On-board mature and stable ESP-12F WiFi module with large capacity of 4M Byte Flash ^^ The I/O port of WiFi module and UART program download port are all led out, which is convenient for secondary development ^^ Support DC8-80V/USB5V/pin port power supply, RST reset key of onboard WiFi module ^^ Onboard 1 5V relay, output switch signal, suitable for controlling and controlling loads with working voltage within AC 250V/DC30V ^^ Onboard power indicator, 1 programmable LED and relay indicator