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Topics Covered

  • Switch Loops
  • Obstacle Detection

    • Lesson Links

    Starting Project
    Check Your Understanding:
    1. 1. Instead of thinking about the four-rotation Obstacle Detection as one big movement, the video suggests thinking about it as...
      2. Using a brand new type of Wait Block that allows multiple sensor checking
      Downloading the program into the robot and using built-in options to run parts of the program at certain times
      A long series of tiny movements that add up for four rotations
      All of the above are valid suggestions
    2. 2. How do repeated decisions allow the robot to watch both sensors at once?
      3. The program resets and restarts at the beginning everytime the readings of any sensor changes
      The robot calculates the path with both sensors at first and runs algorithms for the best way to run the course
      The robot activates a specific sensor at certain times throughout the course
      Every operation is fast, and does not block other commands from running
    3. 3. In the final version of the program, the robot ends up processing the Switch inside the Loop...
      4. Only once, ever, because it's a Switch
      Four times because the Loop goes for four rotations
      Thousands of times, because the robot processes the loop very quickly and encounters the Switch many times
    Mini Challenge

    Mini Challenge 1: Obstacle Detecting Move Until Black Line

    Modify the Obstacle Detection program you wrote so that it will move safely (stopping when an obstacle is in front of it, moving when there is none) until the Color Sensor detects a black line on the table, rather than until the robot has traveled a certain number of rotations.

    • Attach a Color Sensor to the EV3.
    ULTRASONIC AND COLOR ATTACHMENT*
    *ACTUAL DESIGN MAY VARY

    Where can I find the instructions?
    • Change the Switch's mode to Color Sensor > Color, and select Black as the color to detect.

    There is a Sensor set in the Switch, and one set in the Loop. Which one controls the "end of behavior"?

    + hint
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    Copyright(c)2012 Carnegie Mellon Robotics Academy. All rights reserved.