April 10, 2003
A: FROM MENTOR BARB KONTOGIANNIS IN CO
Have you ever taken the ball out of your mouse? You can push down and
turn the piece that holds the ball in, on most models, to take the ball out.
When you do that, you can see that there are three rollers inside the cavity
where the ball is. One senses forward and reverse, one senses side to side
motion, and the other is at a 45 degree angle to those, to sense angular
travel. So as the ball rolls, the little cylidrical rollers inside sense
the direction and speed of the ball, and provide that information to the
sensors in the mouse that are connected to the computer. Try taking a look
inside the ball cavity of your mouse - it's a simple yet very effective
design.