[simpits-tech] Synchro tests

[Matt Bailey]

This may be old hat for some folks, but for an electronics newbie like
myself, it's pretty exciting! I am working on reading and driving
synchro-based instruments with an Arduino.

Couple of vids......

http://www.youtube.com/watch?v=AY-GBwwTLWM

http://www.youtube.com/watch?v=taccKSUJUj0

One thing I have discovered (for position-sensing, at least): synchros
don't seem to care what voltage you use to energize them with (within
reason), nor do they care much about frequency, or waveform. A simple
square wave from the Arduino is just fine. This is highly
encouraging. :)

It also means that I *may* be able to DRIVE synchros with something
like 60hz household voltage. I'm assuming that if I can energize the
cores of a synchro or resolver enough to get good readable voltages out
of them (as I am currently doing), then I can drive a synchro with
similar waveforms and levels.

A 400hz aircraft inverter yielded the best signal....on the Arduino's
1024 steps of resolution, I was seeing my input levels fluctuate by
only 3 or 4 steps...amazing!!! With the Arduino itself providing the
driver signal to the resolver's stator, the numbers vary by as much as
50, but by the time I break that down into degrees, the variation is
only a degree or so. A third try was with a dedicated signal generator,
which got precision down to better than a degree. Keep in mind this is
all with very basic noise filtering code on the Arduino, and no attempt
at noise filtering in my input circuit.

I am going to try cleaning up the signal the Arduino puts out. Worst
case, I can *probably* just run house voltage (60hz) stepped down to the
synchros in the Sabreliner, which I will need for other equipment
anyway. It's just nice to think I might be able to read resolvers
within a completely self-contained assembly.

-- 
Matt Bailey

Keeping It Real:
Sabreliner 60 Flight Simulator
Serial # 306-61 - N1JX
http://sabrelinersim.com