adapter to use Atari 2600 CX-22 trackball as PC mouse?

[madscijr]

I have an old Atari CX-22 trackball:

www.atariage.com/2600/controllers/con_AtariTrakball.jpg

and was wondering if someone has documented some non-invasive way, such as building an adapter (maybe using an Arduino or PIC microcontroller) to use it as a standard PC mouse?  It has a switch for "true trackball mode" (which I am assuming is what I would want) and "Atari 2600 joystick mode" (where the controller just works as digital joystick). 

I would prefer not to take the controller apart, and rather build an adapter box with a 9-pin d-sub jack to plug the trak-ball into, and either a PS/2 or USB mouse cable out that would plug into the computer (I have both USB-to-PS/2 and PS/2-to-USB adapters so either of these should be fine, though I probably would prefer USB since it's more current).

Any ideas or links? 

Thanks

[PL1]

Welcome aboard, Madscijr.

Here is the schematic to the CX-22.


Scott

[madscijr]

Thanks... Although I don't really know electronics, there are plenty of sites on how to read schematics, I'll see if I can get any ideas from this... if I do I will post a followup.
(If anyone else has any more ideas keep em coming!)