Code and supporting documents for Node MCU four relay board (Wifi Quad Relay Board ) You will find Arduino Code for HTTP/MQTT selectable mode with android apk for Http (NodeMCU_four_relay_board Node_Mcu_Four_Relay_WiFiSwitch) Arduino Code for basic TCPserver Arduino Code for basic Mqtt Client Android Apk and Android App raw tcp/ip source code Instructable http://www.instructables.com/id/NodeMCU-ESP8266-Based-Switch-Board-with-Raw-TCPIP-/ Website http://armtronix.net