Jeff Thompson | Blog

After some wrangling with Processing I’ve created a program that writes optical tonewheels in a variety of shapes.  However, I wanted to also be able to include recorded waveforms like optical film sound except in a circle.  The resolution needs to be high and the image scaleable, so distorting a screengrab of a waveform does not work.

Using a little patch I wrote in Max/MSP, I created a list of the average amplitude of a 10-second audio sample.  The result was 10,000 values which were translated into the image above.

Probably not perfect, but at it at least looks really great.

Download the source code (in progress) here.

Similar in theory to optical tonewheels are these rotary encoder.  They’re used for position sensing in robots and high-end machinery.  An optical reader can tell the exact position of the motor shaft to a high level of precision.

An amazingly complicated optical tonewheel.  Not sure who this is made by exactly, though it’s either Jacques Dudon, Daniel Arfib, or Patrick Sanchez.  Collectively, this group made over 1,000 different discs as of 2003.

Via: The Process Photosonique (English translation here) – includes information on making optical “comb filters” for interacting with these discs.