Well I started this project as a photovore and ended up with a line follower. I used the same code as the photovore but instead of using the photo resistors I used two QTI IR sensors
http://itp.nyu.edu/physcomp/sensors/Reports/QTILineSensor. I had to use a 10kohm resistor on each sensor for them to work with the program (check link for reference). I also changed the threshold value in the source code from 8 to 50. It works like a dream. I'll post a video of the robot later. The robot follows a Black line on a white surface.
Thanks admin for the wonderful tutorials and this great forum. I had to build this project for class and would not have been able to finish if it wasn't for all the useful information on your site and forum. Im finishing my electronics major this week and don't know crap about C language. Well I learned a little from experimenting with your codes.
Thanks,
Jose