Clap operated  Switch is circuit which turns ON/OFF devices by using  sound. In this circuit Condenser Microphone is ued as main part of circuit. This Mic is used to sense sound signal and converts it into electrical signal. The main controlled action is performed by IC 555 and its circuitry. When Mic receives signal it converts it into electrical one and immediately transfers it to transistor. As those signal have very small voltage they are given to transistor for BOOSTING purpose. IC 555 is get triggered with the help of transistor Q1.

When there is pulse signal at trigger pin of 555 it starts its main work i.e. time delay generation. Here we re using IC 555 in Monostable mode. It has one Stable state and one Astable state means when we clap in front of Mic it produce trigger signal push IC 555 to give OUTPUT for certain period of time known as delay the OUTPUT is in one state either HIGH or LOW for that period of time only. After that it will be like its original or previous state which was there before sound generation.

Here we are using two LEDs  LED1 and LED2. Before clapping LED1 is ON. As soon as we produce sound LED1 turns OFF and LED2 turns ON. It will remain in ON state till the delay produced by IC 555 is not finished. As soon as delay is completed LED2 turns OFF and again LED1 turns ON.

Circuit Diagram:

Component Values:

  •  Resistor: R1 = 10 Kilo Ohm
  • Color code for 1 Kilo Ohm: Brown-Black-Orange-Golden
  • R2= 1 Mega Ohm
  • Color code for 1Mega Ohm: Brown-Black-Black-Yellow-Brown
  • R3= 150 kilo Ohm
  • Color code for 150 Kilo Ohm: Brown-Green-Yellow-Golden
  • R4,R6,R7 = 1 Kilo Ohm
  • Color code for 1 Kilo Ohm: Brown-Black-Red-Golden
  • R5= 560 Kilo Ohm
  • Color code for 560 Kilo Ohm: Green-Blue-Yellow-Golden
  • Transistor:
  • Q1= BC547
  • Light Emitting Diode: LED1,LED2
  • Ceramic Capacitor: C1,C2=104(0.1uF)
  • Electrolyte Capacitor: C3= 10uF
  • IC1= IC 555
  • Condenser Mic
  • Battery: 9 Volts

Circuit Building Steps:

Step 1:

Mount IC 555 on Bread Board a shown below.

Step 2:

Short pins 7 and 6 with the help of wire as shown in image. This makes IC 555 to work in Monostable Mode.

Step 3:

Connect pin 4 and 8 of IC to VCC.

Step 4:

Connect one resistor R1 of 10k on Bread Board. Insert its one terminal into VCC slot and another to vertical lines of Board.

Step 5:

Connect Condenser Mic on Bread Board. Insert its positive terminal to one end of R1 and negative terminal to the Ground slot.

Step 6:

Mount ceramic Capacitor of 0.01uF ob Board.

Step 7:

Connect one terminal of C1 to terminal of R1 where Mic is also connected.

Step 8:

Mount Resistors R2 and R3 on Bread Board.

R2 = 1 Mega Ohm

R3= 150 Kilo Ohm.

Step 9:

Connect second terminal of C1 to junction formed by R2 and R3 through wire. Connet second terminal of R3 to Ground.

Step 10:

Mount transistor Q1 BC547 on bread Board.

Step 11:

Mount Resistor R4 of 1 Kilo Ohm on Board.

Step 12:

Connect Base of Q1 to Resistor R2 and R3 through wire and Collector terminal to R4 by Blue wire and also connect collector of Q1 to pin 2 i.e Trigger pin of IC 555. Connect Emitter of Q1 to Ground through Black wire.

Step 13:

Connect one terminal of Ceramic capacitor  C2 of 0.01uF (103) to pin 5 of IC and anoter terminal to ground through Black wire.

Step 14:

Mount Resistor R5 of 560 K Ohm and C3 of 10 uF on Bread Board. Connect  one terminal of R5 to VCC and another to positive terminal of C3. Negative terminal of C3 is connected to Ground with Black wire.

Step 15:

Mount LED1,LED2, resistors R6 and R7 on Bread Board.

R6 & R7=1 K Ohm

Connect one end of R6  to VCC.

Step 16:

Connect Cathode of LED1 (RED LED) to pin 3 of IC 555 and anode to resistor R6. Connect Anode of LED2(Green LED) to pin 3 of IC 555 through R7 and connect Cathode to Ground.

Step 17:

Connect Battery terminal on Bread board.

When we give power supply to the circuit LED1 becomes ON and it remain in that state until we clap in front of Mic. When we clap LED1 turns OFF and LED2 turns ON after delay of few seconds LED2 turns OFF and again LED1 turns ON.

Working of Circuit

[su_youtube url=”″ width=”720″ height=”480″]