I’m making progress on the black box to control Seurat. Below is the left half of a recent frame from the program, and below that is a photo of the black box, a breadboard with a small circuit, and an Arduino board.
There are four knobs on the box, two of which are hooked up and two switches which I will mount later. One switch selects the bank of controls to use (I have only six, the number of analogue input pins on the Arduino board). At present I can control color, object size, and frame rate with the knobs and switches. To add: alpha, color velocity, a selector shape.