IR sensor and motor

Recently I took apart an old printer, and it had quite a few useful things inside, including this motor with an infrared transmitter and photoresistor.
The setup for the sensor is like that of the old trackball computer mice.
How would I go about using this as a “prescion” controlled motor, a rotation sensor, or something along those lines.

The setup for the sensor is like that of the old trackball computer mice.
How would I go about using this as a “prescion” controlled motor, a rotation sensor, or something along those lines.

Here is a picture of the trace.

The forum did not have much information on things like this, and Thank you in advance for any help.

This produces a quadrature signal just like a rotary encoder:-
http://www.arduino.cc/playground/Main/RotaryEncoders

Hmm. Thats helpful, I did not know that. (haha)
Thank You for you quick response.