IR-controlling the new air conditioner in the vintage server room
oldvcr.blogspot.com
oldvcr.blogspot.com
Also, having worked with Arduino Nanos and then moved on to ESP32s which have lots of RAM, Wifi and OTA updates, I see a lot of the issues could have been sidestepped. I've built some IR targets that trigger from laser nerf guns and my own IR demodulator from raw electronic components so am a little familiar with IR libraries on Arduino and such myself. Good job at the end - the control loop should work to keep those antique servers at decent temperatures.