I replaced my Beutler HVAC controller and thermostat with a controller of a different brand plus standard thermostats. The only downside was that my Beutler SmartVent that I love was not supported as it requires special software to operate. I decided to make my own SmartVent thermostat to control it, and I started by buying the AZ-Touch MKR 3 from the Pi Hut. I have been totally satisfied with it, it totally LOOKED like a thermostat, and I was able to plug in a Nano 33 IoT microcomputer and was able to make a custom prototype board with my thermostat circuitry and fit it inside the thing. The LCD display and touchscreen work great, and I was able to easily download the necessary libraries to use them. I developed my own C++ button class that elaborated on one that came in the display library, and that worked well for making and using buttons on the display. The Nano microcomputer has issues with its ADC that has caused inaccurate indoor temperature readings, which I'm in the process of fixing by using a different method of reading thermistor resistance. I plan to post my code and schematic and full review of the project somewhere when I'm done. The AZ-Touch has been solid and provided the necessary foundation for this project.