The Clapper is a gadget that uses a sound-activated switch sensitive to hand clapping, to turn off and on any appliance that is plugged into it depending on the number of times you clap.

Step 1: Clapper Circuit Diagram

Components:

C1 = 741 OP AMP
C2 = 555 TIMER
C3 = 4013 Dual D Flip Flop
Q1 = 2N2222 NPN
C1, C2, C3, C4 = .1 uF DISC
C5 = .47 uF Electrolytic
R1, R2, R4, R5, R10 = 10,000 ohms
R6 = 150,000 ohms
R7, R9 = 100,000 ohms
R8 = 1 megaohm
R11 = 220 ohms
R3 = 100,000 ohm trimmer POT
B1 = 9v Battery
K1 = SPST reed Relay 5v DC coil
MIC = Electronic Microphone

Step 2:

What happens inside a CLAPPER:
it has an audio amplifier that has a limiter on the input. Any audio signals that are below a particular threshold will not get through.
When the sound pressure level gets above a certain level it triggers the amplifier which is set to clip â switch on.
This on signal is the trigger to turn on the lights.