Something we used for "tech-days" at our university, when 8th to 10th graders came to visit, was a robot following a black line on the floor, built with Lego Mi

Something we used for "tech-days" at our university, when 8th to 10th graders came to visit, was a robot following a black line on the floor, built with Lego Minsotrm. A set includes the base unit w/ two engines and some sensors, which should be enough to build a simple robot. After we explained the algorithm how the robot can follow the line by keeping the line between it's to photo sensors, we let them implement and experiment on their own. The programming GUI is intuitive and works with function blocks that can be customized and linked together.