How To Make Simple Clap Switch

How To Make Simple Clap Switch

Today we are going to make a simple clap switch, how to switch on the lights, for a while, with a single clap. This will help us to search some objects in the dark, when you are watching TV or lying on bed.  

Introduction

Clap Switch is a basic Electronics mini-project, made with the help of the basic components. Clap Switch has the ability to turn ON/OFF any electrical component or circuit by the clap sound.

It is known as Clap Switch, because the condenser mic which will be used in this Project will have an ability to take the sound having same pitch as the Clap sound as the input. Although it doesn’t mean that the sound will have to be of Clap sound, it can be any sound having the same high pitch as of Clap. We can also say that it converts the Sound energy into the Electrical Energy, because we are giving an input to the circuit as a sound whereas the Circuit gives us the output as a LED glow (Electrical Energy).

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Components Required

• 1-mic
• 1k
• 4.7k
• BC547 X2
• 470R
• 0.1uf X2
• 47k
• 100uf
• 330R
• 555 timers
• led
• 9v battery

 Principle

This circuit (As shown below) is made with the help of Sound activated sensor, which senses the sound of Clap as input and processes it to the circuit in order to give the Output. When sound is given as the input to the Electric Condenser Mic, it is changed into the Electrical Energy as the LED turns on. LED turns ON, as we give sound input and it turns OFF automatically after few seconds. Turn-On LED timer can be changed by varying the value of 100mF capacitor as it is connected with 555 timer whose main purpose is to generate the pulse.

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Although the name of the circuit is the Clap Switch, but you are not restricted to give input as the Clap only. It can be any sound, having same pitch as of Clap so this can also be called as “Sound Operated Switch”. This circuit is mainly based on transistors, because the negative terminal of Mic is directly connected with the transistor. In this circuit, we haven’t used any Electronic Switch to turn on/off the circuit, so when you are connecting the battery with the circuit, it means your circuit is now turned ON and it will take the inputs in the form of Sound Energy. You can modify this circuit by using Relay as Electronic Switch to turn the circuit ON or OFF.

As soon as we give the sound input to the circuit, it amplifies the sound signals and proceeds them to the 555 timers which generates the pulse to the LED, making it turn ON. You are to make sure, that the negative side of the Condenser mic is connected with the amplifier or the circuit will heat-up and may not working with different models of transistors etc. You cannot increase the sensitivity of the Condenser mic for long usage, it has short range by default. It is also applicable for the LAMP, so this circuit has many opportunities for modification.

Working

Consider the above circuit into 2 parts, the job of the left part of this circuit is to give the low signal to the right part, which has 555 timer.

We already seen the right part of the circuit in “ how to get the monostable output using 555 timer “. According to that, all we have to do is to provide a low signal to the 555s TRIGGER pin (pin 2) to switch on the light for a desired time.

NOTE : By default T1 is on and T2 is off.

When we power up the circuit, the current will flow from source to the (+ve) mic and leaves at (-ve). Due to the low resistance of the mic the sufficient amount of current will flow to the base of T1. That current helps the T1 to turn on.

NOTE : the resistance of the mic will become HIGH when it detect the sound.

Due to this, the voltage across the collector-emitter of T1 is zero. So that no voltage across base-emitter of T2 that is the reason why the T2 is in off state by default.

When T2 is turned off the voltage across collector-emitter of T2 was almost equal to the source voltage. As discussed before trigger requires low signal to on the 555.

When the sound was detected by the mic the resistance of the mic will become high. Due to this, there is no current flow to the base of T1 which makes the T1 to turn OFF.

Due to this, the voltage across the collector-emitter of T1 was high, this makes the T2 to turn ON.

Once the T2 was in ON, the voltage across collector-emitter of T2 will be low. This LOW was sensed by the trigger pin (pin 2), which makes the 555 to produce the monostable output

Advantages & Disadvantages

1. It can used to turn ON and OFF the LED or LAMP simply, by clapping your hands.
2. We can also remove LEDs and place a FAN or any other electric component on the output in order to get desired result.
3. The Condenser Mic used in this circuit has the short range as a default, which cannot be varied.

Applications

Clap Switch is not restricted to turn the LEDs ON and OFF, but it can be used in any electric appliances such as Tube Light, Fan, Radio or any other basic circuit which you want to turn ON by a Sound.

                                   please comment if any inquiry .