i took apart an old junk laptop one of the parts i pulled was the mouse ball from the keyboard. i was just wundering how this type of divice works. is it switches ore is it a peazo sensor?
all i can tell by looking at it is that the rubber ball sits ontop of a small metal post that is atached to a tiny PCB with a 5 wire ribon cable off of it. so i was thinking it probly has a sensor in every direction 2 for X 2 for Y and a com. i am thinking it is peazo because the ribon cable is shelded wirth foil this would prevent false voltage and make it do somthing.

 

It's usually an optical encoder of some form or another.