USB Optical mouse as motor encoder

[RodSTAR]

Last friday an idea came to my mind, I just wanted to share an original idea [maybe not original, who knows maybe someone has already done it.. who knows..]

It is to use an ordinary USB Optical mouse as an optical encoder. Some obvious benefits are:
-it tracks direction
-it tracks speed
-it's high resolution
-it's dumb cheap and hyper easy to get
-it's all ready to use/ circuit made/ nice components
-no mechanical or optical high precition stuff to calibrate.
-no need of hard to find absolute or progressive rotary discs, nor printing them.

NOTES:
-must not rubbing (for obvious reasons)
-It has to be really near to rotary surface, AT MOST 1 milimeter.
-surface must be opaque, uniform and clean.
-ideally be in dark environtment (inside a box or whatever)
-for more resolution, just move away from center.
-for less resolution, come closer to center.

I began my mouse lab experiments connecting it to my PC with some C++ and API software stuff to intercept mouse data, and I got incredible presition. A limitation is high speed sensing.

Up to now, I've achieved some 1000 RPM's without problems, comparing to my standard quadrature encoder in a PIC16F628A. over 1000 there are differences...

I don't know wich is the faulty, if my PC optical mouse or my 16F628 optical encoder [show data on LCD]

My next experiments will be:
-test with other motors I have with included quad.encoder at different speeds

NOW I want to do the NO PC versión. Here is PicBasic Pro in action. I'm actually goring my mouse guts and trying to experiment with data and it's speed limits with a PIC18F4550 and trying to conect it. I just begun PIC version some hours ago but can't read data from mouse to PIC.

Any suggestion?
I'll share my advances as soon as they happen.

(I'm addicted to it... USB has some hypnotizing powers that can't almost let me sleep, been all weekend in it, even I've dreamed with USB TX/RX, female connectors, well, whatever. In fact, here in my country it's now 5:43am and I haven't slept.)

[sorry my english]
regards,
Rodrigo
Santiago - CHILE