I was looking at how does my laptop shutdown automatically when I close the lid, but it's not clear to me how is working.
I don't see any switch that is pressed by the lid, or some sensor like the phones have for turning off the screen when you talk.
How does this work?
I've never been interested enough to look, but it's simple enough - either a little mechanical switch somewhere, or a reed switch and a magnet, or even a hall effect switch and a magnet.
yeah, use a magnet near your laptop to find a hall effect resistor... reed switches need bigger magnets so likely too bulky
a mechanical device that works like a pop-up greeting card would also work but is too delicate to be reliable (plus you would notice a rod like item sliding into place)