Clap Switch is a basic Electronics mini-project, made with the help of the basic components. Clap Switch has the ability to turn ON/OFF any electrical component or circuit by the clap sound.

It is known as Clap Switch, because the condenser mic which will be used in this Project will have an ability to take the sound having same pitch as the Clap sound as the input. Although it doesn’t mean that the sound will have to be of Clap sound, it can be any sound having the same high pitch as of Clap. We can also say that it converts the Sound energy into the Electrical Energy, because we are giving an input to the circuit as a sound whereas the Circuit gives us the output as a LED glow (Electrical Energy).


Required Components:

As already mentioned, this project is basic Electronics mini-project, so this project is made of the basic components. Following is the list of the components required to make the Clap Switch.

1K, 4.7K, 47K, 330 and 470 ohm resistors
10µF and 2 100nF capacitors
Electric Condenser mic
Two BC547 transistors
555 timer
9V Battery


IC555 – Timer IC:

Basically, 555 timer is an 8-pin integrated chip which has capable of producing accurate time delays or oscillation. By connecting different values of resistor and capacitor to a 555 timer we can use it for countless applications.
In simple, it was operating in 3 different modes

  • Astable
  • Monostable
  • Bistable


1. Astable State

“Here the output pulse was continuously switches the state(high – low).”

Once we power up the circuit, there is no stable state in the output. Means, it will oscillate at a particular frequency depending upon the RC (resistor – capacitor) values connected with the 555 timer.

Either we can increase or decrease the frequency by changing RC values.


2. Monostable state

“For a single low trigger input, the output pulse goes to high (we can increase or decrease the ‘high state’ time )and come back to low. “

In simple, its an one pulse mode. By default the output of this circuit will be low (‘0’). when we give a low signal to a trigger pin.

The output will goes to high (‘1’) for a certain time and it will come back to the low state. The time for which the output stays high can be controlled by a suitable RC values.


3. Bistable state

“ It is possible to set the output either high or low, by providing low values for a particular ‘ TRIGGER’ or ‘ RESET ‘ pin.” In this circuit, we have two switches called ‘ TRIGGER’ and ‘ RESET ‘.

Once the TRIGGER is set to LOW, the output will stays HIGH until the RESET set to LOW.
In simple,




Our aim is to switch on the light for a particular time..
so for this kind of application obviously we need to use MONOSTABLE mode.


Working Principle of Clap Switch Circuit:

This circuit (As shown below) is made with the help of Sound activated sensor, which senses the sound of Clap as input and processes it to the circuit in order to give the Output. When sound is given as the input to the Electric Condenser Mic, it is changed into the Electrical Energy as the LED turns on. LED turns ON, as we give sound input and it turns OFF automatically after few seconds. Turn-On LED timer can be changed by varying the value of 100mF capacitor as it is connected with 555 timer whose main purpose is to generate the pulse.

Although the name of the circuit is the Clap Switch, but you are not restricted to give input as the Clap only. It can be any sound, having same pitch as of Clap so this can also be called as “Sound Operated Switch”. This circuit is mainly based on transistors, because the negative terminal of Mic is directly connected with the transistor. In this circuit, we haven’t used any Electronic Switch to turn on/off the circuit, so when you are connecting the battery with the circuit, it means your circuit is now turned ON and it will take the inputs in the form of Sound Energy. You can modify this circuit by using Relay as Electronic Switch to turn the circuit ON or OFF.

As soon as we give the sound input to the circuit, it amplifies the sound signals and proceeds them to the 555 timers which generates the pulse to the LED, making it turn ON. You are to make sure, that the negative side of the Condenser mic is connected with the amplifier or the circuit will heat-up and may not working with different models of transistors etc. You cannot increase the sensitivity of the Condenser mic for long usage, it has short range by default. It is also applicable for the LAMP, so this circuit has many opportunities for modification.



clap clap-switch


Advantages & Disadvantages:

  • It can used to turn ON and OFF the LED or LAMP simply, by clapping your hands.
  • We can also remove LEDs and place a FAN or any other electric component on the output in order to get desired result.
  • The Condenser Mic used in this circuit has the short range as a default, which cannot be varied.



Clap Switch is not restricted to turn the LEDs ON and OFF, but it can be used in any electric appliances such as Tube Light, Fan, Radio or any other basic circuit which you want to turn ON by a Sound.