’s. As labour-saving appliances flooded the market, industry grew, and cars had little ignition suppression, television reception suffered. Government technical investigations suggested the common herringbone pattern on Ch 2 was attributed to ‘a transmission frequency variance from the 36 meg frequency used in Australian sets’. The Control Board also recommended a new set of intermediate frequencies. Since television began, Australians have wanted a higher local content. 1959 was no exception, with one writer lamenting stations were following the easy advertising dollar ‘by using packaged-shows of second-rate American films, instead of the hard-won Australian variety show.’ Game shows like the BP Show were huge. Often based on American concepts, viewers were dismayed to hear in 1959 that the American Senate Committee found ‘fixers seduced and coached innocent quiz contestants’. Australia held its head high, with top quality productions like Shell Presents, broadcasting new live plays every week. GTV9 continued to lead with the most popular live shows. Generally the only programs still surviving since 1956 were comedy dramas, with Maverick the most popular western by far. In 1959, drama peaked at 49.5% of viewing time, with variety and talent just 9.3% and children’s also a low 11.2%. Any popularity list should include Father Knows Best, I Love Lucy, Beaver, Bilco (all American) and Graham Kennedy’s In Melbourne Tonight. Teens were excited by the Johnny O’Keefe-produced Six O’clock Rock. 1960 – still do-it-yourself In the 20s to the 40s, people were encouraged to make and repair radio receivers. Despite the infinitely greater complexity and high-voltage dangers of television, books like ‘Australian Television Yearbook’ showed how anyone could fix faults. There wasn’t a circuit in sight but statesiliconchip.com.au ments like ‘90 percent of faults are the valve’, encouraged the amateur sleuth. High-voltage warnings were included, easily overlooked by an enthusiastic amateur. You want fries with that? In 1957, mains voltages in some suburbs and rural areas fluctuated between a low 160 to 200 volts at night, particularly in winter, reaching highs of 255-260 volts. This was due to fewer electricity supply transformers, switching stations and regulators. Excessive voltage caused faults like EHT arc-over, EHT socket and valve breakdown, oversized pictures and numerous component failures. Under-voltage opened up a can of worms. Customers would call with faults like a small picture. Often this was too-easily solved by changing the mains tap on the set to a lower one, not advisable, as it fried the set when the mains supply later rose and/or missed the true problem. In fact, the fault may have been just the vertical oscillator plate resistor going high after the set had been on a while – especially if the TV remained on from children’s viewing time. Changing the transformer tap resulted in up to 100 volts more B+ HT, plus nearly 8 volts on filaments and higher EHT voltages. This preceded an estimated 60 percent decrease in component life, with capacitors and valves greatly exceeding their limits. One owner changed his TV to the 200 volt tap, then was notified by supply authorities his mains supply was upgraded to 240 volts. On returning the tap to 240 volts, the receiver lost horizontal hold, so he reverted to 200 volts. siliconchip.com.au Within two weeks, the picture tube had given up – expensive, the right voltage only needed a simple adjustment of the horizontal hold. Servicemen were faced with the dilemma of solving voltage problems outside the design criteria of equipment. Even a VTVM powered by the mains would introduce its own error, showing approximately double the actual voltage drop. John Williamson again: “I was called to look at a set which had five valves replaced in four weeks under a service contract, now expired. After changing the mains tap from the (incorrect) 210 volt setting, the true faults like a shorted capacitor across the stabiliser coil and other troubles were fixed and the TV gave reliable viewing.” Valves mainly suffered after a time on a low mains tap setting. When reset correctly, faults appeared in most areas of the set. However in the interests of longevity and fewer service-calls, the correct move was to the right mains tap. Problems may not exhibit fully (or at all) when the serviceman arrived, so John Williamson called his Variac (variable mains unit with output meter) the technician’s best friend. Television was becoming a must-have and technology was SC adding more features each year. NEXT MONTH: Australian Television comes of age and valve technology reaches its peak. Credits and references are shown at: www.aaa1.biz/sc.html July 2006 23 m e r e h T i n i m 2 . k M Just move your fingers near the antennas of this Theremin to create your own electronic music or eerie science fiction sounds. It’s easy to build, easy to set up and easy to play. PART 1: By JOHN CLARKE Main Features • • • • • • • • • External pitch & volume span adjustments Linear pitch change with hand movement over four octaves Linear volume control with hand movement Three sound variation controls Signal level adjustment Internal loudspeaker with headphone listening option Loudspeaker/headphone volume control Line output with muting switch for amplifier connection 12V DC operation from plugpack or battery 24 Silicon Chip siliconchip.com.au min when it comes to playing a Theremin easily. It is also critical to ensure the same range of hand movement for each octave and that none of the octaves are compressed into a tight range (which would make playing difficult). As a result, this unit has been designed to provide excellent linearity when it is adjusted correctly. This has been made easier by a special test circuit that’s used when setting up the Theremin Mk.2. Tonal quality O UR ORIGINAL MK.1 THEREMIN was described in the August 2000 issue and has proved very popular. This new Mk.2 version features a better waveform, has more controls for adjusting the tonal quality and is easier to play, with more progressive hand control. So why are Theremins so popular. The answer is because of their extreme versatility and the uniqueness of the sound they produce, compared to conventional instruments. Even relatively simple hand movements can lead to complex and engrossing performances. Many Theremins produce only simple tones but some Theremins – such as the unit described here – also allow adjustments to the tonal quality, so that the performance can be altered to suit the mood. Typically, the controls allow a range of sounds that can be varied between raspy-edged tones through to pure sinusoidal notes. The resulting sound can consist of smooth gliding tones (glissandi) or it can comprise separate notes (staccato) or a combination of both. siliconchip.com.au It really is a versatile instrument that is only limited by the skill of the player. Controls In order to play a Theremin, you must you must be able to accurately position your hands (and fingers) to produce the required tones. The more accurate a Theremin is in producing the same frequency (or tone) for a given hand position (ie, distance from the antenna), the easier it will be to play. Similarly, the volume control needs to produce a consistent effect in response to hand movements. The SILICON CHIP Theremin Mk.2 has been designed to provide good consistency for both the pitch and volume “antenna controls”. In addition, two external controls have been provided (on the front panel) to adjust the pitch (Pitch Range) and volume (Volume Span) settings. These are required to compensate for any changes that may occur over long periods of time or because of temperature changes. The linearity of the response to hand movements is another critical feature Three further controls are included to adjust the tonal quality or “voice” of the Theremin. The most popular “voice” setting reproduces a cello sound at the lower frequencies, changing to a soprano voice at the upper frequencies. This tonal “voice” creates an interesting backdrop against other instruments, such as a piano or violin. If you are interested in hearing some fine Theremin performances, log onto http://www.peterpringle.com/thereminmp3s.html In operation, the “voicing” can be altered to suit using the Waveform, Symmetry and Skew controls. Each control produces its own characteristic variation in the sound. The Waveform control varies the shape of the signal reproduced by the Theremin. At various settings, the unit produces waveforms that are somewhat triangular in shape, while at other settings it produces either squarer wave shapes or more sinusoidal waves. Each wave shape has its own distinctive timbre, the squarer wave shapes producing a hollow sound similar to that produced by a reed instrument. The more triangular waveforms are less hollow, while the sinusoidal shapes gives a neutral or pure sound. The Symmetry control varies the shape of the waveform below the horizontal centre line. You can vary the waveform shape so that it is symmetrical above and below the centre line or so that the lower half of the waveform becomes more rounded. This rounding produces a sound characteristic of a bowed instrument such as the cello. Finally, the Skew control varies the waveform from being symmetrical July 2006 25 ➊ ➋ ➌ ➍ ➎ Above: these traces show the variety of waveforms that can be reproduced by the Theremin. The top four traces are all at 100Hz and show what can be done with just the waveform and symmetry controls, with the skew control set to minimum. Waveform 1 shows the output when the Theremin is set to produce a sinewave. The next waveform (2) is more distorted, with more triangle characteristics, while waveform 3 has a squarer wave shape. Waveform 4 shows what the skew control does to the signal at around 100Hz. As can be seen, it becomes very asymmetrical about the horizontal and vertical axis, exhibiting a more sawtooth wave shape. The final waveform (5) was obtained using the same settings that gave the waveform 4 but at a higher frequency of 250Hz, making it more sinusoidal in shape. This characteristic occurs for all waveform shapes at the higher frequencies. A filter adjustment sets the threshold point where the tone becomes more sinusoidal. to asymmetrical (ie, more sawtooth in shape) about the vertical axis. An asymmetrical wave shape produces a brighter, richer sound. 26 Silicon Chip Waveforms 1-5 show just some of the variety of waveforms that can be produced by the Theremin Mk.2. Note that all three tonal controls interact with one another, so that a whole array of subtle sound variations can be reproduced. These variations in the sounds are due to the harmonic content of the waveform. A pure sinewave comprises only the fundamental frequency and that is the only tone that you hear. If, for example, you play note A4, then you will hear a pure tone at 440Hz. Waveforms that are not pure sine waves include extra signals called harmonics. Harmonics are additional tones that are multiples of the fundamental frequency. So, for example, if you play note A4 again but produce a square wave, you will hear the fundamental 440Hz plus multiples of that frequency. Square wave harmonics are always odd and so you will hear the third harmonic (3 x 440Hz or 1320Hz), the fifth harmonic at 2200Hz and the seventh and ninth harmonics, etc. Note that the harmonic signal level is lower than that of the fundamental and diminishes with increasing frequency. In fact, the third harmonic is one third the level of the fundamental, while the fifth harmonic is one fifth the level, etc. Triangle waves also have only odd harmonics but the harmonic levels drop off much faster than the square wave harmonics. The third harmonic, for example, is only 1/9th the level of the fundamental and the fifth harmonic is 1/25th of the fundamental’s level. When the wave shape is skewed about the vertical axis to produce a sawtooth shape, or if the symmetry is altered about the horizontal axis, the harmonic content will include even and perhaps odd harmonics, depending on the waveform. Even harmonics are those that are twice the fundamental frequency, four times the fundamental, etc. These even harmonics give a stringed instrument sound effect and can enrich the sound produced by a square or triangle wave. Gain control The next control in the lineup is the Gain control. This is included to adjust the audio output level on the Theremin’s line output socket. It basically allows the output level to be correctly adjusted in response to different wave shapes. In practice, the line level output signal is fed out via a 6.35mm mono siliconchip.com.au Fig.1: the Theremin is based on three virtually identical oscillators plus a balanced mixer (IC1). The mixer accepts the signals from the pitch and reference oscillators and generates difference signals to produce the tones. These are then fed to the output stages via a voltage-controlled attenuator stage. jack socket. It can be switched on or off using the Muting switch. Power for the circuit comes from a DC plugpack. Monitoring Block diagram Normally, you would use the line output from the Theremin to feed an external amplifier and loudspeakers. However, the unit also features an internal amplifier and loudspeaker, which can be used for practice sessions (or as a foldback monitor during live performances). A headphone socket is also provided and this automatically disconnects the internal loudspeaker when the headphones are plugged in. OK, let’s now take a look at how the unit works. We’ll start with the block diagram which is shown in Fig.1. A balanced mixer (IC1) is at the heart of the operation. This accepts two signals: one from a reference oscillator (based on coil T1 and Mosfet Q1) and the second from a pitch oscillator (based on coil T2 and Mosfet Q3). The latter’s frequency is controlled using the pitch antenna, which is connected to the oscillator via an equalising coil. Typically, both the reference oscillator and the pitch oscillator are set to the same frequency, at about 455kHz. Any movement of the hand near to the pitch antenna will then alter its capacitance to ground and change the pitch oscillator’s frequency. In operation, the mixer produces several signals, depending on the incoming signals from the reference and pitch oscillators. These signals are: (1) the original reference oscillator signal (455kHz); (2) the sum of the reference and pitch oscillator frequencies; and (3) the difference between the pitch and reference oscillator frequencies. When the two oscillators are at the Presentation As shown in the accompanying photos, the SILICON CHIP Theremin Mk.2 is housed in a plastic case which in turn is mounted on a small camera tripod which serves as a desk stand. The pitch antenna sits vertically in the rear righthand corner of the box, while the volume antenna lies nearly horizontally on the lefthand side of the box. The various controls are arranged along the front face of the box, while the line output, headphone and DC supply sockets are located on the righthand side of the box, along with the power switch and a muting switch. siliconchip.com.au same frequency (eg, 455kHz), then the sum of the two frequencies will be 910kHz while the difference frequency will be close to zero. The mixer’s output is then fed to a low-pass filter which has a cutoff frequency of 3kHz. As a result, the 455kHz and 910kHz signals are filtered out, leaving only the difference signal. In this case, however, there will be no output since the difference signal is zero. However, when the pitch oscillator’s output frequency is lowered by moving the hand closer to the pitch antenna, the difference between the reference and pitch oscillators increases and we get an audible output. The lower the pitch oscillator’s frequency, the greater the difference frequency from the mixer and the higher the tone fed to the amplifier stages. For example, if the pitch oscillator is reduced to 454kHz, the difference frequency will be 1kHz and so we get a 1kHz audio output from the low-pass filter. If it goes down to 453kHz, we get a 2kHz audio output signal. In practice, the difference signal from the mixer ranges in frequency from 65.4Hz to 2093Hz, which is equivalent to five octaves. Equalising coil The equalising coil in series with July 2006 27 The Origin Of The Theremin I N 1919, A RUSSIAN PHYSICIST named Lev Termen (or Leon Theremin as he is called in the west) invented an electronic musical instrument called the “Theremin”. At that time, the Theremin was innovative and unique in the musical world and was essentially the first electronic instrument of its kind. Playing it was also unique, the technique relying solely on hand movements in the vicinity of two antennas to control two electronic oscillators – one antenna to vary the pitch of the sound and the other to change the volume. In operation, the pitch change afforded by the antenna is infinitely adjustable over several octaves, with the frequency increasing as the hand is brought closer to the antenna. An ear for pitch and fine hand control are essential requirements to become proficient at playing the Theremin. To a large extent, the Theremin has been made famous by recitalist Clara Rockmore. Born in Lithuania in 1911, she was an accomplished violinist by 5-years old. She began to learn to play the Theremin after meeting Leon Theremin in 1927 and ultimately developed a unique technique for playing the instrument. This technique involved minute finger movements to capture and modulate the tone of the note and enabled her to play the instrument with great precision. The Theremin was subsequently further developed and manufactured by the Radio Corporation of America (RCA) around 1929. This design consisted of a large box with an attached antenna and wire loop. The antenna provided the control for the pitch while the loop enabled the volume to be adjusted. In practice, the pitch control antenna was mounted vertically while the volume loop sat horizontally, to minimise interaction between them. And of course, the circuit used valves. General Electric (GE) and Westinghouse also made Theremins in the 1920s. However, the number of units produced was quite modest, with only about 500 units being made. Today, the Theremin is hailed as the forerunner to modern synthesised music and was instrumental in the development of the famous Moog synthesisers. Because of its unique sound, it has been popular with music producers for both film and live performances. For example, is was used to produce background music in “The Ten Commandments” feature film by Cecil B DeMille. Its eerie sounds have also made it ideal for science fiction movies, including “The Day the Earth Stood Still” and “ It Came From Outer Space”, and in thriller movies such as “Spellbound” and “Lost Weekend”. In addition, Bands such as the Bonzo Dog Band and Led Zeppelin have embraced the Theremin. The Beach Boys used an instrument similar to the Theremin – called an Electro-Theremin (also named a Tannerin) – in their famous “Good Vibrations” hit from the 1960s. The Electro-Theremin differs from the Theremin in that it incorporates a mechanical controller to adjust the pitch rather than hand movements relative to an antenna. Many commercial Theremins are available on the market today, including the Etherwave series from Moog Music Inc, PaiA’s Theremax and Wavefront’s Classic and Travel-Case Theremins. SILICON CHIP has also published two previous designs for home construction – ie, a basic Theremin in August 2000 and a MIDI Theremin in April and May 2005. the pitch antenna vastly improves the linearity of any frequency changes with hand movement. Without it, these frequency changes would be very non-linear – very large hand movements would be required to produce pitch changes at the low-frequency end, while only minute hand movements would be required at the highfrequency end. This “compression” of the frequency range for hand positions close to the antenna is due to the way a tuned circuit works. The variations 28 Silicon Chip in capacitance with hand movement are linear with the distance from the antenna. However, the frequency of a tuned circuit is inversely proportional to the square root of the capacitance. As a result, greater pitch variations occur for a given hand movement the closer we get to the antenna. Adding the equalising coil has the effect of reducing the hand movements required for the lower octaves and increasing the hand movements required for the upper octaves, so that the overall response is much more linear. When adjusted correctly, the resulting improvement in linearity is almost magical! Basically, the equalising coil works by setting up a resonant circuit. The resonant frequency is set to be just below the “at rest” frequency of the pitch oscillator and is based on the coil’s the inductance (about 10mH) and the capacitance of the antenna (about 12pF). The corresponding components in the pitch oscillator have an inductance of 560mH and a capacitance of 220pF (both inside coil T2). Any hand movement near the antenna will increase its capacitance and thus cause a reduction in the resonant frequency. However, this frequency shift will be much greater than the corresponding frequency change of the pitch oscillator. That’s because the effect of hand capacitance (just a few picofarads) is far greater on the 12pF antenna capacitance than it is on the much larger 220pF capacitor in parallel with the pitch oscillator coil. The overall effect is that your hand has a progressively smaller effect on the pitch oscillator as it is brought closer to the antenna. This introduced non-linearity counteracts the inherent non-linearity of the pitch oscillator and makes pitch changes much more linear for given hand movements. Waveform shaping The wave shape of the output is controlled using the Waveform, Symmetry and Skew potentiometers (VR3-VR5). Both the Waveform and Symmetry controls work by changing the DC bias levels on both the signal and carrier inputs of the mixer. A different bias voltage affects the wave shape that’s applied to a particular input of the mixer and this changes the resulting output waveform. Note that buffer stages (Q2 & Q4) are included in series with the outputs of the reference and pitch oscillators before the signal is applied to the mixer. These isolate the oscillators from the DC bias voltages at the mixer inputs, to prevent unwanted changes to the oscillator frequencies. The Skew adjustment varies the coupling between the pitch and reference oscillators, in turn varying their tendency to lock to the same frequency. When both oscillators are running close to the same frequency, increasing the skew control will cause the two oscillators to lock and so their siliconchip.com.au Fig.2: this graph shows the response of the bandpass filter. It reduces the signal level as the frequency of the volume oscillator decreases. output frequencies will be the same. However, if extra hand capacitance forces the pitch oscillator to change, it will suddenly “snap” to a different frequency. At the same time, the reference oscillator will continue to have an affect and so the resulting output waveform from the mixer will be skewed. Low-pass filter As mentioned, the adjustable lowpass filter following the mixer output removes the higher frequencies from the mixing process, leaving only the difference frequency. Its frequency of roll-off can be varied from 3.3kHz down to 592Hz, depending on the effect required. Following this filter, the signal is fed to an attenuator and then to amplifier stage IC3. This stage has a gain of between two and seven, depending on the setting of gain control VR6. The output from IC3 then goes to the Line Out socket via Muting switch S2. It also goes to power amplifier IC4 via volume control VR7. The power amplifier then drives an internal loudspeaker or a pair of headphones. Volume control oscillator The volume oscillator is based on transistor Q5 and transformer coil T3. As with the pitch oscillator, its frequency varies in response to hand movement. In operation, its frequency reduces as the hand is brought closer to the volume antenna. The resulting signal is then fed to a bandpass filter that rolls off signals above and below its centre frequency. Fig.2 shows the response siliconchip.com.au Fig.3: this is the basic arrangement for the equalising coil tester. It allows the pitch oscillator to be correctly adjusted so that the equalising coil and pitch antenna resonate, as indicated by a voltage dip on the output meter. shape of this bandpass filter. The bandpass filter is set so that its centre frequency is above the frequency range of the volume oscillator – ie, the frequency of the volume oscillator is to the left (or lower frequency side) of the peak in the filter response curve. Therefore, as the oscillator’s frequency decreases, the filter reduces the signal level. The output from the bandpass filter is fed to a slope detector based on diode D3. This converts the signal to a DC voltage which is then applied to a level-shifting amplifier based on IC5. Its output in turn controls the audio attenuator stage. Equalising coil tester Finally, we come to the equalising coil tester which is attached to the pitch oscillator. This tester allows the equaliser coil to be checked with the pitch oscillator, to verify that its value is correct. Fig.3 shows the basic arrangement. In operation, the pitch oscillator’s output is lightly coupled to the pitch antenna via the equalising coil. The oscillator frequency is then is adjusted until the following level detector circuit detects the resonance, as indicated by a voltage dip on the meter. Circuit details OK, that covers the basics. Now let’s take a look at the complete circuit diagram – see Fig.4. The first thing to note is that all three oscillators (Reference, Pitch and Volume) are virtually identical. Each oscillator is based on a junction FET (Q1, Q3 & Q5) and a standard IF (intermediate frequency) transformer coil (T1-T3), as used in low-cost AM radio tuners. Each transformer includes a tapped primary winding and a parallelconnected capacitor to form a tuned circuit. Its corresponding JFET drives a portion of the primary winding (ie, between the pin 2 tap connection and ground), while the signal at the top of the primary is coupled to the gate (which is self-biased) via a 68pF capacitor. This arrangement provides positive feedback to maintain oscillation at the tuned frequency. In the case of the reference oscillator, transformer T1 is tuned to produce an output frequency of about 455kHz. Power for the circuit comes from a +8V rail and this is applied to Q1’s drain via potentiometer VR2 and a 220W resistor. VR2 provides pitch adjustment by varying the drain to source current flow through Q1. This alters the gateto-source voltage and thus Q1’s gateto-source capacitance. And this in turn alters the tuned frequency. T1’s secondary winding at pins 4 & 6 provides a low impedance output from the oscillator. This output is then further buffered using an amplifier stage based on JFET Q2 which is configured as a source follower. This buffering is essential to isolate the oscillator from the following stages, so that it is immune to any capacitance changes caused by varying the bias levels at the inputs to IC1. The pitch oscillator is almost identical, the main difference being the use of a fixed 680W resistor in Q3’s drain circuit. In addition, the pitch antenna July 2006 29 Fig.4: the complete circuit for the Theremin Mk.2. Each oscillator is based on a junction FET (Q1, Q3 & Q5) and a standard IF transformer coil (T1-T3). IC1 is the balanced mixer – it produces the difference signal and feeds this to the audio output stages via an attenuator (OPTO1), in turn controlled by the volume oscillator and its following stages. 30 Silicon Chip siliconchip.com.au is connected to pin 1 of transformer T2 via a 1nF capacitor and the equalising coil (L1). The equalising coil test circuit is also attached to this part of the oscillator circuit during testing. In this case, the oscillator signal at pin 1 of transformer T2 (marked “Test”) is coupled into the pitch antenna via a 100kW resistor. This resistor ensures only minimal loading of the equalising coil and antenna tuned circuit. Diode D2 and the 10nF capacitor form a peak detector and this allows us to measure the relative level of the signal across the equalising coil and pitch antenna. The associated 100kW resistor across the 10nF capacitor helps to discharge the capacitor, so that the voltage on D2’s cathode drops with decreasing signal level. In practice, the ferrite slug inside T2 is adjusted so that pitch antenna and equalising coil resonate. We’ll describe how this is done in Pt.2. siliconchip.com.au The volume oscillator is similar to the pitch oscillator but also includes a variable drain supply. This is provided by potentiometer VR1, which is the volume range (or volume span) adjustment. The volume antenna is connected to pin 1 of T3 via a 1nF capacitor. Mixer The reference and pitch oscillator signals from buffer stages Q2 and Q4 are applied via 1nF capacitors to pins 1 (signal) and 10 (carrier) of IC1 respectively. However, the signal applied to the carrier input is reduced to around 50mV using a resistive divider at the source of Q4. This reduction in signal level is necessary to prevent overloading the mixer stages of IC1. IC1’s signal inputs at pins 1 & 4 and its carrier inputs at pins 8 & 10 are biased using potentiometers VR3 and VR4 respectively. Note, however, that any signal applied to pins 4 and 8 is shunted to ground via 100nF capacitor. In other words, these pins are simply DC biased. The DC bias range provided by VR3 & VR4 is set by the outputs of buffer stages IC2a-IC2d. These op amps are all wired as voltage followers and each buffers a sampled voltage from the +9V rail, as set by trimpots VR8-VR11. In effect, each buffer pair sets the maximum and minimum bias voltages and applies these to its corresponding potentiometer (VR3 & VR4). This ensure that VR3 and VR4 only provide the range of control that is necessary to produce the varied waveforms. A 1kW resistor between pins 2 and 3 of IC1 sets the gain of the mixer, while the bias voltage at pin 5 sets output signal level. The balanced mixer outputs appear at pins 6 and 12. Each output is biased on using 2.2kW pull-up resistors and is filtered to remove the high-frequency components. The output at pin 6 has a fixed July 2006 31 Par t s Lis t 1 PC board coded 01207061, 188 x 103mm 1 plastic UB2 utility case, 197 x 113 x 63mm 1 12V DC 450mA plugpack 1 190 x 105mm aluminium sheet (1mm thick) 1 100mm 4W 2W loudspeaker 2 high-quality stereo switched 6.35mm jack sockets, PCmount (Jaycar PS-0195) 1 2.5mm PC-mount DC socket 2 SPST ultra-mini rocker switches (S1,S2) 1 mini tripod (Jaycar AM-4112 or similar) 1 mini heatsink, 19 x 19 x 10mm 1 M4 x 25mm Nylon screw 1 M4 nut 9 M3 x 6mm screws 9 M3 nuts 3 4mm eyelet crimp connectors 4 4.8mm female spade connectors 7 plastic knobs to suit (do not use metal knobs) 20 PC stakes 1 400mm length of 0.7mm tinned copper wire 1 12m length of 0.25mm enamelled copper wire 1 250mm length of medium duty hook-up wire 1 green banana socket 1 11mm OD x 4mm ID x 2.5mm Nylon spacer or similar (eg, 3 x M4 Nylon washers) 1 300mm length of green hook-up wire Transformers and ferrites 2 pot cores, 26 x 11.5 x 8mm (Al of 4740) (Jaycar Cat. LF-1060 low-pass filter consisting of a 22nF capacitor to ground. By contrast, the output at pin 12 is connected to an adjustable low-pass filter consisting of VR13 and a 22nF capacitor. As stated previously, its roll-off frequency can be continuously adjusted from 3.3kHz (VR13 set to 0W) down to 592Hz (VR2 at 10kW). Volume control Following the low-pass filter, the signal is AC-coupled to a 100kW resistor in series with the pin 3 input of amplifier stage IC3. This input is biased 32 Silicon Chip or equivalent) (L1) 1 bobbin to suit above cores (Jaycar Cat. LF-1062 or equivalent) 3 low-cost 455kHz 2nd IF transformers (white slug) 1 low-cost 455kHz 3rd IF transformer (black slug) Potentiometers & trimpots 2 16mm 1kW linear PC-mount potentiometers (VR1,VR2) 3 16mm 5kW linear PC-mount potentiometers (VR3,VR4,VR6) 1 16mm 10kW linear PC-mount potentiometer (VR5) 1 16mm 10kW log PC-mount potentiometer (VR7) 4 10kW multi-turn top-adjust trimpots (code 103)(VR8-VR11) 1 5kW multi-turn top-adjust trimpot (code 503) (VR12) 1 10kW horizontal trimpot (code 103) (VR13) 1 2kW multi-turn top-adjust trimpot (code 203) (VR14) Antenna Parts 1 375mm length of 16mm diameter plated steel or stainless steel tubing 1 125mm length of 16mm diameter plated steel or stainless steel tubing 2 chromed towel rail end brackets to suit above tubing 2 16mm ID plastic end caps 1 miniature tripod with ¼-inch mount (Jaycar AM-4112 or AM4110) 2 M4 x 10mm screws 2 M4 x 15mm screws 4 M4 nuts 1 ¼-inch Tee nut to 4.5V via the 10kW voltage divider resistors across the 9V supply and a second 100kW resistor. This allows the op amp to produce a symmetrical output voltage swing before clipping. The 4.5V bias supply is decoupled using a 100mF electrolytic capacitor to remove any signal ripple. The signal level applied to pin 3 of IC3 is controlled by OPTO1 which is an opto-coupled LDR (light dependent resistor). This in turn is controlled by the volume oscillator and its following circuitry. As shown, the LDR is connected between pin 3 of IC3 and Semiconductors 1 MC1496 balanced modulator (IC1) 1 LM324 quad op amp (IC2) 1 TL071 JFET input op amp (IC3) 1 LM386 1W power amplifier (IC4) 1 7809 9V 1A regulator (REG1) 1 7808 8V 1A regulator (REG2) 5 2N5484 or 2N5485 JFETs (Q1-Q5) 1 BC337 NPN transistor (Q6) 1 BC327 PNP transistor (Q7) 3 1N4148 diodes (D1-D3) 1 1N4004 1A diode (D4) 1 NSL-32SR3 optocoupler (Silonex) (OPTO1) Farnell Cat. 369-2218 1 5mm red LED (LED1) Capacitors 1 1000mF 16V PC electrolytic 1 470mF 16V PC electrolytic 3 100mF 16V PC electrolytic 7 10mF 16V PC electrolytic 1 2.2mF 16V PC electrolytic 1 220nF MKT polyester 8 100nF MKT polyester 1 47nF MKT polyester 2 22nF MKT polyester 6 10nF MKT polyester 4 1nF MKT polyester 1 470pF ceramic 3 330pF ceramic 3 68pF ceramic Resistors (0.25W 1%) 1 330kW 2 680W 10 100kW 1 330W 1 47kW 2 220W 2 22kW 1 150W 4 10kW 3 100W 1 4.7kW 1 39W 4 2.2kW 3 10W 6 1kW the 4.5V rail. Normally, the LDR has negligible effect on the signal since its resistance is considerably higher than the 100kW resistor at pin 3 of IC1. However, when current flows through the LED in OPTO1, the resistance of the LDR falls. This shunts signal from pin 3 to the 4.5V rail. In operation, the LDR has a resistance range from about 25MW down to 60W, giving an attenuation range from 0db to -64dB. As discussed previously, hand movements over the volume antenna siliconchip.com.au Building the Theremin Mk.2 is straightforward, with all but a few parts mounted on a single PC board. The full constructional details will be in Pt.2 next month. control the amount of attenuation. It works as follows. First, the signal from the volume oscillator (T3 & Q5) is fed to the bandpass filter which is based on transistor Q6 and tuning coil T4. T4 is tuned so that the output signal at its pin 6 decreases in level as the volume oscillator frequency decreases (ie, as the hand moves closer to the volume antenna). Diode D3 rectifies this signal and its output is filtered using a 2.2mF capacitor to provide a DC voltage. The associated 10kW resistor across the capacitor provides a discharge path, thus allowing the voltage across the capacitor to fall if the signal level falls. This voltage is fed to IC5b which is wired as a non-inverting amplifier and level shifter. Trimpot VR14 adjusts the output offset of the amplifier, so that it can be set to vary from about 8V down to nearly 0V with hand movement. IC5b’s output appears at pin 7 and drives PNP transistor Q7 which is wired as an emitter follower. This in turn drives the LED within OPTO1 via a 330W resistor. The anode side of the LED is connected to the 8V supply. Note that there are two supply rails – siliconchip.com.au ie, 8V and 9V. Op amp IC5 is powered from the 9V supply while the LED is powered from the 8V supply. The 1V extra for the op amp is to ensure that IC5b’s output can swing high enough to switch Q7 and the LED fully off. Power amplifier IC4 is also powered from the 9V rail while the more “voltage sensitive” sections of the circuit are powered from the 8V rail. This separation of supply rails ensures that IC4 can drive the loudspeaker at full power without affecting other parts of the circuit. Op amp IC3 buffers the attenuated signal and also provides gain that can be varied from 2-7, depending on the setting of Gain control VR6. The 10nF capacitor between pins 2 & 6 rolls off high frequencies to prevent instability. IC3’s output appears at pin 6 and is AC-coupled to mute switch S2 in series with the line output socket (CON1). The series 150W resistor serves to isolate IC3’s output from the load connected to the line out. IC3’s output is also fed to volume control VR7 via a 10mF capacitor. From there, the signal goes to pin 3 of power amplifier IC4 via a 220nF ca- pacitor. IC4 then drives the Theremin’s loudspeaker or a pair of headphones via a 1000mF capacitor and connector CON2. Plugging the headphones into CON2 automatically disconnects the loudspeaker. Note that a Zobel network comprising a 10W resistor and 47nF capacitor is connected across IC4’s output. This is done to prevent oscillation in the amplifier. Power supply Power for the circuit is derived from a 12V DC plugpack. This is fed in via power switch S1 and diode D4 which provides reverse polarity protection. LED 1 provides power on/off indication, while a 470mF electrolytic capacitor filters the supply rail before it is applied to 3-terminal regulators REG1 and REG2. REG1 and REG2 respectively provide the regulated +9V and +8V supply rails. Their outputs are decoupled using 10mF capacitors. That’s all we have space for this month. Next month, we will give the full construction details and describe the setting-up and adjustment proceSC dures. July 2006 33 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au Easy-to-build de s i g n h a s t w o i n dep en den t l y programmable relay outputs By GREG RADION Low-Cost Analog On-Off Controller Have you ever wanted to control a device based on an analog signal level? Perhaps you want to fill a water tank automatically or control exhaust fans based on humidity or temperature. Well now, you can – provided you have a sensor that gives an analog voltage or current output. T his Analog On-Off Controller unit switch es two independent relays based on the signal level at its input. The “on” and “off” levels for each relay are easily set using only a screwdriver and you can monitor the level of the signal on an LCD panel meter if desired. With its fully adjustable design, the controller accepts inputs in the range of 0-10V or 0-20mA. Its current input capability also means that it can be used with industrial sensors 40 Silicon Chip that provide a 4-20mA current loop interface. Best of all, this unit can be put together for about $65.00 and is very easy to build. All the parts are mounted on two PC boards which are stacked together and connected using rainbow cable. How it works The Analog On-Off Controller is essentially a group of voltage comparators with additional circuitry to translate input signals to a usable voltage range, as well as flipflops to hold the two outputs in their last “on” or “off” state. The complete circuit for the controller appears in Fig.1. Apart from op amp IC1 and relays REL & REL2, the circuit is powered via a 7805 +5V regulator (VREG1). Diode D1 is included in series with the 12V input to protect against supply polarity reversal. An LT1014 precision op amp (IC1c) buffers the input signal. This op amp siliconchip.com.au siliconchip.com.au July 2006 41 Fig.1: the input signal is buffered and normalised to a 0-1V level by an LT1014 quad precision op amp (IC1). The signal is then split into two channels, each consisting of two LM339 voltage comparators with independently programmable rising and falling threshold levels. A pair of D type flipflops provides a setreset function to hold the last event and drive the business end – two high-current relays. is connected as a differential amplifier with unity gain, as determined by the four 200kW resistors used in its input and feedback networks. Jumper JP6 is installed when the controller is used with a current loop type sensor, thus allowing current to flow through the 62W resistor and generate a voltage between the differential inputs. The output from IC1c is fed into a second op amp (IC1d), also configured as a differential amplifier. In this case, a 50kW trimpot (VR1) takes the place of two resistors in the amplifier’s input network, allowing it to be trimmed for a gain of 0-2. This is used to scale the input signal to 1V full-scale ahead of the comparator network. For example, when operating with a 0-20mA input range, the gain would be adjusted to produce 1V at the op amp’s output with 20mA of loop current. For a 0-5V input range, the gain would be adjusted to produce 1V out with 5V in. For a 4-20mA input range, the gain would be adjusted to produce 1.25V with 20mA in. An offset of 0.25V (adjustable with VR2) can be applied to the inverting input via JP2 to subtract from the signal on the non-inverting input, thus producing 0-1V (representing 0-100% of scale) at the output. A simple shunt regulator comprised of a 3.3V zener diode (D2) and 5.6kW resistor forms a stable reference for the circuit. The regulator’s output feeds two 20kW trimpots (VR2 & VR3), with their wiper voltages buffered by two unity-gain op amps (IC1a & IC1b). VR3 is trimmed for 1V at the output of IC1b (pin 7). Further, the reference voltage for each comparator can be adjusted within the 0-1V range using trimpots VLO1, VHI1, VLO2 & VHI2. The outputs of comparators IC2b and IC2c will go high (near +5V) when the voltage at their non-inverting in- Fig.2: follow this parts layout diagram and the screened printing on the PC board during assembly. Leave out the two LEDs (L1 & L2) and links JP4 & JP5 if you’ve purchased the optional display panel! Table 1: Resistor Colour Codes o o o o o o o o No. 6 4 2 10 5 2 1 42 Silicon Chip Value 10MW 200kW 100kW 10kW 5.6kW 2.2kW 62W 4-Band Code (1%) brown black blue brown red black yellow brown brown black yellow brown brown black orange brown green blue red brown red red red brown blue red black brown 5-Band Code (1%) brown black black green brown red black black orange brown brown black black orange brown brown black black red brown green blue black brown brown red red black brown brown blue red black gold brown siliconchip.com.au Par t s Lis t 1 double-sided PC board, 87 x 107mm 2 3-way 5.08mm 10A terminal blocks 3 2-way 5.08mm 10A terminal blocks 2 7A/240VAC relays with 12V DC coils 1 12-way 2.54mm DIL header strip (break in half for 2 x 6-way strips) 1 3-way 2.54mm SIL header strip (JP1/JP2) 5 jumper shunts 3 14-pin IC sockets 1 50kW 10-turn trimpot (VR1) 2 20kW 10-turn trimpots (VR2, VR3) 4 2kW trimpots (VHI1, VLO1, VHI2, VLO2) This is the fully assembled controller board. Check the text for the various linking options. puts is greater than that of the reference level on their inverting inputs. Conversely, the outputs of IC2a and IC2d will go high when the voltage at their inverting inputs is less than that of the reference level on their non-inverting inputs. A high value (10MW) resistor is used to feed a small amount of each comparator’s output signal back to its input, eliminating oscillations near the switching point. Each comparator pair drives the “set” and “reset” inputs of a D type flipflop (IC3a & IC3b). A high from the comparator connected to the set input will cause the Q output to latch high, biasing its associated transistor into conduction and energising the relay. Conversely, a high on the reset input causes the Q output to go low, switching off the relay. As shown, the outputs of each comparator pair can be steered to either flipflop input, depending on the position of the A and B jumpers. This allows each output to be switched on or off on a rising or falling input signal level. Finally, the flipflops’ clock inputs are connected to simple RC networks so that a short positive-going pulse is applied at power up. As the D inputs are grounded, this ensures that the Q outputs are reset (low) at startup and that both relays are initially off. calibrated to suit the intended application. All you need is a digital multimeter and a voltage (or current) source set to the maximum input signal level. To begin, connect a 12V DC power supply to the Vs and COM inputs. Remember to disconnect power when making jumper or link changes. Calibration and setup • • Before use, the controller must be siliconchip.com.au For 4-20mA operation: • • • • • • • Install a link at JP6. Install a jumper in the JP1 position. Supply 20mA to the inputs (IN+ & IN-). Adjust VR1 to give 1.25V at TP1. Move the jumper at JP1 to position JP2. Adjust VR2 to give 1.00V at TP1. Adjust VR3 to give 1.00V at TP6. For 0-20mA operation: • • • • • Install a link at JP6. Install a jumper in the JP1 position. Supply 20mA to the inputs (IN+ & IN-). Adjust VR1 to give 1.00V at TP1. Adjust VR3 to give 1.00V at TP6. For 0-5V (or 0-10V) operation: • • • Remove link at JP6. Install a jumper in the JP1 position. Supply 5.00V (or 10.00V for 0-10V operation) to the inputs (IN+ & IN-). Adjust VR1 to give 1.00V at TP1. Adjust VR3 to give 1.00V at TP6. Semiconductors 1 7805 +5V regulator (VREG1) 1 LT1014 quad precision op amp (IC1) 1 LM339 quad comparator (IC2) 1 4013 dual flipflop (IC3) 3 1N4004 silicon diodes (D1,D3, D4) 1 1N4728 3.3V zener diode (D2) 2 BC548 transistors (Q1, Q2) 2 3mm red LEDs (L1, L2) Capacitors 1 100mF 35V electrolytic 10 100nF 50V monolithic ceramic Resistors (0.25W, 1%) 6 10MW 5 5.6kW 4 200kW 2 2.2kW 2 100kW 1 62W 10 10kW Parts For Optional Display Panel 1 PC board, 57 x 107mm 1 PM128E LCD panel meter 1 DPDT mini toggle switch 1 single pole 12-way rotary switch 1 knob to suit above 4 6mm M3 screws 4 20mm M3 screws 4 10mm M3 tapped spacers 4 25mm M3 tapped spacers 150mm length of 16-way ribbon cable Once calibration is complete, each relay can be set to operate on either a rising (jumper in position in “A”) July 2006 43 actly the same manner using test pads HI2 and LO2 and trimpots VHI2 and VLO2, respectively. Front panel add-on This view shows the controller board wired to the optional front-panel display board. The display board carries an LCD panel meter which makes it easy to adjust the on/off trip levels without using a multimeter (see Fig.3 for the wiring details). or falling (jumper in position “B”) input signal. The rising and falling trigger levels can then be set for both outputs. To set the rising (high) level for the first relay output, measure the voltage at the test pad labelled “HI1” and adjust it using trimpot VHI1. A reading of 0.8V will mean that the relay switches on at 80% of the maximum input signal, while 0.6V equates to 60%, etc. To set the falling (low) level for the first relay output, measure the voltage at the test pad labelled “LO1” and adjust it using trimpot VLO1. A reading of 0.2V will mean that the relay switches off at 20%, while 0.3V equates to 30%, etc. The other output is adjusted in ex- The Analog On-Off Controller can be ordered with an optional LCD front panel, allowing convenient adjustment and monitoring of the unit without the use of a multimeter. The front panel consists of an LCD panel meter mounted on a small section of PC board alongside a 5-position rotary switch and a toggle switch. Two LEDs are also provided to indicate relay activation. The panel mounts above the main board on four 35mm spacers. Rotating the switch through its five available positions shows the input current/voltage level as a percentage of the maximum, as well as the programmed on and off points of each of the relays. Setting of the four switching levels is easily performed with the front panel meter. Simply rotate the switch through positions Hi1, Lo1, Hi2 and Lo2 and adjust trimpots VHI1, VLO1, VHI2 and VLO2 as described earlier. Note that VR1, VR2 and VR3 are set during initial calibration and must not be altered here. The “duty” switch on the front panel swaps the on and off levels of Relay 1 with those of Relay 2. This is useful when a “duty” and “standby” setup is required, allowing the operation of two devices to be periodically swapped to ensure even wear. Example application The Analog On-Off Controller has a large range of potential applications. Let’s look at a couple that involve water pumping. For example, suppose two pumps are to be used to fill a water tank. The “duty” pump (connected to relay 1) could be set to start when the level drops below 40% and stop when it rises above 65%, whereas the “standby” pump (connected to relay 2) could start at 35% and stop at 70%. Table 1: Application Examples Operation Relay 1 Relay 2 Two pumps filling a tank Duty pump Standby pump A (falling) Two pumps emptying a tank Duty pump Standby pump B (rising) 44 Silicon Chip Jumper Block 1 Jumper Block 2 Hi1 Lo1 Hi2 Lo2 B (falling) 65.0 40.0 70.0 35.0 A (rising) 60.0 50.0 70.0 55.0 siliconchip.com.au Fig.3: here’s how to wire the display board to the controller. Leave enough wire length to allow the two boards to be stacked together later. Note that several links (circled in red) must be placed on the LCD panel meter before use. In four places, the pads can simply be shorted with blobs of solder. For the “P1” position, a short length of wire will be required instead. A similar example can be given for emptying a tank. Suppose that the “duty” pump starts at a level of 60% and stops when the level falls below 50%, whereas the “standby” pump starts when the level reaches 70% and stops when it falls below 55%. Table 1 shows the settings required for these two examples. Extended operation In some applications, more than two devices must be controlled from a single input signal. For example, you may have a duty pump switching on at 80% and two standby pumps switching on at 85% and 90%. This is easily accommodated by installing a second controller and making a few minor changes. First, connect the “VOUT” terminals of the two controllers together. The input signal is then connected to the first controller only, while link JP3 is removed from the second controller. Assembly Before starting construction, note that the two LEDs and links JP4 & JP5 siliconchip.com.au must not be installed if you will be fitting the optional display panel. Using the overlay diagram in Fig.2 as your guide, begin by installing wire links in place of jumpers JP3-JP6, noting that JP3 is only fitted when using a current loop input. Next, install 3-way header pins for jumpers JP1 & JP2 and 6-way headers for jumper blocks “1” and “2”. The resistors, capacitors, diodes (D1-D4) and transistors (Q1 & Q2) can all go in next. Note that resistor R6 (shown in red in Fig.2) is not required – just leave this location empty. Take care with the orientation of the 100mF electrolytic capacitor – be sure to align its positive lead with the “+” marking on the overlay. In addition, the banded (cathode) ends of the diodes and the flat sides of the transistors must be oriented as shown. After this, solder in the trimpots (VR1-VR3, VLO1, VHI1, VLO2 & VHI2), LEDs (L1 & L2), voltage regulator (VREG1) and IC sockets. Again, take care to ensure that all these parts are correctly orientated. Don’t plug in Suggested Uses For The Controller The Analog On-Off Controller could be used to: • Operate one or two pumps based on the level in a tank or well. • Operate pumps in a duty-standby arrangement. • Regulate pressure using a compressor and a pressure sensor. • Control a heating or cooling appliance using a temperature sensor. • Regulate humidity using exhaust fans and a humidity sensor. • Control chemical dosing, given an appropriate sensor. • Almost anywhere that an analog signal level can be used to turn a device on and off. July 2006 45 The display board is wired to the main controller board using short lengths of rainbow cable. The two boards are then stacked together using spacers – see Fig.4. Fig.4: the display panel board is mounted above the main board on four 35mm tapped spacers, in turn assembled from shorter 25mm and 10mm items. Here’s how it goes together. the ICs until after you’ve checked the power supply. All that remains now are the terminal blocks and relays; install these now and perform a final check of your board before applying power. Now connect a 12 DC source to the Vs and COM terminals and measure the voltage at the output of the regulator, accessible at pins 7 & 14 of IC3’s socket. Obviously, the supply rail should measure 5V (±5%). If all is well, power off and insert the IC’s in their sockets, noting that the notched (pin 1) ends must be oriented as shown. Display panel The optional display panel is as- Where To Buy A Kit Of Parts The Analog On Off Controller was developed by Ocean Controls, who retain the design copyright. The controller is available as a kit of parts or preassembled and tested. Prices at time of publication were: Analog On-Off Controller kit: $59 +GST ($70 +GST assembled). Analog On-Off Controller kit and Display Panel kit: $84 +GST ($99 assembled, $119 with IP65 box). PM-128E Panel Meter (included with the Display Panel option): $20 + GST. Note that these prices do not include postage charges. Check out the Ocean Controls website at www.oceancontrols.com.au for more information or phone (03) 5983 1163 to order. 46 Silicon Chip sembled next. The PC board provides pads for just two 3mm red LEDs – so install these first. The anode side of the LEDs (indicated by the longer lead) goes into the holes marked with a “+” on the silkscreen. Leave about 5-10mm of length when trimming the leads, so that wires can be attached later. Once the LEDs are in place, mount the LCD panel meter, rotary switch and toggle switch. Note that the rotary switch must be programmed for 5-position operation before mounting. This is easily achieved by inserting the tab of the ring in hole “5”, so that the switch can only be rotated through the first five positions. Before use, five links must be installed on the LCD panel’s PC board, as shown in Fig.3. Short links J1, J2, DC and 2V with blobs of solder. A wire link will be required to connect “P1” to the “ON” side. Short lengths of ribbon cable can now be used to connect the two boards together, as depicted in Fig.3. That done, mount the display assembly above the main board using tapped spacers and screws as shown in Fig.4. Your Analog On-Off Controller is now ready for use. Remember, if you are going to use it to switch 240VAC mains voltages, the wiring must be installed by a licensed electrician. SC siliconchip.com.au PRIZED VALUE AT $399! SUBSCRIBE TO THIS... ...AND YOU COULD WIN THIS! A 20MHz dual trace oscilloscope from Dick Smith Electronics Every reader who takes out a new subscription this month (printed edition only), or renews an existing print edition subscription, goes into a draw to win a brand spanking new dual-trace 20MHz oscilloscope, as reviewed in the March 2006 edition of SILICON CHIP (p62), each valued at $399.00! You could be the envy of all your friends if you had this fine instrument on your workbench. 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I wish to subscribe for Start my subscription from the o next issue or o ............................. issue and enter me in the draw for the oscilloscope! o 2 years ($160) o 2 years with 2 binders ($186.00) o 1 year ($83.00) o 1 year with binder ($96.50) *these prices valid for Australian subscribers only. NZ subscribers will be included in the draw but subscription rates are slightly higher. Please refer to the order form in this issue. Enclosed is my cheque/money order for $______or please debit my: o Bankcard o Visa Card o Master Card We make it easy to subscribe! Card No. Signature ___________________________ Card expiry date_____ /_______ Mail this form (or a copy) to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Name ______________________________ Phone No (___) _____________ Or fax PLEASE PRINT your details to (02) 9979 6503 (inc credit card!). Street _________________________________________________________ Or email the same details to silicon<at>siliconchip.com.au Suburb/town _______________________________ Postcode _____________ July 2006 47 Or log onto siliconchip.com.au and click on “print edition” siliconchip.com.au email: __________________________________________________________ Or call (02) 9979 5644 & quote your credit card details SERVICEMAN'S LOG Looks like a duck, quacks like a duck . . . There’s an old saying that if it looks like a duck, quacks like a duck and has feathers like a duck, then you’ve probably got a duck. If only faults in TV sets were so easy to recognise, although I did recently track down a fault by lightly feathering it with my paintbrush! A Mitsubishi CT-2900AM TV set was fortunately brought into the workshop with a ticklish problem. I say fortunately because I am sure I would not have been able to solve this problem in the customer’s home. The problem was intermittent no horizontal or vertical synchronisation. Worse still, it was so random that it was hard to make it happen to order. Usually, a set as old as this will be starting to become unreliable, with leaky electrolytic capacitors and dry joints. However, this set was pretty good on both counts – its owner had 48 Silicon Chip been sparing with the whip. A glance at the circuit shows that the composite video leaves the AV switching IC (IC251) and goes through Q204 and Q605 to Q207 and then on to pin 33 of the jungle IC (IC201, LA7680). I connected an oscilloscope to pin 33 and eventually caught the lack of signal arriving there. At this stage, I really felt it would be a piece of cake tracking this down with the weapons I had at hand – namely Mr Heater and Mrs Freezer, plus the arbitrator CRO. The problem was that heating and freezing didn’t produce any effect that was measurable and tapping the board gave me no clues either. In the end, I used a small paintbrush which I gently feathered over the components between the two ICs. My reasoning was that the soft bristles might affect the circuit and give me a clue and I was in luck. Gradually, this lead me to coil L211 on the base of the video amplifier transistor Q207. I couldn’t fault it visually but it turned out to be dry-jointed to the solder that covered its leads. Resoldering it fixed the problem. My overall experience with this set is that it has been exceptionally reliable and is a good performer. The only other fault I have had with it that is worth mentioning is a “no-sound” symptom, caused by a leaky diode (D722) to microprocessor IC701 which affected the muting circuits. Intermittent Sanyo A similar intermittent problem occurred with a Sanyo CPP2930 (A8A29 chassis). The set arrived in the workshop dead but the client told our CEO (Mrs Serviceman) that the set was intermittently producing “a line before going off”. siliconchip.com.au Unfortunately, the critical part of this otherwise excellent description was not given: was the line vertical or horizontal? I was unable to find out because our client had promptly gone on holiday and was unavailable for two weeks. It didn’t take too long to work out that the line output transistor (Q403, 2SD1879) was short circuit. I didn’t have one so I stuck in a BU508DF which did the trick. I also noticed several dry joints around the horizontal drive transformer and resoldered them. Feeling pretty sure that I had correctly diagnosed and solved the problem, I put the set on the soak test trolley and moved on. But then, a couple of days later, just as it was getting towards “beer-o’clock”, I looked at the set and noticed it was pulsating on and off. My first impulse was to hit it but bashing the set made no difference, except that it made me feel better. I then removed the back and switched it on, whereupon the set promptly refused to fail again. I then tried heating and freezing it, especially around the new line output transistor, but it made no difference. I even covered the whole set with a blanket in an attempt to overheat it and it still worked. OK, so it was going to play dirty. I put the back on properly and a few hours later it failed again. Ah-hah – a faulty cabinet back! I just knew it! The question was, was it short circuit or open circuit? Infuriated by now that I was unable to get even close to what the problem was, I decided to pull the chassis out and completely dismantle it. It turned out to be a good decision. With the chassis under a “maggie” lamp, I found a number of very fine dry joints around the vertical output IC (IC501) and also around some of the interconnecting plugs and sockets on the board. Resoldering these fixed the problem but why couldn’t I detect it earlier? My theory is that with the chassis firmly back in the cabinet, these dry joints were exacerbated by the tension of the tight fit. When the back was released, the tension was released and the connections improved. Well, it sounds plausible, so I’m sticking with it. The swing to plasma & LCD Sometimes, I am grateful that more Items Covered This Month • • • • • • • Mitsubishi CT-2900AM TV set Sanyo CPP2930 TV set (A8A29 chassis) Panasonic TC-32LX500A LCD TV set (LH41 chassis) Sony KV-EH36M31 FD Trinitron TV set (AE5A chassis) LG DC593W combo VCR + DVD Toshiba 56WHO8G rear projection TV LG RT28FZ10RX TV set (MC022A chassis) work is swinging towards repairing plasma and LCD sets which are not nearly as heavy or bulky as their CRT equivalents. My main whinge about the newer technology is the number of screws that hold the backs on the sets and the sheer monotony of board replacement. This is rather frustrating because many of them could be repaired to component level but manufacturer policy is strictly board level. LTW Harsh Environment Connectors www.ltw-tech.com C-16 Line Multipin Circular Line D-Sub Multipin Multipin Circular C-16 Style RJ45 Miniature DIN Available in Australia from Altronic Distributors Agricultural • Industrial • Mining • Marine LTW connectors represent the ultimate in value and reliability for manufacturers of industrial equipment requiring waterproof connectivity. Available in IP66, 67 & 68 ratings for use in almost any environment. Altronic Distributors carry a range of products ex stock (see website for range available). Other LTW models available upon request. Minimum quantities apply. Sydney Melbourne Perth DISTRIBUTORS PTY. LTD. siliconchip.com.au Phone: 1300 780 999 Web: www.altronics.com.au July 2006 49 board (TNPA3681AA) was supplied. This fixed the set and everybody ended up happy. Serviceman’s Log – continued Now that’s a Sony For example, I recently had a new Panasonic TC-32LX500A LCD using an LH41 chassis in for repair. I even managed to obtain a circuit diagram for it – an almost unheard of occurrence for a flat-panel set. All you generally get nowadays are fault flowcharts that let you diagnose and identify the appropriate board. Anyway, this set was dead after a power surge and all it needed was a new 33W 2W fusible resistor (R7114) and a new “power management” chip (IC7101). For good measure, I decided to also throw in a new optocoupler (PC7102) and duly ordered all the parts. Apparently, however, a problem arose with the part number for IC7101 (C5HABZZ00165), with the result that, instead of only a couple of small components, an entire new power supply This screen photo clearly shows the digital noise present in the yellow areas on the Sony KVEH36M31 FD TV set. The fault was on the B3 digital board. 50 Silicon Chip A 90kg Sony KV-EH36M31 FD Trinitron (AE5A chassis) was delivered to my workshop bench. Apart from nearly killing the two guys who had to carry this widescreen set in, my now “small-looking” bench was nearly buckling at the legs! The set was displaying the sort of fault you have nightmares over (see photo). It is hard to describe but here goes: the picture was partially negative with digital noise on bright yellow scenes. Call me stupid (most do) but I really didn’t have much of a clue as to where to start with this. However, I guessed it would have to be in the video processing circuits of the set. The fault occurred off-air as well as on all AV inputs but the OSD menus were all crystal clear and so was the PIP (picture-in-picture). Initially, I sought the advice of several other Sony techs but no-one had heard of such a fault. However, I was warned about the dressing of the cable wiring loom around the SCART input sockets, as well as capacitor C2001 on the JL Board which should be changed to 3.3mF to prevent intermittent horizontal tearing on 1080i signals. Once again, I subjected this set to shock vibration and heating and freezing tests but these revealed nothing. I then dismantled the set and examined each module in turn for possible defects but couldn’t find anything wrong. Two boards are inside a metalmeshed cage. And that’s where I got my first clue. I tried wiggling the B3 digital board while the set was switched on and the fault symptoms changed! This was the break I was looking for. From now on, I could now concentrate on this module. I soon discovered that the B3 board was sensitive in the area between IC801 (the main microprocessor) and IC302 (the sub A/D converter). At first, I suspected the five surfacemounted 47mF and 10mF electrolytic capacitors (C707, C718, C302, C355 and C354). However, after replacing these, the fault was still there. I then discovered that it was also heat-sensitive; it was surprisingly sensitive when cold but OK when hot, instead of the siliconchip.com.au other way round (which is much more usual). Unfortunately, I never quite got round to identifying the exact components, though I suspect the flow soldering to either the surface-mounted 180-pin IC801 or 80-pin IC302 (which is beyond my ability to resolder) may have been the problem. Instead, an exchange B3 board, part number A1620124R, fixed the problem. As Clint Eastwood put it: “A man’s got to know his limitations”. Fixing the odd VCR Most VCRs aren’t worth repairing these days and even “combos” (VCR plus DVD) are at best borderline. Occasionally, however, I still fix the odd one or two. One that I had in recently was a popular LG DC593W combo unit that had died during a power surge. Fuse F101 was open and after replacing it, you could hear a faint pulsating noise and the two front red LEDs were flashing. I checked the seven main supply rails with an ohmmeter but couldn’t find any short circuits. However, there were only very low pulsating voltages on them when the unit was switched on. The main problem with these units is access or rather, the lack of it. To get to the main board where the power supply is, you have to remove the front panels and the VCR deck and board. It is almost impossible to run the set outside its cabinet. It was fairly obvious that the power supply was oscillating, so I started by replacing C107 (1mF 50V) and C108 (33mF 25V). I also mounted IC101 in an IC socket so that I could swap it later if necessary without removing the chassis. This restored the power to the set but I wasn’t out of the woods yet. The display came on and the DVD did a few turns, as did the VCR, but a few bizarre symptoms remained. First, all the segments of the display were glowing at once. Second, although the remote was working, when I switched it from DVD to VCR, the LEDs changed but the AV output remained in the DVD position. However, if I tuned the TV into the RF output (Ch68), I could choose between the DVD, the VCR and the TV stations but there was excessive RF interference patterning. This red herring disappeared when I removed the aerial, which told me that I was getting co-channel interference from Ch66 or another digital channel. As a result, I chose a lower channel number for the RF output (press Ch Up and Down together for four seconds with the VCR off). Next, I checked all the voltage rails and these proved to a bit high compared to the values marked on the circuit. As a result, I spent a lot of time changing IC101 (the “Power Management” IC), the optocoupler and IC102 (KA431) in an attempt to fix this. In the end, it turned out to be the main filter electro (C103, 100mF 400V). This was slightly low in capacitance and changing it fixed the DVD/VCR switching on the AV output. But that wasn’t the end of it – I still had the Digitron fluorescent display (IC501) glowing too brightly. The filaments seemed OK at 4V and the -29V rail measured -30V at the anode of D108. However, when I checked the voltage on pin 11 of the P6M01 plug and socket for the front panel, it was very low at about -17V and varying. siliconchip.com.au With the board out, I soon tracked the fault down to capacitor C122 which had come loose and broken a very fine copper track. Repairing this fault fixed the Digitron display but I wasn’t out of the woods yet. The last fault was intermittent “no eject” from the DVD. This was caused by a slipping loading motor belt and replacing it fixed that problem. You can see why, generally speaking, these combos are not worth fixing, especially when new units can be had for less than $200. One of the traps one can get into with this unit is the front control panel not working due to inadvertent use of the child lock on the remote control. Rear projection set We had a Toshiba 56WHO8G rear projection TV come in marked “dead” on the job sheet. I hate rear projection TVs at the best of times because of their logistics and lack of access. We found that the set would come on OK for a few seconds but then close down completely. All the voltages checked OK except for one and that was the X-ray protect voltage on pin 13 of Z801, a special thick-film power management IC. The circuit shows this to be 22V but I measured just 3V. The circuit shows that this voltage is derived from pin 9 of the flyback transformer (T461) via D471, R471 and C471. These parts were all changed but that made no difference. We then disconnected this line by removing the GJ14 link and the set now stayed on but was showing a horrible concave picture. This made us think that there could be some ghastly July 2006 51 Serviceman’s Log – continued and convergence adjustments. And that did it – once these adjustments were completed, all the colours were correct! So what had happened? If that’s the way the set had left the factory (highly improbable), why did it take so long for someone to notice this problem? Was the client colour blind? I can only surmise that the set had been dropped at some stage and no-one had owned up! It’s the only explanation that makes sense. Relics of a bygone era fault on the convergence board. It was looking more and more like a complete disaster and we really didn’t want to touch it, especially as the customer did not want to spend money on it. In the end, he bought a new plasma TV and dumped the projection TV on us. As a result, the monster was put aside so that it could be salvaged for spare parts. A few months later, another identical model also came in dead. This time, the fault was R820, a 1.8W fusible resistor that supplies +156.7V to IC801. Well, now that we had this set working, we decided to swap its modules with our faulty unit to track the problem down. Surprisingly, the fault wasn’t in the convergence or deflection circuits as we had thought. Instead it turned out to be the power supply. We then began comparing the two identical power supply modules side by side on the bench and soon realised that their circuits were significantly different to the circuit supplied in the service manual – especially the X-ray protection circuitry. Anyway, swapping parts between the two boards eventually lead us to the power management IC itself – swapping it 52 Silicon Chip transferred the fault and a new one fixed the problem. Does anyone know who wants to buy a secondhand Toshiba rear projection TV? Bizarre fault We recently encountered a really bizarre fault in a 3-year old LG RT28FZ10RX (MC022A chassis) TV set. It came in with “green and pink picture” written on the job sheet and, on the workshop bench, the colour bars looked as though they had been swapped over, or the wrong TV system selected. This was all thoroughly checked out, after which the set was externally degaussed. Everything else, including the software settings, looked OK, the only exception being that the purity was slightly out. This was rather puzzling. The set hadn’t been dropped, the degaussing circuits were OK and no-one had had a fiddle. The ring magnets around the CRT were all sealed with the original manufacturer’s white paint, so they hadn’t been touched either. With no other option available, the decision was made to redo the purity The excellent UK-based magazine “Television” has been around for a long time (I have subscribed since 1963) but just recently the Poms have been running a series of self-congratulatory articles on the brilliance of their AVO 8 multimeters. However, in my opinion, there’s no way you can compare the AVO 8s with a Spitfire for technical excellence. Being an expat myself – and thus in danger of bringing on some heavy criticism – I have to say I don’t share their enthusiasm. Even the latest series was big, heavy and only 20kW/V – and rather expensive. I own two series 5 units which did not bounce when they hit the concrete floor in my workshop and my bank manager will not let me have the mortgage required to fix them. So they sit on a shelf, relics of a bygone era. By now I am sure I have upset at least half of my dwindling readership but you can try to convince me otherwise. I will, however, continue to praise the performance of several other multimeters of the 70s and 80s – eg, Taylor, University, Sanwa and my favourite, Hioki-Peak. These were available in Aussie dollars for a fraction of the UK pounds you pay for an AVO and had an input impedance of 100,000W/V. They also used a 28V battery for ohms measurements, which meant that when you tested a transistor, it was as though it was in a fully working circuit and any leakage problems would stand out like a dog’s proverbials. Unfortunately, my favourite meters also didn’t survive the bench drop and are no longer available except possibly in garage sales from retired or deceased electrical engineers. Anyway, if any of you want to sell me a cheap Japanese meter like the ones I have mentioned, please let me know – I might be inSC terested. siliconchip.com.au Photoelectric Smoke Detector At last, a 12V hardwired smoke detector. Ideal for permanent wiring in homes, boats, caravans or motorhomes, it only draws 5mA from a 12V source. When smoke appears it will close a set of contacts inside the unit which can trip an external unit via an existing burglar alarm system. Supports NO and NC configuration and is supplied with Cat. LA-5045 test, reset buttons and all mounting $ 95 hardware. 24. 16 Amp 12V Car Battery Charger This fully automatic, switchmode, car battery charger utilises a four stage rapid charge design to optimise the life and performance of lead-acid/GEL batteries. Includes a top mounted carry handle and cable storage for the battery leads and clamps. Size 270(W) x 220(H) x 120(D)mm. Kit of the Month Two-Way SPDIF/Toslink Digital Audio Converter Kit Shortwave AM, FM, PLL Receiver Ref: Silicon Chip June 2006. This kit converts coaxial digital audio signals into optical or vice-versa. Use this bit stream converter in situations where one piece of equipment has an optical audio input and the other a coaxial digital output. Kit includes Toslink optical modules, PCB with overlay, case with screen printed lid and all electronic components. • Requires 9-12VDC power (use MP-3030 not incl.) Cat. KC-5425 $ 95 24. Cat. MB-3620 $ 95 189. IP67 Rated DMM for Tough Environments This auto ranging Cat III DMM has the added feature of being rated IP67. This means you can safely take it into harsh environments without the concern of damage by moisture or dust ingress. Features: • Capacitance • Frequency • Relative measurements • Temperature Cat. QM-1541 • Data hold $ 95 4 Channel Multiplexing DVR with 120GB HDD and Ethernet Connection This unit is a combination of a digital video recorder and a four channel multiplexer in one compact, easy to use unit. All the features you would expect are there such as picture in picture, slow playback, and image zoom, but it doesn't end there. It will accept up to four video and audio inputs, with a four way quad or switching display. A hot swappable HDD bay is used, and can hold an IDE hard drive with a capacity up to 250GB! See website or catalogue for full specifications. Was $999 Cat. QV-3072 $ 00 SAVE $100 899. 99. Digital Video Camera and Media Player Jaycar Springvale has MOVED Smaller than an average sized walled, this unit comes with a large 2.5” LCD screen and accommodates, 128MB onboard memory and an external SD/MMC card slot. Features include: • MP4 player • Still camera and video camera • 3 megapixel CMOS sensor • MP3 player (earphones included) • Digital photo album • Games • Software and interface leads included Cat. QC-3232 $ 00 SAVE $100 Was $399 After 19 years our Springvale store has moved 50m to larger premises with excellent off-street parking. Their new location is corner of Springvale and Dandenong roads, in Mulgrave Victoria. 299. Includes Software FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Relax and enjoy quality sound with these fantastic new audio products! The new store is our largest in Victoria and is now open - call in for some great in-store specials. Opening hours, telephone and fax numbers stay the same. Ph: (03) 9547 1022 Featuring 9 pre-settable stations, a blue LED backlight, auto scan, full clock functions, headphone jack, and an LED and stereo indicator this neat unit measures 180(H) x 300(W) x 85(D) mm and is sturdy enough to be taken anywhere. Power is derived either from Cat. AR-1746 the supplied mains adaptor or via 95 4 x D size batteries (sold separately). $ 129. DAB (Digital Audio Broadcasting) Hi-Fi Component Style At last! A DAB receiver to fit into your entertainment or Hi-Fi system. Includes FM band, channel presets etc. Note: At this stage the broadcasting authority requires us to tell you that the current DAB system will not be used in Australia. They intend to use a system that does not currently exist! In the meantime you can enjoy DAB broadcasts on this unit. Cat. AR-1799 $ 95 249. Retro Entertainment Unit This player includes a turntable, AM/FM stereo/mono, manual tuning radio, automatic start play cassette and a programmable CD player. Encased in a cherry timber finish cabinet the two front speakers are mesh protected. See our website or catalogue for specifications. Measures 400 x 378 x Cat. GE-4063 260mm. $ 00 DJ Dual CD Player 199. Enclosed in a rugged, rack mountable chassis it features 8 times oversampling 1 bit D/A converter, 3 different scan speeds, pitch display, seamless loop, 25 second anti-shock, auto locking CD drawers Excellent for the and more! amateur or professional DJ! Cat. AA-0490 $ 00 399. 1 Mains Timer with LCD A switching contact rated at 30 amps! Featuring 8 on/off programmes across 16 combinations of days or blocks of days for unrivalled flexibility. The unit also has a one touch 'summertime' button to convert to daylight saving for time when it arrives. Great , security nics Cat. MS-6110 ydropog and much h $ 95 lightin more 29. 600VA Uninterruptible Power Supply Battery back time is 10 minutes which lets you power down without loss of data! The UPS is supplied with a 7Ah SLA battery, USB interface cable, and software. See our website for full specifications. Cat. MP-5200 $ 00 139. Regulated Variable Lab Power Supply This precision power supply provides a stable voltage and current with a regulated output voltage. Output voltage is adjustable from 0 up to 30VDC in constant voltage mode and output current is adjustable from 0 to 3 amps in constant current mode. The unit features an uncluttered control panel with LCD, voltage and current Cat. MP-3086 adjustment knobs. $ 00 199. Isolate and Protect Your Battery Dual Battery Isolator This unit will direct alternator charge current to your main and auxiliary battery when the engine is running. When you are stationary and drawing battery power (for fridges etc), the unit will isolate one battery before both batteries go flat. Cat. MB-3670 $ 95 99. Battery Protector When you power an accessory through the cigarette socket you stand a real chance of flattening your car battery. Not with this unit! It disconnects itself when battery voltage gets to 11.2 volts, ensuring that there is enough energy left to start your engine. Cat. MS-6120 • Supplied as a 1m automotive $ 95 cigarette plug to socket lead 19. Home Theatre Powerboard Surge protection and filtering are provided for the mains power to all your equipment and further protection is provided by the in-built circuit breaker. This powerboard also has telephone protection, data protection for MS-4024 a network connection, satellite/cable TV Cat. $ 95 video protection, and protection for TV aerials. 59. 2 Amp Regulated DC-DC Converter This converter will operate on 12 and 24 volt car and truck systems. It plugs directly into the cigarette lighter socket and its output voltages are 1.5, 3, 4.5, 6, 7.5, 9 and 12VDC at 2,000mA, fully regulated. • 12VDC output Cat. MP-3038 regulated only on $ 95 24V systems 4 Pack Ni-MH Rechargeable Batteries These rechargeable batteries are supplied in four-packs for convenience and are cheaper than buying them individually! AA 2,000mAh Nipple Was $15.95 AA 2,400mAh Nipple Was $19.95 Cat. SB-1739 $ 95 Pkt 4 Cat. SB-1737 $ 95 Pkt 4 Cat. SB-1735 $ 95 Pkt 4 11. 13. SAVE $2 15. SAVE $4 All our inverters are isolated for added safety 69. 2 Most wet-cell lead acid batteries can develop plate 'sulphation' when stored for prolonged periods or not cycled correctly. Protect, rejuvenate and condition your wet-cell battery with these great products. Lead Acid Battery Conditioner This product dissolves sulphate and can restore a sulphated battery to serviceable condition. • One bottle will do up to a N7OZ size battery (4WD, Cat. NA-1420 boat, truck, etc) $ 95 8. 48. 149. Save that SLA Battery! 49. Cat. MI-5102 $ 95 Cat. MI-5107 $ 95 This premium battery checker will test all types, including standard AA/AAA/C/D/9V/12V, button and lithium batteries. The LCD display indicates the level of capacity as a percentage. Lead Acid Battery Desulphator 150W 12VDC Inverter Delivers up to 400 watts of continuous power, while supplying surge currents up to a massive 1200 watts. Was $169.95 79. Universal Battery Checker with Tester and LCD Display This unit will take energy from the battery and return it as a surge, it helps to reverse the damaging Cat. MB-3660 effects of $ 95 sulphation. 69. 400W 24VDC Inverter Traveller's Ni-Cd and Ni-MH Battery Pack Charger 49. Utilising the existing drink holders in cars, this inverter is held in place and doesn't need any modifications to vehicles. Featuring a 140W power output, this unit has the capability to run a laptop computer or other equipment. Cat. MI-5120 $ 95 Battery Back-Up Module 28V/25A This unit will switch to a battery back-up if the primary power is interrupted or fails. For example, if you have a portable refrigerator running from alternator power. If you stop the engine driving the alternator, this unit will switch to a back-up battery to run the fridge or any other DC appliance within rating. When the alternator power is restored, it switches back automatically with the bonus that the Cat. MB-3675 back-up battery will be automatically $ 95 re-charged via the module. 149. Cat. QP-2255 $ 95 Find the Right Inverter to Suit Your Needs Can Sized 140W 12VDC Inverter With the ability to supply surge currents up to a massive 450 watts, this inverter can run a laptop, recharge batteries, run lights or even a small TV. Simple to operate with full automatic control for a huge range of rechargeable batteries, even button cells! Features a capacity quick test of inserted cells and an auto-diagnosis with automatic start of a refreshing Cat. MB-3548 process, if required. $ 00 This international charger/discharger is for Ni-Cd and Ni-MH packs of 1-10 cells. With switchmode power supply and interchangeable primary plugs this charger includes safety features such as voltage gradient supervision and Delta V switch-off, plus a safety timer. Cat. MB-3583 $ 95 24. AAA 900mAh Nipple 2 in 1 Battery Charging and Testing Station SAVE $20 Battery Fighter® Chargers Designed to fully charge and maintain a lead acid battery at the correct storage voltage without the damaging effects caused by trickle charging. Cat. MB-3600 750mA 12V $ 95 49. SLA Charger Cat. MB-3602 1.25A 12V $ 95 79. SLA Charger We massiv have a e SLA ba range of See in tteries -store! FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Hydrogen Fuel Cell Powered Model Car This kit includes a 30mW proton exchange membrane fuel cell that will convert hydrogen and oxygen to electricity and when connected appropriately, will generate clean fuel to run the model car. • Comprehensive instruction booklet provided • Car chassis measures 235(L) x 100(W) mm • Requires: 2 x AA alkaline batteries and distilled water • Educational kit for ages 12+ Cat. KT-2525 $ 95 149. Proton Exchange Membrane (PEM) Fuel Cell To operate the cell, a low pressure source of oxygen (or air) and hydrogen is required. The cell will convert these gases up to 60% efficiency and run indefinitely (subject to heat removal) given unlimited supplies of 'fuel'. Cell measures 64(H) x 54(W) x 27(D)mm and requires distilled, not purified water. • Instructions supplied Cat. ZM-9080 $ 00 • Voltage 0.65V • Current 300mA • Power Output 30mW 99. Simple Biodiesel Book Save a fortune on diesel fuel! With simple methods spelt out in this book, you can produce fuel for a modern day diesel engine from vegetable oil (even used 'fish and chip' oil). Takes you through everything from starting your oil collection service to testing and using your fuel on Cat. BE-1531 the road. 61 Pages, $ 95 softcover. BUY THIS: High temperature stability and antistatic properties make it ideal for all sorts of soldering work. GET THESE FREE:* 1 x Metal Desolder Tool TS-1512 $6.50 TS-1510 $12.95 Accessories include 6 piece diamond burr set, 10 piece shaped stone set, 1 grinding stone, 6 piece sanding drum set, 4 piece drill set, 3 piece wire wheel set, various polishing wheels, assorted Cat. TD-2450 $ 95 mandrels & collets, storage case 60 Piece Drill also available. TD-2452 $59.95 34. 148 Piece 240 Volt Precision Drill Set This hobby drill kit is one of the most versatile around. Accessories include, 6 piece sanding band set, 7 piece polishing wheel set, polishing compound, 4 piece diamond cutter set, 3 piece HSS cutter set, 18 piece grinding wheel set, 5 piece wire brush set, 2 piece nylon Cat. TD-2454 brush set, 72 cut-off wheels, $ 95 assorted collets & mandrels. 79. Rechargeable Cordless Screwdriver Features a comfortable pistol grip that gives you maximum control. The driver also has a bright LED lamp, a magnetic bit holder and a handy safety strap. SAVE • Bit holder size: 6.35mm. $10 • Mains charger included. • 4-bit set included. Was $29.95 Cat. TD-2498 $ 95 59. 1 x Soldering Iron Tip Conditioner High Temperature IEC320 C15 Socket 1 x Soldering Iron Tip Cleaner Intended for application in higher temperature environments up to 120°C with a current rating of 10 amps. THAT’S $35.20 VALUE ABSOLUTELY FREE! Cat. PS-4013 $ 95 5. Moisture Level Meter This 10MHz CRO has an input sensitivity range from 5mV to 5V per division and sweep time from 0.1uS to 100mS per division. Signal and trigger inputs are BNC connectors and the supplied probe has a 10:1 attenuator as standard. The Breakthrough instrument is price! housed in a strong steel case and has a 70mm CRT with Cat. QC-1920 5mm square graticule. See our website $ 00 or catalogue for full specifications. 155. Roadies Cable Tester This rugged unit will enable quick, convenient and reliable continuity testing of most popular audio cables such as balanced XLR, phono, Speakon, DIN and more. • Requires one 9V battery (not included) • Measures 102(W) x 45(H) x 142(D)mm Cat. AA-0404 $ 95 39. An excellent cutter designed to cut plaster board and ceiling tiles. Features calibrated hole size adjustment. • Includes dust cover Two sizes are available: Cat. TD-2520 69. 95 • 62 to 177mm hole size $ Cat TD-2520 Cat. TD-2522 • 158 to 264mm hole $ 95 size Cat TD-2522 INTERNET> www.jaycar.com.au When it comes to seeing if there's moisture ingress on walls or deckings, you can't go past a quality instrument like this one. Featuring a simple to use and easy to read display, this unit can be used on timber, cardboard, paper, and even on hardened materials such as concrete and mortar. Features an integrated calibration checker in the lid!! Cat. QP-2292 $ 95 59. Pro-Style Pen DMM This precision instrument is made using modern double moulding techniques to make it tough enough to be used every day. It features a spot to put the probe guard when in use, and contains 7 functions in the one unit. See our website or catalogue for full specifications. Cat. QM-1498 $ 95 • Cat III 600V safety design 39. 2-in-1 Network Cable Tester and Digital Multimeter Adjustable Holesaws FOR INFORMATION AND ORDERING 2. When a flammable gas is detected, this unit will provide audible and visual annunciation via its in-built buzzer and LEDs. Simple to use and operate, It is perfect for checking gas bottles while camping or caravanning. • Detectable gases: LNG and LPG • Required 2 x AAA batteries (included) Cat. QM-1660 $ 95 229. $15.75 All Types (ea) $ 45 Flammable Gas Detector Cat. TS-1440 $ 00 TH-1862 Keypad Switches with LED PCB mounting with SPDT momentary action. Contact rating: 24VDC 12mA • Dimensions: 12.45(W) x 13.85(D) x 9.35(H) excluding pins. Colours available: SP-0775 Red SP-0776 Green SP-0778 Blue 10MHz Single Trace Cathode Ray Oscilloscope 44 Piece 12 Volt Hobby Drill TELEPHONE> 1800 022 888 SAVE!!! Goot Antistatic Temperature Controlled Soldering Station * with the purchase of 1 x TS-1440 29. 19. Soldering Station Deal 79. This innovative device is ideal for network installers or technicians. It allows the user to easily check cable integrity or measure AC & DC voltage, etc. without needing to carry two separate devices. See our website or catalogue for full specifications. Cat. XC-5078 $ 95 79. 3 Four Sector Security Alarm System All system components (sensors, sirens) are connected to the control unit via a two core flat wire. The unit has a built-in keypad with status LED and three modes of operation (Home, Out, Off). All sensors and sounders are line 8 secto r protected so any attempt to also av system a LA-547 ilable interfere will sound the alarm. 7 $249 • System includes control unit, 2 movement detector PIRs, 4 door/window contact, external siren, 240VAC adaptor, 50m two-core flat wire, clips & screw/wall plug packs Cat. LA-5475 $ 00 199. Wireless Audio / Video Receiver This 2.4GHz wireless audio/video receiver can connect to your computer and the supplied software allows you to use up to SAVE $50 three wireless cameras (QC-3281) for instant security and surveillance applications. Supports motion sensing, remote Cat. AR-1835 internet viewing and playback, $ 00 automatic event notification Buy the AR-1835 A/V Receiver and much and the QC-3281 Camera more. together this month for just Was $249.00 $303.90 save $134.10 199. 2.4GHz Wireless Colour CMOS Camera F a n t a s t i c Monitor P r i c e R e d u c tions! Two Channel 6" B&W Monitor Small & compact! It has two video inputs with a manual or adjustable auto-switching for input selection. It weighs just 1.5kg and is powered by an external Cat. QM-3409 $ 95 mains plugpack. Was $89.95 SAVE $30 59. 14" B&W 4 Channel Switching Monitor with Quad Processor & Audio Versatile Monitoring! Many SAVE $200 advanced features such as freeze frame, image zoom, picture in picture (PIP), alarm inputs, two-way communication system, synchronised Cat. QM-3418 $ 00 input audio. Was $599 399. The camera has built-in night vision capability, microphone and a 12V mains adaptor for continuous operation. Was $189 • Camera measures Cat. QC-3281 65(W) x 110(H) x $ 00 55(D) mm 139. SAVE $50 4 Channel 14" Video Surveillance Monitor with Audio Two models - B&W and Colour. Both feature an internal 4 channel switcher, alarm inputs, and a whole lot more. See our website for details. QM-3411 - B&W 14" Monitor QM-3414 - Colour 14" Monitor Was $299.00 Was $699.00 Cat. QM-3414 Cat. QM-3411 SAVE SAVE $ 00 $200 $ 00 199. $100 499. IP Camera with 6 IR LEDs Surveillance This compact colour IP camera can be used in a network and will provide world-wide video coverage through internet explorer. The camera incorporates a built-in web-server and includes motion detection software which provides automatic Wirele ss IP intruder sensing. The also av camera a camera has six infrared QC-33 ilable 98 $34 9 LEDs to provide night vision capabilities. Cat. QC-3396 • Supplied with mounting bracket, $ 00 software, and mains power adaptor 249. Vari-Focal Colour Dome Camera with L-Bracket Housed in a strong die-cast aluminium base with an L-shaped bracket and a reinforced polycarbonate dome, this vari-focal camera is designed to withstand the harshest of environments. • Manual focus 3.5 - 8mm Sony TM Senso CS type lens. Cat. QC-3297 r Inside $ 00 299. Downlight Style CCD Colour Camera The 1/3” Sharp colour CCD camera incorporates a downlight holder for flush mounting on any ceiling or flat surface. It SAVE provides a 0-90° adjustable $30 pivoting camera head for securing that perfect angle. Holder is finished in polished metal. Was $249.95 Cat. QC-3503 $ 95 219. Vehicle Security Two-Way Paging Car Alarm with Rechargeable Remotes This alarm utilises FSK technology which will relay the status of your vehicle to the key fob up to 3km (direct line of sight) away. In addition to the system's massive transmission range, the alarm also features remote control arm and disarm, car park locator, auto rearming, antiburglary, anti-hijacking and silent arming. Each remote control has an integrated rechargeable battery, alarm clock, with visual, audible and vibrating alert functions. • Purchase LA-9030 $29.95 for microwave movement sensors • Purchase LA-9019 $99 for spare remotes WHAT YOU GET • Electronic black box controller • 2 x code hopping two way paging remote controls with rechargeable lithium-ion batteries • Vehicle remote control battery charger • Shock sensor with adjustable sensitivity • Ignition cut out relay • Wiring looms • Battery backup siren Cat. LA-9018 $ 00 • Car transmitter 299. 4 Power Locking Kits Take the hassle out of locking and unlocking your car doors when parking or to keep the kids safe in the back seat. These kits are durable and easy to install. Two and four door kits available Two Door Kit Two door kit supplied with, one master and one slave actuator, control relay, hardware and wiring. Cat. LR-8810 Cat. LR-8810 SAVE Was $29.95 $ 95 $5 24. Four Door Kit Four door kit supplied with, one master and three slave actuators, control relay, hardware and wiring. Cat. LR-8812 Cat. LR-8812 SAVE $ 95 Was $39.95 Remote Controlled Central Locking System $5 34. Unlock your car doors as you approach. This system is easy to install and comes complete with wiring loom, two remote keyfobs and is backed with a 12 month warranty. Cat. LR-8839 $ 95 69. Motorcycle Alarm Protect your motor bike with this affordable alarm system. Features a compact control unit, ear piercing 120dB siren, and two slim waterproof remote controls. The alarm is triggered by a shock sensor, which is mounted inside the control unit, as is the immobiliser relay. A flashing LED also acts as a deterrent. Great features at a great price, backed Cat. LA-9020 $ 95 with a 12 month warranty. Portable Burglar Alarm 69. Simple to install, this pack consists of a main unit which houses a passive infrared sensor (PIR) for motion detection, reed switch to alarm a doorway, a loud piezo siren and an IR remote control to arm and disarm the alarm. It's powered by the supplied mains plug pack with the option of fitting 3 x AA batteries (not included). Cat. LA-5400 • Control unit measures 80(W) x $ 95 120(H) x 32(D) mm. • Supplied with a 10m lead for reed switch connection 49. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Impedance Matching 8 Way Speaker Selector Wireless Microphone with Diversity Receiver This UHF wireless microphone system features a true diversity receiver for clear and uncluttered reception from the included microphone. With 16 user selectable channels you can be sure to get a clear signal even when similar devices are used in the area. Cat. AM-4077 • 100m (clear line of sight) $ 00 transmission distance 249. HDTV Distribution Amp Now you don’t need multiple set top boxes! Now you can have top quality TV in more than one room. This unit distributes HDTV signals up to four ways without losing signal quality. Cat. AC-1678 $ 00 Powered from the supplied mains plugpack. 299. Turn on up to 8 pairs of speakers without worrying PROTECT about your YOUR AMP amplifier blowing up. Housed in a rugged metal case, speakers are easily connected via the strong spring terminals mounted on the rear, and then quickly turned on and off via the front mounted push buttons. Up to two Cat. AC-1682 amplifiers can be connected and $ 00 selected. Max power: 100W RMS. 249. Rated at a generous 100WRMS per channel, this two channel amplifier features a microphone input and quality screwdown speaker terminals. See our website or catalogue for full specifications. 39. Touch Screen 16 in 1 Universal Remote Control 79. Cat. AA-0470 $ 00 199. Active 2-Way Speakers with Remote Control Active 2-way speakers for use with PCs, MP3 players, iPodsTM, etc. The magnetically shielded drivers significantly reduce interference with digital equipment such as computers, monitors and televisions. MDF cabinets are faced with a piano black finish. Low Cost Stereo Amplifier This 18W per channel transistor amplifier is protected from accidental speaker wiring shorts and has a front panel microphone input, bass and treble controls as well as a master volume control. Cat. AA-0472 $ 95 39. 79. This universal remote control can operate up to 8 different devices at once including TV, DVD player, VCR, RCVR, satellite TV, cable TV, stereos and air conditioning units. It comes preprogrammed for easy set up, quick search and works with over 100 brands of electrical devices. • Dimensions: 55(W) x 210(H) x Cat. AR-1725 $ 95 30(D) mm. • Power: 2 x AAA batteries (incl.) Control up to 16 devices at once by touch screen: TV, satellite and cable TV, VCR, DVD, tape deck, hi-fi's, CD players, radios, MP3 players, amplifiers, digital recorders and other audio devices. • Dimensions: 60(W) x 210(H) x 25(D)mm • Power: 4 x AAA Batteries Cat. AR-1727 (not included) $ 95 Stereo Amplifier with Remote Control Sound Activated 72 LED Light Equaliser With its sensitive circuitry, the four columns of LEDs will ascend to the faintest audible sound. It incorporates an audio input jack so it can be linked to your amplifier and modulated directly to music. The included stand allows it to be either mounted vertically or horizontally. • Dimensions (excluding base): 650(H) x 115(W) x 85(D) • 12VAC power supply included Cat. SL-2946 $ 95 8 in 1 Universal Remote Control with LCD Display Cat. XC-5183 $ 95 99. In-Car Entertainment 1500WRMS Class D Amplifier Linkable 7" TFT LCD Widescreen Monitor Watch high resolution pictures in wide screen format. A truly versatile colour monitor with low power consumption, wide viewing angle and NTSC and PAL compatibility. • Includes remote control Was $249.00 SAVE $20 Cat. QM-3752 $ 00 229. The receiver will give good performance in strong signal areas and is ideal for city driving. The tuner can be permanently wired into the car with the wiring harness supplied or a temporary installation can be achieved with the cigarette lighter adaptor that Cat. XC-4826 $ 00 is also included. 99. + Response Class D 800WRMS Amplifier A top choice for the audio or SPL enthusiast. • 1 x 400 WRMS <at> 4 ohms • 1 x 700 WRMS <at> 2 ohms • 1 x 820 WRMS <at> 1 ohm 399. 12" Carbon Fibre Subwoofer Cat. CS-2279 $ 00 219. INTERNET> www.jaycar.com.au The kit includes an LCD screen protector providing 100% anti-glare viewing, 2-in-1 function USB power link cable, a PSP and UMD cleaning kit, car charger and a designer black leather Cat. XC-5192 $ 95 strap. * PSP not included. 29. 149. + With carbon fibre construction and dual voice coils this subwoofer offers great performance and durability. • 300WRMS power • 88.2dB sensitivity • 10" version also available CS-2278 $179.95 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 699. Avoid clipping problems from power under supply. These capacitors act as a surge current reservoir for your amplifier and other electrical equipment. Featuring recessed terminals to avoid accidental shorts the units come complete with a multi-coloured LED display, other illuminated graphics and a row of blue LEDs. 1 Farad Cat. RU-6752 2 Farad Cat. RU-6751 $ 95 $ 00 199. PSP Accessory Kit Cat. AA-0429 $ 00 1 & 2 Farad Capacitors with Coloured LED Display Digital TV Tuner Cat. AA-0428 $ 00 This competition series amplifier belts out a whopping 1500WRMS <at> 1 ohm load. A professional piece of equipment designed for the SPL enthusiast and competitor. • 1 x 800WRMS <at> 4 ohms • 1 x 1000WRMS <at> 2 ohms • 1 x 1500WRMS <at> 1 ohm 6" Kevlar Split Speakers The tweeters use smooth sounding 25mm soft domes with a compact and easy to use mounting system with flush, angle or surface options. The outboard crossover features high-grade internal components with variable tweeter attenuation for system tuning and polyswitch overload protection. Cat. CS-2327 • Sold per pair $ 00 139. 12" Speaker Box = Made from 17mm MDF this enclosure comes pre lined, wired and carpeted. •10" also available $49.95 Cat. CS-2535 $ 95 69. Buy 1 x AA-0428 + 1 x CS-2279 + 1 x CS-2535 together and pay just $618.90 Save $69.05 5 Flat Panel 5.1 Surround Sound System Experience that real cinema atmosphere with your computer. This system boasts revolutionary super flat satellite speakers with removable legs that allow for wall mounting. The contemporary design incorporates a boxed subwoofer to provide optimum bass response. • Simple connection to 6 channel computer sound output Our new ergonomically designed mice are finished in rubber paint for improved grip and precision control. Plug and play, these mice are compatible with windows 98/2000/NT/ME/XP USB Optical Mouse with Retractable Lead Perfect for laptops or limited workspaces. Cat. XM-5134 $ 95 Cat. XC-5194 $ 95 2.4GHz Wireless Headphones with USB Transmitter 99. 39. USB Optical Mouse These wireless headphones work brilliantly. They use state-of-the-art digital audio technology to receive 2.4GHz signals from the USB transmitter (provided) which easily plugs into a desktop Cat. AA-2035 $ 00 computer or notebook. Designed to comfortably fit in your hand this mouse is truly ergonomic. Cat. XM-5131 $ 95 14. 119. Wireless USB Rechargeable Mouse The pack contains retractable charger to ensure the mouse batteries are topped up. Digital Voice Recorder with MP3 Player This sleek digital voice recorder has it all! The batteries will last up to a massive 22hrs of playtime (9hrs in high quality mode). The recorder features ID3TAG technology, multi-language support and a large backlit LCD display. Utilising the latest 'plug and play' technology the unit has 8 sub-folders to organise your recorded messages with easy drag and drop file transfer. It also serves as an MP3/WMA player and USB storage device. • Requires 2 x AAA batteries (included) • Earphones, lanyard, software and USB interface cable supplied Cat. XC-0256 $ 95 219. Cat. XM-5132 $ 95 39. USB Mouse with Laser Pick-up 800dpi resolution, that's double the resolution of an optical mouse! This reduces the strain on hands and wrists by minimising the movements Cat. XM-5133 required to $ 95 move the cursor. 39. Gadgets for the Home Ionic Air Purifier Better overall health. This ionic air purifier is much more than just an effective odour removing air purification system. Cat. GH-1196 95 It silently fills the air with negative ions $ which research shows can help promote good health and improve vitality. 69. Water Fountain with Sound Relaxer With the sound of nature accompanied by the soothing sound of flowing water and the mesmerising colour changing LED background you are sure to relax and unwind. • Measures 190(L) x330(H) x165(W)mm • Mains power supply Cat. GH-1820 $ 95 included. 59. Ultrasonic Cleaner The ultrasonic transducer generates millions of microscopic bubbles that reach deep into the cracks to loosen and remove grime. A safe and simple means of cleaning jewellery, stubborn stains on clothes, walls, and carpets. Was $99.95 Cat. YH-5404 $ 95 89. 6 SAVE $10 Laser Pointer with Remote Presentation Control USB Rodents Intelligent Multi-function Vacuum Cleaner Heated Foot Massager Cat. GH-1395 $ 00 139. Your feet are kept warm by the fleece lining and built-in heater. Both the massage function and heater are operated by a handheld controller. SAVE • Comes with mains power $5 supply and 12V lead. • 304(L) x 304(W) Cat. GH-1755 $ 95 x 190(H) mm Was $39.95 34. Intelligent Stainless Steel Rubbish Bin A simple wave of your hand, or whatever you have free, at the sensor on the top of the bin and you have a convenient, germ free, open disposal unit that you need never touch again. • 42L capacity • Accepts standard bin liners • Includes DC power adaptor Mains • Accepts 4 x D batteries ted! Opera (use our SB2418) • Measures 755(H) Cat. GG-2317 x 305(Dia.)mm $ 95 99. SAVE $10 Cat. ST-3108 $ 95 39. USB Missile Launcher Ready! Aim! FIRE! Connected to your USB port the software will allow you to navigate the missiles trajectory, pan 180°, tilt up to 45° and provide realistic sound effects. The missiles are made from soft foam so its safe to use at home or in the office. • Software compatible with Windows 2000 and Windows XP Cat. GE-4072 $ 95 59. Mini 4 Port USB 2.0 Hub The perfect addon to increase the number of USB ports on your computer. Power is derived from the computer's Cat. XC-4824 USB port. $ 95 29. SAVE $20 The little guy will navigate around your house, cleaning as he goes. • Approx. 305mm Dia. • Battery pack and charger included Limited Quantity Was $159.00 The ultimate power point presentation aid. This excellent device incorporates "Page Up" & "Page Down" buttons into a stylish laser pointer, allowing you to move around and still run your presentation and point-out items of interest. With a transmission range over 15 metres you can't go wrong. Was $49.95 Pet's Corner Flea Exterminator The comb emits a mild electronic charge to kill fleas on contact. Safe and chemical free SAVE the comb is suitable for use on $5 cats and short haired dogs. Cat. GH-1202 Requires 2 x AA batteries sold $ 95 separately. Was $29.95 24. Automatic Electronic Pet Feeder SAVE The dispenser can be $10 programmed to slide open the lid at 8, 12, 24 hour intervals and allows you to record a 20 second voice eive message, so your pet knows and rec pet dishted LED dog is th when it is feeding time. y Bu 5! illumina a bonussh worth $19.9 Cat. GH-1190 Was a 04 le 2 -1 H G $ 95 $39.95 Cat. 29. Pet Dishes with Auto Sensor The lid automatically opens as your pet gets within 30cm of the sensor then closes when your pet has had their fill and walks away. • Stainless steel dish • Small measures 80(H) x 150(Dia.)mm • Large measures 95(H) x 200(Dia.)mm Small Large Cat. GG-2319 $ 95 Cat. GG-2318 $ 95 29. 34. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Coughing Lung Ashtray Save on Short Distance Communication Rechargeable 40 Channel UHF Pocket CB Transceiver 40 Channel UHF Pocket CB Transceiver Keep in touch within 1km in the city, or 5km in an open area. Operates on standard 40 channel CB frequencies, and requires 4 x AAA batteries (sold separately). Cat. DC-1010 $ 95 34. Designed to look like a pair of lungs! As soon as you place your cigarette in the novelty ashtray it bursts into a disturbingly realistic coughing and screaming fit. If the auditory pleas are not enough, the visual image of the lungs deteriorating with every cigarette should make any smoker think twice! Requires: 2 x AA Cat. GH-1330 $ 95 batteries (not included) This transceiver uses a small rechargeable battery pack and has a 5km open area transmission range. You can still of course, use non rechargeable AAA batteries as back-up. • Supplied with one transceiver and charging cradle. • Additional transceiver with rechargeable battery DC- 1028 $49.95 ea. • Spare rechargeable battery pack DC-1029 $9.95 ea. Cat. DC-1025 $ 95 Buy two for $59.90 Save $10! 1.5W 40 Channel UHF Pocket CB This high-quality CB radio has an 8km working range with a hi-lo setting to conserve power. Requires 4 x AAA batteries (sold Cat. DC-1040 separately). $ 00 9. Dynamo AM/FM and Shortwave Radio with Alarm 59. A heavy duty radio which will withstand a lot of punishment. This radio is great for fishing or any other outdoor activity. Housed in a sturdy rubber and plastic casing it features an alarm, FM/MW/LW and shortwave radio bands. It can be either self-powered by its hand crank (dynamo) or 2 x AA batteries (not included). 89. Wireless Weather Station with Wind Direction & Rain Gauge Wireless sensors! The system monitors inside and outside temp, air pressure, rainfall, humidity, wind speed and direction, and wind chill factor. Check our website for all the features. 12VDC Electric Blanket SAVE $50 Keep warm on long distance car trips with this versatile 12 volt electric blanket. SAVE • Cigarette lighter socket included $10 • 2.5m power cord for use in the back seat Cat. GH-1205 $ 95 Was $49.95 Travel Mug with Heater Preset you drinking temperature to room temp, luke warm, hot and very hot and the mug will keep it there. Holds 450ml and has a retractable lid to prevent spilling. Includes 12V power lead with Cat. GH-1302 cigarette $ 95 lighter plug. Was $39.95 Cat. XC-0293 $ 00 199. 29. Was $249 Cat. AR-1749 $ 95 49. LED Lantern with Solar Charger 39. See in-store for our extensive range of weather stations A great gift for the unrepentant smoker! SAVE $10 A super bright white LED lamp with an integrated compass. Its internal rechargeable batteries and external devices such as mobile phones can be charged via mains power, car charger or solar panel, all of which are supplied. • 4 x D rechargeable batteries included • Lamp measures 250(H) x 108(Dia.) mm Cat. ST-3128 $ 00 99. Illuminate Your Garden This Winter These rugged yet attractive garden lights are die cast, powder coated and moisture sealed with neoprene gaskets. The range can be powered by 12V halogen globes or 24V globes for large installations where voltage drops would normally be a problem. See in-store or check out our website for bulk buy prices, transformers and globes to suit. Wall Mount Step light Die-Cast Garden Floodlight Ideal for illuminating paths and stairs. • 100(Dia.) x 50(D)mm Cat. SL-2778 $ 75 Ideal for illuminating wide areas or lawns. • 310(L) x 75(Dia.)mm including spike Cat. SL-2770 $ 50 See in-store for Power Supplies to suit 16. Pagoda Light An attractive lamp that can be placed in any location. • 300(H)mm (excluding spike) x 40(Dia.)mm Cat. SL-2784 $ 00 28. General Purpose Spotlight Use this to highlight a particular plant or garden feature. • 100(H)mm (excluding Cat. SL-2774 spike) x 95(Dia.)mm $ 50 22. 22. Die-Cast Pathway Illuminator A contemporary design used to reveal a pathway or garden corridor. • 170(H) x 60(Dia.) mm Cat. SL-2780 excluding spike $ 50 22. Die-Cast Flush Mount This sturdy lamp is ideal for stairways or decks and can be walked on. Cat. SL-2776 50 • 100(H) x 95(Dia.)mm $ FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au 22. Recessed LED Light Kit Designed to be recessed into walls, floorboards, or even used to decorate plants or to highlight an area without the unpleasant look of conventional globes. • Supplied with 4 white LED lamps • Additional lamps also available ST-3885 - White $19.95 ST-3886 - Blue $19.95 • Lamp dimensions: Cat. ST-3887 $ 95 27(H) x 30(Dia.)mm • Mains powered. Waterproof 89. Solar Powered Light Balls Improved Add charm to an Model intimate setting with these environmentally friendly lights. Made from water resistant clear plastic, they feature a solar panel and an extra bright Light Emitting Diode (LED). Charge them up in sunlight for at least 12 hours and enjoy up to 24 hours of continuous use. Stock up for the •110 (Dia.)mm Warmer Months Available in: All Types (ea) ST-3120 Red $ 95 ST-3122 Blue ST-3124 White 24. 7 Starship Enterprise Door Sound Emulator High Performance Electronic Projects for Cars High Performance Electronic Projects for Cars Book There are 16 projects in total, ranging from devices for remapping fuel curves, to nitrous fuel mixture controllers, and more! The book includes all instructions, components lists, colour pictures, and circuit layouts. There are also chapters on engine Cat. BS-5080 management, advanced systems and DIY modifications. 160 pages! $ 80 Smart Fuel Mixture Display This version has a few additional touches such as auto dimming for night driving, emergency lean-out alarm, and better circuit protection. Kit supplied with PCB and all electronic components. • Car must be fitted with air flow and EGO sensors (standard on all EFI systems) for full functionality. 19. Pictured with KC-5422 Cat. KC-5374 $ 95 27. High Range Adjustable Temperature Switch with LCD This temperature switch can be set anywhere up to 1200°C. The relay can be used to trigger an extra thermo fan on an intercooler. Mount a sensor near your turbo manifold and trigger water spray cooling or a simple buzzer or light to warn you of high temperature. Easily dash mounted the LCD displays the current temperature. 9. 39. For All You Trekkie Fans! Tempmaster Kit Intercooler Water Spray Controller Ref: Silicon Chip March 06 Simply add these few components to the Smart Fuel Mixture Display kit (KC-5374) and reduce Cat. KC-5422 $ 95 water consumption by two-thirds. Ref: Silicon Chip June 2006 This kit emulates the unique noise made when the cabin doors on the Starship Enterprise open and close. The unit can be triggered by switch contacts (normally open), which means you can use it in conjunction with a reed switch assembly, IR beam or PIR detector. • Requires 9-12VDC • Kit includes PCB with overlay, case and all electronic components Cat. KC-5423 $ 95 Cat. KC-5376 $ 95 69. Ref: Silicon Chip June 05. This project turns a regular fridge or freezer into a wine cooler by accurately controlling the temperature to make it suitable for wine storage. A much cheaper option than commercial units. Kit supplied with PCB, case, mains plug and all electronic components. YOUR LOCAL JAYCAR STORE Voltage Monitor Kit Freecall Orders: Ph 1800 022 888 NEW SOUTH WALES Albury Ph (02) 6021 6788 Alexandria Ph (02) 9699 4699 Bankstown Ph (02) 9709 2822 Blacktown Ph (02) 9678 9669 Bondi Junction Ph (02) 9369 3899 Brookvale Ph (02) 9905 4130 Campbelltown Ph (02) 4620 7155 Erina Ph (02) 4365 3433 Hornsby Ph (02) 9476 6221 Newcastle Ph (02) 4965 3799 Parramatta Ph (02) 9683 3377 Penrith Ph (02) 4721 8337 Silverwater Ph (02) 9741 8557 St. Leonards Ph (02) 9439 4799 Sydney City Ph (02) 9267 1614 Taren Point Ph (02) 9531 7033 Wollongong Ph (02) 4226 7089 VICTORIA Coburg Ph (03) 9384 1811 Frankston Ph (03) 9781 4100 Geelong Ph (03) 5221 5800 Melbourne Ph (03) 9663 2030 Ringwood Ph (03) 9870 9053 Springvale Ph (03) 9547 1022 Sunshine Ph (03) 9310 8066 QUEENSLAND Aspley Ph (07) 3863 0099 Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 Woolloongabba Ph (07) 3393 0777 AUSTRALIAN CAPITAL TERRITORY Canberra Ph (02) 6239 1801 TASMANIA Hobart Ph (03) 6272 9955 SOUTH AUSTRALIA Adelaide Ph (08) 8231 7355 Clovelly Park Ph (08) 8276 6901 WESTERN AUSTRALIA Perth Ph (08) 9328 8252 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Christchurch Ph (03) 379 1662 Glenfield Ph (09) 444 4628 Hamilton Ph (07) 846 0177 Manukau Ph (09) 263 6241 Newmarket Ph (09) 377 6421 Wellington Ph (04) 801 9005 Freecall Orders Ph 0800 452 9227 8 Ref: Silicon Chip May 06 This versatile kit will allow you to monitor the battery voltage, the airflow meter or oxygen sensor in your car. The kit features 10 LEDs that light up in response to the measured voltage, preset 9-16V, 0.-5V or 0-1V ranges complete with a fast response time, high input impedance and auto dimming for night Cat. KC-5424 time driving. Kit includes PCB with overlay, LED $ 95 bargraph and all electronic components. • 12VDC • Recommended box: UB5 HB-6015 $2.50 19. Universal High Energy Ignition Kit Ref: Silicon Chip December 05 A high energy 0.9ms spark burns fuel faster and more efficiently to give you more power! This versatile kit can be connected to conventional points, twin points or reluctor ignition systems. Kit supplied with diecast case, PCB and all electronic components. Cat. KC-5419 $ 95 94. Battery Zapper Kit Mk II Ref: Silicon Chip May 06 Like its predecessor this kit attacks a common cause of failure in wet lead acid cell batteries: sulphation. The circuit produces short bursts of high level energy to reverse the damaging sulphation effect. The improved unit features a battery health checker with LED indicator, new circuit protection against badly sulphated batteries, test points for a DMM and connection for a battery charger. Kit includes machined case with screen printed lid, circuit board, alligator clips and all electric components. Cat. KC-5427 • Suitable for 6, 12 and 24V batteries $ 95 99. Battery Zapper Add-On Kit Ref: Silicon Chip May 06 If you are one of our many satisfied customers of the original battery zapper kit, buy this add-on and upgrade you zapper to the full functionality of the Battery Zapper Mk II (KC-5427). New components and processed case supplied Cat. KC-5428 however, to complete the upgrade some original $ 95 components need to be recycled. Cat. KC-5413 $ 95 39. Stereo Headphone Distribution Amplifier Ref: Silicon Chip November 05 Enables you to drive one or two stereo headphones from any line level (1 volt peak to peak) input. The circuit features a facility to drive headphones with impedances from about 8-600 ohms. The Jaycar kit comes with all specified board components Cat. KC-5417 and quality fibreglass tinned PCB. $ 95 29. Headphone Amplifier Power Supply Kit Ref: Silicon Chip October 05. To ensure the best possible performance to the Headphone Amplifier Kit, this will provide regulated +/- 15V and +5 outputs. • Toroidal transformer required Cat. KC-5418 $ 95 use MT-2086 $21.95 17. USB Experimenter's Interface Kit Interface your computer to the real world There are five digital and two variable gain analogue inputs. Eight digital and two analogue outputs are available. Supplied with all components, silk screened PCB, assembly manual, and software. Cat. KV-3600 $ 95 69. 59. PRICES VALID TO 31/07/06 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au SILICON CHIP Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 www.siliconchip.com.au PRICE GUIDE: SUBSCRIPTIONS YOUR DETAILS (Note: all subscription prices include P&P). (Aust. prices include GST) Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Please state month to start. Australia: 1 yr ...................... $A89.50 1 yr + binder ....................... $A105 NZ (air): 1 yr ....................... $A96 Overseas (air): 1 yr ............. $A135 2 yrs ...................... $A172 2 yrs + 2 binders .... $A203 2 yrs ...................... $A190 2 yrs ...................... $A260 Address__________________________________________________________ PRICE GUIDE: OTHER PRODUCTS _________________________________________________________________ Postcode_____________ Daytime Phone No. ( )_____________________ Email address (if applicable) ___________________________________________ (all prices include GST on Aust. orders) *SILICON CHIP BACK ISSUES in stock: 10% discount for 10 or more issues or photocopies. Australia: $A9.50 ea (including p&p). Overseas: $A13 each (including p&p by air). Method of Payment: *ELECTRONICS AUSTRALIA: project photocopies. Australia: $A9.50 each (including p&p). Overseas: $A13 each (including p&p by air). o Cheque/Money Order o Visa Card o Master Card *BINDERS: BUY 5 or more and get them postage free. (Available in Aust. only): $A13.95 each plus $7 p&p per order. *ELECTRONICS PROJECTS FOR CARS, VOL.2: Aust. $A14.95; Overseas $A18.00. (Prices include p&p & GST where applicable). Card No. *PERFORMANCE ELECTRONICS FOR CARS: Aust. $A22.50; Overseas $A26.00. (Prices include p&p & GST where applicable). Card expiry date: Signature_____________________________ SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS* * except subscriptions/renewals Qty Item Price Item Description Subscribe to SILICON CHIP on-line at: www.siliconchip.com.au Both printed and on-line versions available Total TO PLACE YOUR ORDER siliconchip.com.au P&P if extra Total Price BUY MOR 10 OR ISSU E BACK ES A 1 0 & G ET DISC % OUN T $A Phone (02) 9939 3295 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9939 2648 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, July 2006 61 Australia 2097 07/06 PRODUCT SHOWCASE DSE’s TENS unit kit looks like a pro... Dick Smith Electronics have submitted their built-up version of the Pocket TENS kit for evaluation (described in SILICON CHIP in January 2006) - and we must say it looks every bit as good as the professional units on the market but of course is just a fraction of the price. For those who might not have seen the issue and are wondering what TENS units do, they provide an electrical stimulation to nerves under the skin via a pair of self-adhesive electrodes (as seen in the photo at left). They’re used extensively by physiotherapists and other health care professionals to relieve pain and stiffness and are said to have soothing properties for labour pain. They’re battery operated so there is no danger of zapping yourself – but don’t wind the wick up before turning the TENS unit on! You could be in for a painful experience . . . The Dick Smith Electronics kit comes complete with the self-adhesive pad electrodes (often the hardest part to come by!) and is completely true to the SILICON CHIP design. It sells in DSE stores or via the website for $69.96 (Cat K-3705). Contact: Dick Smith Electronics (all stores) PO Box 500, Regents Park DC NSW 2143. Tel: 1300 366 644 Fax: (02) 9642 9155 Website: www.dse.com.au Bioloid Robot kit from Tribotix The Bioloid Robot kit is very popular amongst hobbyists and educators, with global acceptance in many universities and secondary schools as an excellent teaching aid. The Robot kit can be used to build a vast variety of robot forms. Some examples are the ever popular Humanoid, Walking Droid, Dog, Spider, Snake, Dinosaur or Excavator. The Bioloid has many significant technological advances over other recently released robot kits. The motors are of the “Smart Actuator” kind, which can function as both a traditional servo positioning device and a full-rotation motor. They are fully networked to one another, each with their own onboard micro. The power that an onboard micro provides is impressive with a large range of accessible parameter settings such as torque, speed, current position and target position. A sensor module also comes with the kit providing an impressive array of sensory inputs. The network that binds the motors and sensors together is a simple daisy chain configuration with fixed connectors making wiring easy. All that is required for assembly is a Phillips screwdriver and a pair of long noise pliers. The kit also comes with 3D motion software which enables the user to create complex motion sequences quickly and easily. The user just positions the robot, saves the pose and repeats this action until a complete motion sequence has been saved to onboard flash memory. This motion sequence can then be called by the software, enabling complex sensory/motion interaction to be developed in literally minutes. The control software itself can be written In “C”, for the control module’s Atmel processor, a proprietary Contact: Tribotix GUI-based language. This is popular for PO Box 55, Union Building, Callaghan 2308 secondar y school Tel: (02) 4957 6255 Fax: (02) 4957 8244 Website: www.tribotix.com users. Contribute, Win And Choose Your Prize As you can see from pages 102-104, we pay good money for each of the “Circuit Notebook” items published in SILICON CHIP. But now there are four more reasons to send in your circuit idea. Each month, the best contribution published will entitle the author to choose the prize: an LCR40 LCR meter, a DCA55 Semiconductor Component Analyser, an ESR60 Equivalent Series Resistance Analyser or an SCR100 Thyristor & Triac Analyser, with the compliments of Peak Electronic Design Ltd 62 Silicon Chip 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. TOROIDAL POWER TRANSFORMERS Manufactured in Australia Comprehensive data available Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fax (02) 9476-3231 siliconchip.com.au PC-based Vector Network Analyser Omicron-Lab, represented in Australia by Emona Instruments, has introduced a unique and cost-effective PC-based Vector Network Analyser called the Bode 100. It covers the frequency range 10Hz-40MHz and can be used as a gain phase meter, vector network analyser, impedance meter and sine wave generator. Because of the wide frequency range it is suitable for AF, video and RF applications while its high accuracy and the PC-based control make it ideal for electronic labs as well as for production fields. The remarkably low price of the Bode 100 also makes it ideal for educational institutions, where Vector Network Analysers have usually been out of able receiver impedance (50Ω/1MΩ) gives you full flexibility in your measurement setups. Contact: Emona Instruments Pty Ltd PO Box 15, Camperdown NSW 1450 Tel: (02) 9519 3933 Fax: (02) 9550 1378 Website: www.emona.com.au reach due to their high price. All test results can be imported to word processing software (eg, MS Word) which simplifies documentation, making data processing and sharing of the results possible. The applications of the Bode 100 range from measuring complex transfer functions of amplifiers and filters to measuring the impedance and reflection in the Smith chart to Bode plots of control systems and more. The switch- New Jaycar store at Springvale, Vic. More often than not, the Jaycar Store in Springvale in Melbourne has been the Company’s No.1 Store. But after 19 years, the old store just got too small. Jaycar has opened a new store right on the corner of Springvale Road & Dandenong Highway. The phone number and opening hours have not changed but everything else has. It is twice the size of the old store and has customer parking right at the door. Locals may recognise the building – it was one of Dickie’s up until last year! The store will be staffed by enthusiasts who understand the products they sell and can provide their customers with knowledgeable advice that few other retailers can give. Products include home and car alarm systems, test equipment, video And the winner is... The May monthly winner of one of these superb DSE 20MHz dual-channel ’scopes is Mr F Wentzel of of Perth, Perth, WA Want to be a winner? Simply subscribe to SILICON CHIP (or renew your subscription) and your name could be drawn! See P47 of this issue for full details! surveillance, car audio, electrical and electronic tools, cable, accessories, kits, electronic gadgets and more. Contact: Jaycar Springvale Cnr Springvale & Dandenong Rds, Springvale Vic 3170 Tel: (03) 9547 1022 Fax: (03) 9547 1046 Website: www.jaycar.com.au Looking for waterproof connectors? Look at Altronics... Altronic Distributors have recently been appointed distributor of LTW products in Australia. LTW are an ISO-certified specialist waterproof connector manufacturer, who have been producing connectors solutions for mining, agricultural, industrial and marine use since 1993. LTW connectors are available in IP66, 67 & 68 ratings for use in almost any environment. Altronics have a selected LTW range in stock, including multi-pin circular DIN, D-Sub and RJ45 in both siliconchip.com.au line and chassis types. More specialised LTW lines are available on an OEM basis. Most chassis connectors have a matching screw or locking cap to ensure moisture and dust does not damage equipment when leads are not connected. Contact: Altronic Distributors 174 Rowe St, Perth WA 6000 Tel: (08) 9428 2199 Fax: (08) 9428 2198 Website: www.altronics.com.au July 2006 63 Studio Series Stereo Preamplifier In s t alli n g T h e Mo du le s In A Cas e At last! – here’s how to assemble your highperformance Studio Series preamplifier modules into a professional quality case! By PETER SMITH B ACK IN THE OCTOBER 2005 issue, we described a stereo preamp lifier module that sets new standards in low-cost, high-performance, buildit-yourself audio. The module boasts a minimalist design that typically produces less than .0005% total harmonic distortion and noise. Five relayswitched RCA inputs and a headphone output simplify wiring and minimise audio signal degradation. A matching headphone amplifier 64 Silicon Chip followed in the November issue. This has already proven quite popular and is undoubtedly the cleanest and quiet est we’ve ever described. Although designed for use with the preamp, the headphone amplifier also works as a standalone unit and can be connected directly to the line output of a CD or MP3 player. It has the ability to drive headphones down to 8W impedance with low distortion, while a second output socket allows connection of siliconchip.com.au Altronics are supplying a custom-built laser-cut case for this project, so that the assembly is dead easy. This is a prototype case - the final version has extra ventilation slots to ensure adequate cooling. siliconchip.com.au July 2006 65 Fig.2: follow this basic wiring layout to assemble your unit. Note in particular that all 240VAC mains terminations must be fully insulated and no low-voltage wiring is to be routed on the mains (left) side of the metal partition. The headphone amplifier is mounted on 10mm spacers, whereas all other modules use shorter 6mm types. 66 Silicon Chip siliconchip.com.au siliconchip.com.au July 2006 67 Fig.2: reproduced from the October 2005 issue, this graph reveals the extremely low total harmonic distortion and noise (THD+N) produced by the preamplifier module (the results are the same with the module both in and out of the case). This measurement was taken driving a 50kW load with a 600mV RMS input signal but the results are virtually identical when driving a 1kW load. two pairs of higher impedance units. Then in April this year, we provided details of an infrared remote control module to mate with the preamplifier. Using virtually any universal remote, this module allows you to take charge of the preamp from your lounge chair – an indispensable addition to any audio setup! As promised, this month we wrap up the series by showing you how to install these modules, along with a low-noise power supply, into a lowprofile steel case. To achieve a truly professional appearance, Altronics has produced a laser-cut steel chassis especially for this project. It is similar to their “1U” deluxe rack cases, featuring 2-piece construction and a bevelled front panel. Unlike the standard catalog item, Fig.4: if you’re making your own enclosure, here’s how to install the chassis earth point. Two nuts are used to permanently lock the assembly in place. Make sure that it forms a sound electrical contact with the steel base. 68 Silicon Chip Fig.3: here we’re measuring from one preamplifier input to the headphone output. The 32W and 600W cases exhibit slightly higher THD+N than the standalone headphone amplifier measurements, as we’re now using a smaller input signal to develop 200mW into 32W (ie, 382mV RMS) and 100mW into 600W (ie, 850mV RMS) – so noise (not distortion) becomes a larger overall factor. this custom design includes an internal divider for the 240VAC mains section and is finished in an attractive grey metallic paint. Naturally, the front and rear panels are screen printed with the necessary labelling, so you know what goes where. The finished product looks a lot like what you see in the photos – need we say more? Measuring up So how does the assembled unit perform? Measured individually, the performance of the preamplifier and headphone amplifier modules remain the same as described in their respective articles. This indicates that the layout within the case works well, with no additional noise induced from the mains transformer. The performance of the preamp input to headphone amplifier output is shown in Fig.3. As you can see, the 600W case in particular reveals slightly higher THD+N measurements than in the graph published in November 2005. This is to be expected, as we’re now using a considerably smaller input signal to develop our 100mW output – so noise (not distortion) becomes a larger overall factor in the measurements. Nevertheless, the results are excellent! Cooling down During testing of the completed assembly in a 1U rack case, we were initially concerned about the temperature rise of the power supply module in high ambient temperatures. This issue was resolved by machining additional ventilation slots above and below the supply. We recommend that you do the same if you decide to construct your own case. As noted in the headphone amplifier article, it’s imperative that all three of the voltage regulators are fitted with heatsinks. To maximise heat transfer, insulation pads must not be used between the regulators and their heatsinks. Instead, a thin smear of heat transfer compound is used on the mating surfaces before assembly. Note that without insulating pads, the heatsinks of the LM317 and LM337 regulators will be “live”. After tightening the securing screws, make sure that they are sitting squarely in position, so as not to contact nearby components. To maximise reliability, we also recommend that all of the electrolytic capacitors in the power supply module be upgraded to 105°C temperature rated types. Attention to these small details will ensure that your finished preamplifier provides long and reliable service. Mains wiring We’ll start by hooking up the 240V AC wiring in the unit – see Fig.1. As shown, all the mains wiring is located in the partitioned-off area in the lefthand side of the case. In fact, siliconchip.com.au this area is reserved exclusively for mains wiring! Fit the transformer first, noting that the large flexible washer supplied with the unit must be installed between the transformer and chassis. Orientate the transformer so that the wires exit at the top, with the primary (brown and blue) wires nearest to the rear of the case – see Fig.1. The secondary side terminations (orange, black, white and red wires on the Altronics transformer) can now be fed through the grommetted hole in the partition, ready for connection to the power supply board. Position all the wires so that there will be plenty of clearance to the lid when it is installed later. We expect that the Altronics case will already have a suitable chassis earth point, consisting of a doubleended 6.3mm spade lug fastened securely to the base. If you’re building your own enclosure, position the lug approximately as shown and attach with an M4 x 10mm screw, shakeproof washer and two nuts – see Fig.4 for details. Next, slip the mains rocker switch and IEC socket into their respective cutouts, noting that the earth pin side of the socket must be closest to the chassis earth point. You can now run and terminate the mains wiring. Use only 7.5A or 10A/250VAC mainsapproved cable for all connections. The Active (brown) lead from the transformer will be long enough to extend forward to the switch, with an additional length of brown and yel- low/green cable needed to complete the switch and earth point wiring, respectively. Use small cable ties where applicable to keep everything neat and tidy. Refer to Fig.1 and the photos for all the details. Do not solder the wires directly to the switch or socket pins! These devices are not designed to withstand the high temperatures seen during soldering and may be damaged. Instead, terminate each wire end in a fully insulated 6.3mm female spade crimp terminal. Note that a ratchet-driven crimping tool is required for this job. Low-cost automotive type crimpers are not suitable and their use will result in unsafe connections. Once the mains wiring is complete, go back and check that each connection is secure and well insulated. If necessary, use heatshrink tubing to completely cover any exposed terminations. That done, use your multimeter to check for continuity between the earth pin of the IEC socket and any convenient point on the chassis that is devoid of paint, such as the countersunk screws in the side panels. This test must be repeated later when the top panel of the case is fitted. At that time, use your meter to check that the top and both side panels are earthed. If not, carefully remove the paint from beneath the heads of the retaining screws to ensure a reliable connection. Module installation The modules may be installed into the case in any order, although you may find it easier to leave the headphone amplifier until last. The audio cable passes beneath this module on its way to the remote control module. To avoid hiccups, careful attention must be paid to the following points: • Adjustments to the lead bend of the LEDs and infrared receiver on the remote control module will be required to get everything in line. Ideally, the LEDs should all protrude through the panel by the same amount, while the body of the infrared receiver should just contact the rear of the panel. • If the infrared receiver includes an external metal shield (see photo), then steps must be taken to ensure that it is insulated from the chassis. We suggest a short strip of ordinary insulation tape on the inside of the front panel, with a hole cut out to match the hole in the panel. Do not rely on the paintwork to provide insulation! • All modules apart from the headphone amplifier are mounted atop 6mm untapped spacers and held in place using M3 x 10mm screws, shakeproof washers and nuts. Use taller 10mm spacers for the headphone amplifier only. • Although the preamplifier PC board has four 3mm corner mounting holes, only two of these are used to attach the PC board to the base of the chassis. The other end of the board is held firmly in place by the RCA sockets, which are attached to the rear panel via seven self-tapping screws. Similar mounting arrangements apply to the headphone amplifier and remote control modules soccer ball GO TO www.rsaustralia.com Easier access to over 150,000 electronic, electrical and industrial products siliconchip.com.au July 2006 69 Top: the supply wiring to the various modules is twisted together to improve the appearance and reduce noise. Note the dress of the flat IDC cable between the preamp module and the control module. Bottom: the self-tapping screws that secure the RCA sockets should be tightened before the two chassis-mounting screws for this module. – only the pair of holes furthest from the front panel should be used for mounting. • For the three main modules, fit the base-mounting screws first, winding on the nuts so that they’re only finger 70 Silicon Chip tight. Next, make sure that each module is in firm contact with the front/ rear panel and fit the nuts or screws on the pot shaft, jack sockets or RCA sockets, as appropriate. The idea is to tighten everything gradually, so that no stress is placed on board-mounted components. • Don’t tighten anything up just yet anyway – you’ll almost certainly need to remove one or more boards to run cabling underneath and to get access siliconchip.com.au Par t s Lis t For Complete Preamplifier 1 1U high steel case with internal divider 1 32mm black aluminium knob with grub screw (Altronics H 6236) 1 15V+15V 30VA (or 20VA) toroidal transformer (Altronics M 4915A) 1 SPST 6A 250VAC slimline rocker switch (Altronics S 3202) 1 snap-in fused male IEC socket (Altronics P 8325) 1 M205 500mA 250VAC slow-blow fuse 1 240VAC 3-pin IEC mains power lead 1 6.3mm double-ended chassis-mount spade lug 7 6.3mm female spade insulated crimp connectors Modules 1 preamplifier module (Altronics K 5502) 1 power supply module (Altronics K 5501, Jaycar KC-5418) 1 headphone amplifier module (Altronics K 5503, Jaycar KC-5417) 1 remote control module (Altronics K 5504) Wire & cable 470mm heavy-duty red hook-up wire 470mm heavy-duty blue hook-up wire 470mm heavy-duty brown hook-up wire 940mm heavy-duty black hook-up wire 400mm light-duty purple hook-up wire 650mm figure-8 shielded audio cable (Altronics W 3022) 250mm 7.5A 250VAC brown wire for mains cabling 650mm 7.5A 250VAC green/yellow wire for mains cabling 40mm length of 3mm bore heatshrink tubing 2 10-way IDC cable-mount sockets 390mm 10-way IDC ribbon cable 14 small nylon cable ties Mounting hardware 7 self-tapping screws (supplied with the RCA sockets) 8 M3 x 6mm untapped spacers 2 M3 x 10mm untapped spacers 10 M3 x 16mm pan head screws 10 M3 shakeproof washers 10 M3 nuts 1 M4 x 10mm screw 1 M4 shakeproof washer 2 M4 nuts Where To Buy Complete & Shortform Kits A complete kit of parts for the preamplifier – including the four modules (power supply, preamp, headphone amplifier and remote control) and a pre-punched steel chassis similar to that shown in the photographs – is available from Altronics, Cat. K-5500. The price at time of publication was $299.00. Alternatively, you can purchase a shortform kit that includes just the chassis, transformer and other hardware (but not the PC boards or on-board components) for $154.00 (Cat. K-5500S). Check them out at www.altronics.com.au or phone 1300 780 999 to order. Note: the infrared remote control handpiece must be purchased separately. We used an Altronics AIFA Y2E (Cat. A 1013) with the prototype but almost any universal remote should be suitable. to the terminal blocks for the audio cable wiring. Low-voltage wiring Now for the low-voltage wiring. First, trim the secondary leads of the siliconchip.com.au transformer to the right length, scrape the insulating enamel off the ends and tin them with solder. You should have about 8mm of nicely tinned wire protruding from the spaghetti tubing. That done, twist one start and one finish lead of each winding together to form a centre tap (the black & white leads on the Altronics transformer) and connect all three leads to the power supply module’s AC input (CON1). Before connecting anything to the July 2006 71 “SWITCH” terminal of CON7 on the preamp to the “JACK SW” pad on the headphone amplifier. This connection ensures that the audio signal is routed to either the RCA output or to the internal headphone output, as determined by the insertion and removal of a headphone jack. Important: if the headphone jack switch isn’t connected to the preamp board as described above, then you must insert a shorting link between the two terminals of CON7; otherwise, you’ll get no signal from the RCA out put (CON14)! Grounding The leads of the five red LEDs and the Acknowledge LED (we used blue) are bent at right angles, so that they go through their matching front panel holes. Similarly, make sure that the infrared receiver module lines up with its hole and is flush with the rear surface of the front panel. output of the supply, power up and measure the three rails at the supply outputs (CON2 & CON3). Assuming all is well, the +15V, -15V and +5V rails should all be within ±5% of the rated values. Now switch the power off and physically disconnect the 240VAC mains lead to prevent accidents while working under the hood! The ±15V and 5V cabling for all of the modules can be run next. Use heavy-duty, multi-strand hook-up wire for the job and twist the wires tightly together to reduce noise and improve appearance. Be sure to use the exact connection arrangement shown, with each module having its own set of power leads back to the power supply outputs. If your infrared receiver module has a metal shield like this one, then be sure to insulate it from the front panel as described in the text. 72 Silicon Chip Prepare each wire end by stripping off about 10mm of insulation. Tin the bare ends with solder and then trim them to about 8mm in length. If you’ve done it right, you should be able to fit two wires into one terminal block hole. Audio wiring All audio connections are made using twin (figure-8) shielded cable. Run the cable between the volume pot and CON2/CON3 on the preamplifier module first, positioning it beneath the headphone amplifier. The “left” volume cable should be fed through the large hole just to the rear of CON4 on the remote control board. We’ve labelled the terminal block connections “WIPER”, “GND” and “POT” to make identification easy. To prepare each wire end for connection to its terminal block, strip off about 18mm of the outer insulation, then twist the two shield wires tightly together and tin them with solder. An 8mm length of small heatshrink tubing can then be slipped over the shield wire to improve its appearance. Finally, strip about 8mm of insulation off the red and white wires and tin these as well. The connections to the headphone amplifier inputs are made with RCA plugs so fit these to the cable ends first before wiring the far ends to CON6 on the preamp module. Finally, run a single light-duty wire from the So far, you should have only one wire connected to the chassis earth point – the mains earth wire from the IEC socket. Now run an additional mains-rated green/yellow earth wire from the point marked “EARTH” on the remote control module to the chassis earth point. This solidly earths the body of the volume control pot to prevent motor hash or mains hum finding its way into the audio path. Next, use your meter to make sure that mains earth is not connected to the 0V (GND) rail of the power supply. If it is, you’ll need to find the source of the problem before continuing. Even though we intend to earth the audio input as the next step, it is very important that this occurs only via the provided earth point marked on the preamplifier board. To earth the audio ground, run a second wire from the chassis earth point to the pad marked “EARTH” on the preamp module, again using mainsrated green/yellow wire. Both earth wires should fit into a single spade crimp terminal to mate with the free end of the chassis-mounted lug. This earthing method will reduce the chances of creating an audible “earth loop” in your system but success is not guaranteed! For example, if your power amplifier also earths the audio signal, an earth loop will exist once the two are hooked together. This may or may not be a problem. If you notice more hum in your audio system after connecting the preamp, then try disconnecting the earth wire to the preamp module. Never, ever disconnect the mains earth from the chassis! Well that’s about it. We hope you enjoy listening to your new preamp SC lifier! siliconchip.com.au Salvage It! BY JULIAN EDGAR There’s lots of good bits inside junked photocopiers If you haven’t noticed, these days you can pick up used photocopiers for a pittance. Nope, not pretend little desktop photocopiers but the full-size office monsters that weight 40kg or more. Some are working, some aren’t – but when you pay less than $15, all are excellent salvage value! So what bits and pieces can you get out of a typical photocopier? ➊ ds a epen nts d re’s no e n o p e ll l com ely th usefu nfortunat til you pu but f o r e n – U b u . s t r m u ie an go er less f u’ve and n tocop stepp ality cific pho y what yo DC brush ve large ich u q e e h p ha ve Th ctl the s tors w piers ents g exa any fi lot on f knowin ave as m photoco us AC mo compon e d o h way rt. Some two. Som ynchrono e salvage use of the e h s a h it apa have only thers use lthough t ore), bec 10-$15. T t $ a m o e s n o e u h m j l a S c i . u so h er for ore th seful rs, w (or m moto uch less u orth $50 t spend m ht by tend o g are m be well w wise to n was bou t e r ’s h t e g i mi dh ty, rtain cture unce copier pi photo 0 $15.0 siliconchip.com.au ➋ Inside all photocopiers you’ll find lights and fans. The lights – high voltage, high power incandescent filament bulbs – are used to both illuminate the material to be copied and also as a heater to cook the toner as the photocopied sheets are on their way out of the machine. The latter light often includes an over-temperature switch mounted nearby. In addition, you’ll sometimes find rows of mains-powered neon lamps and/or rows of low-voltage LEDs. Fans consist primarily of conventional PC-type fans (although often running on 24V – but they’ll work down to 12V without problems) but sometimes – if you get lucky – you’ll find a bunch of squirrel-cage fans of the sort that move a lot of air very quietly. These are usually AC mainspowered but a few work on 24V DC. July 2006 73 ➌ You can also be guaranteed of finding an excellent quality lens (typical focal length = 180mm) and a number of mirrors. The lenses are razor sharp and make ideal hand magnifying glasses – they’re also large and bright and some are coated for better light transmission. The mirrors are frontfaced and their length corresponds to the width of the photocopy area. Typically, they’re 10-20mm wide, so they’re long and narrow. To be honest I haven’t found a lot of use for them (except, oddly enough, winding high powered resistors on them!) but if you’re into lasers or other optical systems and need very low-cost, highquality mirrors, they should do the job quite nicely! Rat It Before You Chuck It! Whenever you throw away an old TV (or VCR or washing machine or dishwasher or printer) do you always think that surely there must be some good salvageable components inside? Well, this column is for you! (And it’s also for people without a lot of dough.) Each month we’ll use bits and pieces sourced from discards, sometimes in mini-projects and other times as an ideas smorgasbord. And you can contribute as well. If you have a use for specific parts which can easily be salvaged from goods commonly being thrown away, we’d love to hear from you. Perhaps you use the pressure switch from a washing machine to control a pump. Or maybe you salvage the high-quality bearings from VCR heads. Or perhaps you’ve found how the guts of a cassette player can be easily turned into a metal detector. (Well, we made the last one up but you get the idea . . .) If you have some practical ideas, write in and tell us! 74 Silicon Chip ➍ Even if the photocopier’s main transport system is powered by an AC motor, there will still be a few low-voltage stepper motors inside. For example, if the copier uses a document feeder, there’ll be a stepper buried in that part of the machine. However, occasionally you stumble across gold – huge stepper motors (as big as a man’s fist) with built-in reduction gearboxes. These are highly prized (and if you don’t want them, you can make a good profit “eBaying” them) and can be used to drive robots or 3-axis milling machines, or they can be driven backwards as really “grunty” alternators. Alternatively, you may find an AC motor with a built-in reduction gearbox. The one pictured here has an output shaft speed of just 53 RPM, making it ideal for spinning an advertising sign or the like. Note that most of the extensive gear-train you’ll find inside a copier cannot be extracted whole – not unless you keep the complete chassis intact. Instead, look for sub-gear assemblies that mount on separate baseplates. ➎ There are two completely different classes of switches inside photocopiers. The most numerous are the tiny tactile PC-mounted pushbuttons which are located behind the membrane keypad. By using a heatgun directed at the solder side of the PC board and a pair of pointy-nosed pliers to pull them out, a lot can be salvaged in a very short time. There will also be another pair of switches with very different current ratings to the pushbuttons – the main on/off switch (normally on the back of the photocopier) and a pushbutton switch that goes open-circuit when the top half of the copier is pivoted up for repair or toner replacement. The latter two switches are definitely worth salvaging – they are heavy duty with typical ratings of 16A at 250V AC. siliconchip.com.au ➐ ➏ There’s also a w ho scrounging. The le lot of hardware that’s worth fo 2-position hinges ld-down lid often uses snap-act ion , there are hund re screws, many sp rings, pulleys, ca ds of machine bles and toothed and a bunch of cogs and gears. There’s also som belts, potentially even ething more useful – pa inted or plated metal brackets sheet and panels. Thes e to construct custo are ideal if you need m brackets, mak panel or similar. e And don’t forget a new faceplate very easy to rem th ove (do it first so e glass: it’s usually there’s less chan breaking it!). ce of ➑ Think “photocopiers” and you’re probably immediately thinking of high-voltage power supplies. After all, photocopiers use kilovolts inside! However, while the power supplies are able to be salvaged (most copiers have at least two HV power supplies), there aren’t too many practical uses for a power supply with an output of just 290mA at 5kV! In addition, there’s also usually a conventional linear power supply, typically providing 5.2V at 0.4A and 1.6A at 24V. If you decide to strip these rather than use them whole, you’ll find a range of medium and small aluminium heatsinks that are easily removed. Make sure that any high-voltage capacitors are completely discharged before touching them. When you’re pulling apart a photo copier, there are a few precautions to keep in mind. First, disassemble the copier outside while wearing old clothes – inevitably, toner will get everywhere. Second, some copiers use torsion bar springs to counterbalance the weight of the open top half. These springs are very powerful and if you undo their retaining screws while they’re under tension, they can fly out and possibly cause injury. Other copiers use small gas struts – another excellent salvage part. Finally, the high-voltage power supplies have on-board capacitors that could give a nasty bite – they should be OK if the copier hasn’t been powered-up recently but keep it in mind or you could get a nasty shock. siliconchip.com.au This list of parts hasn’t been exhaustive – I haven’t mention ed the LED displays, the electro-mechanical counter, the electric clutches, bearings or shafts. There are usually plenty of good bits to salvage. But even if you don’t keep a lot of stuff, pulling apart a photocopier is a fun exercise in itself. It’s fascinating to see how the engineers have fitted a complex machine into a compact package. ❾ July 2006 75 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/ Ever wanted to control switched 240VAC outlets with your PC? You can do it with this project which controls two 240VAC outlets. You can switch virtually anything, at any time under full Windows control. It uses your computer’s parallel port and virtually any old (or new) computer can do the job. Features: • Full optical isolat ion protection • Fuse and Power Surge protection • Control two GPOs independently • Control up to 16 GPOs (optional) • Up to 32 timing ev en • Simple PC parallel ts per GPO port connection • Automatically log all • All settings autom actions atically saved • Full access contr ol including passwo rd • Connection to PC required only for switching devices on and off PC-Controlled Design by Trent Jackson T Mkll cludes a password and user access his is the safest way to control level facility which means that the 240VAC appliances from your project could function as a low cost PC’s parallel port. security switch. We have used the parallel port as Interestingly, you don’t need to it is still the most cost-effective way keep your PC turned on permanently to control external devices. Using a is housed in a plastic box with two to control the project since the circuit 3-bit address, up to 16 240VAC mains flush-mounted 240VAC 3-pin sockets. uses latches to retain the switch setoutlets can be controlled from your There are four indicator LEDs under tings until they are changed by the computer using Windows 95, 98, 2000, a Perspex panel. Two of those LEDs incomputer. XP or ME. dicate when one or both of the outputs The PC-controlled Mains switch You can create up to 32 different are switched while timing events and the third indicates save them to a directhat power is present tory for later recall. in the PC switch itThe software will self. The fourth LED actually reload the indicates successful last used settings connection to your the next time that PC. you run the program. Block diagram Applications can Fig.1 shows the range from lightblock diagram of the ing and security to circuit. Eight optoifull-on home autosolators are used to mation. Fig.1: the circuit uses optocouplers for safe islation from 240VAC. connect the PC’s parThe software in80 Silicon Chip siliconchip.com.au Mains Switch allel printer port to the interface which decodes the port addressing and drives two latches, one for each relay. The relays then switch power the 240VAC sockets. The circuit All told, it is a simple concept although the full circuit in Fig.2 (overleaf) looks a lot more complex. So let’s break it down into bite-size chunks. On the lefthand side of the circuit is the 8-bit parallel port and each of the eight data lines is fed to its own optoisolator. Data lines D5, D6 & D7 are coupled via optos to IC1, a 74HC138 1 of 8 decoder which works in conjunction with an 8-way DIP switch. IC1 decodes the 3-bit binary code from the parallel port and pulls one siliconchip.com.au of its eight outputs low as result. The desired output is selected by switching one of the 8-way DIP switches on. The DIP switch outputs are connected WARNING This is a mains-powered device and many sections of the circuit operate at full mains potential and are therefore dangerous. This project should only be constructed by those experienced in mains-powered projects and the testing procedure detailed here must be fully complied with before connection to a PC. via eight diodes to the commoned emitters of optoisolators 5, 6, 7 & 8. So when the desired output of IC1 goes low, it enables the internal transistors of the above-mentioned optos so that they control the relays via IC2 and transistors Q1 & Q2. IC2 is a quad Schmitt trigger NAND gate which is configured as two RS latches or flipflops. Such flipflops have two inputs, Reset & Set; hence the name RS. Notice we can use “latch” and flipflop interchangeably here. They are called flipflops because the outputs can change from high to low or low to high when they received an R or S input and they are called latches because the output states are “latched” permanently until the next input occurs. Each RS flipflop is made of two cross-connected NAND gates and the R & S inputs are each driven by an July 2006 81 82 Silicon Chip siliconchip.com.au optoisolator – nice and simple. But while RS flipflops are simple they do need to be reset each time the power is turned on. This is achieved with diodes D15 & D16 and the associated 22mF capacitors and 220kW resistors. These work as follows: when power is applied, the 22mF capacitors at pin 5 & 13 (reset inputs) of IC2 are at 0V while pins 1 & 9 (set inputs) with just 39pF present can immediately go high. This sets pins 3 & 8 low and keeps transistors Q1 & Q2 off so the relays are unenergised. Subsequently, the 22mF capacitors charge up to 6V via the 220kW and so all the inputs of the latches are under the control of the optoisolators. When power is turned off, diodes D15 & D16 discharge the 22mF capacitors via the collapsed 6V rail. The use of these latches along with addressing ensures that if multiple units are connected to the one PC, the units can retain their switch states. Along with having three optos to control the addressing, four to control the set and reset lines of the two latches, an eighth opto is used to enable IC1. This in turn allows us to use a LED that indicates that the unit is indeed connected to the PC. When the unit is enabled, transistor Q3 becomes forward biased and in turn switches on LED4. On the facing page is Fig.2, the complete circuit diagram.Figs 3 (right) and 4 (below) show the component overlays for the display board and main board, respectively. Not shown on the overlay below is the heatshrink safety covering over the opto couplers. The numbers in green circles (below) correspond to the pin numbers on the D-25 connector. No ground connection Interestingly, the cathodes of all eight optos are not connected directly to the port’s ground return (pins 18-25). Instead, they are switched to ground via transistor Q4, itself controlled by the port’s strobe line (pin 1). Why is this so? The simple answer is that when a PC first boots up all of the lines on the printer port except for the strobe get toggled. If the optos all had their negative returns connected directly to the ground of the PC, the result would that the 240VAC outputs would be erratically switched on and each time you turn on your PC. So, by controlling the return path with Q4 and the strobe signal, the optos are only enabled when commanded by the software. Finally notice the 220W resistor connected between pins 10 & 18-25 on the parallel port D25 connector. This resistor tells the software that a unit is connected, so the software can then initialise and perform accordingly. The software is the real heart of this project while the electronics is just a siliconchip.com.au July 2006 83 dumb interface between the PC’s parallel port and the two relays. Power supply Two supply rails are required for the circuit. 6V for the CMOS ICs and a 12V rail for the two relays. These are derived directly from the 240VAC mains via a bank of three 470nF 250VAC class ‘X2’capacitors and a series 47W resistor, which feed the bridge rectifier. The rectifier’s output is filtered with a 2200mF capacitor and clamped to 12V with a 5W zener diode, ZD1. A 470W resistor and 6.2V zener diode, ZD2, are used to derive the 6V rail from the 12V rail. This 6V rail actually drops down to about 5V or so once under full load with both relays active and all of the LEDs on. Note that the 12V zener diode does not dissipate 5W. In practice, it dissipates 1W or less under the worst case conditions which apply when both relays are off. With both relays on, the 12V rail drops down to about 9V. The relays will actually operate down to 6V or less. Hence, by not having a well-regulated 12V supply we reduce overall power consumption and keep the worst-case power dissipation in ZD1 to a comfortable figure (ie, below 1W or thereabouts). Directly connected across the 240VAC mains line after the 10A fuse is a 47nF c apacitor and a varistor. The 47nF capacitor provides a small degree of filtering for the mains supply while the varistor protects the entire circuit against voltage spikes of more than 275VAC. A 1.2MW resistor connected across the 240VAC mains input and a 100kW resistor in parallel with the three 470nF capacitors ensures that when power is disconnected the capacitors are discharged. Note that by virtue of the bridge This photo of an early prototype has minor changes to the component overlay shown in Figs. 4 & 5 – follow the overlay in case of differences. This shot was also taken before the heatshrink was applied to the right side of the PC board and cable. 84 Silicon Chip siliconchip.com.au Fig. 5: follow this diagram carefully when completing the wiring. Remember that significant portions of the circuit are at mains potential so never work on the project when plugged in and/or without the cover screwed into place. rectifier (diodes D1-D4), the 12V and 6V supply rails are tied close to the Neutral line of the 240VAC mains, so provided you connect to a correctly wired GPO (240VAC socket), most of the circuit is nominally at low potential and quite safe. However, you cannot always depend on this and if your GPO or power cord has Active & Neutral wires transposed, most of the circuit will be at the full 240VAC potential and definitely not safe to touch. That is why we have incorporated the eight high-voltage optoisolators into the circuit. Construction The PC-controlled Mains Switch is housed in a plastic case measuring 196 x 112 x 62mm. The lid is used as the base of the case and has the main PC board mounted on it. The main PC board measures 185 x 104mm and is coded 10107061. Also there is a small PC board to mount the four LEDs. It siliconchip.com.au Computer connection is via a standard 25-pin D connector, which emerges from a cutout in the end of the case, This connector is internally earthed via a length of earth wire back to the mains earth on the PC board. July 2006 85 Figs. 6 (right) and 7 (above): full-size PC board artwork for the display board and main board, respectively. mounts on the bottom of the case, next to the two GPO sockets. A short 6-way ribbon cable with a 6-way connector links the boards together. A 25-pin D socket for the parallel port interface is mounted at one end of the main PC board. A cutout needs to made at one end of the case for this socket. Other cutouts in the case are required for the Perspex window for the four LEDs, the two GPO sockets, the mains fuse and the mains cord cable gland. Before you start assembly of components onto the main PC board, you should use it as a template to drill the lid of the case. You need to mark out the positions of the four Nylon screws and nuts to mount the board. Note: do not use metal screws and nuts to mount the PC board. Having drilled the lid, note that the main PC board also needs cutouts to provide clearance for the four corner pillars in the case. If your board does not have these, you will need to cut and file them. Then use the diagram of Fig.3 to guide you in the PC board assembly. Install the wire links first, followed by the resistors and diodes. Make sure that you install the diodes with correct polarity and ensure that zener diodes are in their correct positions. Next, install the capacitors, making sure that the electrolytics are correctly polarised. Then mount the 8-way DIP switch; note the orientation shown on Fig.3 and in the photos. Then you can mount the two relays, the varistor, the integrated circuits and the four transistors. Finally, install the 25-pin D socket, the 6-way polarised header connector for the LED board and the three 3-way insulated terminal blocks for the 240VAC connections. Do not make Resistor Colour Codes o o o o o o o o o No. 1 8 1 1 11 4 1 3 1 86 Silicon Chip Value 1.2MW (VR25) 220kW 150kW 100kW (1W) 4.7kW 1.2kW 470W 220W 47W (1W) 4-Band Code (1%) brown red green brown red red yellow brown brown green yellow brown brown black yellow brown yellow purple red brown brown red red brown yellow purple brown brown red red brown brown yellow purple brown brown 5-Band Code (1%) brown red black yellow brown red red black orange brown brown greenblack orange brown brown black black orange brown yellow purple black red brown brown red black red brown yellow purple black black brown red red black black brown yellow purple black black brown siliconchip.com.au any connections to 240VAC power at this stage. Next, assemble the LED board, as shown in Fig.4. This board measures 60 x 35mm and is coded 10107062. Four rectangular LEDs and two diodes need to be mounted as well as the 200mm long 6-way ribbon cable which is clamped to the board with a small cable tie. The ribbon cable is terminated in a 6-way plug to match the polarising header connector on the main board. Note that the ribbon cable should be sheathed in heatshrink sleeving, for extra safety. Testing with a DC supply When both boards are complete, they can be connected together via the ribbon cable but do not connect 240VAC to the main board. Instead, it can be safely powered from a variable DC supply capable of delivering between 14V and 16V or thereabouts so you can perform the tests needed without risk. Connect the positive lead to the junction of the three 470nF capacitors and the 47W resistor and connect the negative lead to the Neutral supply line. This connection will let current flow via the bridge rectifier to the 12V zener diode, ZD1. Apply power and you should be able to measure 12V across ZD1 and 6.2V (or close to it) across ZD2 and between pins 16 & 8 of IC1 and pins 14 & 7 of IC2. Assuming that all is as it should be you can now test out the logic on the unit by firstly placing DIP switch 8 in its ON position, with all the rest off. Then connect a wire between 0V and pin 1 of the 25-pin D connector. Now we are going to enable the unit by connecting a wire between the +6V rail and pin 6 of of the 25-pin D connector. This effectively enables the unit and LED4 should come on. If we briefly connect another wire between +6V and pin 4, this should cause relay 1 to switch on; you should be able to hear the click. Do the same with pin 3 and relay 2 should come on. To reset the flipflops and switch off the relays, briefly make a connection between +6V and pin 2 to de-energise relay 1 and between +6V and pin 5 to de-energise relay 2. You should hear both relays switch off. If you haven’t managed to get this far and hear the relays click on & off, siliconchip.com.au Parts List – PC-Controlled Mains Switch 1 main PC board coded 10107061 1 display PC board coded 10107062 1 2mm thick red perspex “window”, 55 x 14mm 2 DPST PC-mount 12V relays with 10A/250VAC contacts (RLY1, RLY2) 1 V275LA20A varistor (MOV1) (Altronics R 4408, Jaycar RN-3400) 1 D-25 PC-mount male connector (CON1) 1 D-25 male connector with backshell 1 D-25 female connector with backshell 2 panel-mount GPO sockets 3 3-way 10A/250VAC terminal blocks 1 3AG panel-mount fuse holder with 10A/250VAC slow-blow fuse 1 waterproof cable gland to suit 240VAC mains lead 2 14-pin IC sockets 1 8-way DIP switch (S1-S8) 1 ‘UB2’ size jiffy box 2 M3 x 10mm (or 12mm) untapped Nylon spacers 4 M3 x 12mm Nylon screws 2 M3 x 20mm Nylon screws 14 M3 Nylon nuts 600mm length of brown and blue 10A/250VAC cable for mains wiring 850mm length of green/yellow 10A/250VAC cable for mains wiring 400mm length of 0.7mm tinned copper wire for links 300mm length of 6-way rainbow cable 2m length of 9-way shielded data cable 220mm length of 10mm diameter heatshrink tubing 70mm length of 85-100mm diameter heatshrink tubing 1 240VAC mains lead with moulded 3-pin plug Semiconductors 6 1N4007 diodes (D1-D6) 12 1N4148 small signal diodes (D7- D18) 1 12V 5W zener diode (ZD1) 1 6.2V 1W zener diode (ZD2) 4 5 x 2mm rectangular red LEDs (LED1-LED4) 8 SFH601-3 or CNY17-3 optocouplers (OPTO1-OPTO8) (do not substitute) 2 BC548 NPN transistors (Q1, Q2) 1 BC558 PNP transistor (Q4) 1 MPSA65 PNP Darlington transistor (Q3) (DSE Z-2088) 1 74HC138 1-of-8 decoder (IC1) 1 74HC132 quad NAND gate (IC2) Capacitors 1 2200mF 16V PC electrolytic 1 100mF 16V PC electrolytic 2 22mF 16V PC electrolytic 2 10mF 16V PC electrolytic 4 100nF 50V MKT polyester 2 39nF 50V MKT polyester 3 470nF 275VAC class ‘X2’ polyester 1 47nF 275VAC class ‘X2’ polyester (code 104, 100n or 0.1) (code 393, 39n or 0.39) (code 474, 470n or 0.47; X2) (code 473, 47n or 0.047; X2) Resistors (0.25W 5%) 8 220kW 1 150kW 11 4.7kW 4 1.2kW 1 470W 1 100kW 1W 1 47W 1W 1 1.2MW VR25 (do not substitute) (Farnell 947-7152) 3 220W Note: the SFH601-3 optocoupler is available from Wiltronics Research, phone 1800 067 674 or see www.wiltronics.com.au. The alternate CNY17-3 is available from Farnell (stock no. 359-8380), phone 1300 361 005 or see www.farnellinone. com.au. Large bore heatshrink is available from www.batterypower.com.au (choose the 125mm flat width product) or your local electrical wholesaler. July 2006 87 The completed project with heatshrink fitted for safety (in the unlikely event of a mains lead “letting go”). Once again, there are some minor component differences between this and the overlay diagrams of Figs. 4&5 shown earlier. If in any doubt, follow those diagrams! don’t go any further with the project until you do. Get some assistance if need be. The case When the PC board is fully checked out, the 240VAC mains wiring for the unit can be done and the rest of the assembly completed. Before proceeding though, you will need to do some more work on the case to provide the cutouts for the 25-pin D socket (in the end of the case), the two GPO sockets, the window for the LED board and holes in the other endo the case for the mains cable gland and the fuseholder. The LED window needs to be 55 x 14mm while the holes for the cable gland and fuseholder are 12.5mm in diameter. Fig.5 shows the complete wiring diagram. All the mains wiring must be run in 250VAC-rated wire and it should be tied in place with cable ties as shown. Don’t forget to run the green/yellow earth wire on the main PC board. This earths the 25-pin D socket. 88 Silicon Chip When all the wiring is complete, you need to fit pieces of heatshrink, to prevent the admittedly unlikely event of a mains wire coming loose and touching the PC side of the optos. The photo above shows the completed project, with both pieces of heatshrink fitted. First, a sleeve of heatshrink is fitted over the entire socket end of the board. After sliding the heatshrink over the D-socket and PC board (back as far as the row of resistors adjacent to the opto isolators) it must of course be shrunk into position. A hair dryer on highest heat should be able to do this but a heat gun will be better (but be careful with those – they can easily melt plastic or damage other components!). After fitting, a small amount of minor surgery will be needed – the corners have to be trimmed out with a sharp knife or blade to match the PC board profile underneath, allowing the PC board to fit into the case. Also, two holes need to be punched or drilled through the heatshrink to allow the mounting screws to pass through. A much thinner length of heatshrink should be used to shroud the ribbon cable between the main and display PC boards. Reality check You should make a few last checks before you connect the PC switch to your computer’s parallel port and power up. First, do a continuity test between Active & Neutral on the power lead with your DMM: if you get a reading of about 1.2MW, you’ve done well. Again with your DMM, make doubly sure that the Earth pin of the plug is connected through to the shell of the D25 socket. Finally, make sure there is no circuit between Active & Earth and Neutral & Earth. If, and only if, all those tests are satisfactory, proceed with loading the software and moving on to the setting up of your PC-controlled switch. siliconchip.com.au Driving the Controller First thing, load the setup for the parallel port. The most usual software (imaginatively named port address for LPT1 is H378, setup.exe; downloadable in a while LPT2 is usually H278. zip file from siliconchip.com. The H3BC base address was au). originally introduced used for Follow the install prompts parallel ports on early video cards. and get the main interface This address then disappeared for program (shown at left/right/ a while, when parallel ports were indifferent) on the screen. later removed from video cards. Assuming that you have They’ve now reappeared somewhat done all the testing as detailed as an option for parallel ports inearlier and given the board a tegrated onto motherboards, upon final sanity check, connect the which their configuration can be unit to your PC’s parallel port changed using BIOS. via a suitable cable (ie, straight One small wrinkle: the PC Conthrough, pin to pin) and power trolled Mains Switch requires the up. use of an “Enhanced Capabilities” By the way, you can dummy- This is the screen which should greet you once the (ECP)-enabled parallel port and at run through the software setup software is loaded and run . . . least originally, H3BC did not supwithout a unit connected, just to see what does what. port ECP. If you have problems with your controller, check that you Click on GPO A’s “manual on” button – it’s at the bottom right have the port set up for ECP and it is a valid address. of GPOA’s panel. Immediately you should see a couple of changes: If the unit’s adthe “LED” image below the switches changes from black to red, dress (set by the while a lightning bolt symbol appears across GPO A - both saying DIP switches) is that GPO A is on. still set to 8, seYou should also see a system message appear in the box at the lect unit 8 on the base of the screen saying, for example, “GPOA Switched ON <at> software, click 06:06:06 06-06-2006” Devilishly clever, what? on the “ON” butNow try the auto part: check your exact system time (double ton for GPO A click on the time at far bottom right of the PC screen). You might and the relay for like to correct the time now if it is out. GPO A should Select a time which is, say, a minute from the current time and click on and the enter it, in 24 hour format, into either GPOA or GPOB along with associated LED the date in DD/MM/YY format, into the “Start Date & Time” panel. should light. Alongside this, enter a stop date and time in similar manner – Now do the same for GPO B: click on the “ON” button and the make it, say, a minute later. Click the “ADD” button and all these other relay should click on and the LED for GPO B should light. details will appear in the appropriate GPO’s window. Now try selecting a few different addresses on the DIP switch and When your PC’s clock changes to the selected minute, you will ensure that all of the logic circuitry is working as it should be. again see the red “LED” and lightning bolt, showing the outlet is This done, you can finalise the settings on the software by setting turned on – and naturally the reverse when it turns off. SC up the access control part, assuming that this is required. Password protection Unless your PC, the Controller and all controlled devices are locked away, password protection would seem to be a bit of overkill (what’s to stop someone pulling a plug, or connecting to another [uncontrolled] outlet?). Still, the option is there, at the bottom of the screen, should you ever need it. The “keys” symbol allows you to log on and off, while the “heads” symbol allows you to set up access control. Parallel port and address The software gives you the option of three different addresses siliconchip.com.au July 2006 89 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 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 Stop those zaps double insulated If you have experienced mild tingles or shocks from double insulated equipment, you will want to know how to prevent them. Here’s our “Tingle Terminator”: a simple solution to this vexing problem. There is no need to gain access inside the equipment and it will not void the warranty. M odern double insulated equipment such as DVD players and digital set top boxes (STBs) can give you a mild electric shock. The experience is not unlike the static zap you sometimes get when alighting from a car in dry weather or from the metal hose of a vacuum cleaner. Such a shock may well reduce your confidence in the safety of the appliance even though there is no inherent fault. Whether or not you experience such a shock will depend on the installation. But perhaps we need to describe the problem first. These days most home entertainment equipment is double insulated. This includes most TV sets (CRT, plasma, LCD, projection, etc), VCRs, STBs, DVD players and amplifiers. This means they are powered from the mains using a 2-pin mains plug – one that does not include a mains earth connection. Normally though, such equipment has a metal case or some exposed metal in its construction. When double insulated, the case is left floating and its safety is reliant upon the insulation between the mains and the metal case. Double insulation does not necessarily mean there are only two layers of insulation. Often there are more than two insulation layers between the mains wiring and any exposed parts. For example, the mains lead is double insulated with a sheath of tubing over the two active and neutral wires. This lead passes through into the chassis using a plastic cord grip grommet that adds further isolation between the mains and the case. The connections inside are also made to ensure insulation is up to standard. Any appliance with Compare the difference in conventional (older) style power supplies (Fig.1, above) with the “switch mode” supplies found in the vast majority of modern electronics (Fig.2, right). In the older style supply, the entire power supply is isolated by the mains transformer but in the switch-mode supply, there are components on the primary side of the high frequency transformer. These can have small leakage currents which can give you a tingle. They’re not (in normal circumstances) dangerous. But they are certainly annoying! 92 Silicon Chip siliconchip.com.au from equipment! By JOHN CLARKE double insulation wiring is marked on the outside of the box with a double rectangular symbol. Older style double insulated items like VCRs and CD players used a 50Hz mains transformer. The transformer is wound on an insulating bobbin with complete isolation between the primary and secondary windings. This supply arrangement is shown in Fig.1. Thus there is no connection between the 240VAC mains supply and the low voltage power supply and so there is complete isolation. More recent double insulated equipment uses a switchmode power supply which is much more efficient and typically consumes much less power If it has this symbol on it (usually on the back) it is double insulated! when on standby. This dispenses with the 50Hz transformer in favour of a smaller, lighter and cheaper high frequency transformer. These highfrequency transformers have a core made of ferrite material rather than the iron used for the 50Hz transformers. This supply can then power a highfrequency driver circuit that switches Inside a modern DVD player. The switch-mode supply is on the brown PC board at the right of the unit – note the size of the high-frequency transformer compared to older conventional power supplies. Also note the interference suppression components close to where the mains voltage is applied. While essential, it’s these which cause the tingle problems. siliconchip.com.au July 2006 93 Here’s how we solved the tingle problem: a single mains (X2) rated capacitor, mounted inside a plastic box stuck on the back of the player. Fig.3 (below) shows the simple wiring necessary. It’s important to note that you are NOT interfering with the Active and Neutral mains wiring – in fact, you don’t even have to open up the DVD player (or other device) case. the primary of a high-frequency transformer at a very fast rate. The switching is typically several hundred kilohertz, much higher than the 50Hz mains frequency. The secondary output of the transformer is isolated from the primary via insulation between the primary and secondary windings. One problem with this type of supply is that it produces electromagnetic interference (EMI), caused by fast switching at the high frequencies. The switching produces harmonics that extend well into the radio spectrum. These must be attenuated in order to comply with EMI standards. This involves using filter circuits with capacitors connected from the switching supply to the output signal earth and the metal case. As you can see in Fig.2, some of this bypassing is on the 240VAC mains side of the supply. These include capacitors C1 and C2. The total amount of capacitive coupling is only relatively small and amounts to about 3.3nF and so the current flow is only a mere 260mA. However, the small current coupled with the high voltages will mean that the metal case of the double insulated item can be sitting as high as 170VAC. If you make a connection between this 94 Silicon Chip charged case and mains earth then you will experience a small zap while the voltage on the case passes through you to ground. In some cases the shock repeats itself once every second or so if the person keeps making contact. The shock is a harmless one and is more a nuisance than a safety concern. Even so, it can be an unnerving experience from a mains-powered product and can raise doubts about the safety of the appliance. Some equipment that has a brushed finish metal case will give nasty tingles even without a direct connection to earth. In normal circumstances you may not notice the floating voltage, for one of two reasons. Firstly, all of your equipment could be floating at this high voltage and with no earthed equipment nearby, there will not be any means to conduct the current. This is typically the case where people have double insulated equipment such as a TV set, DVD player and a VCR all connected together in a timber cabinet. Secondly, when you connect a double-insulated DVD player to an earthed stereo amplifier, for example, the signal earth (and case) of the player will be earthed via the amplifier. This means that any hazard is avoided. However, there can be a shock hazard if you have a bank of double-insulated equipment connected together and earthed equipment nearby. In that case you might get a tingle every time you touch both sets of equipment. The problem can be worse where siliconchip.com.au Fig.4 (right): the wiring is very simple – just make absolutely sure that you attach the earth wire from the Tingle Terminator to the earth pin (and only the earth pin) on the 3-pin plug. The earth pin is always labelled “E”. A side-entry type is used because these have a clamp which holds the wire in place. a sound system is connected to a micro-phone for public address or for karaoke use. It is important that the shell of the microphone is not sitting at around 170VAC with respect to earth! Another problem arises when disconnecting double insulated equipment from equipment that earths the signal. Often a shock will be experienced if the signal leads are disconnected before the mains plug is removed, even if the equipment has been switched off! This is a common situation with a public address system that comprises a mixer, amplifier and a CD/DVD player. This happens often when the DVD player is borrowed and the person using the equipment is not aware of the hazard. The obvious solution to this last problem is to disconnect power before removing the signal leads. However, this is not practical since non-technical people will not necessarily follow this procedure or even be aware that siliconchip.com.au they should disconnect it this way Solving the zap problem A simple solution to all the above problems is to connect the case of a double-insulated appliance to mains earth. This will very effectively remove the shock hazard. However, we do not recommend it, for a number of reasons. First, it could be argued that earthing a double-insulated case decreases safety because an incorrectly wired plug or mains socket can produce a situation where the metal case is directly connected to mains Active. We don’t accept this argument because earthed mains appliances such as fridges, washing machines and microwave ovens are still very prevalent and quite safe. Second, if you modify the mains wiring to a double-insulated appliance such as a DVD player, you will probably void the warranty and pos- sibly cause other circuit hazards – if the job is not done to normal safety standards. Third, earthing the case will definitely cause a hum loop where the equipment is connected to another piece of the earthed gear such as a large stereo amplifier. This will produce a nasty hum in the audio signal and is caused by currents circulating around the loop created by the signal connections and multiple connections to mains earth. Ultimately, the only practical solution is to couple the case of the DVD player (or whatever) to mains earth via a small capacitor. The capacitor value needs to be small enough to cause minimal AC current into the earth but large enough to reduce the case voltage to a low value. We found a 22nF 250VAC class X2 capacitor to be a good compromise. For example, a DVD player which had its case floating at 170VAC had the July 2006 95 Connecting the Tingle Terminator requires only a powerboard or double adaptor. The powerboard itself is unaltered so the other two outlets can be used for other 240V devices (TV, etc) in the normal way. case voltage reduced to 27VAC while not causing hum loop problems. The Magnavox DVD player pictured in this article had a floating case voltage of 82VAC when it was off and 120VAC when it was on. When the capacitor earthing modification was added, these case voltages were reduced to 2.8VAC and 4.5VAC, respectively. Warranty OK, that’s the solution but how do you it without voiding the warranty? You must not modify the existing mains wiring or modify the existing 2-core mains cord and moulded plug. With our approach, you do not have to open the case, which may in itself cause the warranty to be voided. We mounted the 22nF 275VAC capacitor inside a small plastic box which was attached to the rear of the case with double-sided foam adhesive tape. One side of the capacitor is connected to the case via a short lead and eyelet secured by one of the case screws. The other side of the capacitor is connected to mains earth via a single lead terminated (only) to the Earth pin of a side entry 3-pin moulded plug. The side entry plug is used because it has extra clamping that enables thinner cables to be securely clamped. The earth wire is sheathed with tubing in the region of the cord clamp. The earth wire with its 3-pin plug is wrapped around the existing 2-core mains flex and 2-core plug and both are plugged into a 240VAC GPO or mains power board. This arrangement is shown in Fig.4. Fig.3 shows the mounting arrangement for the 22nF class X2 capacitor. It is terminated to a 2-way insulated terminal block with one lead con96 Silicon Chip nected to the earth wire that connects to an existing screw on the case and the other wire to the 3-pin mains plug Earth terminal, as described above. Safety first: wiring the plug While you do not make any changes to the DVD (etc) mains wiring, you do have to connect to the earth pin on a mains plug. If you have never opened up a mains plug before, you need to carefully read and understand the following. Even if you have, read it anyway! There are three pins in a standard (Australian) mains plug. The Active and Neutral are both angled, while the Earth is always vertical and between and below the active/neutral. All three pins are also always la- Parts List – Tingle Terminator 1 3-pin mains side entry plug 1 double adaptor or mains power board 1 length of 250VAC-rated earth (green/yellow) wire (to match length of appliance power cord) 1 short length of earth wire (to suit distance to crimp eyelet) 1 plastic bulkhead box (Jaycar HB-6065 or equivalent) 1 2-way mains terminal block 1 22nF 275VAC X2 capacitor 1 M3 x 15mm screw 1 M3 nut 1 4mm crimp eyelet Length of black spaghetti tubing insulation or heatshrink (optional – for appearance only) Double-sided foam tape or adhesive foam pad belled A (Active), N (Neutral) and E (Earth) – usually inside the plug. It is absolutely vital that you do not connect anything to the A or N pins – and just as essential that you don’t have any strands of wire floating inside the plug which could conceivably short to other pins (the first time you plug it in there would be a brief flash, a bang and a blown fuse – but you want to avoid even that!). Inside the side-entry plug specified you will also find a clamp which helps to hold the wire in place. Normally it clamps three wires in a mains cable but when assembled, the clamp does help to hold the wire in place. Finally, the wire itself should be mains-rated. There is almost no current flow in the wire – that’s not the reason mains-rated wire is specified. It is because the insulation is rated at 240V AC (or better) which means that if for some reason the insulated wire did come into contact with the Active or Neutral pins inside the mains plug, there would be no danger of the insulation breaking down. Ordinary hookup wire insulation is usually rated at 100V or less, so don’t take the chance. We covered the green/yellow earth wire in black heatshrink so it didn’t look so obvious against the black mains lead. Finishing it off Once you have finished wiring the Tingle Terminator and checked the AC voltage with your digital multimeter (both before and after!) to ensure it is working, you should glue the plastic case closed. While there are of course no dangerous voltages inside the case, this does prevent inquisitive fingers poking around. A drop of super glue on the case lid to body join will do this perfectly – and it will also mean that if necessary later, you can “crack” the case open. That’s it! OK, so this approach should solve problems with being zapped by doubleinsulated audio & video equipment. And if you do have to make a warranty claim, remember to completely remove the capacitor box and earth wire and its 3-pin plug from around the mains lead. If they don’t understand it, they’ll blame your Tingle Terminator for any ills your DVD player might have! SC siliconchip.com.au Vintage Radio By RODNEY CHAMPNESS, VK3UG AWA B33: the ultimate Australianmade transistor portable Designed for the well-heeled, AWA’s Radiola B33 was a very impressive transistor portable that tuned the broadcast band and three shortwave bands from 1.6-30MHz. Restoring and aligning it is not the easiest of tasks, however. A WA produced some superb receivers over the years and the 4-band AWA B33 9-transistor portable was one of them. In addition, a broadcast-band only model of this receiver – designated the B32 – was manufactured and this was described in the August 2005 issue. I lamented at the time that I didn’t have a B33 and a few readers responded by offering me sets that were just gathering dust or had been pulled to pieces. In the end, I obtained two of these receivers and this article describes the restoration of one of those sets. Although sets like the B33 were produced, Australian-made multiband transistor receivers were not all that common. Australian manufacturers did produce transistor receivers in quantity during the 1960s and early 1970s but these were mainly broadcast-band sets. However, Japanese manufacturers were starting to flood the Australian market and many of their sets featured one or two shortwave bands in addition to the broadcast band. Despite this, Australian-made transistor radio receivers performed far better than the Japanese offerings but that didn’t stop the flood of imported sets. Japanese sets were cheaper and people wanted the cheaper item – even if it was inferior. During that era, it is arguable that Australian-made transistor receivers were the best performing AM sets in the world. Most other countries had FM as well as AM and their radio stations were not spaced as far apart as in Australia, even in rural environments. As a result, Australian-made radios had to be better performers in order to adequately receive stations over longer distances. Of course, AM in many cases was the poor relation in regards to performance on AM/FM receivers and still is today (except on high-quality communications receiving equipment). Shortwave reception This is the fully restored B33 receiver. Scrounging parts from a second set allowed it to be restored to almost new condition. siliconchip.com.au As well as listening to AM stations, many people also wanted to listen to the many shortwave services available both within Australia and overseas. However, they didn’t want the inconvenience of having a home-installed receiver tethered to an outside antenna. Instead, they wanted a portable receiver that didn’t normally require an outside antenna for “run of the mill” listening. The AWA B33 filled that role but like many receivers of the era, also had provision for an external antenna and July 2006 97 to northern Australia in times of disaster – such as during the recent cyclone Larry. The B33 receiver This view shows the rear of the chassis plate, after its removal from the cabinet. The PC board is mounted upside down on this plate. The front of the chassis plate carries the dial scale and various trimmer capacitors which are used for alignment. The faults in the receiver were all mechanical. earth, which noticeably improved the already good performance. Provision was also made for the connection of an external 9V power source. Used with an outside antenna system, the B33 would have easily received the ABC inland radio services situated near several capital cities. All these stations have since closed down and the Lyndhurst site near Melbourne is now a housing estate! However, the ABC still provides 98 Silicon Chip a service to remote areas of inland Australia from Alice Springs, Tennant Creek and Katherine, on 2310kHz, 2325kHz and 2485kHz at night and 4835kHz, 4910kHz and 5025kHz during the day. Unfortunately, the daytime services from these three 50kW stations can not heard in southern Australia but the night-time frequencies can be received without problems. In addition, Radio Australia at Shepparton, Victoria carries services The AWA B33 was produced around 1965 and is essentially a “high-end” receiver. It has a large 195 x 12mm loopstick antenna with two sets of windings – one for the broadcast band and the second for “shortwave 1” which tunes from 1.6-4.25MHz. The other two shortwave bands tune 4-30MHz and rely on the use of the telescopic whip antenna for signal pick-up when the set is used as a portable. Fig.1 shows the set’s circuit details. The first thing to note is that the bandswitched input circuits are connected to an RF stage based on a 2N2083 transistor (VT9). Its collector signal is then fed via another bank of four tuning coils to a transistor mixer stage based on another 2N2083 (VT10). Most transistor receivers use an autodyne converter stage but not so the B33 which uses a separate oscillator (VT11). This provides better performance and more stable operation. The output from the mixer (VT10) is then fed to a 2-stage 455kHz IF (intermediate frequency) amplifier based on transistors VT3 and VT4. The IF output in turn feeds diode detector MR3 which is then followed by three stages of audio amplification (VT5-VT8). The audio amplifier includes a push-pull output stage and this is coupled directly to a speaker with an 80W centre-tapped voice coil. Hopefully, the speaker will never need changing, as obtaining a suitable replacement would be impossible unless salvaged from another similar receiver. Case details The B33’s case is dark blue/black leatherette, while the front is plastic with vapour-deposited chrome to give it a metal appearance. This is attached to a plastic inner frame. The case is quite substantial for a transistor receiver and measures 320mm long x 200mm high (not including the handle) x 110mm deep (including the knobs). It’s quality is quite good and is noticeably better than the cases fitted to down-market AWA transistor receivers. siliconchip.com.au Fig.1: the circuit for the B33 4-band receiver used nine PNP transistors. Note the transformer-coupled push-pull audio output stage and the centre-tapped 80W loudspeaker. Due to its size, the set is quite heavy, weighing in at 3.6kg, or 4.6kg with its heavy-duty batteries. The set was designed to use the now unobtainable 2761 battery. However, two D-cell battery holders – one for four cells and the other for two cells – will fit into the space that the 2761 occupied, provided the speaker’s terminals are orientated towards the top of the cabinet. In practice, the two holders were wired in series to give 9V. The “output” leads were soldered to the ends of the battery plug to keep things as authentic as possible, with heatshrink tubing fitted over the exposed plug prongs to prevent shorts. Provision has also been made for the attachment of an external 9V power supply. However, there is one important thing to note here: like most transiliconchip.com.au sistor receivers using PNP transistors, this set has a positive chassis. This means that the sleeve of the DC plug must be positive (centre negative). Finally, the B33 is fitted with a bayonet socket on the lefthand end of the receiver. This allows an external antenna and earth to be connected for a worthwhile performance boost. Cabinet restoration The first job in the restoration process was to remove the control knobs and this proved to be a very difficult task – it was if they had been glued in place. Fortunately, I was able to squirt some Inox cleaner/lubricant into the backs of the knobs and also on the control shafts to help free them. The wave change switch had also completely “frozen” and it took some time to work the Inox down the shaft and into the switch sleeve. Eventually, I was able to get it to move but I had to use a small spanner on the shaft to achieve this. Initially, I was concerned that the switch might break but the lubricant eventually did its job, after which the switch operated freely. With the knobs removed, it was now time to remove the chassis from the cabinet. This is achieved by first undoing six screws and removing the escutcheon around the power and antenna sockets. That done, the chassis is lifted up slightly and the screw holding the telescopic antenna in place removed. The chassis is then slid out far enough to allow the centre-tap wire to the speaker to be desoldered, after which it is fully removed from the case (the leads to the voice coil July 2006 99 The leatherette covering was re-attached to the receiver’s plastic inner case using contact adhesive, with a G-clamp and some small pieces of wood used to hold everything together while the adhesive dried. are long enough to be left connected to the speaker). Having removed the chassis, I install ed a longer centre-tap lead to make future work easier. I then undid the four screws holding the speaker in place and removed it, while undoing four more screws allowed the front panel to be removed as well. Finally, I refitted the antenna to the chassis, as this would be needed later for testing. By the way, it’s important not to lose any screws with this sort of job – it can be very time consuming if you have to replace them. My approach is to store all screws in a small container as they are removed. Leaving them laying around the workbench is just asking for trouble, as they are easily lost. Cleaning up Having dismantled the set, it was The B33 receiver came complete with its original instruction manual, as well as an external DC power supply. 100 Silicon Chip time to clean all the parts and repair any damage to the cabinet. A small paintbrush was used to clean the dust from the chassis and PC board, while the cabinet was scrubbed in soapy water using a nailbrush and, for in the awkward spots, a toothbrush. The knobs were also scrubbed clean in soapy water and they look almost like new. Unfortunately, the leatherette covering had come away from the plastic inner case on one side and really looked tatty. This was repaired using contact adhesive, with a G-clamp and two small pieces of wood used to hold everything together while the adhesive dried. This repair was quite satisfactory but in the end, I decided to use the cabinet from the second set, as it was in better condition overall. The dial scale also had to be re-glued to its frame and this was done using clear nail polish. Servicing The B33 is far more complex than its single-band brother and requires disassembly to do any real work. It’s a pity AWA didn’t make it easier for the serviceman. On the other hand, it’s likely that very few of these sets ever required servicing during their lifetime! With the set out of the cabinet, I applied 9V to the PC board and was immediately able to receive some stations. However, as I tuned across the broadcast band, there were more scraping noises than stations. I lubricated all the moving surfaces on the dial tuning mechanism but the problem remained. A subsequent close examination revealed that a number of plates in the antenna and RF sections of the tuning gang were intermittently shorting together. This problem can usually be fixed by gently bending the offending plates but not in this case. In fact, it was quite likely that this tuning gang had been faulty from new, as the oscillator section was perfect. One way around this problem was to use the gang from the other radio. It looked to be in good order and so it was worth a try. However, swapping in the new gang without having the dial cord end up in a mess would be a challenge. First, I released the cord from the pulley at the lefthand end of the drive, which meant that I could then ease siliconchip.com.au VALVES AUDIO HI-FI AMATEUR RADIO GUITAR AMPS INDUSTRIAL VINTAGE RADIO We can supply your valve needs, including high voltage capacitors, Hammond transformers, chassis, sockets and valve books. WE BUY, SELL and TRADE SSAE DL size for CATALOGUE The 2761 9V battery originally used the B33 in no longer available. This problem was solved by fitting six 1.5V cells to two D-cell battery holders, which fit the available space. the dial drum along the gang’s shaft. I then removed the three screws holding the gang to the chassis although this wasn’t exactly straightforward – the middle screw couldn’t be accessed until I removed the screws from the dial drive assembly and gently swung it aside. That done, I replaced the drive assembly and gently eased the drum off while I slid the gang out to the right. It came out without the dial cord coming off the main pulleys which was just what I wanted. Finally, the replacement gang was mounted in position, the drum refitted and the dial cord refitted to the lefthand pulley. It all worked and this time there were no crackles as I tuned across the band, with stations coming in as expected. However, with a new gang fitted, a complete realignment of all the frontend sections was necessary. This was done by placing a signal generator on the other side of the workshop, to give a weak signal into the receiver. One problem I struck was that some of the tuned circuits either had too much or too little parallel capacitance across their trimmer capacitors to allow proper peaking at the high-frequency end of the dial. Apart from that, the procedure was straightsiliconchip.com.au forward, if a little complicated. Overall, this set performs quite well, although the second and third harmonics of the IF amplifier, which occur on 910kHz and 1365kHz, do cause some instability in the form of a whistle. In practice, it is normal for diode detectors to generate harmonics of the fundamental frequency (in this case, 455kHz). However, there is a design deficiency in this set in that the detector output goes to the volume control, which is located right alongside the broadcast-band RF amplifier. As a result, the harmonics from the detector are induced into the broadcast band coils. To prevent this, I tried inserting a miniature 1.5mH RF choke between C37 and C49 and this noticeably reduced the problem. In fact, with a strong signal, the instability was no longer evident. By contrast, in the B32 broadcast-band only version, only C37 is needed. The front-end layout is somewhat different in that model and the IF harmonic problem is not evident. Summary Like the B32 broadcast-band set, the B33 was an expensive receiver. As such, these sets would not have been produced in large numbers. ELECTRONIC VALVE & TUBE COMPANY PO Box 487 Drysdale, Vic 3222 76 Bluff Rd, St Leonards, 3223 Tel: (03) 5257 2297; Fax: (03) 5257 1043 Email: evatco<at>pacific.net.au www.evatco.com.au All receivers that tune from 1030MHz in one sweep, such as this set, are quite critical to tune. AWA overcame this problem by fitting a small bandspread control, concentric with the main tuning control, and this does make tuning much easier. On the other had, these sets are difficult to dismantle and align because of their layout. Care also needs to be taken to avoid damaging the tuning gang when the unit is being aligned at the high frequency-ends of the tuning ranges. In addition, access to the PC board involves desoldering the board from its supports. Perhaps a bit more thought could have been put into making the set easier to service. The much more complicated Barlow Wadley XCR30 (see September, 2002) is simpler to get at, for example, although not easy to align without high-quality equipment. In summary, this is a set that’s well-worth having – especially as it is complete with its instruction manual and a DC power supply (PS9). It now sits alongside its single-band brother SC in my collection. July 2006 101 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. Mains frequency monitor Here is a simple frequency counter designed to monitor the 240VAC 102 Silicon Chip mains supply. It has a frequency range of 0-999Hz, so it could also be used with 400Hz equipment. Standard TTL/CMOS logic is employed for the counters and display drivers, while an ELM446 (IC1) generates accurate 1Hz pulses for gating. This device utilizes a 3.579545MHz crystal for its timebase, as commonly found in TV and siliconchip.com.au siliconchip.com.au Two op amps and their associated components make up a 4th order 1dB dip Chebychev low-pass filter. The filter is tuned to a frequency slightly less than the oscillator frequency, giving a low distortion sinewave output with a 10V supply rail. Malcolm Sharp, Berala, NSW. ($45) through it establish initial conditions for oscillation. Three 2.7nF capacitors and three 22kW resistors act as the phase shift network, shifting the collector signal by 180° before feeding it back into the base circuit. The resultant oscillations are buffered by Q4, which is wired as a simple emitter-follower. This circuit provides a sinewave output with a frequency of approximately 1kHz and an amplitude of around 3Vpeak-peak. It uses four transistors and two op amps and is powered from a 9-13V DC source. The circuit can be broken into three sections, being an RC phase-shift oscillator, a buffer and a low-pass filter. Three transistors and their associated components make up the oscillator. Transistor Q3 acts as a constant current generator for differential pair Q1 and Q2. The 13kW collector load for Q1 together with the constant current RC phase-shift oscillator video circuits and even on old PC motherboards. The mains frequency is sensed on the low-voltage side of the power supply transformer. Each positive going half-cycle illuminates the LED in an optocoupler (OPTO1). A diode (D1) across the input protects the optocoupler from excessive reverse bias voltage during negative half-cycles. In turn, the optocoupler’s phototransistor drives the non-inverting input (pin 2) of a voltage comparator (IC6). The comparator’s job is to convert the slowly changing voltage into a square wave suitable for clocking the counter logic. This is achieved by biased the inverting input (pin 3) at the mid-point of the supply rail. Each pulse from the comparator’s output advances IC4’s count, which occurs about 50 times a second. IC4 is a 3-digit BCD counter, with each of the counter outputs latched on O0-O3 in a time-multiplexed fashion. Further, outputs DS1-DS3 indicate which digit is latched, hence their use to enable the individual LED displays (DISP1DISP3) via transistors Q1-Q3. A BCD to 7-segment decoder/driver (IC5) powers the selected display segments. Referring back to the timebase generator (IC1), you can see that its 1Hz output is gated with the clock signal applied to IC3a. This means that the counter is enabled for exactly one second at a time. At the end of each 1-second period, the accumulated count is latched by a rising edge on pin 10 of IC4, after which the master reset signal on pin 13 clears the count for the next cycle. This timing sequence is generated with the aid of three NAND gates (IC3b-IC3d), together with two simple RC networks. As mentioned, the crystal can be scrounged from any number of sources. The ELM446 50Hz timebase generator is available from www.elmelectronics.com. Readers in areas with 60Hz mains frequencies should order the ELM440, which can be substituted with only minor circuit modifications. Craig Kendrick Sellen, Carbondale, PA, USA. ($40) July 2006 103 Circuit Notebook – Continued Add tick ‘n’ tock to a quartz clock Classical clocks built using quartz movements miss out on one important thing – the comforting tick and tock of passing time. This simple little project idea corrects this deficiency, showing you how to add authentic sound to your master timepiece! You’ll need a small voice recorder, such as the type that attaches to a key ring. You’ll also need access to a real clock – perhaps at a friend’s home, clock dealer or museum. The recorder must have non-volatile memory, such that it doesn’t lose its contents if the battery is disconnected, as well as a replay feature that requires only a brief push on the button. First up, two wires are connected to the replay contacts so that replay can be controlled externally. Check which of these wires is positive with respect to the other, and mark it for later identification. Now record one tick and one tock (not more) from the real clock. Next, open the clock movement and run two wires from the pads that connect to the drive coil. The two pairs of wires may now be connected using the simple circuit shown here. In operation, the lead from the coil pad to the base of Q1 goes to 0V very briefly every two seconds. This brief negative-going pulse turns on the PNP transistor and this in turn activates the recorder long enough to hear a tick and a tock, marking two seconds on a long-case clock. Note that the tick and tock of a clock are different from one another. One sound is due to an impulse action, the other a release, hence the need to record both sounds for an authentic effect. The sound recorder runs non-stop, so it should be powered from a plugpack to save on batteries. Incidentally, a similar idea that uses a piezo transducer to produce a 1-second tick was presented in the November 2004 edition of SILICON CHIP. A. J. Lowe, Bardon, Qld. ($30) ndwyk Joe Bra nth’s o m is this of a r e n win las Test Peak At ent Instrum Simple judging system for photography clubs This simple judging system was designed for use at a photographic club. It consists of three small handheld boxes and an inexpensive multimeter. Each box contains a 12-position rotary switch (set to six positions), which is used to select from a series of taps along a string of 1kW resistors. The boxes are wired in series, such that the total resistance value can vary between 0W and 15kW. The multimeter is set to measure 20kW, with the last two digits blanked off with tape. This gives a convenient display of 0-15. A 100W resistor in series with each box prevents the meter from reading too low. Since installation some years ago, the system has 104 Silicon Chip proven reliable and easy to use. If a multimeter with backlighting was used, the display would be readable in total darkness. However, light spill from the projector makes the display quite readable. Joe Brandwyk, Happy Valley, SA. 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 Interfacing a Picaxe to the 45s voice recorder I’ve built the 45-Second Voice Recorder featured in the May 2005 issue and it works fine. However, I’m trying to interface it with a PICAXE 08M and have encountered some difficulty. Should the output of a PICAXE be enough, when toggled from low to high then back to low, to activate the rewind/playback of the chip when directly connected to pin 23 (/M7_End) of the HK828 via the 10pin IDC header? Or do I require extra components? My original plan had been to replace the Rew/Play switch with a small relay, although I would prefer to interface more directly. (B. B., via email). • It should be possible to control the HK828 voice recorder IC with a PICAXE micro. A falling edge on M1-bar (pin 1) initiates playback, so you’d set the chosen PICAXE port bit as an output, idle high. You’d then pulse it low and back high again. Experiment to find the minimum siliconchip.com.au pulse width – 100ms would be a good starting point. Refer to the HK828 datasheet for more information. It’s available from http://www.honsitak-taiwan.com/list. files/list_pdf/hk828-2.pdf High power 13.5V DC supply I’m looking for a project published years ago in SILICON CHIP or “Electronics Australia” magazine. It was a high current 12V supply using phasecontrolled SCRs in the primary side of the transformer. Any ideas as to when it might have been? (R. C., via email). • The project you refer to was a 13.5V 25A power supply for amateur transceivers, published in the May & June 1991 issues of SILICON CHIP. It used a Triac in the primary of the transformer. We can supply the back issues for $8.80 each, including postage. Garage door remote controller I am building the Garage Door Remote Controller featured in the October 2004 issue. On testing using the manual button on the PC board, the correct response is obtained; ie, Stop, Up, Stop, Down, Stop, Up, etc. However, when using the remote, I usually achieve Up, Down, Stop. It hardly ever stops until it has done a reverse. Why is this so? The above tests have been done on a small 12V motor not connected to anything. Then, when I connect it to the motor coupled to my garage door, it failed to lift the door up (it got up about 30cm) and simply stopped. I have adjusted VR1 and VR2 in various ways to no avail. On a closer inspection, I realise that the output current draw for the kit is not enough to power my motor and lift the door up. Is there a way to increase the current output on the receiver unit or do you have a better suggestion? (R. E., via email). • It’s possible that you have a fault in the RF module. Check that it is properly soldered to the PC board and that the supply is 5V. If these checks are OK, you may need a new module. As far as the limit current is con- July 2006 105 Enhancing The Video Enhancer I refer to the Video Enhancer & Y/C separator described in the August 2004 issue of SILICON CHIP. I have constructed this unit and found that although the adaptive digital comb filtering works well, the edge enhancement does not. Because of the low bandwidth (3MHz) of VHS recordings, the rise time of the highest frequency luminance edges exceeds 100ns. The circuit explanation for the video enhancement states “all signal changes which last longer than selected delay lines will be cancelled out”. I have found that the output of the enhancer with VHS video is essentially zero. The enhancer is bypassed during sync because, as cerned, you can increase this by reducing the sense resistors to 0.1W or by increasing the 220kW resistors associated with IC3a & IC3b. UHF/VHF tuner project for older TV sets I have an old B&W VHF-only TV set sitting in my spare room which I would like to be able to use if I could “upgrade” it to also handle UHF and perhaps also digital as well as analog. My suggestion would therefore allow for any old B&W or older colour TV set to be brought back into service. My idea is that the project might include either a separate VHF & UHF per the article, spikes would be added to the sync. The sync rise time from a VHS recording is about 300ns which exceeds the length of the delay lines by a large amount and would therefore not suffer distortion with spikes on edges. I have checked the circuitry very carefully and all appears to be as it should be. I would appreciate your comments. (D. M., via email). • The length of the longer delay line in the Y/C Separator/Enhancer was indeed something of a compromise, because the full cable length necessary to give a good measure of enhancement to low-bandwidth VHS signals was around six metres. This length was almost impossible to fit inside the box, so we reduced selector knob or an “up” and “down” button with an optional remote control available for both versions. Also, if suitable “black box” tuner units were available that would simplify the design, then so much the better. Among the features of the “adapter” during the construction process would be the ability to either preselect a VHF output channel or allow the user to select the VHF output channel to be fed into the TV when installing the unit. The unit would be powered via a low voltage plugpack and would be located external to the TV as per the attached diagram. Since drawing the diagram I have just noticed that the addition of a 2-digit channel display would be Deep Cycle Battery Charger Has Low Output I have finished building the Deep Cycle Battery Charger (November & December 2004). It all seems to be functioning but I have a question. The battery voltage reported by the unit seems to be lower than what I measure at the battery with a multimeter. For example, the charger shows 14.2V but a measurement across the battery terminals reads 14.5V on a digital multimeter. As you can imagine, I am a bit worried about cooking some expensive batteries. Is this normal or 106 Silicon Chip is there some further testing I can do to find out if there is a problem? I did all the testing and test-point measurement and setup as per the article and it all looks good. (B. D.,via email). • The circuit was designed to compensate for voltage drops across the leads. Make sure you used the specified length and gauge of wire. Alternatively, you can slightly recalibrate the battery reading so it is correct. So adjust VR4 a little for the display reading. it empirically to a length which still seemed to give useful enhancement using the prototype. If you want to achieve better enhancement of VHS signals, you might care to run a short length of cable from the “DL2” terminal pins on the PC board out to a BNC socket added to the rear panel of the box and then use this socket to connect a suitable long length of cable coiled up neatly outside the box. The external cable would have a BNC plug at one end and a short circuit at the other, of course. This external cable arrangement would let you experiment with round-trip delay times and let you achieve the optimum edge enhancement for your system. required in the “up and down button” model. (P. M., via email). • The solution to your quest is quite simple: use any old VCR, preferably one with a working remote control. It will tune over the entire UHF and VHF band. Just plug its modulated output into your old TV’s aerial socket. Reverse display for Speedo Alert In your Speed Alarm kit (November & December 1999 issues), can you tell me how I can get the display to show in reverse? (R. W., Wellington, NZ.) • The display cannot be shown in reverse without changing the lookup table that determines which segments are driven for a particular number to be displayed. This table is located within the software. We have not published or written any revised code for this although it is a very simple change in the lookup table to rearrange the segments that are driven. Motorcycle power for GPS unit I use a GPS on a motorcycle quite often. My son and I go riding in the bush and the GPS stops me from getting lost. I have a problem with the GPS switching off due to battery bounce from the bike vibration. I want to run the GPS from the power siliconchip.com.au Notes & Errata PICAXE-Powered Thermostat, February 2006: the reset signal from the output of the PICAXE is coupled to the rest of the circuit via a 100nF capacitor, whose output is connected to ground via a resistor. On the circuit (Fig.1), this resistor is shown as 22kW in value, whereas on the overlay diagram (Fig.2), it’s shown as 20kW and in the parts list as 100kW. Although all of these lead but my bike is a 1984 model with AC electrics (6V). I was looking for a voltage converter that will step up the 6V AC to somewhere around 10-12V DC as my GPS will run from 8-30V (Garmin GPS12cx). Would the 3V-9V DC-DC converter from March 2004 issue be suitable for this application with some mods or have you produced any other kits that would be suitable? (C. L., Ingham, Qld.) • The 9V DC-DC Converter has a maximum output current of 100mA (ideally), which is probably too low for your GPS. One possible solution would be to modify the “Adjustable DC-DC Converter for Cars” (June 2003). Assuming a 6V AC input and 13.8V DC output with about 500mA maximum load, the following changes to the converter will be required: (1). Replace the two 1000mF input capacitors with 2200mF 25V low-ESR units (Jaycar RE-6330). (2). Replace the 1nF capacitor connected to pin 3 of IC1 with a 680pF ceramic disc type. (3). Replace the 0.1W 5W resistor with values will work, the correct value is 22kW. IO Controller, November 2005: the Windows-based software program can crash after running for an extended period – ie, when the logger reaches its maximum 2048 number. This bug has been fixed and the revised software posted on the SILICON CHIP website. 2 x 0.33W resistors (1W or higher) connected in parallel. (4). Replace MOSFET Q1 with a “logiclevel” type; eg MTP3055EL or Jaycar ZT-2271. (5). Replace D3 with a wire link. (6). Using the specified wire diameter (1.0mm), increase the number of turns on L1 so as to make one complete layer without gaps. We expect that the toroid will accommodate at least five turns more than specified in the construction details. (7). Wire up a 2A (or higher) bridge rectifier (eg, Jaycar ZR-1314 or ZR-1360) between the AC input leads and the converter’s 12V DC input terminals. After construction, be sure to adjust and test the unit on the bench using a transformer and a dummy load. You can use the 6.3V tap of a type 2155 transformer (eg, Jaycar MM-2002) and a 68W 5W resistor would make a suitable load (it will get very hot!). Adjust VR1 to get 13.8V at the output. Once the unit has been tested, the entire assembly should be thoroughly cleaned and all components (apart Want cheap, really bright LEDs? We have the best value, brightest LEDs available in Australia! Check these out: Luxeon 1, 3 and 5 watt All colours available, with or without attached optics, as low as $10 each Low-cost 1 watt Like the Luxeons, but much lower cost. •Red, amber, green, blue and white: Just $6 each! Lumileds Superflux These are 7.6mm square and can be driven at up to 50mA continuously. •Red and amber: $2 each •Blue, green and cyan: $3 each Asian Superflux Same as above, but much lower cost. •Red and amber: Just 50 cents each! •Blue, green, aqua and white: $1 each. Go to www.ata.org.au or call us on (03)9419 2440. from the 0.25W resistors) securely glued to the PC board to prevent vibration related problems later. Depending on your installation, you will probably also need to seal the case to prevent moisture ingress. Spraying the assembly with circuit board lacquer may also help. You might also consider an off-theshelf solution such as Jaycar’s DC-DC Step-Up Converter (Cat. AA-0264) coupled with a rectifier and filter. SC WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. siliconchip.com.au July 2006 107 ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for these pages: Classified ads: $27.00 (incl. GST) for up to 20 words plus 80 cents for each additional word. Display ads: $49.50 (incl. GST) per column centimetre (max. 10cm). Closing date: five 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) 9979 6503, 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 Bankcard o Visa Card o Master Card Card No. Signature__________________________ Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town ___________________________ Postcode______________ Phone:_____________ Fax:_____________ Email:__________________ FOR SALE USB KITS: Gas Sensors (CO, LPG, Alcohol), GPIB Interface, Thermostat Tester, LCD Module Interface, Stepper Motor Controller, PIO Interface, DTMF Transceiver, Thermometer, DDS HF Generator, Compass, 4 Channel Voltmeter, I/O Relay Card, USB via LabVIEW. Also available: Digital Oscillo scope, Temperature Loggers, VHF Receivers and USB ActiveX (and USBDOS.exe file) to control our kits from your own application. www.ar.com. au/~softmark More control solutions for you! NEW iUSBDaq Data Acquisition Module: features 8 12-bit analog inputs, 16 digital I/O, 2 PWM outputs, 1 high speed counter. High sampling rates. 110 Silicon Chip Free software, Labview driver and dll component. N1500LC Load Cell Panel Meter: New Low Cost, Great Accuracy, Fully programmable Indicator with 4-20mA and 2 relay outputs. USB to RS422/RS485 converter: with 1500V Isolation, RTS or Auto Data Flow control. Heaps of other features. Electronic Thermostats: with digital temperature displays, 2 control relays, can be used in heating and cooling. NTC thermistor or J TC or Pt100 sensors. Temperature and Humidity Sensors: Great accuracy, 4-20mA output. Wall and Duct mounting available. Signal Conditioners non isolated and isolated: convert thermocouples, RTDs to 4-20mA or 0-10V Fully programmable. Stepper Motors: we have a selection of Stepper motors for hobby and high torque CNC applications. DC Motors for both hobby and high torque applications. DC, Stepper and Servo Motor controller kits. Counter and Timers: 7-digit and 10year battery operated. Multi Function Timer and Cyclic Timer/ Pulse Generator Serial and Parallel Port relay controller cards. Pump and Trip Alarm controller card. Duty-Standby operation. PIC MicroProgrammers: serial and USB port operated. 2, 4 & 8 Relay Cards: suitable for TTL and Open Collector Outputs. Switch Mode, Battery Chargers and DC-DC converters. Full details and credit card ordering available at www.oceancontrols.com. au Helping to put you in control. PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 9593 1025. sesame<at>sesame.com.au www.sesame.com.au siliconchip.com.au SPK360 3/5/06 1:10 PM Page 1 High End Processors 20 years experience! HEADLINE HI-FISPEAKER REPAIRS Specialising in UK, US and Danish brands. Speakerbits are your vintage, rare and collectable speaker repair experts. Foam surrounds, voice coils, complete recone kits and more. Original OEM parts for Scan-Speak, Dynaudio, Tannoy, JBL, ElectroVoice and others! SPK360 YOUR EXPERT SPEAKER REPAIR SPECIALISTS tel: 03 9647 7000 www.speakerbits.com TAIG MACHINERY Micro Mini Lathes and Mills From $489.00 Stepper motors: 200 oz in $89.00, 330 oz in $110.00 Digital verniers: 150mm $55.00, 200mm $65.00 59 Gilmore Crescent (02) 6281 5660 Garran ACT 2605 0412269707   Laceys.tv ™ 42 Brunel Rd Seaford VIC 3198 Tel (03) 9776 9222 web:www.laceys.tv also Sydney, CoffsHarbour, Ulverstone 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 CLEVERSCOPE USB OSCILLOSCOPES     ELNEC IC PROGRAMMERS High quality Realistic prices Free software updates Large range of adaptors Windows 95/98/Me/NT/2k/XP 2 x 100MSa/s 10bit inputs + trigger 100MHz bandwidth 8 x digital inputs 4M samples/input Sig-gen + spectrum analyser Windows 98/Me/NT/2k/XP  IMAGECRAFT C COMPILERS S-Video . . . Video . . . Audio . . . VGA distribution amps, splitters, standards converters, tbc’s, switchers, cables, etc, & price list: www.questronix.com.au FLANAGAN TRANSFORMERS Australian manufacturer of: • Transformers 1P / 3P • DC power supplies • Custom battery chargers Phone (02) 9824 1095 www.flanagan.com.au WEATHER STATIONS: windspeed & direction, inside temperature, outside temsiliconchip.com.au Best high end DIY audio kits on the planet! www.aksaonline.com perature and windchill. Records highs and lows with time and date as they occur. Optional rainfall and PC interface. Used by government departments, farmers, pilots and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write for our FREE catalog and price list. Eco Watch: phone (03) 9761 7040; fax (03) ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 GRANTRONICS PTY LTD www.grantronics.com.au 9761 7050; Unit 5, 17 Southfork Drive, Kilsyth, Victoria 3137. ABN 63 006 399 480. www.davisinstruments.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 July 2006 111 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. RFMA BiM2-433-64-5V 10mW UHF Transceiver 1~99 Pieces $66.00+GST ea In stock NOW! Range: 250m Tx I: 14mA Rx I: 18mA Data rate:64Kbps 33mmx23mmx4mm 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. Alternative Tech. Association...... 107 Altronics............................. 49,76-79 Amateur Scientist CDs............... IBC Aspen Amplifiers........................ 111 Av-Comm................................... 111 BitScope Designs......................... 13 Dick Smith Electronics............ 34-39 Eco Watch.................................. 111 Elan Audio.................................... 21 Elexol........................................... 49 RF Modules Australia Low Power Wireless Connectivity Specialists Applications Rural Utilities Industrial Commercial Emergency Services Government BiM1-151.300-10 VHF Transceiver 100mW 1~99 Pieces $99.00+GST ea In stock NOW! Range: 5km+ Tx I: 80mA Rx I: 8mA Data rate:10Kbps 33mmx23mmx10mm RF Modules Australia, PO Box 1957, Launceston, TAS, 7250. Ph: 03-6331-6789. Email: sales<at>rfmodules.com.au. Web: rfmodules.com.au QUALITY LED TORCHES, 1-watt R-bin: Fenix L0P, L1P, L2P using AAA, 1 or 2 AA cells. 3-watt: Nuwai QIII, TM-301X-3 using 1 or 2 CR123 cells. AIT Nightstar using no batteries at all! www.torchworld.com.au/sc/ LEDS: SUPERBRIGHTS from just 25 cents each. Flexible LED light strip available off the roll in white and RGB. Silicon Chip Circuit Ideas Wanted Do you have a good circuit idea? If so, sketch it out, write a brief description of its operation & send it to us. Provided your idea is workable & original, we’ll publish it in Circuit Notebook & you’ll make some money. We pay up to $60 for a good circuit idea or you could win some test gear. Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 112 Silicon Chip Advertising Index 12 volt LED lightbars, great for solar/ camping. Nixie clock kit $150. Giant LED clock kit coming soon – 265mm high digits! www.ledsales.com.au POWER LEDs, Super Flux LEDs, 12VDC LED modules & blank PCBs. Quantity discounts. www.luxtronics. com.au Evatco........................................ 101 FreeNet Antennas...................... 110 Furzy Electronics........................ 111 Grantronics................................. 111 Harbuch Electronics..................... 62 Hills Industries.............................. 17 Instant PCBs.............................. 111 Jaycar ........ IFC,53-60,90-91,63,112 JED Microprocessors..................... 5 Laceys TV.................................. 111 Microgram Computers.................... 7 MicroZed Computers.................. 105 Ocean Controls.......................... 110 Quest Electronics....................... 111 Radio Parts.............................. OBC RCS Radio................................. 111 RS Components........................... 69 RF Modules................................ 112 Silicon Chip Bookshop........ 108-109 SC Perform. Elect. For Cars......... 62 WANTED Silicon Chip Subscriptions...... 47,61 WANTED: EARLY HIFIs, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, Ortofon, SME, Western Electric, Altec, Marantz, McIntosh, Goodmans, Wharfedale, Tannoy, radio and wireless. Collector/ Hobbyist will pay cash. (07) 5471 1062. johnmurt<at>highprofile.com.au Silvertone Electronics................ 111 KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au Silicon Chip Technology Awards... 52 Siomar Batteries............................ 3 Speakerbits................................ 111 Taig Machinery........................... 111 Telelink......................................... 23 The Loudspeaker Kit.................... 12 Tribotix.......................................... 63 Worldwide Elect. Components..... 51 PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. siliconchip.com.au