This post shows how to use a I2S microphone with the ESP32 to show graphical representation of the recroded frequencies
ESP32/ ESP-EYE: Browser Based Spectrum Analyzer
squix78 on 
Category: ESP32
squix78 on ESP32: M5 Camera Module
squix78 on The M5 stack has some clever hardware in its portfolio. Honestly, so far I only had contact with this camera module. Here is a super quick guide to get the camera running in your Arduino IDE