Last year we used a triple color sensor array. We used this to track lines as well as be able to stop at lines that branched off of the main line.
Color sensors are sensitive to ambient light, which is light that comes from the surroundings. To prevent that from affecting our sensors we put a bar in front of them to block as much ambient light as possible.
Color sensors are also sensitive to the distance from the mat to the sensor. We did some tests to find the best distance from the mat to the sensor. We measured the total reflected light as the sensor was moved up and down at different heights. We found the optimal distance to be 2/3 of a bar.
We found that the sensors could also be affected by reflected from the other sensors. We spaced them out to help alleviate cross-contamination.
The spacing was also due to the line following algorithm. Two sensors were used as the primary line following algorithm, one on each side of the line the robot is following. In a line following algorithm you don't follow the line, you follow the edge of the line where the reflected light is 50 (half white and half black.) We spaced them to perfectly fit both sides of the line.
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