Libraries.Robots.Lego.GyroSensor Documentation

The GyroSensor class is an object representation of the LEGO Mindstorms EV3 Gyro Sensor. It is used to measure the rotation and rotation speed of the robot if the robot is turning. This is useful if we need to have information on the orientation of our robot, for example, to keep the robot moving in a straight line.

Example Code

use Libraries.Robots.Lego.Motor
use Libraries.Robots.Lego.GyroSensor
use Libraries.Robots.Lego.Utility

class Main
    action Main
        Motor motor
        GyroSensor gyro
        Utility utility

        gyro:SetPort(2)

        motor:RotateForward(motor:MOTOR_B)
        motor:RotateForward(motor:MOTOR_C)

        repeat while true
            // if robot is moving too far to the right, adjust speed of motor
            // C (the left motor) to keep the robot moving in a straight line
            if gyro:GetRotation() < -1.0
                motor:Stop(motor:MOTOR_C)
                motor:SetSpeed(motor:MOTOR_C, motor:GetSpeed(motor:MOTOR_C) + 5)
                motor:RotateForward(motor:MOTOR_C)
            // if robot is moving too far to the left, adjust speed of motor
            // B (the right motor) to keep the robot moving in a straight line
            elseif gyro:GetRotation() > 1.0
                motor:Stop(motor:MOTOR_B)
                motor:SetSpeed(motor:MOTOR_B, motor:GetSpeed(motor:MOTOR_B) + 5)
                motor:RotateForward(motor:MOTOR_B)
            end
            // wait a second before sampling the angle again
            utility:DelayMilliseconds(1000)
        end
    end
end

Inherits from: Libraries.Language.Object

Summary

Variable Summary Table

VariablesDescription
integer PORT_3
integer PORT_1
integer PORT_4
integer PORT_2

Actions Summary Table

ActionsDescription
Compare(Libraries.Language.Object object)This action compares two object hash codes and returns a CompareResult.
Equals(Libraries.Language.Object object)This action determines if two objects are equal based on their hash code values.
GetHashCode()This action gets the hash code for an object.
GetRotation()This action measures the rotation angle in degrees of the robot with respect to its starting orientation.
GetRotationSpeed()This action reports the rotation speed of the robot in degrees per second.
Reset()This action resets the gyro sensor so that any measurements taken after the sensor was reset will be with respect to the orientation of the robot at that time.
SetPort(integer portNumber)This action lets the program know which port on the robot that the gyro sensor being used is plugged into.

Actions Documentation

Compare(Libraries.Language.Object object)

This action compares two object hash codes and returns a CompareResult. The compare result is either larger if this hash code is larger than the object passed as a parameter, smaller, or equal.

Example Code

use Libraries.Language.Support.CompareResult
        Object o
        Object t
        CompareResult result = o:Compare(t)

Parameters

Return

Libraries.Language.Support.CompareResult: The Compare result, Smaller, Equal, or Larger.

Equals(Libraries.Language.Object object)

This action determines if two objects are equal based on their hash code values.

Example Code

use Libraries.Language.Object
        use Libraries.Language.Types.Text
        Object o
        Text t
        boolean result = o:Equals(t)

Parameters

Return

boolean: True if the hash codes are equal and false if they are not equal.

GetHashCode()

This action gets the hash code for an object.

Example Code

Object o
        integer hash = o:GetHashCode()

Return

integer: The integer hash code of the object.

GetRotation()

This action measures the rotation angle in degrees of the robot with respect to its starting orientation. If the robot has turned clockwise with respect to its starting orientation, the gyro sensor will report a negative angle. If the robot has turned counter-clockwise with respect to its starting orientation, the gyro sensor will report a positive angle.

Example Code

use Libraries.Robots.Lego.Motor
    use Libraries.Robots.Lego.GyroSensor
    use Libraries.Robots.Lego.Utility
    use Libraries.Robots.Lego.Screen
    use Libraries.Robots.Lego.Button

    class Main
        action Main
            Motor motor
            GyroSensor gyro
            Utility utility
            Screen screen
            Button button

            integer lineNumber = 0

            gyro:SetPort(2)

            motor:SetSpeed(motor:MOTOR_B, 100)
            motor:SetSpeed(motor:MOTOR_C, 10)

            motor:RotateForward(motor:MOTOR_B)
            motor:RotateForward(motor:MOTOR_C)

            repeat while lineNumber <= 7
                text message = "Rotation: " + gyro:GetRotation()
                screen:Output(message, lineNumber)
                lineNumber = lineNumber + 1
                utility:DelayMilliseconds(1000)
            end

            motor:Stop(motor:MOTOR_B)
            motor:Stop(motor:MOTOR_C)

            repeat until button:IsButtonPressed(button:CENTER_BUTTON)

            end
        end
    end

Return

number: The rotation in degrees of the robot with respect to its starting orientation.

GetRotationSpeed()

This action reports the rotation speed of the robot in degrees per second. If the robot is turning clockwise with respect to its starting orientation, then the rotation speed is negative. If the robot is turning counter-clockwise with respect to its starting orientation, then the rotation speed is positive.

Example Code

use Libraries.Robots.Lego.Motor
    use Libraries.Robots.Lego.GyroSensor
    use Libraries.Robots.Lego.Utility
    use Libraries.Robots.Lego.Screen
    use Libraries.Robots.Lego.Button

    class Main
        action Main
            Motor motor
            GyroSensor gyro
            Utility utility
            Screen screen
            Button button

            integer lineNumber = 0

            gyro:SetPort(2)

            motor:SetSpeed(motor:MOTOR_B, 100)
            motor:SetSpeed(motor:MOTOR_C, 10)

            motor:RotateForward(motor:MOTOR_B)
            motor:RotateForward(motor:MOTOR_C)

            repeat while lineNumber <= 7
                text message = "Speed: " + gyro:GetRotationSpeed()
                screen:Output(message, lineNumber)
                lineNumber = lineNumber + 1
                utility:DelayMilliseconds(1000)
            end

            motor:Stop(motor:MOTOR_B)
            motor:Stop(motor:MOTOR_C)

            repeat until button:IsButtonPressed(button:CENTER_BUTTON)

            end
        end
    end

Return

number: The rotation speed of the robot

Reset()

This action resets the gyro sensor so that any measurements taken after the sensor was reset will be with respect to the orientation of the robot at that time. For best results, the sensor should not be moving while it is being reset.

Example Code

use Libraries.Robots.Lego.Motor
    use Libraries.Robots.Lego.GyroSensor
    use Libraries.Robots.Lego.Utility
    use Libraries.Robots.Lego.Screen
    use Libraries.Robots.Lego.Button

    class Main
        action Main
            Motor motor
            GyroSensor gyro
            Utility utility
            Screen screen
            Button button

            integer lineNumber = 0

            gyro:SetPort(2)

            motor:SetSpeed(motor:MOTOR_B, 100)
            motor:SetSpeed(motor:MOTOR_C, 10)

            motor:RotateForward(motor:MOTOR_B)
            motor:RotateForward(motor:MOTOR_C)

            repeat while lineNumber <= 4
                text message = "Angle: " + gyro:GetRotation()
                screen:Output(message, lineNumber)
                lineNumber = lineNumber + 1
                utility:DelayMilliseconds(1000)
            end

            motor:Stop(motor:MOTOR_B)
            motor:Stop(motor:MOTOR_C)

            gyro:Reset()

            utility:DelayMilliseconds(3000)

            motor:SetSpeed(motor:MOTOR_B, 100)
            motor:SetSpeed(motor:MOTOR_C, 100)

            motor:RotateForward(motor:MOTOR_B)
            motor:RotateForward(motor:MOTOR_C)

            repeat while lineNumber <= 7
                text message = "Angle:" + gyro:GetRotation()
                screen:Output(message, lineNumber)
                lineNumber = lineNumber + 1
                utility:DelayMilliseconds(1000)
            end

            motor:Stop(motor:MOTOR_B)
            motor:Stop(motor:MOTOR_C)

            repeat until button:IsButtonPressed(button:CENTER_BUTTON)

            end
        end
    end

SetPort(integer portNumber)

This action lets the program know which port on the robot that the gyro sensor being used is plugged into. This action must be called before any other action in the GyroSensor class will work.

Example Code

use Libraries.Robots.Lego.GyroSensor

    GyroSensor gyro1
    GyroSensor gyro2            // we can have multiple gyro sensors attached to the robot
    
    gory1:SetPort(1)            // this tells the robot that the gyro sensor is in port 1
    gyro2:SetPort(gyro2:PORT_2) // we can also use the class constants to set the port

Parameters