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WeMos D1 ESP8266 Web Controlled Switch

Last year I made Room automation with Raspberry Pi and few Arduinos for switching lights and air conditioner on and off using my phone. It required lots of components for accomplishing a simple task. The reason was that Arduino itself cannot connect to wifi and NRF24L01+ module doesn’t support TCP/IP protocol, so I needed Raspberry Pi for wifi connection. Also using new Raspberry Pi for each light switch is just too expensive. This time I used WeMos ESP8266.

ESP866 is an inexpensive Wifi Module for Arduino that supports 802.11 b/g/n protocols and it can also run Arduino code. There are multiple versions of this SOC. Some require serial to USB adapter for programming and some have micro USB port. They also vary by amount of GPIO ports and memory they have.

List of parts that I also used for this project:

  • WeMos D1 ESP8266
  • Relay module
  • MB102 Breadboard Power Supply Module
  • Old notebooks power adapter

For assembly I connected notebook’s PSU to MB102 PSU module, MB102 to ESP8266 with USB cable and GPIO ports 0, 2 and ground on ESP8266 to Relay module.

ESP8266  WeMos
ESP8266 WeMos

I modified ESP8266 library example code and uploaded it on the WeMos ESP8266:

Module automatically connects to wifi when powered and receives an IP address from router ( for example). It’s IP may change every time module disconnects from wifi, so I assigned it static IP address on my router.

You can switch GPIO on by sending HTML request to “http://[ESP8266s ip address]/gpio/0” and to turn it off “~/gpio/1”. This is done simply by visiting url in a web browser.
Disadvantage of the code from libraries example is that you can’t tell whether GPIO is on or off. I modified it so that html response includes info about its status when you visit ~/status.

Turning the air conditioner on by typing into a browser and making sure that it’s on or off by visiting it’s not very practical, so I made a simple web interface and added it to my homes dashboard webpage.

It displays a button with text “Turn on” or “Turn off” depending on the GPIOs current status. When you click it, it sends a html request to the module to change its GPIO state.
You can use as many ESP8266 modules as you want and manage them from a centralized web application.

Everything connected
Everything connected

Edit: Someone on Reddit requested code for managing multiple ESP8266s. So here is the code. To add new module, just add its IP address and name in the array.

Here is a video demonstration of last years system. Front-end webapp is the same and it functions the same.