track balls

> From: "Arne Chr. Jorgensen" <instel@...>
>Subject: Remarks



>Tracker ball: ( Elliot )

>Yes, they are nice, but they often collect dirt, and that is a
>problem. I wonder how wheel those image recognizers would work. (
>Colored pots on the ball )

Maybe I was just assuming they worked the same way as mice. A mouse uses
two encoders wheels driven by friction from the ball that rolls on the mouse
pad. There is a not very complex serial message that is sent every time the
mouse is moved or polled.

Since they use encoders, its seems natural to use them for this application.

The dirt issue could be dealt with by bringing the encoder shafts out of the
mouse or trackball to some usable handwheels, and seeling the mouse.

Elliot Burke
Hightide Instruments