Quote:
Originally Posted by
Riou 
Yes. It is just the scroll wheel and the components that registers the wheel movement. Example:

The above is an optical encoder iirc. I believe below is a mechanical encoder.

Should be the other way around

(although it's not easy to see the differences in these)
EDIT: that's a good view on an optical encoder:

If you watch closely you can see the LED on the right side of the scroll wheel and on the left side is the wheel with the pins that either lets the light pass through to the sensor below or cuts it off depending on its position when the scroll wheel is turning.
Edited by MONVMENTVM - 7/5/12 at 5:07pm