CLAP SWITCH

TITLE:

Simple circuit to activate devices on clap.

CIRCUIT:

COMPONENTS :

Transistor: BC 547       x 3

Resistor : 

                   33 K            x 2 

                   1 M             x 1 

                   5 k               x 1 

                   270 R          x 2

                   47 K            x 2 

 Capacitor:

                   10 uF           x 2

                   1 uF             x 2         

                   100 uF         x 1  

Electret mic   :                 x 1

LED's            :                  x 2

Diodes : 1N4148            x 2

6 V Battery

DESCRIPTION:

• This is the simple clap switch circuit which toggles LED's whenever a clap or tap or a short whistle is detected.The second 10u capacitor is charged via the 56k and 33k resistors.When the sound is detected then negative excursion of waveform takes the positive end of the waveform towards 0 volts rail.        

• The negative end of 10 uF will pull two 1N4148 diodes so that anode ends will have 0 volts on them.As the voltage drops, the transistor in the bistable circuit that is turned on will have 0.6 v on the base while the transistor that is turned off will have 0 volts on the base.

• As anodes of two signals are brought lower transistor is turned on.This will begin to turn off and other to turn on via its 100 uf and 47k.As it begins to turn on transistor that was already turned on will get little dim and thus the two switch over completely.

• In order to interface with other devices , collector of transistor can be taken as buffer transistor.

APPLICATION: 

• This project can be used to turn on light, fan etc.
• This can also be used as a door bell when you have got lot of stuff in your hands and can't ring the door bell.