With LEGO 51515 you can learn how to make a simple and reliable proportional line follower for an FLL robot! The proportional line follower is the go-to algorithm for getting an FLL robot or a WRO robot to follow a line smoothly. Today I use LEGO MINDSTORMS 51515 Robot Inventor to re-introduce proportional line following to the fourth generation of LEGO MINDSTORMS robotics! A proportional line follower uses a single LEGO 51515 color sensor to monitor reflected light intensity values. Corrections to the robot’s path are proportional to the robot’s error relative to the line. Line following was among the most popular topics for my EV3 tutorials, and today I am happy to re-introduce the topic to LEGO 51515.

In today’s LEGO MINDSTORMS 51515 programming tutorial, I explain the conceptual thinking behind the proportional line follower, teach you how to acquire a target reflected light intensity value, walk you though writing the line follower code, and teach you how to tune the parameters (proportional constant and target path) for optimal line following performance!