On Sat, Jan 7, 2012 at 7:34 AM, Alexis Kotlowy
I still don't know how this could be controlled by 35mm film. The best I
can
think of is a few phototransistors arranged like you would find in a paper
tape machine. This wouldn't produce free flowing changes in voltage. but
would
move up and down in steps.
You run it through a slew limiter.
http://www.synthesizers.com/q105.html