VEX Workcell - Using an End Effector - Lab 6

Teacher Toolbox - Facilitating the Exploring the Z-Axis 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.
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.

In VEXcode V5, follow the steps in this video to add [Linear move] blocks to the project and enter these predetermined coordinates for the first point, and the location above the first point.

First point: (6, 0, 1.8)
Location above first point: (6, 0, 3)

Download and run the project. The arm will draw the first point on the whiteboard and then lift the marker up off of the whiteboard.

If your arm did not draw the first point and then lift the marker up off of the whiteboard, notify your teacher.

Once you have finished coding the arm to draw the first point and then lift the marker up off of the whiteboard, stop the project.

In VEXcode V5, follow the steps in this video to add [Linear move] blocks to the project and enter these predetermined coordinates for the location above the second point, and the second point.

Location above second point: (8, 2, 3)
Second point: (8, 2, 1.8)

Download and run the project.

After the arm moves to the first point and the location above the first point, it will move to the location above the second point off of the whiteboard, and then move the marker down to second point on the whiteboard.

If your arm did not move to the location above the second point off of the whiteboard, and then move the marker down to second point on the whiteboard, notify your teacher.

Once you have finished coding the arm to move to the location above the second point off of the whiteboard, and then move the marker down to second point on the whiteboard, stop the project and check in with your teacher.

Teacher Tips

If students are having difficulty seeing each distinct movement of the arm, have them add a [Wait] block between each [Linear move] block.
In the videos above, a green circle around the cursor indicates a right-click while a black circle indicates a left-click.

Teacher Toolbox - Troubleshooting

If groups are finding that the arm does not draw the two dots when they run their project, try the following troubleshooting techniques.

Change the z-value in the first and last [Linear move] block.
1. The dry-erase marker may not reach the whiteboard at each of these points. Have students set lower z-values, like 1.5 or 1, and test the project.
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.
Check the VEXcode V5 project.
1. Have students compare their project to the video 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
Check the build.
1. There may be a mechanical issue with your Workcell. Instruct students to look at the Lab 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 - Check in

Review the following with the group during their check in:

Ensure groups have built their project correctly. All groups should have [Linear move] blocks in their project with these x and y-values.

Ask groups to describe the movement of the arm when they run the project. What direction does it move? Why?
- The arm will move down to the first point. Then because the z-value has increased, the arm will move up into the air.
- The arm will then move diagonally with x and y-values increasing. Then because the z-value is decreasing, the arm will move back down to make contact with the whiteboard.