ESP8266 modules are amazing devices, allowing you to connect via WiFi and control “whatever” you want. However, as they produce only low-voltage DC power, you’ll need a relay board to activate lights, fans, or anything that requires much more power than a simple LED or two. As a solution to this challenge, appropriately named Tindarian “Universal-Solder” is selling a WEMOS D1 mini DIY kit, that allows it to control 4 relays on a custom PCB.
This setup would allow you to control up to four items from the comfort of your phone (via downloadable code that you can modify as needed). The device can also be expanded via I2C, allowing it to interface with other microcontrollers, for either control of external devices, or perhaps for sensing duties. Imagine, for instance, if when you walk into your shop, that the lights are adjusted to your previous setting, the fan turns on, and the soldering iron starts to heat up via a PIR sensor. Or perhaps you’d like to start an AC unit installed in your garage, via your phone or computer, a few minutes before entering the previously-sweltering chamber.
Of course, this isn’t the only relay board listed on Tindie. For more channels, and reliable operation, here’s an 8-channel solid-state relay board, and another that gives you 16 channels if you need a massive amount of solid-state control.
