line trackers work better the closer they are to the ground, I recommend mounting them on the intake tray, so that when you lift the arm for crossing the bump the line trackers come up with the arm, and once you lower the arm the linetrackers go back to the ground again. Just have a piece of metal from the tray going down the the ground hovering barely like a mm or so. And attach the line trackers there. They are protected because you only cross the bump with the arm up, and you can get them in virtually in any position in the U chassis, with them very close to the ground.
Thanks man… Nice advice!
There are a few reasons why this may not be the best idea. The line sensors will not always be the same distance to the ground, and the different in values that the line sensors give when 10mm way vs. 15mm is pretty large. Also, you will have to use a ton of extensions. The easiest method is to have your line sensors in line with your front or back wheels.
Our team found that we could not get sensors in the middle and close to the line (as started this post) so we put one on each side and programmed an interesting system with trig to determine the angle a robot makes with a line by how far it travel between when each side notices the line. Using this information, the robot can drive till its center of rotation is over the line and turn the appropriate angle to align perpendicular or parallel to the line. This is a more advanced approach and takes some math and programming to figure out, but if you have encoders and a decent turning function for the angle you want to turn, they can give you any navigational information you could want from line sensors with very better accuracy than when I try to turn it driving.
