What Is a Line Follower Robot?

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  • Written By: Mary McMahon
  • Edited By: Nancy Fann-Im
  • Last Modified Date: 11 August 2014
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A line follower robot is a robot that can track lines and follow them, proceeding along a preset path that can be altered by moving the lines. Sophisticated robots can distinguish between different colors, making it possible for them to follow one among several lines accurately. Such devices can be subjects of competitions in robots and computing, and they also have a number of real world applications. For example, robots in warehouses can follow lines to pick up and deliver products along a specific route.

The line follower robot design requires a chassis that can allow it to move, whether on wheels or via another mode of locomotion. It also needs detection devices to find lines, and on-board computing to process information. A simple camera often provides an inexpensive method for spotting and following lines. A processor interprets the input from the camera and controls the movement of the robot.

In testing to determine how well a line follower robot works, a number of challenges can be presented. One is a complex path with lots of sharp turns and overlapping lines, which can confuse a robot with limited programming. Technicians can also place lines of different colors to see how the robot responds, and may set up a course on an incline or with other obstacles to determine the degree of sophistication in the programming. An advanced robot can compensate, while others may not be prepared for rough terrain or other problems.


Competitions usually provide a set of rules entrants must follow with each line follower robot they submit. The rules typically discuss the type of course so entrants can prepare, and also limit the types of programming and technology available. This creates a more level playing field for contestants, who will not need to worry about things like entrants substituting robots from other sources to win the contest. Robots may be taken through a series of challenges to see which performs the best by staying on track and completing courses at rapid speeds.

Commercial line follower robot kits are available, and it is also possible to build and program one from scratch. Robotics manufacturers produce robust models for industrial and other applications. These robots may include a variety of features, depending on the purpose they are designed for, and typically communicate with a computer so they can receive upgrades and other information from the manufacturer. This allows a company to take advantage of robotics technology without having a staff member capable of programming and maintaining the devices.


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Post 4

@SkyWhisperer - It’s at the competitive level that you really see what these things are capable of. Personally I doubt the robots that win competitions are solely built from kits. Otherwise, how would one robot stand out from another robot?

I believe some of the winning robots are built from scratch. If you are a real whiz kid with math and science, then a line follower robot project might be up your alley.

That’s where the programming talent comes in too, which can make the difference between how well the robot “reads” the lines.

Post 3

@nony - A line following robot algorithm can be simple or easy. If it’s a simple, square black line one a white surface for example, then yes I think it would be easy. But to differentiate different colored lines on a variety of surfaces is a challenge.

For that you need real artificial intelligence in my opinion. At that stage you’re outside the domain of simple robotic kits; it takes real engineering to do that kind of stuff.

As far as practical applications, I’ve heard of these robots also being used in airports. They carry the passenger’s luggage from the plane to the terminal. I don’t know if their use is widespread but I can see how it would work.

Post 2

@hamje32 - Yeah, the robotics kits are a good start. They usually come prepackaged with everything that you need so you don’t need to do a lot of thinking.

But I don’t think the kits for line following robots are all that hard. I don’t exactly how they do it, but I would bet anything they come with simple photoresistors to use as the “eye” of the robot.

A black line might interrupt the light hitting the photoresistor and so this could be used as a relay mechanism of some sort. I believe the principle is simple, really.

Post 1

Some people like to build robots as a hobby. I think it's neat that there are a whole bunch of kits that you can buy that will let you do this.

At first glance you might think it would be easy to figure out how to build a line following robot. After all, how hard can it be to follow lines?

But as I think the article makes quite clear, it is indeed very challenging. Even simple shapes can require sophisticated computing algorithms and of course differentiating colors is an added challenge too.

So if you’re just starting out, I don’t recommend that you tackle the line following robot. Start with an “unintelligent” robot, one that is manipulated by simple commands from you, the operator. Then I think you should brush up on optical sensors and image algorithms if you want to get into line following robots.

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