I’ve been playing around with the M5Stack Core2 and thought it might be fun to have a look at its audio capabilities.

The M5 Stack Core2 has an SPM1423 MEMS microphone

This microphone is slightly different from the I2S microphones we’ve looked at so far which have all been PCM microphones where the audio signal is represented as a number on the I2S interface.

With a PDM microphone, the audio signal is represented using Puls Density Modulation - this should not be confused with PWM which is Pulse Width Modulation.

In this video, we record some audio using the I2S interface and DMA to see what kind of quality we can get. And then we have a fun little project using the TFT screen to visualise the audio signal using a spectrogram and graphic equaliser.

Hope you enjoy the video - let me know in the comments what you think!

GitHub repo is here: https://github.com/atomic14/m5stack-core2-audio-monitor

If you like ESP32 audio videos - I’ve got a complete set on this playlist: https://www.youtube.com/playlist?list=PL5vDt5AALlRfGVUv2x7riDMIOX34udtKD

You can get an M5Stack Core2 here: https://amzn.to/3g61O7S

Want to help support the channel? I’m accepting coffee on https://ko-fi.com/atomic14