On Sun, 26 Jul 1998, Chuck Rice wrote:

- snip -
> If you just want simple, connect a magnet to the shaft, and put a coil
> around it. It then becomes a small generator. Add a diode, and a zero
> voltage is CCW or stopped (or really slow), and + voltage is CW.
> Should be good enough for a winding machine. -Chuck-

Beware the 'real slow'. Winding machines tend to be run very slowly, and
you need a multi-pole generator for reliable operation, which is more
expensive than a commercial optical quadrature encoder. So use a
quadrature encoder. If on a tight budget, examine the possibility to use
your previous mouse's innards (2 very good quadrature encoders provided,
some assembly required ;). Belt-coupling should be ok, use a flat & wide
VCR belt and a medium VCR belt wheel on the encoder shaft, running the
belt directly on the winding machine's shaft in a safe flat place. Belt
slip should not be a problem with the torque (not) required to turn the
encoder, just don't make the belt too tight.

Peter