A diagram of a mechanical mouse, showing how these pointing devices operate.
Diagram: Jeremykemp and Pbroks13
- Friction with the surface below the mouse turns the ball as the mouse is slid along.
- X and Y rollers grip the ball and transfer movement.
- The rollers turn optical encoding disks.
- Infrared LEDs shine through holes in the disks.
- Sensors count the light pulses to derive X and Y velocities. The computer interprets these readings and moves the mouse cursor correspondingly on the screen.