Plugged in a computer-mouse's encoder, 48 slots -> 768 measurable positions.

This guy's a great (unintentional) test of the system's functionality despite somewhat dramatic calibration-error... The software's configured for a sine wave from 0 to 2.5V, (no software change from the previous experiment) and the encoder's outputting 1V to 3V (whoops), yet seems to be working surprisingly well.