PDM Microphone Breakout

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PDM Microphone Breakout

Post by parkview » Tue Feb 21, 2023 10:57 am

I was always a bit mystified about PDM MEMS microphones. I had a chance to use one that talks over the i2S bus when I helped design up the version 0.4 of the Open Source Smart Glasses PCB URL: https://github.com/TeamOpenSmartGlasses ... SG_v0p4-2P Note: the V0.5 is an updated PCB version and easier to assemble so use that one.

I made up this PDM microphone breakout PCB So I could test out a few different microphones. Seems to work well with either of the:
  • LCSC P/N: C966942 - MSM261D4030H1CPM PDM Microphone
  • LCSC P/N: C498192 - GMA3526H10-B26 PDM Microphone
These work over the i2S bus, but use one less wire than a true i2S based microphone like the SPH0645

You can find the PCB design files and some example Python (host server) and PlatformIO Arduino ESP32 i2S example code here: https://gitlab.com/parkview/ESP32-PDM_M ... e-Breakout The ESP32 code will transmit 10 seconds or so of audio to a remote computer running some Python socket server code. It will dump the audio into a file that can then be played back. All just test/example code. Thanks to Cayden Pierce for creating the Arduino and Python code examples.

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