CertiGuide to A+ (Core Hardware)  9  Chapter 0111:  Peripheral Devices       9  VI  Mice

VI  Mice 1 Optical Mouse

The most common type of mouse found in most PCs is the opto-mechanical mouse. This mouse works by using a small rubber ball that rotates as the mouse is moved around the mouse pad.

The movements of the ball engage two small rollers that track movements on the x-axis and y-axis. At the end of each roller there's a small wheel with holes in it. On one side of the wheel is a small LED and on the other side a photo sensor.

As the wheel spins the holes allow light through them that is picked up by the photo sensor.

This generates the necessary signals to tell the processor how far and how fast to move the pointer on the screen on both the x-axis and y-axis.

A derivative of the opto-mechanical mouse is known as a trackball. This is simply a regular mouse that has been flipped upside down and your fingers move the ball. The mechanics of how input signals are sent to the processor are identical to a standard mouse.

VI  Mice 1 Optical Mouse