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Topics Covered

  • Medium Motor Block (Arm)

    • Lesson Links

    Starting Project
    Check Your Understanding:
    1. 1. What does the Medium Motor block?
      2. Controls both of the large motors
      Controls the medium motor like the one on the arm
      Controls the ultrasonic sensor
      Controls all the motors
    2. 2. What happens when you use a negative power level?
      3. The motor runs backwards
      The robot moves faster
      The motor does nothing
      The program crashes
    3. 3. What happens when you put more than one block in a program?
      4. The program runs backwards
      The program runs in sequence
      The program doesn't run at all
      The program runs the largest motor block first
    Try It!
    Try it! 1

    Negative Power

    The Move Steering command also accepts negative power values to move backwards.
    Try entering -50 in the power blank on a Move Steering block.
    What happens?

    The robot moves in reverse for the number of rotations specified.
    Mini Challenge

    Mini Challenge 1: Cargo Retrieval

    Program your robot to:

    • Raise its arm
    • Move 50cm to the box
    • Drop the arm down
    • Back up to robot's starting position with the box

    Place two pieces of black electrical tape 50 cm apart.
    Your robot should travel to the block and bring it back to the starting line.

    Remember to raise the arm before moving the robot forward.

    Line up the block for the robot to use its arm around it.

    Use some fine-tune commands (i.e. pausing after stopping, moving slower)

    Pause for a couple of seconds after commands for consistency.

    + hint
    Did You Notice?

    Did you notice?

    Getting the Program Stuck
    What happens if a block cannot complete its action?
    Try running you program with its arm already in the "up" position. Watch carefully so you can answer the following questions.
    1. 4. Does the program ever end?
      2. The program keeps running
      The program ends immediately
    2. 5. Does the second medium motor block ever get to run?
      3. The second motor block never runs
      The second motor block is skipped over
    3. 6. What happens if a block cannot complete its action?
      4. The program will immediately skip to the next block
      The program will try for a while, then display an error and quit
      The program will try for a while, then skip the "stuck" block and move on to the remaining commands
      The program will get "stuck" trying to complete the action, and later blocks will never be run
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    Copyright(c)2012 Carnegie Mellon Robotics Academy. All rights reserved.