Clap switch not working properly

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
Hello Folks! I am making a clap switch activated relay circuit in which the bulb will glow on first clap and will shut off on the second clap. The circuit is working but in order to make it work I have to clap very hard as well as close to the condenser mic which makes it unsuitable to use for any application. So please let me know how can I increase the sensitivity of the circuit? Whether by using any other condenser mic of higher range and sensitivity or amplifying the output of the condenser mic and then feeding it to the 555 Timer. The circuit diagram is attached.
 

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JohnInTX

Joined Jun 26, 2012
4,787
Search AAC for 'clap switch' . We have several threads on the subject. If you still have questions, ask them in this thread.
 

dl324

Joined Mar 30, 2015
16,943
So please let me know how can I increase the sensitivity of the circuit?
We need information on your condenser mic. You could try a darlington transistor configuration, but I'd replace the transistor with a comparator which would make it easier to set sensitivity.

I'd also do something about the supply voltage or the flip flop. 74S won't tolerate VCC=9V well. You should also use a current limiting resistor with the LED because the outputs don't like low resistance loads.

There are a lot of questionable schematics on the internet; this is one of them. At least the author didn't embarrass himself by putting his name on it.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
We need information on your condenser mic. You could try a darlington transistor configuration, but I'd replace the transistor with a comparator which would make it easier to set sensitivity.

I'd also do something about the supply voltage or the flip flop. 74S won't tolerate VCC=9V well. You should also use a current limiting resistor with the LED because the outputs don't like low resistance loads.

There are a lot of questionable schematics on the internet; this is one of them. At least the author didn't embarrass himself by putting his name on it.
Thanks for your suggestion but the main concern here is increasing the sensitivity of the condenser mic so that it works on slow claps despite of this circuit is working fine and at the output of 74S, I am connecting relay as I want to actuate it using the clap sound. The condenser mic which I am using is electret microphone and the image is attached.
 

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jjw

Joined Dec 24, 2013
823
It is a bad circuit.
The transistor is always saturated.
The mic is biased at Vbe of the transistor, about 0.7V, which is too low.
It is wonder, if you get any response from the circuit.
Search for a condenser mic amplifier.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
It is a bad circuit.
The transistor is always saturated.
The mic is biased at Vbe of the transistor, about 0.7V, which is too low.
It is wonder, if you get any response from the circuit.
Search for a condenser mic amplifier.
if the transistor is always saturated what can I do to correct this and can you provide a simple circuit for condenser mic amplifier.
Thank you
 
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