Features 1. Onboard, mature, and stable ESP32-WROOM-32E module with a large 4M BYTE FLASH; 2. All I/O ports of the ESP32 module and the UART programming download port are exposed, facilitating secondary development; 3. Onboard AC-DC switching power module, supporting AC90-250V power supply; 4. Onboard ESP32 module RST reset button and IO0 programmable button; 5. ESP32 supports the use of the ARDUINO IDE development tool, providing reference programs under the ARDUINO development environment; 6. Onboard two 5V relays, outputting switch signals, suitable for controlling loads with a working voltage within AC 250V/DC 30V; 7. Onboard one programmable LED and two relay indicator lights.