SPH0645 I2S MEMS Microphone to .wav file using ESP32

This code help users to record sound and dump into SD card, later use ffmpeg and batch script to format into WAV

Prerequisite

1. ESP32 I2S devices
2. FFmpeg in %PATH% (Windows system in this case) Tutorial link by wikihow
3. SD Card

Pinout

SPH0645	ESP32
WS	IO15
SD	IO32
BCK	IO14
VCC	3.3V
GND	GND

SD Card	ESP32
Chip select	IO26

Usage

Screen shot of serial monitor (BUADRATE: 115200)

1. Continue outputing 's' means in "stand by mode", waiting for start command 'a' input.

2. Enter file name

3. Enter recording time (sec)

4. Wait for *** DONE WRITING *** shows up and insert SD Card into PC

5. Run i2s_to_wav.bat in folder where .i2s file locates (etc. SD Card)

6. File would be format into wav file with timestamp

Known Issue

• 2023/07/27 Recording result sounds slightly faster, maybe due to mismatch of sample rate cause by SD card write time.