How to detect the output voltage of a mic using arduino?

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yaantey
 
Posts: 4
Joined: Mon Dec 19, 2011 2:26 pm

How to detect the output voltage of a mic using arduino?

Post by yaantey »

Hey guys,

Can anyone point me to a simple circuit that can be used to wire a MIC to a speaker so that the speaker can output the inputs to MIC. Also then I can connect the output from mic to arduino to see the maximum and minimum voltage output of the MIC.

Im a newbie, so please help me out. Thanks.

mwilson
 
Posts: 46
Joined: Sun Oct 23, 2011 11:17 am

Re: How to detect the output voltage of a mic using arduino?

Post by mwilson »

I've got nothing that does exactly that. But...

The LM386 is the "standard" chip for building little audio amplifiers. The first typical application in the data sheet http://www.ti.com/lit/ds/symlink/lm386.pdf is probably close to what you want.

The main unknown is gain: is the microphone signal hot enough to be noticed by the LM386 or Arduino. If not --
1) another circuit in the LM386 datasheet shows how to get higher gain.
2) for that or Arduino input, an operational amplifier between the mic and the rest of the circuit can give you whatever gain you need. The fundamental circuit is simple, but high-gain circuits can get tricky with respect to layout. (On the bench here I've got a breadboarded op-amp circuit that's turns into an oscillator if you jostle the parts.) Google a bit,

(later)
I guess it wouldn't kill me to explain where I'm coming from. This, http://www.generalguitargadgets.com/ric ... iceman.pdf is the schematic for an entire guitar amp using op-amps and an LM386. You'd have to filter out what you need. The op-amp gain stage I'm talking about would be the parts C4, R21, U3A, R19, C13, R20, and the voltage-divider R6, R7, C5 that feeds the Vbias voltage. (The similar parts around U3B do the same thing, but with a lower gain.) That's a starting point -- you'd better study up regardless.

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