Libraries.Robots.Lego.ColorSensor Documentation

The ColorSensor class is an object representation of the LEGO Mindstorms EV3 Color Sensor.

Example Code

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Motor
use Libraries.Robots.Lego.Utility


class Main
action Main
    ColorSensor colorSensor
    Motor motor
    Utility utility
    
    colorSensor:SetPort(3)                      //tells the robot that the sensor is plugged into port 2
    motor:SetSpeed("B", 540)                    //two motors to move the robot
    motor:SetSpeed("C", 540)
    motor:RotateForward("B")
    motor:RotateForward("C")
    repeat until colorSensor:GetColor() = "red"
        utility:DelayMilliseconds(20)           //interval between color checks
    end
end
end

Inherits from: Libraries.Language.Object

Variables Table

VariablesDescription
integer WHITEpublic constant integer ORANGE = 5
integer BLACKpublic constant integer PINK = 8
integer YELLOWpublic constant integer ORANGE = 5
integer PORT_4This action lets the program know which port on the robot that the color sensor being used is plugged into. As such, this action must be called before any other action in the ColorSensor class will work. After calling this action, the color sensor's red light will turn on once it has fully initiated.
integer NONE
integer BROWNpublic constant integer CYAN = 12
integer PORT_1public constant integer CYAN = 12
integer RED
integer GRAYpublic constant integer PINK = 8
integer PORT_2
integer PORT_3
integer GREEN
integer BLUE

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.

Parameters

Return

integer: The Compare result, Smaller, Equal, or Larger.

Example

Object o
Object t
integer result = o:Compare(t) //1 (larger), 0 (equal), or -1 (smaller)

Equals(Libraries.Language.Object object)

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

Parameters

Return

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

Example

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

GetColor()

This action uses the color sensor to read the color in front of it and send back the color as a text variable. The color sensor is capable of reading 7 different colors: red, green, blue, yellow, brown, white, and black. If the color sensor is too far away from the color it is trying to read, it will return the text "none". During the measurement, the color sensor's white light will be emitted to help determine an object's color.

Return

text: the color that was read by the sensor in all lower-case letters. Possible colors that can be returned are: red, green, blue, yellow, brown, white, or black. If the sensor cannot read a color, it will return the text "none".

Example

use Libraries.Robots.Lego.ColorSensor

ColorSensor colorSensor

colorSensor:SetPort(3)
text color = ""
repeat while true
    color = colorSensor:GetColor()
    if color = "none"
        output "No color found."
    else
        output "Color: " + color + "."
    end
end

GetHashCode()

This action gets the hash code for an object.

Return

integer: The integer hash code of the object.

Example

Object o
integer hash = o:GetHashCode()

GetLightColor()

This action gets the color of light being emitted from the color sensor.

Return

text: the color currently being emitted by the color sensor in all lower-case letters. Possible return values are: "red", "white", "blue", or "none", where a value of "none" indicates that the light is currently off.

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Sound

ColorSensor colorSensor
Sound sound

colorSensor:SetPort(3)
text lightColor = colorSensor:GetLightColor()
if lightColor = "red"
    sound:Beep()
elseif lightColor = "blue"
    sound:BeepTwice()
elseif lightColor = "white"
    sound:BeepSequenceUp()
else
    sound:Buzz()    //the light is currently off
end

GetLightLevel()

This action uses the color sensor to measure the amount of incoming light.

Return

number: a number between 0.0 and 1.0 that represents the intensity of light measured by the color sensor. The values range from complete darkness (0.0) to direct sunlight (1.0).

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Motor

ColorSensor colorSensor
Motor motor

colorSensor:SetPort(3)
motor:RotateForward("B")
motor:RotateForward("C")      //two motors used to move the robot forward
repeat until colorSensor:GetLightLevel() > 0.15
   output "Light level: " + colorSensor:GetLightLevel()
end

GetRedGreenBlueLevels()

This action will provide information on the red, green, and blue levels of a measured object.

Return

Libraries.Containers.Array: a number array with three values representing the intensity of red, green, and blue measured, respectively. Values will range between the color not being read at all (0.0) and the color being fully present in the reading (1.0).

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Screen
use Libraries.Robots.Lego.Button
use Libraries.Containers.Array

ColorSensor colorSensor
Screen screen
Button button

colorSensor:SetPort(3)
Array<number> redGreenBlueLevels = colorSensor:GetRedGreenBlueLevels()
screen:Output("Red: " + redGreenBlueLevels:Get(0), 0)
screen:Output("Green: " + redGreenBlueLevels:Get(1), 1)
screen:Output("Blue: " + redGreenBlueLevels:Get(2), 2)
button:WaitForButtonPress()

GetReflectionLevel()

This action uses the color sensor to measure the reflection of an object. It accomplishes this by projecting a red light and then measuring the intensity of that light reflected back.

Return

number: a number between 0.0 and 1.0 that represents the intensity of light being reflecting. The values range from no reflection (0.0) to complete reflection (1.0). If an object is too far away, no reflection will be picked up by the sensor, resulting in a value of 0.0.

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Motor
use Libraries.Robots.Lego.Screen
use Libraries.Robots.Lego.Utility

ColorSensor colorSensor
Motor motor
Screen screen
Utility utility

colorSensor:SetPort(colorSensor:PORT_3)
motor:RotateForward("A")  //two motors used to move the robot
motor:RotateForward("B")
repeat 8 times
    screen:ScrollUp("Reflectivity: " + colorSensor:GetReflectionLevel())  //displays reflectivity of object
    utility:DelayMilliseconds(500)
end

IsLightOn()

This action is used to determine if the color sensor's light is currently on or off.

Return

boolean: a boolean value with a value of true if the color sensor's light is on or false if the color sensor's light is off.

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Sound

ColorSensor colorSensor
Sound sound

colorSensor:SetPort(3)
if colorSensor:IsLightOn()
    colorSensor:SetLightColor(colorSensor:BLUE)
else
    sound:Buzz()
end

SetLightColor(integer color)

This action is used to change the color of light projecting from the color sensor. By default, the light is off. The color sensor can emit red, white, blue, or no light.

Parameters

  • integer color: is an integer code that represents the color of light to be set. The ColorSensor class has constants that can be used for this. Valid colors for the light are: red, white, blue, or none.

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Button
use Libraries.Robots.Lego.Utility

ColorSensor colorSensor
Button button
Utility utility

colorSensor:SetPort(3)
repeat until button:IsButtonPressed(button:ESCAPE_BUTTON)
    colorSensor:SetLightColor(colorSensor:BLUE)
    utility:DelayMilliseconds(500)
    colorSensor:SetLightColor(colorSensor:RED)
    utility:DelayMilliseconds(500)
end

SetLightOn(boolean value)

This action turns the flood light on or off entirely.

Parameters

  • boolean value

Example

use Libraries.Robots.Lego.ColorSensor
use Libraries.Robots.Lego.Sound

ColorSensor colorSensor
Sound sound

colorSensor:SetPort(3)
colorSensor:SetLightOn(false)

SetPort(integer portNumber)

This action lets the program know which port on the robot that the color sensor being used is plugged into. As such, this action must be called before any other action in the ColorSensor class will work. After calling this action, the color sensor's red light will turn on once it has fully initiated.

Parameters

  • integer portNumber: specifies the port on the robot that the color 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.

Example

use Libraries.Robots.Lego.ColorSensor

ColorSensor colorSensor1
ColorSensor colorSensor2
ColorSensor colorSensor3

colorSensor1:SetPort(1)                     //we can have multiple color sensors plugged into the robot at once
colorSensor2:SetPort(2)                     //after setting the ports, we can now use any other action in the ColorSensor class
colorSensor3:SetPort(colorSensor3:PORT_3)   //we can use a class constant to designate a port, as well