Turns your awkward "Kinderen voor kinderen" collection into nice noise. Description of this hackerhotel soldering kit:
Small PCB with 4 jack 3.5mm connectors and potentiometer. Turns audio into a squarewave and mixes this with another squarewave. Has a gate and CV input. Only consumes about 2mA at 5V. Accepts line-ish level or piëzo contact microphone signal on the input.
ERRATA: PCB layout error, but it's fixed easily. Stay tuned for the solution...