sorry to let you down, but its realy hard to write "canned" line sensor code. things like the mounting of the sensors; how close/far they are apart, how high they are off the ground, even how many of them there are; all go into the code. you could have a very simple 2 sensor tracker with 2 if statements, or you could have 8 sensors and historisas with the acceleromitor from last year helping to. there is the some old PBASIC code
here if you have
no idea where to start. best of luck, Jacob