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Robot Arm
Lab 4 - Using the Eye Sensor

Teacher Portal


Launch the Engage Section

ACTS is what the teacher will do and ASKS is how the teacher will facilitate.

  1. Drop an object on the floor in front of you. As students share what to do, draw/write it on the board as a process, using images or words.
  2. Write the words “Boolean Condition” on the board, and note any student responses that reflect a true/false value.
  3. Write the Eye Sensor question on the board beneath "Boolean Condition."
  4. Beside "Boolean Condition," write the words "Control Block," and note any student responses that are connected.
  5. Write the phrase [Wait until] block under "Control Block" on the board.
  1. We began to use code to control our Robot Arm’s movement in Lab 3. Today we’re going to think about using code to make our Robot Arms more intelligent. Let’s say I drop something on the floor. It’s in my path. What do I do? (See the object, pick it up, put it on the shelf, etc.)
  2. Our brains intuit that I’d need to put this away, or step over it. What if we wanted our Robot Arm to do something like that? Now we’re asking the robot to make a decision. We have to take that process and turn it into code. We do that using Boolean conditions and Control blocks. Does anyone know what a Boolean condition is?
  3. A Boolean condition is something that can be boiled down to a True or False value, like sensor data. The Eye Sensor on our Robot Arm can give us a True/False value - Does it see something? Yes, then it’s True. No, then it’s False.
  4. But True and False are just values. They can’t do anything by themselves. They CAN be used to make something else happen. That’s where our Control blocks come in. Can anyone describe what a control block does in a project?
  5. A Control block can use the value from a Boolean condition to control what the robot does next, or the flow of our project. If we are asking if the Eye Sensor sees something, what would we want the Robot Arm to do with that information? We want it to Wait until it sees something, right? So we would use a [Wait until] control block. What will that tell the Robot Arm to do? Wait until our Eye Sensor value is True, then do something. So, our project flow now would tell our Robot Arm to see something and do something with code.

Getting the Students Ready to Build

How do you think we can use the Eye Sensor on the Robot Arm to make it more intelligent? Let’s build the Robot Arm (2-Axis) to help us find out!

Facilitate the Build

  1. InstructInstruct students that they are going to build the Robot Arm (2-Axis) today, and use it to explore how the Eye Sensor can be used to help the Robot Arm detect and move objects.

    Build the Code Robot Arm (2-Axis)
    Build the Code Robot Arm (2-Axis)

    Students should join their groups from the previous Lab, and complete the Robotics Roles & Routines sheet. Use the Suggested Role Responsibilities slide in the Lab Image Slideshow as a guide for students to complete this sheet.

    • Encourage students to rotate between the kinds of Builder/Journalist roles they’ve developed as well.
  2. DistributeDistribute Code Robot Arm (2-Axis) Build Instructions to each team. Journalists should gather the materials on the checklist.
  3. FacilitateFacilitate building process and discussions while students work.

    Builders can begin building. Journalists should assist with build instructions as needed. To prompt students thinking about how the Eye Sensor works on the Arm ask questions like:

    • Where would an object need to be in order for the Eye Sensor to detect it?
    • Why do you think we positioned the Eye Sensor here on the build?
  4. OfferOffer suggestions and note positive team building and problem solving strategies as teams build together.
A VEX GO character

Teacher Troubleshooting

Facilitation Strategies

  • Deconstruct Previous Builds and Work in Smaller Groups - If you would like to return to the smaller groupings for Labs 4 and 5, you can. Deconstruct all Code Robot Arm (1-Axis) builds from Lab 3, and have each smaller group build the Code Robot Arm (2-Axis) from scratch for this Lab. This build will be used again in Lab 5, so the smaller grouping can stay the same.
  • Think of a Condition as a True/False Question - If students are struggling to understand the concept of a condition, help them frame it as a True or False question. For instance, “What is your favorite color?” would not be a condition, because it could not be a True/False answer. “Your favorite color is blue?” however, could be either True or False, so it could be a condition. Have students brainstorm a list of condition style questions about things they see to help connect the condition concept to the Eye Sensor in the Lab.
  • Note: the Robot Arm moves quickly and a disk may be knocked off of the Electromagnet when it moves around the base. This can be surprising (and fun) for students.