angle sensor for model

Google on 'shaft encoder' - loads of them out there

AWEM

Ones that give an absolute position measurement tend to be expensive, and the ones that would be used e.g., for servo positioning would need zeroing every time you switch on.

What sort of resolution do you need?

Regards, Tony

Thanks

I'm hoping to build a wind direction monitor that feeds to a sail control on a model yacht. I reckon on 10 degree resolution ie 36 sectors is probably all we need, certanly for the mark 1 version anyway.

Richard

Quadrature-Encoders are quite easy to build. A disk with slots (9 in your case) and two optical interrupters (diode photo-transistor combo). And a bit of software in a µC. Built one last Saturday. Less than 30 minutes of coding, more time spent on finding the right resistor-values and mechanically connecting the interrupters. They are very immune to electrical noise and see the direction in which the shaft is rotated. You maybe have to add a reference signal.

HTH, Nick

Still has the bug that you need to zero the encoder every time you turn it on (i.e., it is incremental rather than absolute). You could easily do a Gray code encoder vthe same way - 6 bits of Gray code would give an absolute position readout. Wouldn't be that much harder to do either.

Regards, Tony

QE is 2 bit Gray code. With 1 slot and two pickups you get 4 absolute positions.

ACK, 64 positions

Nick

...but with the 9 slots you proposed, you don't get absolute positioning...

Yep. Or maybe 5 bits if 32 positions is good enough.

Regards, Tony

........oooh, you are naughty! --

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"