what is clap switch

Clap switches are the devices used to switch ON and OFF devices with a clapping sound, as a hobbyist of electronics I always wish to switch ON the light without touching on it and even carrying any other object on hand, producing a sound with our normal gesture, much more systematic way to produce sound is clapping.

  In this article we write about clap switch for lights, clap switch projects had different applications for lights in particularly at home automation systems, here we explain about the miniature version of clap switch, they have very few components and having clap ON clap OFF light control.

Circuit explanation of clap switch for lights 

It is an experimental circuit having only had one application to activate the light with a clap, main component used at the clap switch circuit is the condenser mic, followed by that we have two BC547 transistors are the amplifier section for the slight amplification of signal generated at the mic output.

Then next we have CD4017 counter IC, the signal generated on the amplifier section will be passed into the CD4017 IC clock pin, which will lead to trigger the IC.


The CD4017 IC has multiple output pins on that, the first three of the pins will be taken as output in this circuit, along with at we have a relay and a BC547 transistor as the driver component, which is to connect the load at the output of the relay.


clap switch for lights on off circuit
clap switch for lights on off circuit

CD4017 counter IC

cd4017 counter IC
cd4017 counter IC


CD4017 is a counter IC having 16 pins, it could run 10 outputsat a time and they mostly had counter applications, in this circuit itself, we have a counter application.


The whole clap switch circuit depends on the trigger CD4017generated during the operation, the output from the amplifier section connected to the clock pin of cd4017 which will enable clock generation, 15th pin or reset pin connects to 4th pin that is an output pin, which is been for to act as a counter.


We have two outputs pin 2 and pin3, o/p 0 connected to LED for indication, and o/p 1 is our output followed by the relay.


Working of clap switch for lights

When clap sound is produced adjacent to the condenser mic, they pick the sound and generate an equivalent electrical signal and an amplifier circuit amplifies the signal.


The R1 resistor will decide the mic sensitivity, R2, and R3resistors are the drivers for BC547 transistors, after the amplification, the signal from the amplifier section will be passed into CD4017 output block pin14, and they are the clock pin which is to enable the triggering operation.


The pin15 reset pin will be connected towards the output pin3, in this cd4017 IC we have 10 outputs, and each of them will be the transistors, so when we connect the reset pin to certain output pins rest of them will get disabled.


Output pins such as pin3 and pin2 will be enabled, R4 resistors are to drive the LED1 and R5 is for drive LED2, these LEDs are the indicator, which will activate during clap switch circuit become ON.

Clap switch for lights with relay

clap switch for lights on off circuit diagram
clap switch for lights on off circuit diagram


We have two sections for this circuit, initial block that is the LED block will be enable working and both the LED lights will be activated and here we don’t connect heavier loads such as AC loads.

But at this relay section, we activated the relay block and passes the trigger towards the AC power load.

The R6 resistors are used to provide base voltage toward Q3 transistor BC547, which is the driver component for the relay, we know the relay had three connections 1st normally open, 2nd common, and 3rd normally closed.

The normally open NO is connected to the AC power source and common COM connected to bulb load, then connect the AC source and bulb each other.

When the clap sound reaches the mic the indicator LEDs 1 and 2 are activated and the relay switches and AC bulb load glow within a minute of a second.

Pin Diagram of relay


Pin Diagram of relay
Pin Diagram of relay

Advantages and disadvantages of clap switch


  • Few numbers components are used for the circuit
  • We had multiple numbers of applications on the AC load.
  • Circuit making and components cost is very low


  • The frequency of the sound will not be picked correctly.
  • The quality of the relay mostly depends on the life of the whole circuit.  

Applications of clap activated light bulb 

    A different light application such as home automation, vehicular automation, and industrial application is specifically used on LED lamps and emergency lamps of the houses and industrial lighting.

And not only clap switch limited to lighting applications, but also every appliance at home will be activated and controlled using clap switch devices.

1.clap switch circuit using transistor

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