This custom built synth, called the “Abyssal” by Atomosynth (who we covered in Make back in the fall) is an analog, photo-noise and oscillating filter synth that features one square wave and saw waveform generator with a large pitch range, from subsonic to ultrasonic sound. Everything is controlled from a large photocell visible from the front that allows it to work as a photo “Theramin”. Pretty cool videos of it in action at the link below.

Abyssal