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

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A musical flashing pyramid art piece

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A whatchyamacallit

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Peltier effect device

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A medication delivery device

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Digital voltmeter / frequency meter

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Hi-fi amplifier

Electronic projects on separate sub-pages include:
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Computing includes PIC programs

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Models including solar and steam powered cars

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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.

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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!

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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.

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Peltier devices can be used in reverse to generate a voltage from a temperature difference.  Here is the 100W Peltier device generating 126.6 mA at 359.3 mV which is a total of 45 mW.  I have poured liquid nitrogen on to the top surface.

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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.

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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.

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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.


 

This page was last updated January 30, 2011