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
Variables | Description |
---|---|
integer PORT_3 | |
integer PORT_4 | 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. |
integer PORT_1 | |
integer PORT_2 |
Actions Summary Table
Actions | Description |
---|---|
Compare(Libraries.Language.Object object) | This action compares two object hash codes and returns an integer. |
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 an integer. The result is larger if this hash code is larger than the object passed as a parameter, smaller, or equal. In this case, -1 means smaller, 0 means equal, and 1 means larger. This action was changed in Quorum 7 to return an integer, instead of a CompareResult object, because the previous implementation was causing efficiency issues.
Example Code
Object o
Object t
integer result = o:Compare(t) //1 (larger), 0 (equal), or -1 (smaller)
Parameters
- Libraries.Language.Object: The object to compare to.
Return
integer: 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
- Libraries.Language.Object: The to be compared.
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
- integer portNumber: specifies the port on the robot that the gyro sensor is plugged into. The port number corresponds to the actual number printed above the port on the EV3 brick. Valid port numbers are 1, 2, 3 or 4.