The Clapper, recreated: lights that turn on when you clap

A hobby recreation of the clap switch effect made famous by The Clapper: clap once and the light turns on, clap again and it turns off. This is my own circuit, not the one inside the commercial product, and it switches an LED, not a mains lamp.

An electret microphone picks up the clap and a 2N3904 NPN transistor amplifies it. A CD4013 dual D flip-flop does the rest. The first flip-flop is wired as a one shot: the clap sets it, and a 1M resistor with a 470nF capacitor resets it about a third of a second later, so the whole noisy burst becomes one clean pulse.

That pulse clocks the second flip-flop. Its inverted output feeds its own data input, so it flips on every clap and holds. A second 2N3904 drives a red LED through 220 ohms from 5V. The parts library has no microphone, so the video draws one in the Footprint Editor first, from the CUI (Same Sky) CMA-4544PF-W datasheet.

The Clapper is a trademark of its owner. This build is not affiliated with or endorsed by them.