🚀 go-pugleaf

To construct a real tiny shaft encoder (might cause problems with
the optical part of the encoder) reduce a printout (need not be
very small) of a radial wheel by photograping it (on b/w film?),
and directly using the film as a shaft encoder wheel. That's major
resolution. Perhaps you can make an interference pattern with a 
laser diode, and such a wheel. Two optical diodes can detect the
motion of the interference pattern and with that, the direction
of the wheel turning:             #     laser diode
             ----------------------     wheel 
rotation axis           ^         P     two photo diodes
The photodiodes must be on the same radial distance to the axis,
close to eachother, perhaps with a slit on top of them ?
any comments, catches or flaws ?
ard