Onboard the ESP8266 WiFi module has three work modes: STA (client), AP (hot), STA + AP (hot +client). According to the work mode of the WiFi relay module to choose the corresponding mode of the ESP8266 WiFi module.
 Module needs configuration by serial debugging software and the USB to TTL module sends a serial command. TX, RX & GND pins of USB to TTL module connect to RX, TX & GND pins of ESP8266 relay module, and IN+ & IN- connect to DC5V power.
Specification:
- AT+CWMODE=2, select AP mode;
- AT+RST, reset;
- AT+CIPMUX=1, open multiple connections;
- AT+CIPSERVER=1,8080, configure the TCP server, set the port number;
- AT+CIFSR, view the IP address in AP mode, such as: APIP, “192.168.4.1″;
- AT+CIOBAUD=9600, set Baud rate to 9600.
