We’ll be perfectly honest: sitting inside a heated box sounds just a bit too much like torture for our tastes. But if we did somehow find ourselves in possession of a fancy new sauna, we’d more than likely follow in the footsteps of [Al Betschart] and make the thing controllable with the ESP8266. After all, if you’re going to be cooked alive, you might as well do it on your own terms.
The sauna itself was purchased as a kit, and included an electric heater controlled by a thermostat. As explained in his detailed documentation, [Al] integrated a Sonoff TH16 into the original heater circuit so he could control power to the coils remotely. The TH16 also includes support for a thermal sensor, which allowed him to get a reading on the sauna’s internal temperature. The new electronics were mounted in a weather-proof box on the back of the sauna, complete with an external WiFi antenna to help get a good signal back to the house.
At this point the project could technically be done if all you wanted was remote control, but [Al] wanted to create a replacement firmware for the Sonoff that was specifically geared towards the sauna. So he came up with some code that uses MQTT to connect the heater to his home automation system, and allows configuring things like the maximum temperature and how long the sauna will run before turning itself off.
Interestingly, the company who makes these saunas thought the work [Al] did to integrate their product into his home automation system was so impressive they actually interviewed him about it and put it up on their site for others who might be inspired by his work. We’ve covered a lot of hacks to consumer devices here at Hackaday, and it’s exceedingly rare for a company to be so supportive of customers fiddling around with their products (especially in a case like this where there’s a real chance of burning your house down), so credit where credit is due.
The last time we brought you a sauna hack it was quite literally in a van down by the river, so the addition of an ESP8266 certainly brings this more into our comfort zone. Figuratively, if not literally.
[Thanks to Jon for the tip.]