mic and its circuit!!

[ericlafesse]

Hi All

Attached is a tiny microphone I will be using on breadboard that will be used to listen to musical tone and will be fed to some microcontroller...

there's also a circuit I used for a mic when I was doing some voice recognition project...BUT i am dealing with musical tone...and this is too much circuitry...

So I need some help re-designing the mic circuit reducing the gain to 300 and add automatic gain control

Please contact me if needed!!

Thanks!

 

[rfredel]

Hello ericlafesse,

to design an automatic gain control is not easy, if you don't say what output level is need.

Give me the output level and the range of the gain control. Then I can help you.

Regards

Rainer

 

[ericlafesse]

Thanks so much for your reply...

I am not too sure how to answer your two questions as my electronics is very poor...but attached is what I am trying to achieve...so I will be dealing with frequencies ranging from 65Hz to 987Hz...Also I guess if I change my feedback resistor from 100k to 30k...I'll be reducing the gain to 300.

But this is too much circuitry ...I need to breadboad a good but quick circuit for the mic!


thanks again!

- - - Updated - - -

what about the Zero crossing?? do I need a circuit for that or...?

thanks!

 

[chuckey]

You can buy audio chips that include an ALC function. I have one at home so I can not remember its type number - Try Google.
Frank

 

[rfredel]

Hello ericlafesse,

here you have a circuit for your microphone with a AGC.



With Jmp1 you can change the amplification between 40dB and 60dB. The microphone capsule don't need any more power supply, if you connect it like you see.

The output can adjusted with P1.

Regards

Rainer