Gsm to Arduino

I understand that interfacing a mobile with a microcontroller has been done to death with the whole at command thing and that now there are gsm modules that are well priced and small however I am wanting to try different appraoch that I have not seen and would be intrested in some views.

The arduino -> gsm is covered by means of wiring up the pads on the keypad however getting an instruction from the phone to the arduino is the fun part. For this I propose using a optical mouse sensor to read the lcd of the phone and use the image as a code for an action.

Just one char is all that is needed for a large number of functions.

A guy called bidouille has done some good work in this area and shows that it is feasable.

The idea for this is to create a bike tracking system. As I am sick of having my bike stolen >:(

Does anybody have any experience examples of using mouse sensors for such a task?

Thanks in advance

Has anybody hooked up a gameboy camera to an arduino?