(Kit - Soldering Required)

sound activated switch
(Click Picture to Enlarge)

Sound Activated Switch

Every wonder how "The Clapper" works?  This circuit will turn on and off based on a loud sound such as clapping your hands.  You can adjust the sensitivity (how loud of a sound will activate the circuit) from a pin drop to a Mack Truck Horn.  Very practical for a variety of projects.  Add a relay to turn on a light when your dog barks, or set of a siren when an intruder makes a loud noise.


  • L: 4-3/8" W: 2-1/2" H: 1/2"
  • Operates on 9 VDC battery.
    (or Use this Power Supply instead of a Battery)
  • Uses an Electret Microphone (very sensitive).
  • Sensitivity can be adjusted via potentiometer.
  • Turns on/off an LED mounted on the board.
  • Has connection for a relay (not included, 9v 500ohm coil recommended). (more info on how relays work)
  • Circuit activates upon sound and stays active until another sound triggers the circuit.
  • Connections for relay on board.

See K36.pdf for complete details, including schematic and theory of operation.  Requires Adobe Acrobat Reader available at for FREE!

Also See K125 - Voice / Sound Activated w/ Relay

Note: This is a kit, you will receive parts to build the item pictured.  If you do not know how to solder you can check out our learn to solder kit. K36 - Sound Activated Switch - $17.95

Quantity and Educational discounts?


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