We’ve covered the Sonoff a few times–a very inexpensive box with an ESP8266, a power supply, and an AC relay along with a way to tap into a power cord. Very inexpensive means $5 or $6. The supplied software will work with several systems (including, recently, Alexa). But what self-respecting hacker wants to run the stock firmware on something with an ESP8266 inside?
[Tzapu] certainly didn’t. But he also knew he didn’t want to start from scratch every time he wanted to deploy a switch. So he built SonoffBoilerplate and put the code on GitHub. The code manages taking configuration (including network settings) using a web-portal, can update itself over the air, and integrates with Blynk and MQTT. If you don’t like that code base, there are other choices including one that has a failsafe reconfiguration mode.
You do have to solder a header to the board to reflash it. Since all of these provide for updating over the air, you could probably press fit the header just to get the initial flash, if you like.
Of course, if you want you can totally reprogram it, too. Or use the stock firmware and control it like all the normal people do.
If you plan to use Blynk, we’ve covered it before. For that matter, we’ve talked about MQTT, too. You can see more details about Sonoff, including a quick reveal of the insides, in the video below.