A simple and easy electronic project that uses sound to control 220V AC appliances is the clap switch circuit.
We can help you in building each steps for clap switch circuit with a 555 IC and relay in this post.
What is a Clap Switch Circuit using 555 IC and Relay:
A 555 IC and relay are used in a clap switch circuit which is an electronic circuit that allows you to operate a load or device by clapping your hands.
This circuit operates on the basis of sound detection using a 555 timer integrated circuit as a monostable multivibrator to activate a relay which regulates the attached load.
Parts List:
| Component | Quantity |
|---|---|
| Resistors (all 1/4 watt unless specified) | |
| 47k | 1 |
| 1k | 1 |
| 100k | 1 |
| 220Ω | 1 |
| Capacitors | |
| Electrolytic 10μF | 1 |
| Semiconductors | |
| 555 IC | 1 |
| Condenser Microphone (Mic) | 1 |
| Transistor BC547 NPN | 1 |
| LED Red 20mA 5mm | 1 |
| Clap Sound Source | 1 |
| Diode 1N4007 | 1 |
| Relay 9V | 1 |
The circuits central part is the 555 IC that functions as an astable multivibrator.
The normal range of the 555s oscillation frequency is 670–680 Hz.
This configuration functions as a monostable multivibrator which sometimes referred to as a one shot multivibrator.
The external R-C (Resistor-Capacitor) network attached to the 555 IC controls the pulse duration that this circuit generates.
Formulas:
Below are the formulas for Clap Switch Circuit using 555 IC and Relay:
Formula for Pulse Width T:
T = 1.1 × R1 × C1
where:
- T is the pulse width in seconds.
- R1 is the resistance in ohms.
- C1 is the capacitance in farads.
How to Build:
To build a Clap Switch Circuit using 555 IC and Relay follow the below steps:
- Connect the condenser microphone to the input of the circuit.
- The mic will pick up sound and convert it from sound energy to electrical energy.
- Connect a transistor to the output of the microphone.
- When sound is detected it raises the potential at the base of the transistor turning Q1 ON.
- Connect the output of the transistor to the TRIG pin 2 of the 555 IC.
- When the transistor turns ON the potential at TRIG pin 2 becomes low (below Vcc/3) triggering the 555 IC.
- Connect an LED to the output PIN 3 of the 555 IC.
- When the TRIG pin 2 goes low the output at pin 3 becomes high and a positive clock pulse is applied to the internal flip flops causing the LED to turn ON.
Circuit Working:
When you produce a sound near the condenser mic it converts the sound into electrical energy which in turn raises the potential at the base of transistor Q1 turning it ON.
As the transistor turns ON the potential at TRIG Pin 2 of the 555 IC becomes low triggering the IC.
The output at pin 3 becomes high and a clock pulse is applied making the LED turn ON.
The SET state of the flip flop will remain until the next clock pulse.
Advantages and Disadvantages:
Advantages:
- Simple and cost effective circuit.
- Can be used to control various appliances.
- No physical switch required.
Disadvantages:
- Sensitive to background noise.
- Limited range for sound detection.
Clap Switch Circuit with Relay for Operating 220V Appliances
If you want to operate 220V appliances with clap sound then you can use the following circuits which uses a relay for switching all 220V loads.
Applications:
The Clap Switch circuit is not limited to turning LEDs ON and OFF.
It can be applied in various electric appliances such as fans, radios or any other basic circuits that you want to activate using sound.
Conclusion:
Clap Switch Circuit using 555 IC and Relay is a fun and educational project that demonstrates the conversion of sound energy into electrical energy.
With its simple components and working principle it opens the door to creative applications in home automation and electronics projects.
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