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What is a Vision Sensor?

Teacher Toolbox icon Teacher Toolbox - The Purpose of this Page

This page will introduce students to what a Vision Sensor is and some of its capabilities. The students will then analyze a partial image of an example project to view how the Vision Sensor can be used with VEXcode IQ.

The Motivate Discussion questions at the bottom of the page can be completed as a class discussion or individually in the students' engineering notebooks.

Description

The Vision Sensor allows your robot to collect visual data from a live feed. A live feed is a streaming transmission of what a video camera is capturing. The Vision Sensor is like a smart camera that can observe, select, adjust, and store colors and objects that appear in its visual field.

VEX Vision Sensor with the top of the sensor shown to the left and the bottom of the sensor, with ports for connections shown to the right.
Vision Sensor 276-4850

Capabilities:

  • This sensor can be used for recognizing colors and color patterns.
  • This sensor can be used to follow an object.
  • This sensor can be used to collect information about the environment.

The Vision Sensor allows the robot to use visual input data from its environment. The project can then determine how the visual input data should affect the robot's behavior. For example, the robot could perform actions (output) such as spinning motors or displaying results on the LCD screen.

The Vision Sensor can also capture a snapshot of what is in front of it and analyze it according to what the user is asking. For example, a user can gather data from the snapshot such as, what color is the object? Is there an object detected at all? How large is the object (width and height)?

The robot can then make decisions based off of this data. The partial example project below shows how this is done. In this first part of the example project, the robot will print "Blue Object Found" if a blue object is detected and "No Blue Object" otherwise. That is the first of three decisions within the example project but the second and third decisions are not shown here.

The start of a VEXcode IQ project with a When started block with an attached Forever block. Within the forever block are commands to clear all rows on the brain, then a comment to detect blue, then a command to set cursor to row 1 column 1 and take a snapshot of Bluebox. Next is an if then block with the condition set to Vision12 Object exists then print blue object found, else, print no blue object.

Motivate Discussion icon Motivate Discussion

Q: What types of human jobs would benefit from having the help of a robot with a vision sensor?
A: Listen for human jobs that would benefit from the ability to see into environments and/or manipulate surroundings from remote distances (e.g., observing animals in the wild, disarming explosives, or performing robot-assisted surgery).

Q: Name a device and describe how it uses input, output, and process.
A: A possible answer could be a calculator that takes the sequences of numbers and mathematical operators a person inputs, processes those numbers and operations to calculate a result, and then outputs that result on a screen for the person.

Q: Why do you think a forever loop was used in the project shown above?
A: A forever loop was used so that the Vision Sensor continuously checks the multiple snapshots taken to see if a red object comes into view of the sensor.