Dynamic mic amp as clap switch

[Technician Tonny]

Hello.......
i need help to improve my circuit
Wanted to make a clap on clap off circuit, and i found lots of circuit on the net,,
But most of them required ic's and resistors which i wasn't able to find
and some worked as timers, switching without any signal and turning off automatically

I then found a Bi-stable circuit using 555 ic with two buttons, reset and set which worked well as on when set is pressed and off when reset is pressed, I want to replace the two buttons with transistors, mic and a relay, to make a clap on off switch

whereby if a mic detects a clap signal it sends it to the mic amp,
mic amp output goes to Q1'S base through a relay to N/C which is connected to Q1,
Q1 switcthes on hence triggering the set button
which triggers the 555 IC and the IC's output activates a relay trough R2 and Q3 which changes the relay state from N/C to N/O, i.e from base of Q1 to base of Q2 , so that.... the next clap signal will trigger the reset button through Q2
Hope it can work!!!!
am having trouble with mic amp circuit
Some ideas please

This is the schematic

 

[Audioguru]

Hope it can work!!!!

Any echo of a clap sound will cause a malfunction because the sound must completely stop before the relay contacts change connections. Every indoor room has an echo.
0.6V is too high at the output of the preamp for it to turn a transistor off. Make it 0.4V or less like for TTL logic.

am having trouble with mic amp circuit

Then please post its schematic.

 

[Technician Tonny]

Any echo of a clap sound will cause a malfunction because the sound must completely stop before the relay contacts change connections.

That's what i need, suggest me any circuit which can perform that action

Every indoor room has an echo.
0.6V is too high at the output of the preamp for it to turn a transistor off. Make it 0.4V or less like for TTL logic.

I wanted 0.6v to appear at the output in a split second and only when the preamp detects a clap signal

Then please post its schematic.

have no any suitable schematic yet, the one i tried was a mic amplifier

 

[Audioguru]

Most little transistors need a base voltage more than 0.6V to properly turn on. They also need the voltage with enough current.
Your schematic has no supply voltage shown so we cannot calculate how much base current a typical little transistor will need.

How will you cut the clap sound short so that it does not sound like an echo that will not toggle the relay? You need a circuit that toggles each time an input signal occurs.
Why can't you copy the schematic of the mic preamp and post it here?

 

[Technician Tonny]

 

[Audioguru]

During the clap sound, the relay will flip and the sound that is still occurring plus its echo will cause the relay to flop back to the original position and maybe this will cause the relay to flutter a few times. You need a flip-flop circuit that latches at the beginning of a sound.

Your first transistor has no bias causing it to be turned off so it will do absolutely nothing. Your second and third transistors also have no bias and might not do anything if the first transistor citcuit is fixed so that it is a mic amplifier.

R4 has a very low value that will destroy any type of microphone. R4 will cause a dynamic mic to move its diaphragm to one end and lockup. Remove R4 if the mic is dynamic. An electret mic draws about 0.5mA so with your 12V supply then R4 should be about (12V - 3V)/0.5mA= 18k ohms. actually, the 12V probably has a lot of noise so R4 should connect to a 1k resistor instead of 12V and the 1k resistor should connect to 12V. Then a 47uF capacitor to ground can connect to the junction of the two resistors as a filter.

 

[Technician Tonny]

Ohk let me search for aflip flop circuit,
Thanks....
And am using an electric mic, i made a mistake in my post

 

[Audioguru]

Ohk let me search for aflip flop circuit,
Thanks....
And am using an electric mic, i made a mistake in my post

A CD4027 has two flip-flop circuits inside. It has low output power but it can drive a transistor or Mosfet for lots pf power. What will it drive?
There is no such thing as an electric mic. Maybe you have an electret mic that is a condenser mic with 48V stored in its electret material, and a Jeft as an impedance converter at its output..

 

[Technician Tonny]

haaa i was just confused with its real name thanks for correction, that's why i wrote dynamic instead of electret bcause i had two names in my head (dynamic and electric)
and
Can a mic store 48v !!!!!

I found a schematic of a clap on switch using ne555, which automatically turns off after 5 seconds,
the on time was set by c1 which was 10 uf, i added it to my orignal circuit and it worked
but at first the relay was buzzing, clicking and fluttering, i decreased the c1's value but the relay was still vibrating upto when i removedthe c1 completely

It works fine but if i put something in my extension, the relay vibrates and when i switch on any electronic device it changes state automatically,

And how to add bias to my transistors

Thanks!

 

[Audioguru]

Sorry, I do not have time to teach you the basics of transistors.

 

[Technician Tonny]

Basics of transistors ok also that information helps, knowing what to search for, Thanks Audioguru and nice times

 

[73's de Edd]

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Sir Technician Tonny . . . . .

I think that you will find that this circuit will work much better for your application.




73's de Edd

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