This circuit was intended to activate a relay by means of a hand clap. Further claps will turn-off the relay. An interesting and unusual feature of this project is the 3V battery operation. The ...

Circuit operation is as follows. A single hand clap will be picked up by the electric mic which is coupled through C1 into the op amp IC1. The output of IC1 triggers the 555 IC timer IC2 which is ...

Clap on, clap off -- clap on, clap off -- The Clapper! We've all seen this one advertised on television for years. Instead of using your fingers, just clap to turn your lights on and off. This sound ...