Electronic projects on this page include:
(from the sublime to the ridiculous in reverse order)

Green ring 2002 (below) uses a 6 volt miniature battery, microswitch and a 120 ohm dropping resistor. The green super high intensity Gallium Indium Nitride LED is rated at 14,000 mcd at 20 mA (= 5 mW) and is dazzling in line with its 15 degree beam. They cost A$10. The microswitch is operated by a thumb press.

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3 colour ring 2002

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Three high intensity LEDs (red 8,000 mcd, blue 3,000 mcd, green 14,000 mcd) are flashed at different frequencies although the little battery doesn't handle the full rated power of the LEDs. It uses 3 x 555 IC's, 3 capacitors, 6 resistors, a microswitch and the battery.

Toe ring 2002

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This was a bit of silliness as a one off for a "sock hop' dance to give my toe tapping some visual impact. The red Aluminium Gallium Indium Phosphide LED is rated at 8,000 mcd and is visible through a light pair of socks. It is flashed with a microswitch as your foot hits the ground.

Flashing glasses 1981

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This model was made in about 1981. I think you have to be drunk or stoned to get much pleasure out of these and as I don't do either, they are only brought out on special occasions. It is interesting watching them circulate though a disco from person to person. I haven't lost them yet. They use a 555 timer driving a 4017 CMOS decade LED driver with each leg driving 4 standard low intensity LED's (?20 mcd) with each side rotating in opposite directions and cycling through different colours. There is a speed control to go from standstill to continuously on. It takes a lot of interconnections around the frames. If I was to remake them I would use a smaller rechargeable battery and high intensity LEDs.  The coloured rings are, of course, the appropriate fashion accessory for the glasses.

High power white LED 2004.  This LED (Luxeon Star) is 180,000 mcd and draws 1 watt (350mA at 3.4 V) and was claimed to be the worlds brightest series of LED's in 2003.  Since then 5 W LEDs are available.  It has a heat sink and a separate collimator for a 10 degree beam.  It cost AUD$36 on eBay.  Shown below after I mounted it on some acrylic with a voltage regulator in the handle.  The brightness comparison with a pencil torch is dramatic and is over 10 times brighter than the LED's above. It comes with its specifications on a floppy disk.

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Pyramid 1980's

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This is an electronic art piece made in the early 1980's inspired by a sound only version in a local art gallery. This has a variety of circuits to flash the 50 or so LEDs in various ways. There are 3 mercury switches to sense the position of the pyramid which can be tipped with any of the 3 apices up with different results. It turns on in response to decreasing ambient light intensity hence will turn on as you approach. The actual light intensity controls the flash rate. It 'plays' electronic sounds and also has a door bell chime chip to play 24 tunes in sequence as one of the options. There are no printed circuit boards and all wiring is point to point and supported by the inner and outer pyramids which are also the supply rails.

Solar car (Photoelectric) 2003

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A model  for a school project. Features include two 1 Farad supercapacitors which give an ability to charge in relatively low light and also to drive about 10 yards through a shaded area out of direct sunlight.  The solar panels can be tilted to either side to best catch oblique sunlight. Two LEDs indicate the charging with the high intensity blue LED being visible in sunlight. It can be charged in low light from a light bulb.

Solar Car (Steam powered!)  March 2004
The next childs Dad-assisted school project. Not really electronic but is a contrast with the car above.  This utilised a model steam engine for marine use that I bought 20 years ago. The sunlight is focused by 2 Fresnel lenses (used for reading magnification).  Each beam is reflected to strike the boiler on each side which is blackened to absorb heat. The lens and mirror structures are able to be tilted to aim towards the sun. So far the engine works when externally heated with a burner and has a satisfying red flywheel.  Not enough power to work with sunlight without extra heat assistance.  Note the focusing of the overhead light by the lenses.  A Stirling engine would work better.

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A whatchyamacallit  1980's   Not sure what to call this thing made about 20 years ago.

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It used some sort of transistor oscillator (now covered in tape) driving an E core iron electromagnet at >20 kHz. It runs from a small 9 V battery and has a reed switch in it to turn on. You bring the box of matches with a hidden magnet just visible here close to turn it on. It induces a current in the coil of unknown turns to drive two LED's on a smiley face. The LED's still light up about an inch away.   It still works but I have replaced the LED's after the leads broke and replaced some of the tape.  So, remote signalling and remote power transfer 1980 style!

Peltier effect device (thermo-electric cooler) These are semiconductor heat pumps that use electrical energy to cool one side and heat the other.  This 100W device runs on 15V 6A or so and are meant to cool Pentium like processors.   It requires a good heat sink to get rid of the heat and preferably fan cooled.  There is an optional controller to fix the temperature between 30 - 40 C.

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On the left picture, ice is forming on the top plate while the fan-cooled heatsink is getting hot as it has to handle the 100 W input plus about 50W of heat pumped away from the top plate.  The right picture shows a smaller Peltier device from inside a laser component which I have mounted on a small heatsink and fan.

Medication delivery device (AutoDose) 1990

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This is a device I made in 1990 for use by elderly forgetful patients who may not remember medication times. In essence it is preloaded with one weeks medications. The internal timers then rotate the platter such that the medications are visible to be taken. A light flashes and buzzer sounds until the medications are removed (triggering an infrared beam). It has an internal rechargeable battery which can last a week if unplugged. There are safety interlocks. The most complicated part was designing a programmable timer for up to 4 medications times from scratch using discrete parts.

Power supplies 1971

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My sentimental favourite power supply was made in 1971 and was developed over the years. It appeared in the local newspapers 8 times as a backdrop to photos about two of four state wide talent quest prizes I won between 1970 and 1973. Currently (no pun intended) it is defunct but previously supplied 1-30 V DC at 1 A with a LM317 regulator, and a range of AC voltages from 3 V to 500 V.

Digital voltmeter / frequency meter  1980's

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A combination of two kit projects crammed in a small case made in the 1980's.

Hi-Fi power amplifier 1990

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This was fan cooled and rated at 100 W/channel into 8 ohms.  It was used in my Honda Civic for many years running from a 300 W 12 V / 240 V inverter. It powered a set of efficient large Cerwin Vega speakers with 12 inch woofers which took up all the space behind the front seats.

Computer interfaces 1983

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These were digital to analogue and I/O cards I designed for the VIC-20 computer of about a thousand years ago (even before the Commodore 64). It had 3.5 k of memory (not a misprint) but was an easily understood computer and it was possible to program in 8 bit binary machine language as well as Basic. 

Computer printer / plotter  1984

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