Don't know if this will work, but if it does, it's propably been done berfore.
The attached drawing didnīt work, so bear with me
The idea is to use a photoresistor as a "gate" for the output of a sound, serving as a trigger for a bend,
nothing new here.
The photoresistor is put inside a small lightproof housing that has a little hole on one side to let the light in.
under this contraption runs a lightproof rubberbelt 0,5 -1,0cm wide that is set around wheels, sort of like a conveyorbelt or a tapeloop. The wheels are controlled with a varispeed electrical motor.
Under the belt, in line with the photoresistor is a LED or some other light.
On the rubberbbelt one can then pierce holes of different sizes and lengths to let the light thru whenever a hole passes the photoresistor. By measuring the belt these holes can be arranged so that they form a rhytmic loop that can be speeded up and down by controlling the motor that runs the belt.
is that enough explained?
I guess you could transform an old cassettedeck for this purpose and use a looped tape and a paper-punch-hole thingy for the belt..
All sorts of variations come to mind like linking 4 of these with different patterns to the same motor and use a simple "punch in" button for each so you could like... jam.. and stuff..
So, has anyone tried/seen/heard of something like this? Any further ideas on the subject?