What is the VEX line tracker?

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ArduinoArduino Tutorials and Guided ProjectsVEX + Arduino, Mobile Robotics Platform → Tutorials/Arduino Projects/Mobile Robotics/VEX/What is the VEX line tracker

What does it do?

The VEX line tracker is a sensor which can determine the reflectivity of a surface. This may not seem all that useful until you realize that this allows a robot to know whether it is looking at a black surface, a white surface - even any shade of grey!

The VEX line tracker.

What is it used for?

This ability to determine shade can be used for all sorts of things, including:

  • Custom built encoders
  • Rudimentary color sensing with filters
  • Its most common use - line following.

An array of three sensors, side-by-side, is most commonly used for line following.

A typical line tracker setup on a VEX robot.

How does it work?

The VEX line tracker is an IR (Infrared) sensor - it emits and detects IR light that is just outside of the visible spectrum - it's invisible light.

This is actually a huge advantage for the robot, as it means that normal light sources won't influence it hugely - it will work perfectly in a well-lit room, or even in the dark!

Of course, it can also be negatively influenced by this invisible light. IR interference from other devices (e.g. TV remotes, some types of lighting, the Sun...) can affect its readings. Sometimes, then, it may be a good idea to shield it from this kind of interference.