Sensors

Introduction

The VEX AIR Drone includes an Inertial Sensor for measuring rotational movement and for detecting changes in motion as well as a Range Sensor for detecting distances. The VEX AIR Drone can also keep track of its battery levels. These sensors allow the drone to track its orientation, heading, acceleration, and distance from objects.

Below is a list of all available blocks:

Inertial - Track the drone’s rotational movement.

• rotation — Returns how much the drone has turned since it started.

• heading — Returns the drone’s heading angle (0 to 359.99 degrees).

• orientation — Returns the drone’s roll, pitch, or yaw (–180.00 to 180.00 degrees).

• acceleration — Returns acceleration along the forward, rightward, or downward axis.

• get turn rate — Returns the drone’s current rotation speed in degrees per second (dps).

• reset rotation — Resets the rotation value to zero.

• reset heading — Resets the heading value to zero.

Range - Detect distances from the drone’s Range Sensor.

• distance — Returns the distance from a Range Sensor.

Battery - Return the drone’s battery level.

• battery level — Returns the drone’s battery level in percent.

Inertial

rotation

The rotation block returns how many degrees the drone has turned since it started. It adds up all turns and returns the total in degrees: positive for clockwise, negative for counterclockwise.

The Rotation reporter block.

    (rotation in degrees)

Parameters	Description
	This block has no parameters.

Example

when started :: hat events
[Display the rotation after turning.]
take off to [500] [mm v] ▶
turn [left v] for (450) degrees ▶
print (rotation in degrees) on console ▶
land ▶

heading

The heading block returns the drone’s heading angle. This returns a decimal number in the range 0 to 359.99 degrees.

The Heading reporter block.

    (heading in degrees)

Parameters	Description
	This block has no parameters.

Example

when started :: hat events
    [Display the rotation after turning left.]
    take off to [500] [mm v] ▶
    turn [left v] for (90) degrees ▶
    print (heading in degrees) on screen ▶

orientation

The orientation block returns the drone’s roll, pitch, or yaw in the range –180.00 to 180.00 degrees as a decimal number.

The image below uses arrows to show the direction of positive rotation for roll, pitch, yaw.

The Orientation reporter block.

    orientation of [roll v] in degrees

Parameters	Description
axis	The orientation axis: roll pitch yaw

Example

when started :: hat events
[Display the drone orientation as it is rotated by hand.]
forever
clear screen
set cursor to row (7) column (1) on screen
print [Roll:] on screen ▶
print (orientation of [roll v] in degrees) on screen ▶
end

acceleration

The acceleration block returns the drone’s acceleration in a specified direction. The returned value represents the rate of change in velocity, measured in units of g (where 1g ≈ 9.81 m/s²), as a number ranging from -4.00 to 4.00.

The image below uses arrows to show the direction of positive acceleration for forward and rightward, and negative acceleration for downward.

The Acceleration reporter block.

    (acceleration of [forward v] axis in g :: custom-controller-inertial-timer)

Parameters	Description
axis	The axis to return the acceleration of: forward rightward downward

Example

    when started :: hat events
    [Display the acceleration as the drone takes off.]
    take off to [500] mm ◀ and don't wait
    forever
    clear screen
    set cursor to row [1] column [1] on screen
    print (acceleration of [downward v] axis in g) on screen ▶
    wait [0.5] seconds
    end

get turn rate

The get turn rate block returns the rate at which the drone is rotating along the specified axis. This returns a value in degrees per second (dps) as an integer.

The image below uses arrows to show the direction of positive rotation for roll, pitch, yaw.

The Get Turn Rate reporter block.

    (get turn rate of [roll v] axis in dps)

Parameters	Description
axis	The axis to return the turn rate of: roll pitch yaw

Example

when started :: hat events
    [Display the drone turn rate as it is rotated by hand.]
    forever
        clear screen
        set cursor to row (7) column (1) on screen
        print [Roll:] on screen ▶
        print (get turn rate of [roll v] axis in dps) on screen ▶
    end

reset rotation

The reset rotation block resets the drone’s rotation value to 0 degrees.

The Reset rotation stack block.

    reset rotation

Parameters	Description
	This block has no parameters.

Example

when started :: hat events
[Display the rotation after resetting.]
take off to [500] [mm v] ▶
turn [right v]
wait until <(rotation in degrees) [math_greater_than v] [360]>
hover
reset rotation
wait [1] seconds
print (rotation in degrees) on console ▶

reset heading

The reset heading block resets the drone’s heading to zero degrees.

The Reset heading stack block.

    reset heading

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Turn to the same heading before and after resetting.]
    take off to [500] [mm v] ▶
    turn to heading [90] degrees ▶
    wait [1] seconds
    reset heading
    turn to heading [90] degrees ▶
    wait [1] seconds
    land ▶

Range

distance

The distance block returns the distance between a Range Sensor and the nearest object.

move forward stack block

    (distance [forward v] range in [mm v])

Parameters	Description
range	The Range Sensor to use: forward — The distance from the front of the drone. downward — The distance from the bottom of the drone.
units	The unit that represents the distance: mm (millimeters) inches

Example

    when started :: hat events
    [Hover at 200 mm.]
    take off to [500] [mm v] ▶
    climb [down v]
    wait until <(distance [downward v] range in [mm v]) [math_less_than v] [200]>
    hover
    wait (3) seconds
    land ▶

Battery

battery level

The battery level block returns the drone’s battery charge level as a percentage. This returns a number from 0 to 100.

The battery level in percent reporter block.

  (drone battery level in %)

Parameters	Description
	This block has no parameters.

A stack of blocks that begins with a when started block, followed by a comment block reading Get the battery level and display it. A print block then displays the battery level percentage on the screen.

  when started :: hat events
  [Display the battery level.]
  print (drone battery level in %) on screen ▶