Drivetrain#

Introduction #

The drivetrain controls how the VR Robot drives and turns. The drivetrain can move forward or reverse, turn left or right, turn to headings, and track its rotation.

There are many ways to code the drivetrain. Below is a list of all Drivetrain blocks:

Actions — Move and turn the robot.

drive — Moves the robot forward or reverse forever.
drive for — Moves the robot forward or reverse for a specific distance.
turn — Turns the robot left or right forever.
turn for — Turns the robot left or right for a specific number of degrees.
turn to heading — Turns the robot to face a specific heading.
turn to rotation — Turns the robot to a specific rotation.
stop driving — Stops the robot’s movement.

Settings — Adjust drivetrain settings.

set drive velocity — Tells the robot how fast to drive.
set turn velocity — Tells the robot how fast to turn.
set drive heading — Changes the robot’s current heading to a new heading.
set drive rotation — Changes the robot’s current rotation to a new rotation.
set drive timeout — Sets how many seconds the robot will try to finish a movement.

Values — Check movement status.

drive is done — Reports whether the robot is finished moving.
drive is moving — Reports whether the robot is moving.
drive heading — Reports the robot’s current heading from 0 to 359.99 degrees.
drive rotation — Reports the robot’s current rotation.

Actions #

drive #

The drive stack block moves the robot forward or reverse forever. The robot will continue to move until it is given another action, like turning or stopping.

  drive [forward v]

Parameters	Description
direction	The direction the robot moves: forward or reverse.

Example

  when started :: hat events
  [Drive forward, then stop.]
  drive [forward v]
  wait (2) seconds
  stop driving

drive for #

The drive for stack block moves the robot forward or reverse for a specific distance. The project will wait until the robot is done moving before the next block in the stack runs.

  drive [forward v] for (200) [mm v] ▶

Parameters	Description
direction	The direction the robot moves: forward or reverse.
distance	The distance the robot drives. This can be an integer or a decimal.
unit	The distance unit: mm (millimeters) or inches
and don’t wait	Select the arrow ( ▶ ) to expand the block to say and don’t wait, so the next block in the stack will run right away.

Example

  when started :: hat events
  [Drive forward.]
  drive [forward v] for (500) [mm v] ▶

turn #

The turn stack block turns the robot left or right forever. The robot will continue to turn until it is given another action, like driving or stopping.

  turn [right v]

Parameters	Description
direction	The direction the robot turns: left or right.

Example

  when started :: hat events
  [Turn right, then stop.]
  turn [right v]
  wait (2) seconds
  stop driving

The turn for stack block turns the robot left or right for a specific number of degrees. The turn is relative to the current position of the robot. The project will wait until the robot is done turning before the next block in the stack runs.

  turn [right v] for (90) degrees ▶

Parameters	Description
direction	The direction the robot turns: left or right.
angle	The number of degrees the robot turns. This can be an integer or a decimal.
and don’t wait	Select the arrow ( ▶ ) to expand the block to say and don’t wait, so the next block in the stack will run right away.

Example

  when started :: hat events
  [Turn left, then turn around to the right.]
  turn [left v] for (90) degrees ▶
  turn [right v] for (180) degrees ▶

turn to heading #

A heading is the direction the robot is facing, measured in degrees. The turn to heading stack block turns the robot to face a specific heading from -359 to 359 degrees. The robot will turn the shortest direction to reach the target heading.

The starting heading is 0 degrees.

The project will wait until the robot is done turning before the next block in the stack runs.

  turn to heading (90) degrees ▶

Parameters	Description
heading	The heading the robot should face, from -359 to 359 degrees.
and don’t wait	Select the arrow ( ▶ ) to expand the block to say and don’t wait, so the next block in the stack will run right away.

Example

  when started :: hat events
  [Turn to face the cardinal directions.]
  turn to heading (90) degrees ▶
  wait (2) seconds
  turn to heading (180) degrees ▶
  wait (2) seconds
  turn to heading (270) degrees ▶
  wait (2) seconds
  turn to heading (0) degrees ▶
  wait (2) seconds

turn to rotation #

The turn to rotation stack block turns the robot to a specific rotation.

Rotation is how much the robot has turned, measured in degrees. At the beginning of a project, the rotation value is set to 0 degrees. Rotation can also be set using the set drive rotation block.

Rotation values are absolute. This means the direction of the turn depends on the robot’s current rotation. Turning right increases the rotation, and turning left decreases the rotation.

For example, if the robot starts at 0 degrees and you turn to a rotation of 720 degrees, it will turn right twice. If you then turn to a rotation of 360 degrees, it will turn left once, because 360 is less than 720.

The project will wait until the robot is done turning before the next block in the stack runs.

  turn to rotation (90) degrees ▶

Parameters	Description
rotation	The rotation value, in degrees, that the robot will turn to. This can be an integer or a decimal.
and don’t wait	Select the arrow ( ▶ ) to expand the block to say and don’t wait, so the next block in the stack will run right away.

Example

  when started :: hat events
  [Turn left, then spin in a circle clockwise and face right.]
  turn to rotation (-90) degrees ▶
  wait (2) seconds
  turn to rotation (450) degrees ▶

stop driving #

The stop driving stack block stops the robot’s movement.

  stop driving

Parameters	Description
	This block has no parameters.

Example

  when started :: hat events
  [Drive forward, then stop.]
  drive [forward v]
  wait [4] seconds
  stop driving

Settings #

set drive velocity #

The set drive velocity stack block tells the robot how fast to drive. A higher percentage makes the robot drive faster and a lower percentage makes the robot drive slower.

Every project begins with the robot driving at 50% velocity by default.

Note: A higher velocity makes the robot drive faster, but it may be less precise. A lower velocity makes the robot drive slower, but it can be more precise.

  set drive velocity to (50) [% v]

Parameters	Description
velocity	The velocity to drive with from 0% to 100%.
unit	The velocity unit: %

Example

  when started :: hat events
  [Drive forward at the default velocity.]
  drive [forward v] for (100) [mm v] ▶
  wait (1) seconds
  [Move slower.]
  set drive velocity to (20) [% v]
  drive [forward v] for (100) [mm v] ▶
  wait (1) seconds
  [Move faster.]
  set drive velocity to (100) [% v]
  drive [forward v] for (100) [mm v] ▶
  wait (1) seconds

set turn velocity #

The set turn velocity stack block tells the robot how fast to turn. A higher percentage makes the robot turn faster and a lower percentage makes the robot turn slower.

Every project begins with the robot turning at 50% velocity by default.

Note: A higher velocity makes the robot turn faster, but it may be less precise. A lower velocity makes the robot turn slower, but it can be more precise.

  set turn velocity to (50) [% v]

Parameters	Description
velocity	The velocity to turn with from 0% to 100%.
unit	The velocity unit: %

Example

  when started :: hat events
  [Turn at default velocity.]
  turn [right v] for (100) degrees ▶
  wait (1) seconds
  [Turn slower.]
  set turn velocity to (20)%
  turn [right v] for (100) degrees ▶
  wait (1) seconds
  [Turn faster.]
  set turn velocity to (100)%
  turn [right v] for (100) degrees ▶
  wait (1) seconds

set drive heading #

A heading is the direction the robot is facing, measured in degrees. The set drive heading stack block changes the robot’s current heading to a new heading value.

For example, if the robot has turned to face right, setting the heading to 0 degrees makes that right-facing position the new 0 degrees. Then the robot can turn to other positions based on that new heading.

  set drive heading to (0) degrees

Parameters	Description
heading	The heading value, in degrees, to set for the robot.

Example

  when started :: hat events
  [Turn to the left.]
  set drive heading to (90) degrees
  turn to heading (0) degrees ▶

set drive rotation #

Rotation is how much the robot has turned, measured in degrees. At the beginning of a project, the rotation value is set to 0 degrees. The set drive rotation stack block changes the robot’s current rotation to a new value.

For example, if the robot has made two full turns to the right, its rotation value will be 720 degrees. Setting the rotation to 0 degrees will reset that rotation from 720 to 0 degrees. Then the robot can turn to rotations based on that new value.

  set drive rotation to (0) degrees

Parameters	Description
rotation	The rotation value, in degrees, to set for the robot. This can be an integer or a decimal.

Example

  when started :: hat events
  [Spin counterclockwise two times.]
  set drive rotation to (720) degrees
  turn to rotation (0) degrees ▶

set drive timeout #

The set drive timeout stack block sets how many seconds the robot will try to finish a movement. If the robot cannot finish in that time it will stop trying and move on to the next block in the stack. This keeps the robot from getting stuck on a movement.

  set drive timeout to (1) seconds

Parameters	Description
time	The number of seconds the robot can try to finish a movement. This can be a whole number or a decimal.

Example

When started, limits drive time to 1 second and then turns 90 degrees.#

  when started :: hat events
  [Drive forward for 1 second, then turn.]
  set drive timeout to (1) seconds
  drive [forward v] for (25) [inches v] ▶
  turn [right v] for (90) degrees ▶

Values #

drive is done #

The drive is done Boolean block reports whether the robot is finished moving. This can be used to control the timing of other behaviors based on the robot’s movement.

True — The robot is finished moving.
False — The robot is still moving.

This block works together with drivetrain blocks that have the and don’t wait parameter.

    <drive is done?>

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Start spinning when the drive is complete.]
    drive [forward v] for (200) [mm v] ◀ and don't wait
    wait until <drive is done?>
    turn [right v] for (360) degrees ▶

drive is moving #

The drive is moving Boolean block reports whether the robot is moving. This can be used to control the timing of other behaviors based on the robot’s movement.

True — The robot is moving.
False — The robot is not moving.

This block works together with drivetrain blocks that have the and don’t wait parameter.

    <drive is moving?>

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Print that the robot is moving while it is still driving.]
    drive [forward v] for (200) [mm v] ◀ and don't wait
    while <drive is moving?>
    print [Still Moving...] ▶
    wait (0.1) seconds
    clear screen
    end
    print [Done!] ▶

drive heading #

A heading is the direction the robot is facing, measured in degrees. The drive heading reporter block reports that heading from 0 to 359.99 degrees.

The robot’s starting heading is 0 degrees.

    (drive heading in degrees)

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Display the heading after turning.]
    turn [right v] for (450) degrees ▶
    print (drive heading in degrees) on screen ◀ and set cursor to next row

drive rotation #

Rotation is how much the robot has turned, measured in degrees. At the beginning of a project, the rotation value is set to 0 degrees. The drive rotation reporter block reports the robot’s current rotation.

Turning right increases the rotation, and turning left decreases the rotation. For example, making two full turns to the right will report a rotation of 720 degrees.

    (drive rotation in degrees)

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Display the rotation after turning.]
    turn [right v] for (450) degrees ▶
    print (drive rotation in degrees) on screen ◀ and set cursor to next row