Ravensburger 3D Puzzle (e.g. 11248) with LED and clapping mechanism. What's inside the clapper lamp powered by 3xAAA batteries?
There is a 3-way-switch, a piezo element and a PCB. The PCB has on the one side the LED, on the other a small circuit with an ASIC. The piezo-electric is used to receive the clapping sound.