I recently became super fascinated with ESP8266 hardware, and it wasn’t long before I also found out about and ordered a couple of ESP8266-based Sonoff AC switches to play with (immediately flashing them with some generic MQTT firmware). They work wonderfully and are just too cheap to resist.

It also wasn’t very long until I began wondering whether I could jam the bare PCB from the Sonoff right into a power strip. I took apart the closest one and was pleased to find that (with only a little bit of creative modification of the plastic ribs and bosses) the bare Sonoff PCB fit inside perfectly. Too perfectly:

Obviously, this is extremely unsafe, so don’t ever do this – or will burn your house down, kill your pets and loved ones and so on. More pictures of how not to do this follow..

Does it fit? I think it does. Happily, the input and output terminal blocks on the PCB are perfectly positioned to accept the incoming AC.

This is important: The (10A) relay on the Sonoff board is single-pole, and naturally, neutral passes straight through the PCB un-switched. Because of this (and from a position of general electrical safety) it is critical to make sure that the AC is connected the correct way around, and not reversed (or a mis-wired appliance could end up energised, or some other unsafe scenario could occur). In my case, I used a meter to verify that the neutral prong of the plug was connected to the neutral socket of the power strip, and was glad I did so, because the wire colours on the power strip’s cord were actually back to front.

The finished creation, with the tactile membrane switch poking nicely out of a hole. The first socket is not usable so I really should covered or taped over that.