Thank you for your reply. Unfortunately, there no serial information shows in the serial monitor for all the baud rate after flashed the OpenCatEsp32.ino. But I tried the "testbuzzer", "testI2cDevice" and "testI2cEEPROM" all working and having a response. Is there anything I needed to flash or configure before uploading the OpenCatEsp32.ino? thank you.