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How can I interface an electret microphone (condenser) to STM32F4?

DElec.1
Associate II

I want to interface two electret microphones (stereo sound) to STM32F446 chip. I don't know how to connect it or what protocol or pins I have to use. I have found a lot of information about digital microphones but nothing on this topic.

Thanks.

24 REPLIES 24

@Andrew Neil​ 

No, it is not an school assignment. The requierement of the use of that model is set by the company.

I am using this model of electret microphone (which meets all the freq requirements 20-20kHz): https://www.digikey.es/es/products/detail/pui-audio-inc/AOM-5024L-HD-F-R/12152286

Having capture the sounds I just will keep them in a memory. The natural sounds I want to detect are birds and mammals (humans too) (nothing about bats and ultrasounds).

I don't have any specifications about sampling (by Nyquist would be 40 kHz), number of bits or anything. In fact, I am a bit lost on this topic of sound. I just want to record sounds in a good quality. All the specifications of that electret mic are good for me.

I am considering connecting it to ADCs and manage to set the "stereo" effect in the firmware o connecting it to au audio codec (but this is what we have talked about; specifications, function and all that).

I am glad there are so many people interested on this topic and helping the community. I say sorry in advanced if any question is too basic.

Thank for your time.

By the way, @Andrew Neil​ 

I have found this preamp to that mic model. It meets the impedance requirement and the voltage one too.

I know in the industry of music, preamps are use to achieve the line level to record. would it be neccesary to preamp this mic before connecting to the ADC? I guess so...

https://www.mouser.es/ProductDetail/Texas-Instruments/LMV1012UP-20-NOPB?qs=7lkVKPoqpbac82UrMPr1hA%3D%3D

"if you are serious about recording stuff. Get yourself a high-quality commercial audio recorder"

Even a low-cost commercial recorder will give better results than anything using cheap electrets...

"The requierement of the use of that model is set by the company"

Your employer?

"I am a bit lost on this topic of sound"

Then you should really be speaking to your employer about getting some proper support and/or training in this - if it's part of your job.

"would it be neccesary to preamp this mic before connecting to the ADC?"

Again, as for *any* interfacing problem:

  1. look at the output specs of the microphone;
  2. look at the input specs of the ADC;
  3. If they match, you're good to go; if they don't, you'll need something that makes up for the difference(s).

Almost certainly, a preamp will be required.

"I have found this preamp"

As for any component, Take a look at the support materials available on the manufacturer's website:

0693W00000Nqe3QQAR.png

Yes, my employer.

Thank you.