Skip to main content
Teacher Portal

Teacher Toolbox icon Teacher Toolbox - Facilitating the Divert the Red Disk Page

What the Teacher Will Do:

  • Bring students together for whole-class instruction.
    • Explain to students how the red disk will move when they complete the project on this page. 
      • Walk students though each of the steps needed to move the red disk from the entry conveyor to the exit conveyor.
      • Watch the video on this page on how the red disk should travel through the conveyors and be diverted off. 
      • If students are struggling at any point as they are working on their projects, encourage them to re-watch the video of how the disk should travel.
    • Ensure all students are on the same page with the expectations of how the red disk will travel before moving on. Then, instruct students that they will be working together in their groups to follow the steps on this page.
  • Break students off into their groups to follow the steps on this page.
  • Circle the classroom as students work through these steps and answer any questions that arise.
  • As groups check in, ensure they have built their project correctly before moving on. Guidance for this check in is provided in a Teacher Toolbox at the bottom of this page.

The red disk, acting as a faulty package or product, will move through the following path:

The red disk will begin at the entry conveyor in front of the Optical Sensor.

Red enter

The red disk will then be loaded onto the transport conveyor from the entry conveyor.

Red transport

Once the red disk is loaded onto the transport conveyor, it will pass in front of the load sensor. When the red disk passes in front of the load sensor, the diverter needs to be set to position in order to divert the red disk to the exit conveyor.

Diverter callout

Once the red disk is on the exit conveyor, it will pass in front of the exit sensor. When the red disk passes in front of the exit sensor, all conveyors will need to stop.

Red exit

The red disk will have followed this complete path to be diverted off of the exit conveyor.

Now that you have recorded the low and high threshold values of the Line Trackers and understand the path that the red disk will travel, you will now code the sensors using the Line Tracker values to divert a red disk off of the Workcell.

Add blocks to the {Define My Block} block for the red disk to create the stack of blocks shown in this image.

These blocks will code the entry and transport conveyors to spin forward, so that the red disk moves from the entry conveyor onto the transport conveyor.

Project 1

For Your Information

The [Wait until] block waits for a Boolean block to report true before moving to the next block in the stack.

In this project, the [Wait until] block will be used to wait until the Optical Sensor detects a disk, and also wait until a disk is detected by the Line Tracker that is reported by the (Reflectivity of) block.

The (Reflectivity of) block reports the amount of light reflected using the Line Tracker.

Wait until

Add blocks to the project to create the stack of blocks shown in this image.

Use your low threshold value for the load sensor in the <Greater than> block and not the one shown in this image.

These blocks will code the transport conveyor to spin forward until the load sensor detects a light value greater than the lower threshold value.

Then, once the red disk is in front of the load sensor, the diverter will be set to the 90 degree position to divert the red disk to the exit conveyor.

Project 2

Load a red disk onto the entry conveyor and download and run the project.

The red disk will travel from the entry conveyor, onto the transport conveyor, and then be diverted off onto the exit conveyor.

Once the red disk has been moved onto the exit conveyor, stop the project.

If the red disk has not been diverted off onto the exit conveyor, notify your teacher.

Diverter callout

Add blocks to the project to create the stack of blocks shown in this image.

Use your low threshold value for the exit sensor in the <Greater than> block and not the one shown in this image.

These blocks will code the exit conveyor to spin forward until the exit sensor detects a light value greater than the lower threshold value.

Then, once the red disk is in front of the exit sensor, all conveyors will stop spinning.

Project 3

Load a red disk onto the entry conveyor and download and run the project.

The disk will follow the shown path to be diverted off of the exit conveyor.

Once the red disk is in front of the exit sensor and all conveyors stop spinning, stop the project and check in with your teacher.

If the red disk did not follow the path shown, notify your teacher during the check in.

Red path

Teacher Toolbox icon Teacher Toolbox - Troubleshooting

 If groups are finding issues with their conveyors and diverter moving when the red disk is detected, try the following troubleshooting techniques.

  1. Check the VEXcode V5 project.
    1. Review the project with the group ensure the order of the blocks match. Make sure students are re-downloading their project each time they make a change and before they run the project.define red disk my block code
      1. Ensure students are paying close attention to the parameters of the (Reflectivity of) blocks. These should match the low values they recorded for the load sensor on the previous page. If students are still having issues with their Line Trackers, have them adjust this threshold value and test again.
        code snippet parameter
      2. Ensure the [Spin to position] block for the diverter is set to 90 degrees. Students may accidentally leave it at 0 degrees or 9 degrees, which would not spin the diverter enough to divert a disk onto the exit conveyor.
        Diverter parameter
  2. Check the build.
    1. There may be a mechanical issue with your Workcell. Instruct students to look at the Lab 10 build instructions first and verify that the additions to their Workcell match

Teacher Toolbox icon Teacher Toolbox - Check in

Review the following with the group during their check in:

  • Check that all groups have successfully gone through all the steps on the page. Ask them to run their project for you, so you can see the red disk diverted off onto the exit conveyor. If the project does not run as expected, see the Teacher Toolbox - Troubleshooting note above.
  • Ask students the following questions as students are presenting their projects.
    • What did you use for the low threshold value and why? Did this work when you tested it?
    • Did your project run the first time you tested it? If not, what did you change?
    • How was this project different than the project in Lab 9? What is the value of adding the sensors to the Workcell?