Sound Activated Switch – Relay

  • Rajkumar Sharma
  • 30677
  • medium
  • Tested


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



Parts List

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  • Casaol John Rex

    did this project worked and tested ?

    4 years ago
    • Electronics Lab

      This project is tested and working properly

      4 years ago
    • JRex

      thanks. but why is it that the schematic and the list of materials doesn’t sum up? the IC part.

      3 years ago
  • Adeel

    all projects send me at my email

    3 years ago
  • JRex

    hey! thanks ! ^_^

    3 years ago
  • angella benedict

    hello, it has been a good schematic diagram and i tried and worked very well. thanks so interesting and lovely.

    3 years ago
  • Andy Lee

    Can I get these several products? I will pay for it.

    3 years ago
    • Nlabla

      Are y still wanting some electrical items made if so emakl me at and let me know what u want and we can start makeing those up

      2 years ago
  • deepak

    I want to use through hole components instead. Of. Surface mount device . So what should I use instead of bc847? ? Plz help.

    2 years ago

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