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Electrical/Electronics Blogger

Clap Controlled Electronic Switch by 555 Timer and 4013 D Flip-Flop

This electronic switch allows you to control an electronic device by only clapping your hands twice. It is based on three integrated circuits; 741 Op-Amp, 555 timer, and 4013 dual D flip-flop.

A 9V battery is ample to operate the circuit.

When you first clamp your hands, mic detects the sound and triggers the 555 timer via the operational amplifier. The timer stretches the signal and applies it to the clock input of the flip-flop. Because of the three state arrangement of the flip-flop , one more clamp is needed to change the output state. Second clamp sets the flip-flop output to high and this forward biases the 2N2222 BJT. Relay closes so the device connected to the relay switches on. Same procedure applies for the opposite. When you clap your hands twice, relay closes and turns off the device connected to it.

R3 trimpot adjusts the sensitivity of the circuit. You should turn it till the room noise does not effect the switch operation.

Tags: clap, electronic switch, 555 timer,

Comments on this post:

By anna feliciano 0Score: 

5 years ago:  How far can the circuit detects the clap of a person? What if a book falls on the ground and it sounds like a clamp, will it respond to the sound?

By vicky 0Score: 


By manoj mumawat 0Score: 

5 years ago:  hi dear did any one cen tell me that i wana make a circuit for car stereo demonstretion system in my shop so i wana a 8ch cenal push buton flip flop swich circuit.

By christian coronel 0Score: 

5 years ago:  the circuit should not be too sensitive so that it will not respond to a louder sound other than claps...

By chsbarrios 0Score: 

5 years ago:  a 1M pontentiometer will work better, with 100k yo need to clap too close to the microphone

By William 0Score: 

4 years ago:  I don't understand this circuit! I've built it exactly after the Scematic but it just won't work!
I get the Relay to hold if I touch the base of the transistor, but that's all..

By wella 0Score: 

4 years ago:  we also made this circuit, but once the relay is connected to the positive connection, the relay kept on alarming without even clapping the hands....even if you removed any connections from the mic or either the timer, still there is a continuous sound....

By jon 0Score: 

3 years ago:  Is the "2 claps" have a time limit (2 fast claps)? If no, can you redesign the circuit that only allows "2 fast claps" for switching on and vice versa...

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