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

What the Teacher Will Do:

  • Instruct students that they will be working together in their groups to follow the steps on this page.
  • Circle the classroom as students work through these steps and answer any questions that arise.
    • Many of the steps here are similar to steps shown to students in Lab 7. If they need additional assistance, direct them back to those Play steps.
  • 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.

Now that you have created the 'Lab 8- Sort Colors' project, you will code the arm to pick up the red disk from the pick up location, determine the color using the Optical Sensor, and then drop the disk into the red drop off location.

In VEXcode V5, enter the coordinates for Point 1 and Point 2 into the [Joint move] blocks to create the stack of blocks shown in this image. 

These blocks will code the arm pick up the disk from the pick up location.

Use your coordinates for Point 1 and Point 2, and not the ones shown in this image.

Point 1 and Point 2 Callout

Follow the steps in this video to add a [Joint move] block, a [Wait] block, and to enter the coordinates for Point 3. 

These blocks will code the arm to hold the disk over the Optical Sensor for one second in order for the sensor to determine the color of the disk.

Use your coordinates for Point 3, and not the ones shown in this video.

Add a [Joint move], [Wait], and [Energize electromagnet] block to the project. Then, enter the coordinates for Point 4 into the [Joint move] block and set the [Energize electromagnet] block to 'drop,' to create the code snippet shown in this image. 

These blocks will code the arm to drop the disk into the red drop off location.

Use your coordinates for Point 4, and not the ones shown in this image.

Point 4 Callout

Place the red disk into the pick up location and then download and run the project.

Red disk in pick upDownload and run

Press the Brain's screen to trigger the arm's movement. The arm will pick up the red disk from the pick up location and hold it over the Optical Sensor for the sensor to determine that the color is red. Then, because the Optical Sensor is detecting a red disk, the arm will move to the red drop off location and sort the disk by dropping it into the standoffs. 

If your arm did not sort the red disk, notify your teacher. 

Step 6

Once you have finished coding the arm to pick up and sort the red disk using the Optical Sensor, stop the project.

stop

Teacher Toolbox icon Teacher Toolbox - Troubleshooting

If groups are finding that the arm does not pick up and move the red disk when they run their project, try the following troubleshooting techniques.

  1. Check the VEXcode V5 project.
    1. Have students compare their project to the videos and images on this page and 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.
    2. Check the location and parameter of the <Optical detects color> and [If then] blocks. Have students confirm that the [Joint move] and [Energize electromagnet] blocks for the red disk's drop off location are within the [If then] block.

code snippet detecting red

  1. Check the mastering values.
    1. Instruct students to check that the mastering values they recorded in their engineering notebook during Seek match what is in the [Set mastering] block.
    2. If the problem still persists, have students follow the steps in Seek to rerecord their mastering values.
  2. Check the build. 
    1. There may be a mechanical issue with your Workcell. Instruct students to look at the Lab 8 build instructions first and verify that the additions to their Workcell match.
    2. Have students go back to the Lab 1 build instructions for a complete look at the build and check that all elements match. Even one small detail being wrong can affect the movement of the arm on the Workcell.

Teacher Toolbox icon Teacher Toolbox - Check in

Review the following with the group during their check in:

  • Ensure groups have built their project correctly. All groups should have the same elements in their projects, but the layout may differ from one group to another.
  • Ask students about how the arm moved when they ran the project.
    • What triggered the arm to move to the pick up location?
    • What happened when the arm paused over the Optical Sensor with the red disk attached to the electromagnet?
  • Ensure each group has successfully sorted the red disk using the Optical Sensor before moving on.