Turns out, that for their recommended line width of 3/4" 19mm, then the two middle sensors are on the line.
QuoteTurns out, that for their recommended line width of 3/4" 19mm, then the two middle sensors are on the line.Which makes detecting the edge of the line faster, since an edge is closer to one of the sensors. The sooner you detect a change in the position of the follower vs. the line, the sooner you can make a correction, and the smaller the correction needs to be.
7th graders make Lego Mindstorm line following robots with just 1 light/dark sensor. Having 5-6-7-8 seems like overkill.
I've never messed around with line followers, but I think that the increased number of sensors also relate to how to sense when the vehicle crosses over a line "perpendicular" to the line being followed (so it can be ignored in preference to the actual path being taken).