I have some aircraft instruments I'd like to be able to use, a couple are ww2 and I'd lik to keep them original, I dont mind bypassing the internal circuit but I dont want to go to the stage of fitting a servo.
I have used the lm1819 to drive air core instruments, in fact I had a couple of boards from old guages with them on, however I'm finding ti difficult to get them now for less than silly money.
Is there a replacement to this ic, or does anyone know of a schem for a simplish circuit to generate the sine and cosine signals.
Maybe I should write some code to do it.
I'd not come across these before and wonder whether they always need two sine/cos waves or will two DC currents still give 360 movement? Could these be driven with two pwm outputs and two H-bridges?
Out of curiosity, could you post some pictures of the instruments?
Isn't that what the sine/cos drivers provide (albeit with selectable polarity)? As I understand it the magnitude of the current is a sine/cos function of the angle you want the pointer to turn to.
Could these be driven with two pwm outputs and two H-bridges?
Thanks cruts for some reason I didnt find some of those.
Pomm, go back to the link cruts posted and looks at the youtube vid, you can see on his 'scope the drive waveform for a vehicle air core guage, I was wondering if a squarewave would work too, and it obviously does, this is the avenue I'll take methinks, these old plane guages were probably designed for sine and cosine wave, but I bet they'll work as well or better with squares.