The Über 540, a circuit bent Casio MT-540. 24 bends, external audio input (& loopthrough) or internal clock for triggering.

Video demo below:

This is a circuit bent Casio MT-540 keyboard. It has 24 “bends”. The upper horizontal aluminum bar has infrared LEDs which face down, and the lower bar has 49 phototransistors (1 for each key) that see the iR light from the LEDs. It has an external audio input which can generate triggers from transients, or it can take triggers from an internal clock. When there is a trigger present and the IR light is blocked by inserting an object or hand between the bars, the corresponding keys are triggered. At the beginning of the video, it is being triggered by my circuit bent Alesis SR-1 drum machine. At 1:30, I switch to internal clock triggering.