To follow a simple line with our EV3 is a very simple task, you only need to program a switch with two opposite turns and the robot will advance by doing a kind of "zig-zag movement" of his body, as you can watch here:
But try to solve a maze made by black lines on a white surface is a real challenge for our students. There are some crossing point that difficult to the robot following an easy path, and it decides usually to turn to each side, depending of the kind of line it detects at the same time at the ligth sensors.
That is why our robot needs a minimum of three ligth detectors: the central one is necessary to follow the main line and the others, in both sides and aligned, decide simultaneously where to turn.
Look at our first attempt, it really works fine except when the sensors are all in white, so we will continue improve it!
Finally we arrived in Afyon for yhe second mobility and we put in action the robot in order to show and explain the task to our Erasmus+ partners, with this final result: