[yjftsjthsd-h]

> What is it about AC that makes it impossible to control?

Nothing; there is something about my AC and the badly hand-assembled ESP8266 and IR transmitter I made that doesn't work.

[slug]

I was able to record/playback fujitsu mini-split commands using a simple wemos d1 IR shield + wemos d1 mini (esp8266) a few years ago.

https://www.wemos.cc/en/latest/d1_mini_shield/ir.html

https://www.wemos.cc/en/latest/d1/d1_mini.html