I made a custom robot with two continuous servos for the wheels, and I'm trying to figure out the best way to maneuver it to the center of a multicolored target using a phototransistor. Right now, I have the phototransistor set up to detect the different colors, but I'm troubled about how to make the one phototransistor control the movement of the robot so it will reach the center (the target is a circle). The transistor is located at the front of the robot, and has it's own light source to ensure the phototransistor reads consistent values. The target has 5 colors before reaching the center, and the floor is a solid color not in the range of the target. I'm thinking I can swivel the robot back and forth to test the colors and make sure its driving toward the center, but I'm not sure if that will work... I'd be interested to hear any suggestions.