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electret mic conversion to dc

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blewisjr:
Hello everyone

I understand an electret mix emitts an analog signal which is in the low millivolt range.

I need to hook up the mix to a uC analog input pin to trigger an interrupt when sound comes in.

the issue is see is that I need to
a) amplify the signal
b) filter out the neg voltages
c) filter further to remove signals below a threshold.

I am new to this stuff and I have no clue where to even begin.

My first thought was to use a voltage doubler to amplify which should remove the neg voltages.  I have no clue where to move from there.  Any thoughts?

Thor-Arne:
This page shows how to hook up a electret microphone to a PIC microcontroller.

There's no negative voltage if the mic is connected like this, so it only needs to be amplified.

A diode and small RC network could provide some peak-hold (see EEVblog #490), if you need that.
The rest of the "filtering" can be done in software, just ignore the readings below a certain reading.

blewisjr:
From what I see from that it is already amplified.  So if I am thinking right I can just run the signal through a single opamp bandpass filter and be good?

Thor-Arne:
Yes, you can use a bandpass filter between that amp and the microcontroller.

blewisjr:
Ok thanks I will experiment with that on a simple example before I go all out on my project thanks again.

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