Youtube demo here:
http://www.youtube.com/watch?v=YbwSl5Hp3r8
This is a round about way of using a servo to move an analog sensor to 3 points to triangulate the servo degree where the photocell experiences the most light.
The servo sweeps back and forth and then another servo points to where the brightest point was.
It is very simple wiring, but the code is a little fancy. It’s all commented up here, but as always deduction is your friend.
Raspberry pi soon?
Hey! This post was written a long time ago, but I'm leaving it up on the off-chance it may help someone. Proceed with caution. It may not be a good idea to blindly integrate this code or work into your project, but instead use it as a starting point.