Early 1970's adventures (long winded post)

[CGS2510.SEP.STUDENT.UCA at CUB.UCA.EDU]

> One experiment that I saw performed went like this: The theater stage has a
> black back drop. Set up in front of it was a laser with the "galvos" and a
> high speed photodetector with a lens. A sequencer is used to step an
> oscillator, the DC from the sequencer drives the X "galvo", the oscillator
> drives the Y "galvo". This produces a series of vertical lines across the
> stage like this |  |  |  |  |  |  | now each of these lines is at a
> different frequency because the oscillator pitch is being changed by the
> sequencer. A dancer in a white leotard gets up on stage. Now wherever the
> laser beam touches the dancer, its reflected back to the photodetector,
> amplified and put out through a speaker. So if the dancer places one hand
> in the beam, a single pulse is output at the frequency of that line. Two
> hands, two pulses and so on.

> You can draw different shapes onto acetate with India ink and tape them to
> the screen with transparent tape. Take a drawing of a tree like structure
> that starts with a single line, splits, splits again and so forth. With the
> CV pedal at the bottom, the signal sweeps through a single interruption and
> outputs a single pulse per sweep. As you increase the control voltage it
> sweeps the two branches and outputs two pulses per sweep etc. For such a
> simple gadget it really has amazing capabilities as a waveshaper.

Have you ever considered using one of the old flying spot tv raster 
generators for test patterns and such for this.  You can find them 
occasionally for real cheap and could have a dedicated digital 
waveshaper like you are describing!