Don't use a 5V relay module with ESP32

You cannot easily use a 5V relay module with your ESP32. The ESP32 operates on 3.3V logic, so its GPIO pins cannot reliably trigger a 5V relay. The IN pin on this relay expects a 5V trigger, but an ESP32 can only send 3.3V– even though most ESP32 boards can pass 5V through the VIN pin. I couldn't find any straightforward information about this online and ended up wasting time. If you have one of these 5V relays, just use it with an Arduino or another board that supports 5V logic. Otherwise, get a 3.3V relay module to use with your ESP32.