nice. i've done simliar projects with unipis in hotels as its cheaper than crestron. Seeing that din rail brought back some memories. you can attach an infrared reciever to the pins and use lirc to then basically do whatever from a universal remote aswell which is a cool upgrade. put infra on a pizero on the network so it can go in ceiling or discretely somewhere. you might also find the AC has an http interface . they often modbus but samsung have http ones too. so u may be able to control that. one thing you can do is read the serial signals coming out of an AC controller and record the bytes. then just store them as instrucitons and send the same bytes over the same wire to hack it. takes a lot of fiddling.
