Lesson 2: Drive to Number '5'

In this Lesson, the VR Robot will drive to the number ‘5’ and back to the number ‘1’ on the Number Grid Map Playground!

Notice that the VR Robot will be traveling along the X axis with X values increasing to move to the number ‘5’ on the Number Grid Map Playground.

The VR Robot will drive to the location of the number ‘5’ on the Number Grid Map Playground. However, before the VR Robot can navigate to that number, the VR Robot has to be told where that number’s location is. Beginning at the center of the Playground, the coordinates of number ‘5’ are (-100, -900).

• To begin, the VR Robot needs to be facing the number ‘5.’ Drag in or type a turn_for command.

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

• Drag in a while loop under the turn_for command. Your project should look like this:

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while condition:
        wait(5, MSEC)

• Just like the Distance Sensor Unit, this project will use the condition of the Location Sensor position with a comparison operator to navigate the Number Grid Map Playground. Set the condition for the while loop to the position command in the X-axis less than -100 in millimeters (mm). Your project should look like this:

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while location.position(X, MM) < -100:
        wait(5, MSEC)

• Drag or type the non-waiting drive command inside the while loop. Your project should look like this:

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while location.position(X, MM) < -100:
        drivetrain.drive(FORWARD)
        wait(5, MSEC)

• Note that the less than operator is used instead of the greater than operator because the VR Robot is driving to the right from the left side of the Playground. The VR Robot is starting at an X-value of -900 millimeters (mm). As the VR Robot drives forward, the X-values increase, and thus the robot will keep driving forward while the X-value is less than -100.

# Add project code in "main"
def main():
    monitor_sensor(location.position)
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while location.position(X, MM) < 500:
        drivetrain.drive(FORWARD)
        wait(5, MSEC)
    drivetrain.stop()

• Drag or type a stop command outside the while loop. Your project should look like this:

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while location.position(X, MM) < -100:
        drivetrain.drive(FORWARD)
        wait(5, MSEC)
    drivetrain.stop()

• Open the Playground Window  if it is not already open. Be sure the Number Grid Map Playground opens, and run the project.
• Watch the VR Robot drive to number ‘5’ on the Number Grid Map Playground.

• In this project, the VR Robot drives to the number ‘5’ on the Number Grid Map Playground. The while loop is used so that the VR Robot will continue to drive forward while the X-value is less than the X-value of the coordinate that the indicated number is on.
• Once the X-value is greater than -100, the project moves to the next command outside the loop, which is a stop command. Since the X-value of the number ‘5’ is -100, the VR Robot will stop driving once the X-value is greater than -100.

# Add project code in "main"
def main():
    drivetrain.turn_for(RIGHT, 90, DEGREES)

    while location.position(X, MM) <= -100:
        drivetrain.drive(FORWARD)
        wait(5, MSEC)
    drivetrain.stop()