Color Line following

Can the 3pi robot follow lines that are not just black on a white surface? Ex. green line on a orange surface?


It probably can. But you will have to do experiments to find out and to determine whether the green looks darker or lighter than the orange to the 3pi.


well those colors were just examples, but my project actually requires the robot to follow a yellow line on a purple course. I figured the line sensors aren’t set for just black or white, but rather a difference in color/wavelength detected through the phototransistor on the base of the 3pi.


The 3pi sensors are phototransistors that conduct based on the intensity of incident IR light (they are paired with IR emitters with a peak emission wavelength of around 940 nm). They do not detect the color of a surface, they detect how much of the emitted IR is reflected by the surface. White surfaces typically reflect more IR than black, and I expect yellow would reflect more than purple, but you’d need to try it out and see what sort of readings you get. The contrast will probably not be as good as white on black, but you might have decent results after calibration.

- Ben

Thank you a lot Ben! That makes sense. Well the yellow I am hoping that the yellow will reflect much more than the purple will. The purple is very dark, as opposed to the vibrant yellow. Thanks a lot again!