Connect two pin microphone

Projects General Guidance
1

Hi

I am now really that great at this Arduino stuff yet.

I have an Arduino Uno and I am trying to connect a two pin microphone to it. My basic goal is to make a baby monitor. So I pulled the microphone off of an old baby monitor and I would like to wire it in so that when it goes above a curtain sound level a LED lights up.

Any help would be greatly appreciated.

2

You need 3 things -

  1. Assuming it's an electret microphone, it needs power (through a resistor with capacitor to block the power/bias from the signal path).

  2. You need an amplifier (preamp) to boost the millivolt microphone output to around 1V. (You build that with an op-amp.)

(3. You need to bias the Arduino's input because it cannot accept the negative half of an AC audio signal. That's usually another capacitor and a pair of resistors, but the circuit below uses two resistors to bias the op-amp's reference and doesn't require the capacitor.)

[u]This board[/u] includes the microphone and the required circuitry. Or, there is a link on that page to the schematic if you want to build a similar circuit yourself and use the microphone you already have.