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Activity (Hands-On)Grades 5 - 7

Line-Follower Challenge

A photograph shows six students in a circle watching two LEGO EV3 robots travel an oval line on the floor made with black tape.Students test their EV3 robots

Student groups are challenged to program robots with color sensors to follow a black line. Learning both the logic and skills behind programming robots for this challenge helps students improve their understanding of how robots "think" and widens their appreciation for the complexity involved in programming LEGO® MINDSTORMS® EV3 robots to do what appears to be a simple task. They test their ideas for approaches to solve the problem and ultimately learn a (provided) working programming solution. They think of real-world applications for line-follower robots that use sensor input. A PowerPoint® presentation and pre/post quizzes are provided.

Engineers incorporate sensors into machines in order to make them perform complex, precise and/or tedious tasks. For example, engineers who work for car manufacturers design robots that paint car parts, such as car bodies, hoods and doors. To achieve an even coat of paint, these robots must maintain a consistent distance between the paint applicator and the part. The robots use sensors to determine the distance between the paint applicator and the surface to be painted. The line-follower concept shown in this activity has applications for running mass transit systems and autonomous cars on highways, as well to deliver mail in office buildings, move items through factory assembly lines, and deliver medications in hospitals.

After this activity, students should be able to:

  • Explain how a color sensor works.
  • Develop and explain the logic behind programs that instruct robots to use color sensor readings to make decisions.

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