555 timer ic

9 Way Clap Switch Circuit

This Clap Switch Circuit helps you to manage your appliances in your home devoid of getting off from your bed. All you need is to just clap or you can puff  in front of the microphone and after that, the device attached to the microphone becomes “ON” or “OFF”.

The plus points of this circuit are as follow:

  • At the same time,  you can either “ON” or “OFF” up to three devices.
  • To “ON” or “OFF” the device, it is not necessary for you to shift from your place.
  • It will give you visual indication of the appliances also like it is “ON” or “OFF”.

9 Way Clap Switch Circuit Diagram:

Clap Switch Circuit

Circuit Components:

  • IC
  • NE555 – 1
  • 7490 – 1
  • Resistor
  • R1, R2 (10K) – 2
  • R3, R4 (100K) – 2
  • R6, R7, R8, R9 (100E) – 4
  • R10, R11, R12, R13, R5 (1K) – 5
  • VR1 (1K) – 1
  • C1,C2,C3,C4(.1uf) – 4
  • T1 (BC548) – 1
  • T2,T3,T4,T5(BC547) – 4
  • LED – 3
  • MIC – 1
  • RELAY – 4
  • Switch – 1

9 Way Clap Switch Circuit Description:

This circuit is mainly built in the region of the two IC’s  along with a few other components –

  1. NE555 Timer – This IC is set up in a monostable configuration. The 555 acts as a “one-shot” pulse generator in this mode. Timers, lost pulse recognition, bounce free switches, contact switches, frequency separator, capacitance measurement, pulse-width modulation (PWM), and many other applications are just a few examples.

The IC 555 timer is one of the most widely used ICs in the world of electronics, and it is utilised in a wide range of electronic circuits due to its resilience and stability. It is used to generate square-waves with a duty cycle ranging from 50% to 100%. Oscillators can also provide time delay in circuits. The 555 timer gets its name from three 5k ohm resistors.

As you can observe, the trigger input is detained HIGH by the 10 kΩ drag up resistor moreover is pulsed LOW at the time the trigger switch is pushed. The circuit is triggered by a declining edge, that is, by a rapid move from HIGH to LOW.

The trigger pulse, created by pressing the button, has to be of less period than the proposed output pulse.

The period, t, of the output pulse can be calculated from the design equation:

T=1. 1 (R*C)

2. IC 7490 — This IC functions as both a decade and a binary counter. This integrated circuit contains four master slave flip flops, as well as a divided by two and divided by five counter. It can also be used as a divided by 9 counter by connecting Q0 to the clock input pin 1 (CP1) and providing a clock pulse to CP0 (pin 14). By connecting Q0 and CP0 and delivering an input pulse at CP1, this IC can also be used as a divided by 6 counter.

The IC 7490 provides 9 possible combinations for turning on and off the four completely separate appliances in 9 claps. Similarly, the 7492 IC is also available on the market, which provides 11 completely separate sets of output for controlling four different appliances. Another sort of IC, the 7493, is on the market, and it comes in 15 distinct varieties to hold the four appliances.

When you clap or puff on the microphone’s face, the sound of clapping is converted into electrical energy. These weak signals are now amplified by the transistor that acts as a preamplifier. The signal’s sensitivity can be improved with the help of variable resistor VR1. The monostable circuit now receives the output from the transistor T1, which is connected to the NE555 IC.

When you clapped in front of the microphone, IC1’s pin 3 output goes high, and this signal is sent to IC2’s pin 14 clock input. With the help of a 100 ohm resistor, the output of IC2 is now sent to the transistor T2-T4 to drive the relay attached to it. Different colours of LED are also attached to the circuit to indicate the conditions of the various appliances. The presence of a glowing LED signifies that the appliance is “ON,” whilst the absence of a glowing LED shows that the device is “OFF.” The table below shows the stages of the output for the IC7490 (Q0-Q3) for various numbers of claps.

In the above table, logic 1 shows that the corresponding transistor carries out to energize the equivalent relay and the device linked with it activated. While the logic 0 in the above table shows that the device is inactive state.


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