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Arduino LM386 Pre-Amp for Mic ? Answered

I am trying to (pre) amplify the signal from an electret microphone using an LM386. The output goes into the Arduino analog input 5. I have tried multiple circuits, but none of them succeeded. Either the value settles at some constant or its 0/1023 and even when its in the 500- 550 range, the value doesn't seem to be changing with varying sound levels.

I tried these circuits:

http://wiring.org.co/learning/basics/microphone.html
https://randomskk.net/projects/lightstrip/schematic.pdf
http://www.josepino.com/circuits/mini_amplifier_lm386
http://www.diyaudio.com/forums/chip-amps/114698-preamp-using-lm386.html

and a couple of more ones.

I only have an LM386 on hand and cannot change it, as I need this to work out ASAP(in 2 days) for a science fair project. Hope you guys can help me on this.

Kabir

Discussions

How are you connecting it to the Arduino ? Have you remembered that the MEAN effect on the pin is 0V ?

Steve

I designed a shield for my Arduino from the first circuit (wiring.org) and it directly plugs into the Arduino.

I am not sure what you mean by the 'mean' effect on the pin

Kabir

Mean, as in average. The average of a zero referenced AC signal, with no DC content is.......

Steve

I'm doing DSP with the signal, so I need a fast sample rate. The circuit that you quoted uses an op-amp and I think that the LM386 is not an op-amp.

A 386 is an amplifier, it doesn't matter whether you call it an op-amp or not.

Besides, try my second suggestion.

Steve