Angle sensor for stepper

I recently fixed an old fluxgate compass and it occured to be the mechanical heading display would be a useful concept to use in other projects. The display looks very similar to the movement used in analog meters but it allows full 360 movement, similar to the old magslip displays.

I’ve not been able to find a source for these movements and I assume they are no longer made. A stepper would be a good alternative but it would need an absolute position sensor of some kind. A simple sensor e.g. hall effect that detects the zero degrees position would be enough. I assumed they would be easy to find but no luck. Does anyone know a source for either the analog movements or a position sensor that could be used with a stepper? Since the stepper will directly drive the indicator, ideally it would fit directly on the motor spindle.


In some stepper installations (ie. my car dash board) the steppers are "homed" by running them one way to the stop. I mean, if the stepper is 200 steps to move from one extreme to the other, send 205 steps. That way you know that it is against the stop ans is homed. This is, of curse, assuming that no harm is caused by running against the stops.

I think most steppers with a stop aren't full 360. Unless you know different...

Right. A compass would not have stops, I guess.

I use QRE1113 reflective opto sensors to home the stepper in my CNC router rotation axis.

This problem is usually solved with a break beam optical sensor (aka optointerruptor). Put a metal flag on the stepper or indicator shaft, and run the motor until it breaks the beam.