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Part 1 - Step by Step

  1. InstructInstruct each group that they will be opening and starting the 'Avoiding Obstacles' example project in VEXcode GO to see how the Eye Sensor detects objects.

    Code Base in the corner of the VEX GO Field, facing the Wall to indicate that that Eye Sensor on the front of the robot will detect the wall.
    Code Base Avoiding Obstacles

     

  2. ModelModel for students the steps to launch VEXcode GO.

    Note: When you first connect your Code Base to your device, the Gyro built into the Brain may calibrate, causing the Code Base to move on its own for a moment. This is an expected behavior, do not touch the Code Base while it's calibrating.

    • Students will be using an example project to help them learn about commands related to the Eye Sensor in VEXcode GO. Model for students how to open the 'Avoiding Obstacles' example project.

      Example project icon reads Avoiding Obstacles at the bottom and shows a blue illustration of a robot moving toward a wall, with an eye indicating the sensor used and an arrow indicating turning around.
      Avoiding Obstacles Project

       

    • Model for students how to save the example project, and name it Avoiding Obstacles. Students should then place their Code Base in the Field and start the project.
    • Note: If you do not have Walls for the Tiles, use classroom items such as books to set up a space for students to test the projects. The test area should be flat, and have objects on all fours sides if possible.
    • A top down view of the 2x2 VEX GO Field with walls, with the Code Base in the starting location in the bottom left corner, centered on the vertical black line.
      Code Base in the Field

     

    • This project has a [Forever] block around it. To make the project stop running after the Code Base detects a wall, students will need to be sure to select  'Stop' in the Toolbar.

      The VEXcode GO Toolbar with the Stop button highlighted in a red box. The icons from left to right show a green Brain icon, then Start, Step, Stop, Share, and Feedback.
      Stop the Project

       

    • Students should observe that the Code Base detects a wall, backs up, then turns right. Have students start the project again and see how long the Code Base will repeat this pattern when a wall is detected. 
  3. FacilitateFacilitate a discussion with students about the project and the Eye Sensor.
    • How long do you think the Code Base will detect objects and then turn right? Point out to students the [Forever] block that goes around the main part of the project.
    • Describe how the Code Base would move if it detected four walls. What shape would the Code Base move in?
    • About how far away from a wall does the Code Base get before detecting it? Estimate or use your hands to explain how far.
  4. RemindRemind students that the Eye Sensor must be attached to the Brain before powering the Brain on in order to work properly. If the Eye Sensor is attached or removed after the Brain has already been powered on, the Brain must be power cycled (turned off and then back on) in order for the Eye Sensor to function properly.

    Remind groups to open and observe the Monitor Console after the project is started. They will be able to observe when the <Eye found object>  reports ‘TRUE.’ 

    The Monitor Console in VEXcode GO shows the drive velocity in % reported as 0, and the eye found object reported as false, indicating how the sensor data can be viewed while a project is running.
    Monitor Console

     

  5. AskAsk students how they could use object detecting in their everyday life.

    For a silly example, if they wanted to walk backward down the hallways at school, they could use a sensor to tell them when they get too close to a wall or another person! What other ways to use the object detecting function of the Eye Sensor can they come up with?

Mid-Play Break & Group Discussion

As soon as every group has tested the ‘Avoiding Obstacles’ example project, come together for a brief conversation.

  • What did the Eye Sensor detect in this example project?
  • The Eye Sensor can also detect color! We will create a project next where if the Eye Sensor detects green, blue, or red, the Code Base performs different actions.
    • Let’s practice first. When you see green, raise your right hand. When you see blue, raise your left hand. When you see red, raise both hands. (The teacher should then hold up 3 objects and see if the students can follow along with the pattern. Repeat the game as many times as needed.)

Part 2 - Step by Step

  1. InstructInstruct each group that they will be creating a project where the Code Base uses the color detection function of the Eye Sensor to navigate a color disk maze. Students will add Disks to their field to create the color disk maze. Then, they will create a project where the Code Base drives through the maze and turns right, left, or stops depending on the color of the Disk that is detected.

    Watch the animation below to see how the Code Base will move to complete the maze. In this animation, the Code Base starts in the lower left corner of the Field, opposite the Green Disk on the Field. It drives forward until the Green Disk is detected, then reverses and turns right 90 degrees to face the next disk. The robot then drives forward until the Blue Disk is detected, then reverses and turns left 90 degrees to face the final disk. Lastly, the robot drives forward until the Red Disk is detected, then stops.

  2. ModelModel using a group’s setup, how to launch VEXcode GO. If they already have VEXcode GO open from Play Part 1, model for students how to open the File menu and select 'New Blocks Project.'
    • Once the project is open, have students save the project as Color Disk Maze.
    • Students will need to configure the Code Base to see the blocks they need in the Toolbox. 
    • Model the steps to connect a Brain to your device.

    • Students will first build a project to detect the Green and Blue Disks in the maze. Model for students how to replicate the project in this image. They will need to add blocks and change parameters as needed to replicate the code.

      VEXcode GO project starts with a When started block and has a stack of 8 blocks attached. The blocks read from top to bottom: drive forward; wait until eye detects green; drive reverse for 100mm; turn right for 90 degrees; drive forward; wait until eye detects blue; drive reverse for 100mm; and turn left for 90 degrees.
      Color Disk Maze: Detect Green and Blue

       

    NOTE: Students may need to change the parameters in the project depending on the placement of the Disks in the color disk maze set up.  We suggest that you set up your 2x2 field before starting the Lab, and test the project. If possible. See the "Color Disk Maze " slide in the Lab 4 Image Slideshow for guidance in the placement of each Disk in the color disk maze. If you do not have enough Tiles or Walls for the color disk maze, set up colored Disks in a similar configuration on a smooth surface like the floor or a desk.  

     

    • Now that the Code Base is configured, the Brain is connected, and the project is replicated, model for students how to save the project, and name it Color Disk Maze.

      The project name box in the center of the VEXcode GO Toolbar is highlighted with a red box, and reads Color Disk Maze.
      Name the Project

       

    • Students should add the three colored Disks to the Field to create the color disk maze.

      Three Disks, one of each green, blue, and red, are shown standing up on the Field attached to yellow connectors and beams. Each standing disk is constructed by attaching a Disk to a Yellow Connector with a pin. The Yellow Connector is then attached to the center of a Yellow Beam, so that the Disk can be free standing on the Field and detectable by the sensor.
      Disk Construction

       

    • Once the Disks are added, students should then place their Code Base at the start of the color disk maze (with the Eye Sensor lined up on the black line of the Tile) and start the project. Have students observe how the Code Base responds when the Eye Sensor detects the colors green and blue. Once the project is done running, instruct students to stop the project.

      A top down view of the Color Disk Maze setup on a 2x2 VEX GO Field with Walls. The Code Base is in the starting position in the bottom left corner, facing the center of the Field, centered on the vertical black line. Directly opposite the robot is the green disk, standing just past the center horizontal black line on the Field. To the right of the robot, the blue disk is facing the robot near the right wall, on the first black horizontal line. On the far side of the Field, the red disk is standing facing the center of the Field, just to the right of the center line.
      Color Disk Maze

       

    • Students will now edit their code to include the Red Disk. Model for students how to add additional blocks to their project so the Code Base drives to the Red Disk and stops.

      The same VEXcode GO project as before with the following blocks added to the stack: drive forward; wait until eye detects red; and stop driving.
      Color Disk Maze: Add Detect Red 

       

    • Have students place their Code Base at the start of the color disk maze and once again start the project. Once the project is done running, instruct students to stop the project.
  3. FacilitateFacilitate a discussion with students while they edit and test their projects.
    • About how far away from a Disk does the Code Base get before detecting the color? Estimate or use your hands to explain how far.
    • What do you think would happen if the last block in the project was a [Drive] block? Would the Code Base know when to stop driving?
  4. RemindRemind students that the Eye Sensor must be attached to the Brain before powering the Brain on in order to work properly. If the Eye Sensor is attached or removed after the Brain has already been powered on, the Brain must be power cycled (turned off and then back on) in order for the Eye Sensor to function properly.
    • Also, remind groups to check their parameters after recreating the project to ensure they match with the image of code.
    • While the projects are running, remind students to open the Monitor window and to observe when the Eye Sensor detects a color.

    Three disks, one of each color, are shown with an Eye Sensor positioned as though detecting the Disk's color, with a 'bubble' of color above the sensor illustrating what the sensor would report.
    Eye Sensor Detects Color

     

  5. AskAsk students what devices or items they can think of that use eye sensors. Some examples could include smart doorbells or cameras with motion sensors.
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