Some years ago (3-5) there was an article in a hobby electronics
magazine about using an Agilent 2051 Optical Mouse Sensor as a small
low res camera. The article talked about the effects of magnification
vs distance and specifically showed how to connect the non-standard
2051 2-wire SPI (Clock/Bidirectional data line) with a standard 3-wire
SPI interface. I want a reprint of the article showing how to make the
SPI connection.
I'm not certain but I believe that the magazine was either Circuit
Cellar, Nuts & Volts or Servo.