555 timer ic

Clap Switch Circuit for Devices using 555 and 4017

The circuit schematic, operation, and applications of the 9-way Clap Switch Circuit have already been discussed. Now we’ll look at a circuit called the clap switch circuit for devices. I’ll show you two clap switch circuits, both of which are based on the 555 and 4017 integrated circuits.

Clap Switch Circuit

Using these circuits, you can control electrical appliances by simple clapping. Summary of the project given below:


  • Clap Switch Circuit Summary
  • Clap Switch Circuit using 555 and 4017
    • Circuit Diagram
    • Components Required
    • PCB for Clap Switch Circuit
  • Clap Switch Circuit for Multiple Devices
    • Circuit Diagram
    • Circuit Components
  • Clap Switch Circuit Description
  • How Clap Switch Circuit Works?

Clap Switch Circuit Summary

  • This circuit is useful if you want to “ON” and “OFF” the gadget without leaving your current location.
  • Another advantage of this circuit is that there is no risk of electrical shock because no direct contact with the mechanical switches is necessary.
  • You will also be given a visual depiction of the gadgets.
  • The fan’s speed can also be regulated using this circuit by connecting the regulator to various outputs.

Clap Switch Circuit using 555 and 4017

In the initial circuit, I’ll be employing a clap switch to manage a solitary relay. Upon the first clap, the relay is triggered, switching the light or any load to the ON state. Upon the second clap, the relay is deactivated, thereby turning off the light.

Circuit Diagram

Components Required

  • 555 IC
  • CD4017 IC
  • Relay
  • Resistors – 100Ω, 560Ω, 4.6KΩ, 18KΩ x 3, 33KΩ
  • Capacitors – 0.1µF x 2, 4.7µF
  • Microphone
  • BC547
  • 1N4004 Diode
  • LED

PCB for Clap Switch Circuit

I have made a simple PCB for the above mentioned clap switch circuit. The PCB layout is shown on the following image.

If you want to make your own PCB, I have included the Eagle CAD PCB Files. You can download them from here.

Clap Switch Circuit for Multiple Devices

In the second circuit (similar to the one above), I have added a few extra relays to control additional devices.

Circuit Diagram

Circuit Components

  • IC
    • IC1(NE555) – 1
    • IC2(CD4017) – 1
  • Resistor
    • R1,R4(10K) – 2
    • R2,R7,R8,R9(1K) – 4
    • R3(2.2K) – 1
    • R5(220E) – 1
    • R6(150) – 1
  • C1,C2(.1uf) – 2
  • C3(1uf) – 1
  • C4(4.7uf) – 1
  • Mic – 1
  • LED – 3
  • T1(BC548) – 1
  • T2,T3,T4(BC547) – 3
  • Relay – 3

Clap Switch Circuit Description

This circuit predominantly relies on two integrated circuits, namely the NE555 timer and the CD4017, in addition to a few other components.

Within this configuration, the IC 555 timer is configured as a monostable oscillator. The NE555 IC monostable function generates a clock pulse, which is employed to produce an oscillating waveform at IC1 pin 3, serving as an output pin in this design. A monostable circuit possesses only one stable state, and it can be externally triggered to return to its initial state.

Another key component is the CD4017, a CMOS counter/divider IC. It receives a clock signal through its clock input, sequentially activating all ten output pins each time it receives a clock input pulse.

To comprehend its operation more thoroughly, it is essential to familiarize oneself with the functions of each pin on these ICs. These integrated circuits feature three input pins, ten output pins, one ground pin, one power supply pin, and one carry-out pin.

The IC’s pin diagram is shown below —

Input Pin:

  • Reset Pin (Pin 15) – The counter is reset to the zero position by this pin. Suppose you wish that the counter will only count till third position then you need linked the fourth pin with 15 pin. So after reaching to the third output it will automatically begin its counting from zero.
  • Clock Pin (Pin14) – In each of the timing pin 14 moves at high the output will be given to you. From the initial clock pulse output will be received at the pin 3 likewise for the next clock pulse output will be received at the pin 2 and so on.
  • Clock Inhibit Pin (Pin 13) — This pin toggles the counter between “on” and “off.” Pin 13 must be in the high condition if the counter is to be turned off. If the pin is set too high, the clock pulse will be ignored, regardless of how long you press the switch, and the count will not advance. In our circuit, pin 13 is grounded.

2. Pin Q0-Q9):

This pin is utilised to get the input in chronological order. For example, pin 3 will produce the first pulse, and so on.

3. Ground Pin (Pin 8) and Supply Pin (Pin 16)

These pins are utilised to provide ground as well as power supply to these ICs.

4. Carry out Pin (Pin 12)

These pins are employed for interconnecting multiple CD4017 ICs. When connecting an additional CD4017 IC, link pin 12 to the clock input of the preceding one. The carry pin of the first CD4017 is linked to the clock input of the second, and the carry pin of the second is linked to the clock input of the third, and so forth. In our particular circuit, we chose to maintain this pin in its designated position.

How Clap Switch Circuit Works?

When someone slaps in front of the microphone, the condenser microphone converts the sound signal into an electrical signal. These impulses are subsequently sent to the transistor T1 base, which causes the IC1 pin2 to be triggered. And the time duration during which the output remains in the high position can be determined using the method below –

T = R5C4 R5C4 R5C4 R5C4 R5*C4

Currently, the output from IC1 pin 3 is sent to CD4017 decade counter 14 pin, which provides a clock pulse for IC2 to function properly. After receiving the clock input, the CD4017 starts counting from zero. And whenever pin 14 moves to high, it moves ahead one at a time (as in front of the mic we clap). For the first clap, we obtain output from pin 2, which means Q1 and LED1 will light up, and the device attached to the relay will begin to operate. The second clap output will be received at pin 4 and LED2 will light up, while LED1 will switch off, and so on. Individual relays must be connected to each output point. The he can control up to ten different devices.


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