Look at these clever guys. I live in a hotel styled like a castle. Well, there are old wooden frames, rusty grills on the windows, somewhat crooked walls, beamed ceilings, etc. And I noticed that when you open a window, the air conditioner turns off. Right then and there. And it turns back on when you close the window. Just like magic. Probably how some people marvel at the escalators in the subway.
I roamed around there with a flashlight, and not without some difficulty, found it! Everything was almost “overgrown” with something like cobwebs, and I managed to take a clear picture only at the second window.
It turns out, a sensor is embedded in the window frame. Just a reed switch with a little magnet. When it opens, it sends a command to pause the air conditioner.
Hi, I'm Rauf Aliev. 