Question: How does a laser mouse work?

Daniel Scully answered on 16 Nov 2011:

Laser mice work by shining the laser onto the surface below the mouse.

A small camera on the bottom of the mouse looks at the surface being shined on. The camera is low-resolution, but the bright laser allows it to see the small bumps and holes in the surface underneath.

The camera is constantly taking pictures, and when you move the mouse it can tell which way you moved it from how the bumps and holes have moved from the previous picture. And so it tells your computer where to move your cursor.

This is why laser mice don’t work well on very flat surfaces – where there aren’t any little bumps and holes – or very shiny surfaces – where the glare hides the bumps and holes.