Multi-colored line tracking

Hi all,

I have a problem and I would like your opinion. I made a small robot that uses a Baby Orangutan B-328 Robot Controller and two QTR-RC sensors to track a line on a whiteboard.

So far I have implemented successfully a black line tracking using the Pololu library and the qtr_read_line() function. I have also implemented a PD controller, as in the example of Library User’s Guide, and the robot tracks smoothly the black line.

Now my problem is if I can do the same but this time having a multicolored line instead of black. I know that the qtr_calibrate() command provides a max-min value for a specific color that is calibrated with. However, qtr_read_line() or qtr_read_calibrated() functions can still detect color variations providing a little different values for each color, no mater what initial color has been used in the calibration sequence.

Any thoughts or ideas of how to do that would be greatly appreciate it.




You might try testing each color to see which gives you the weakest IR signal. Then calibrate over that color to get the lowest threshold value. Ideally, the other colors should give you a higher return signal, so your line follower might be able to see them all. We get questions similar to this surprisingly often, so I would be interested to know how it turns out.