this example file implements a esp32 as slave that can communicate with another esp32 (as master)
ESP32 master:
- SDA: GPIO 18
- SCL: GPIO 19
- GND
wired to ESP32 slave:
- SDA: GPIO 21
- SCL: GPIO 22
- GND
NOTE: it turned out to be very important to connect GND of both esp32 (just connecting them via USB to the same Computer is not enough!)
Find the code for the master here.