LEGO EV3 : Dual Colour Sensors on July 25, 2017 Get link Facebook Twitter Pinterest Email Other Apps Detecting the Intersections The color sensors need to set into compare Reflected light intensity 1. As the robot moves from side to side along the line it will stop at an intersection 2. If LS1< LS2 then turn Left 3. If LS1>LS2 then turn Right