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Topic: Adafruit Electret Microphone w/ Battery Power? (Read 284 times) previous topic - next topic

bmoe24x

Hello,

I was wondering if anyone could tell me if it was possible to power an electret microphone like this one with battery power instead of the on board power and ground.

Currently I have a 9volt battery going into something similar to this and set to 3.3 volts (although I tried 5 volts as well, and changed my code accordingly but now back).

I have it working powered from the board's 3.3v and ground but when I try it with the battery power it is not very sensitive at all. Like I have to clap close to or tap the microphone to get a .25 volt reading. I understand I could change the sensitivity and my coding but I have it working perfectly fine with the board's power and ground.

Long story on why not just the board's pins then but in general just wondering if there is a reason for this and/or if there is a way to get it to work. Thanks

szilvasyz

Hi bmoe24x,

Is I see, this mic is a simple electret mic with built-in preamplifier. I am sure that you can power it with seaparated battery. In this case the "external" battery should be connected to the GND and VCC pins of microphone. You must then connect microphone's GND to Arduino GND and microphone's OUT to the desired Arduino input. It should work.

As the amplifier on the microphone module needs a power supply of 2.4-5.5V, I would recommend a 3xAA or 3xAAA battery case for mic power (instead of a 9V battery with that over-complicated power regulator that you linked).

Regards,
Zoltan

DVDdoug

Quote
I have it working powered from the board's 3.3v and ground but when I try it with the battery power it is not very sensitive at all. Like I have to clap close to or tap the microphone to get a .25 volt reading.
There's supposed to be a gain/sensitivity pot on the back of the board.   

The power supply voltage wont' change the gain (assuming it's adequate) but a higher supply voltage will allow a larger output-voltage swing before clipping (distortion).

bmoe24x

There's supposed to be a gain/sensitivity pot on the back of the board.   

The power supply voltage wont' change the gain (assuming it's adequate) but a higher supply voltage will allow a larger output-voltage swing before clipping (distortion).
Yeah as I said I didnt change the code or sensitivity settings from the working setup that was also 3.3v but I figured the issue wasn't that.

lol I was being dumb on the 3.3v and 5v swap, duh. Thanks for pointing that out I should have figured that

bmoe24x

Hi bmoe24x,

Is I see, this mic is a simple electret mic with built-in preamplifier. I am sure that you can power it with seaparated battery. In this case the "external" battery should be connected to the GND and VCC pins of microphone. You must then connect microphone's GND to Arduino GND and microphone's OUT to the desired Arduino input. It should work.

As the amplifier on the microphone module needs a power supply of 2.4-5.5V, I would recommend a 3xAA or 3xAAA battery case for mic power (instead of a 9V battery with that over-complicated power regulator that you linked).

Regards,
Zoltan
Okay connecting the ground resumed operation as normal. Makes sense too. I figured the 9v wasn't the most efficient I just happen to have the stuff around to try that out, if this ends up seeming to work I will go down that route, thanks for the recommendation.

The reason for this is that I am actually using a NodeMCU (starting back on a project I worked extensively on months ago) and I was told using a buck converter "doesn't play nice" with microphone circuits, so the only way to get it to work was with a linear source and a seperate source for the other part of my project.

Then I thought oh  maybe a battery powering the microphone would work while I use a buck converter for the board but I am also now just realizing maybe the issue has to do with an erratic reference voltage on the analog pin. Idk. This is my second to last hope, the last being a separate ADC board powered seperately then send the data to the main board. I will test this out but my idea seems a bit frivolous now.

Any suggestions are appreciated,

Thanks again

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