long time, tho i thought i post this up if your still interested.
I bought off ebay an old dashboard off an Honda Civic [postage was 10 times the item cost
]. and have thus ripped it apart for the air coils, tho it has also lots of SM LED's, crystals, a twisly knob thingy [dunno the technical name, but looks like a POT], a buzzer, a massive Zener diode i assume it it from the silk-sheet marking "ZD1", few power resistors, and some other things which i have yet to identify as well as some IC's and capacitors.
Theres got to be some circuitry to regulate the 12V battery down to 5 or 3 volt for the IC's, i assume some mofets, and things labeled "D" - i assume diode but in the silk layer their two terminals are called "A" and "K", i first thought Anode and Cathode, until i realised a second later Cathode is with a "C" :S.
heres some pics of the air-coils which you maybe interested in:
the board
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needle head construction, with counterweight:
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2 of the Air-coils only have 3 pins, i haven't tested those [for fuel and oil temp], the RPM and speedometer have all 4 pins and tested it with a half-dead AA battery and it span round [fairly slowly]
Have a look on ebay for some old dashboards if your interested
.
if you want to make your own aircoils, for the magnets try this guy:
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good luck.
[edit]
sorry for large images, and bad focus, couldent hold it still enoughf apparnetly.