Home Projects Security and other sensors and detectors Sound Activated Switch


Sound Activated Switch
author: Rajkumar Sharma

This project is a sound activated switch.


Clap switch/Sound-activated switch designed around op-amp, flip-flop and popular 555 IC. Switch avoids false triggering by using 2-clap sound. Clapping sound is received by a microphone, the microphone changes the sound wave to electrical wave which is further amplified by op-amp.

555 timer IC acts as mono-stable multi-vibrator then flip-flop changes the state of output relay on every two-clap sound. This can be used to turn ON/OFF lights and fans. Circuit activates upon two-clap sound and stays activated until another sound triggers the circuit.


- Supply 12V DC @ 60mA
- On board preset to set the sensitivity
- On board LED to indicate the Relay on/off state
- On board Microphone
- Relay switch 5Amps, 110V-230V


click for full resolution


Parts List

PCB Design







120x90 spot



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