The first thing you’ll want to do is order and print all of the necessary components. The printed components are all available on Github here. After the initial design, I ultimately had to add a hole for the temp sensor on the fan enclosure and I didn’t modify the design to include this. I also found that the slots I made for mounting the fan enclosure to the fan with zip-ties weren’t big enough for some of my zip-ties, so you might want to check this measurement for yours

For the fan controller, I used a small PCB proto board and for the temp sensor I simply soldered the sensor directly to the Xenon. It’s all quite simple, but follow the schematic below for the fan controller and you shouldn’t have any issues

With the finished boards and the printed enclosures, assemble everything. I originally had intended to wrap the temp sensor on the back-side of the temp sensor enclosure. Unfortunately, I broke the leads doing this and ended up wedging a replacement one in the hole and securing it with hot glue. I then used a drill bit and by hand made small holes in both of the 3M Command strips I used to attach it to the back of the fireplace.

I’m going to assume that you’ve already made connections to your specific fan. All that’s left is to mount the fan controller enclosure to the fan and connect the wires you’ve now got for the fan.

The code is located on Github here. It’s written for a Particle Photon for the fan controller and a Particle Xenon for the temperature sensor but should be easily edited to work on a similar Arduino.

The fan controller starts up in ‘heating’ mode, but if it’s summer-time you’ll need to publish a ‘Fan_Command’ with data of ‘Cooling’.