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Project ESP audio sensor
ESP-based audio sensor
Status Initializing
Contact bertrik
Last Update 2019-04-14


This project is about using an ESP-32 together with an I2S digital microphone to create an audio sensor.

This could be a decibel meter, or perhaps an environmental noise meter.


Audio levels are generally measured in dB using the A-weighted scale. A-weighting calculates a subjective loudness level from a physical loudness.

Energy it calculated per octave and an A-weight factor is applied. In decibels this means adding a octave-specific number to the loudness.


The physical device consists of:

  • an ESP32 (or possibly an ESP8266), it has an I2S digital audio input.
  • a digital I2S microphone, like the INMP441 (datasheet)

The microphone is connected as follows:

  • INMP441 GND to ESP32 GND
  • INMP441 VDD to ESP32 3.3V
  • INMP441 SD to ESP32 A4/32
  • INMP441 SCK to ESP32 A16/14
  • INMP441 WS to ESP32 15
  • INMP441 L/R to ESP32 GND


Initial code can be found on github.

See also: