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 a highly popular integrated circuit within the realm of electronics, renowned for its robustness and reliability. It finds application in a diverse array of electronic circuits, owing to its capacity to generate square-waves with a variable duty cycle spanning from 50% to 100%. Additionally, 555 timers are instrumental in furnishing time-delay functions within circuits. The nomenclature “555 timer” derives from the inclusion of three 5k ohm resistors in its design.

As evident, the trigger input remains in a HIGH state due to the presence of the 10 kΩ pull-up resistor, and it experiences a momentary transition to a LOW state when the trigger switch is pressed. The circuit is activated by a falling edge, which refers to a rapid shift from HIGH to LOW.

The trigger pulse generated by pressing the button must have a duration shorter than the desired 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 serves a dual function as both a decade and binary counter. It encompasses four master-slave flip-flops along with a division-by-two and division-by-five counter. By connecting Q0 to the clock input pin 1 (CP1) and providing a clock pulse to CP0 (pin 14), it can also function as a division-by-9 counter. Additionally, by linking Q0 and CP0 and supplying an input pulse at CP1, this IC can operate as a division-by-6 counter.

The IC 7490 offers 9 distinct combinations to control four separate appliances using 9 claps. Similarly, the market also offers the 7492 IC, which provides 11 separate sets of outputs to manage four different appliances. Another type of IC, the 7493, is also available in 15 different versions for controlling the four appliances.

When you clap or blow on the microphone’s surface, the sound is converted into electrical energy. These weak signals are then amplified by the transistor, functioning as a preamplifier. The signal’s sensitivity can be adjusted with the variable resistor VR1. Subsequently, the monostable circuit receives the output from transistor T1, which is linked to the NE555 IC.

Upon clapping in front of the microphone, the output at pin 3 of IC1 goes high, and this signal is transmitted to pin 14, the clock input of IC2. The output of IC2 is directed to transistors T2-T4 via a 100-ohm resistor, to activate the connected relay. Various colored LEDs are integrated into the circuit to indicate the status of the various appliances. An illuminated LED signifies that the appliance is “ON,” while an unlit LED indicates that the device is “OFF.” The table below outlines the output stages for IC7490 (Q0-Q3) corresponding to different 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.


Related Articles

Leave a Reply

Your email address will not be published.

Back to top button