how to estimate sound intensity using MEMS Microphone?

[kajetan]

Posted on February 08, 2015 at 19:05

hi,

I've been looking for a way to estimate sound intensity using MEMS microphone for a very long time. I am using STM32F4DISCOVERY board with a MEMS microphone on it (it's MP45DT02). I wrote an application that receives sound using this this microphone, writes it into a buffer and converts it from PDM to PCM using library given by ST. So far it works very similar to a program given by ST - ''Audio playback and record''. Later I use fast fourier transform to get the signal spectrum.

I need to estimate how the amplitude of the sound will be reflected on the spectrum's bars height. The datasheets are modest or even say nothing about it. How can I solve the problem? 

#mp45dt02-mems-microphone-fourier

[Alessandro MORCELLI]

Posted on April 08, 2015 at 11:29

Hi Sir,

in order to understand the realtion between the digital audio output and the sound intensity i would suggest to read the ST aplication note AN4426 at the MEMS microphone web page:

http://www.st.com/stonline/stappl/resourceSelector/app?page=fullResourceSelector&doctype=application_note&SubClassID=1564

Regards,

Alessandro

[jeannot]

Posted on May 12, 2015 at 16:09

hi,

i am new on this page but i need some help.

Please im working on STM32F4  and i want now to write an code with the microphono on board. I want to have finally an 16 bit on output(PCM).

there is a way to do it?

thanks

giovani