gyro

Introduction

The VEX IQ Gyro Sensor allows for measuring rotational movement and detecting changes in motion. These sensors allow the robot to track its orientation and heading.

Below is a list of all available methods:

Methods – Measure rotational movement and detect changes in motion.

• calibrate – Calibrates the Gyro Sensor for stable heading tracking.

• setHeading – Sets the Gyro Sensor’s heading to a specified value.

• setRotation – Sets the Gyro Sensor’s rotation value.

• heading – Returns the current heading.

• rotation – Returns the cumulative rotation.

• rate – Returns the angular velocity around the x, y, or z axis.

• isCalibrating – Returns whether or not the Gyro Sensor is calibrating.

• resetHeading – Sets the heading of the Gyro Sensor to 0.

• resetRotation – Sets the rotation of the Gyro Sensor to 0.

• changed – Registers a function to call when the Gyro Sensor detects change.

• installed – Returns whether or not a Gyro Sensor is connected to the Brain.

Constructors – Manually initialize and configure a Gyro Sensor.

• gyro – Creates a Gyro Sensor.

Methods

calibrate

calibrate calibrates the Gyro Sensor. Calibration should be done when the Gyro Sensor is not moving.

Default Usage:
calibrate(type)

Parameters	Description
type	One of the valid calibration types: calExtended – An extended calibration. calNormal – Normal calibration speed. calSlow – Slow calibration speed.

// Start calibration.
DrivetrainGyro.calibrate();
Brain.Screen.print("Done calibrating");

Overload Usage:
calibrate(type, wait)

Parameters	Description
type	One of the valid calibration types: calExtended – An extended calibration. calNormal – Normal calibration speed. calSlow – Slow calibration speed.
wait	Whether or not to wait before executing the next command: true – Wait before executing the next command. false – Do not wait before executing the next command.

// Do not wait after starting calibration
DrivetrainGyro.calibrate(calNormal, false);
Brain.Screen.print("Done calibrating");

setHeading

setHeading sets the heading of the Gyro Sensor to a specific value.

Usage:
setHeading(value, units)

Parameters	Description
value	The heading value to set.
units	The unit that represents the new heading: degrees turns

// Turn the robot around
DrivetrainGyro.setHeading(180, degrees);
Drivetrain.turnToHeading(0, degrees);

setRotation

setRotation sets the rotation of the Gyro Sensor to a specific value.

Usage:
setRotation(value, units)

Parameters	Description
value	The rotation value to set.
units	The unit that represents the new rotation: degrees turns

// Turn the robot around
DrivetrainGyro.setRotation(-180, degrees);
Drivetrain.turnToRotation(0, degrees);

heading

heading returns the current heading of the Gyro Sensor in degrees.

Usage:
heading()

Parameters	Description
	This method has no parameters.

// Display the heading after turning
Drivetrain.turnFor(right, 450, degrees);
Brain.Screen.print("%f", DrivetrainGyro.heading());

Overload:
heading(units)

Parameters	Description
units	The unit used to represent the heading: turns

// Display the heading after turning
Drivetrain.turnFor(right, 450, degrees);
Brain.Screen.print("%f", DrivetrainGyro.heading(turns));

rotation

rotation returns the current rotation of the Gyro Sensor in degrees.

Usage:
rotation()

Parameters	Description
	This method has no parameters.

// Display the rotation after turning
Drivetrain.turnFor(right, 450, degrees);
Brain.Screen.print("%f", DrivetrainGyro.rotation());

Overload:
rotation(units)

Parameters	Description
units	The unit used to represent the rotation: turns

// Display the rotation after turning
Drivetrain.turnFor(right, 450, degrees);
Brain.Screen.print("%f", DrivetrainGyro.rotation(turns));

rate

rate returns the current rate of change of the Gyro Sensor’s rotation in dps.

Usage:
rate()

Parameters	Description
	This method has no parameters.

// Display the rate of change of rotation while turning
Drivetrain.turn(right);
wait(1, seconds);
Brain.Screen.print("%f", DrivetrainGyro.rate());
Drivetrain.stop();

Overload:
rate(units)

Parameters	Description
units	The unit used to represent the gyro rate: rateUnits::rps

// Display the rate of change of rotation while turning
Drivetrain.turn(right);
wait(1, seconds);
Brain.Screen.print("%f", DrivetrainGyro.rate(rateUnits::rps));
Drivetrain.stop();

isCalibrating

isCalibrating checks if the Gyro Sensor is currently calibrating.

• 1 - The Gyro Sensor is calibrating.

• 0 - The Gyro Sensor is not calibrating.

Parameters	Description
	This method has no parameters.

wait(1, seconds);
// Calibrate without waiting
DrivetrainGyro.calibrate(0);
// Print that the Gyro is calibrating while waiting for it to
// finish calibrating
while(DrivetrainGyro.isCalibrating()){
  Brain.Screen.clearScreen();
  Brain.Screen.setCursor(1, 1);
  Brain.Screen.print("Gyro Calibrating");
  wait(50, msec);
}
Brain.Screen.clearScreen();
Brain.Screen.setCursor(1, 1);
Brain.Screen.print("Done!");

resetHeading

resetHeading resets the heading of the Gyro Sensor to 0.

Usage:
resetHeading()

Parameters	Description
	This method has no parameters.

// Turn the robot before and after resetting the heading
Drivetrain.turnToHeading(90, degrees);
wait(0.5, seconds);
DrivetrainGyro.resetHeading();
Drivetrain.turnToHeading(90, degrees);

resetRotation

resetRotation resets the rotation of the Gyro Sensor to 0.

Usage:
resetRotation()

Parameters	Description
	This method has no parameters.

// Turn the robot before and after resetting the rotation
Drivetrain.turnToRotation(-90, degrees);
wait(0.5, seconds);
DrivetrainGyro.resetRotation();
Drivetrain.turnToRotation(-90, degrees);

changed

changed registers a callback function for when the Gyro Sensor’s heading changes.

Usage:
changed()

Parameters	Description
callback	The callback function to be called when the Gyro Sensor’s heading changes.

Returns: None.

// Callback function to print the heading
void gyroChanged(){
  Brain.Screen.clearScreen();
  Brain.Screen.setCursor(1, 1);
  Brain.Screen.print("Heading: ");
  Brain.Screen.print("%f", DrivetrainGyro.heading());
}
    
int main() {
  vexcodeInit();
  // Display the heading when the gyro detects a change
  Drivetrain.turnFor(90, rotationUnits::deg, 50, velocityUnits::pct, false);
  DrivetrainGyro.changed(gyroChanged);
}

installed

installed returns a Boolean indicating whether the Gyro Sensor is connected to the Brain.

• 1 - The Gyro Sensor is connected to the Brain.

• 0 - The Gyro Sensor is not connected to the Brain.

Usage:
installed()

Parameters	Description
	This method has no parameters.

// Display a message if the Gyro Sensor is
// installed.
if (DrivetrainGyro.installed()){
  Brain.Screen.print("Installed!");
}

Constructors

Constructors are used to manually create gyro objects, which are necessary for configuring an Gyro Sensor outside of VEXcode.

For the examples below, the configured Gyro Sensor will be named DrivetrainGyro and will be used in all subsequent examples throughout this API documentation when referring to gyro class methods.

Gyro

gyro creates a Gyro Sensor.

Usage:
gyro(port)

Parameter	Description
port	Which Smart Port that the Gyro Sensor is connected to as PORT followed by the port number, ranging from 1 to 12.

// When constructing Gyro Sensor "drivetrain_gyro" with a 
// SmartDrive "drivetrain"
motor LeftDriveSmart = motor(PORT2, 1, false);
motor RightDriveSmart = motor(PORT3, 1, true);
gyro DrivetrainGyro = gyro(PORT1, true);
smartdrive Drivetrain = smartdrive(LeftDriveSmart, RightDriveSmart, DrivetrainGyro, 200);

DrivetrainGyro.setHeading(180, degrees);
Drivetrain.turnToHeading(0, degrees);