Hello.
The sensors on the 3pi detect reflected IR, so while different colors/surfaces might reflect different amounts IR, you are not actually sensing the color (e.g. two different yellow surfaces might appear completely different in terms of reflected IR). The only color sensors we carry are Parallax ColorPALs. You might be able to use that to detect the color of the line you are following while still using our QTR reflectance sensors to detect the line itself, but this really depends on whether there is a significant difference in IR reflectivity between your course’s line and its background. I’m worried that, for example, the yellow line and green surface might look approximately the same in IR, in which case you need a better way to detect the line (maybe a simple camera?).
The 3pi was not designed for the addition of encoders, and there are several big obstacles to adding them, perhaps the main one being the 3pi’s lack of free I/O lines (you can get around this if you use another processor to read the encoders). Still, at least a few people have managed to add encoders to their 3pis:
If you are actually making your own 3pi-like robot, it should be much easier to add encoders. Here is an example:
roboticsindia.com/entry.php/ … ot-(Part-2
Note that I’m not sure exactly what you mean by “remember the track”, but I suspect what you want to do will be much more difficult than you expect.
- Ben