Setting up a smart home can be a costly affair, if every device needed an expensive proprietary smart switch you would spend quite a bit of money. With a very tiny amount of soldering and some custom firmware, the Sonoff Basic model can be turned into a locally controlled MQTT enabled WiFi smart switch for about $7 each. These tiny little esp8266 based boards can be spliced into a power cord to add WiFi control to anything.
I have about a dozen of these and they work great. Because of how cheap they are, I have started adding them to some ridiculous devices. Today’s DIY WiFi retrofit: my coffee mug warmer.
I want my mug warmer to come on automatically when I enter my office in the morning, but only if I’ve made coffee already. But first, I need to flash some new firmware onto my Sonoff.