This instructables show how to use ESP8266 module as a HTTP + Web Socket server to build a low lag time (fast response) WiFi remote robot.

There are tons of WiFi remote robot on the web. Most of them have a simple web interface that can control the robot by a few arrow buttons. It is good enough for demonstrating the circuit works. However the response time is too slow even compare it with a few bucks RC car :(

Every remote control command can be only 1 or 2 bytes, but a single HTTP request introduce hundreds bytes overhead and require wait establish a new connection each time. WebSocket can eliminate this overhead and get over 10 times of performance gain.

You may not familiar with Web Socket, but the implementation can be very simple. This Arduino source code file only 5 KB in size, already included client side HTML + Javascript and server side HTTP + Web Socket server. It is a good starting point for learning Web Socket.”