Alright, so let me tell you about this sauna room thermometer I put together. It wasn’t anything super complicated, but it was a neat little project, and now I actually trust the temperature in there!

It all started because the old thermometer, one of those cheap dial ones, finally gave up the ghost. Or maybe it was just lying to me all along, who knows? Anyway, I figured, instead of buying another one that might also be rubbish, I’d try to make something a bit more reliable myself.

First things first, I had to gather the bits and pieces. I dug around in my electronics stash. You know how it is, you always have these components lying around from other ideas or half-finished projects. I found a temperature sensor, one of those digital ones that are pretty accurate. I think it was a DS18B20, something like that. They’re good because they’re small and pretty tough.

Then, I needed a way to see the temperature. I had a small OLED display module that I’d bought for something else and never used. Perfect! Nice and clear, and doesn’t use much power.

I also grabbed a microcontroller. Just a basic one, an ESP8266, because I had a few spare. Overkill for just reading a temperature, maybe, but hey, it’s what I had, and it’s easy to program.

Next up was getting everything to talk to each other. I started by wiring the sensor to the microcontroller on a breadboard. A few jumper wires here and there. Then I got the display hooked up. This part always takes a bit of fiddling, making sure the pins are right. You check the datasheets, then you check them again.

Once the hardware was loosely connected, I jumped onto the computer. Wrote some simple code. The goal was straightforward: read the temperature from the sensor, then show that number on the little OLED screen. Took a couple of tries to get the libraries for the sensor and display working together smoothly, but eventually, I saw numbers popping up! That’s always a good feeling.

Now, the tricky bit: the enclosure. A sauna is hot and steamy. Not exactly the best place for exposed electronics. I needed something to protect the circuit but still let the sensor get a good reading of the air temperature. I found a small wooden box. I liked the wood look, felt right for a sauna. I drilled a hole for the sensor to poke out slightly, and another for the display to be visible. I also made sure to seal any gaps where moisture might sneak in, using a bit of silicone sealant around where the wires for the sensor came out.

I mounted the microcontroller and display inside the box. Had to be a bit careful with the wiring to make it all fit neatly. Powering it was simple, just a USB cable to a regular phone charger brick, tucked away outside the hottest part of the sauna.

Testing time! I put the whole thing in the sauna. Turned the sauna on and just watched. The temperature on my little display started climbing. I had another, older (but supposedly working) thermometer in there to compare, and the readings were pretty close. Success!

• Sensor picked up changes quickly.
• Display was easy to read even when it got a bit steamy.
• The wooden box seemed to handle the heat okay.

So, that was pretty much it. I installed it properly on the wall, in a spot where it’s easy to see but not directly in the way of the hottest steam. Been using it for a while now, and it’s been great. It’s just a simple thing, but it works, and I made it. There’s a certain satisfaction in that, you know?