Optical Sensor#

Introduction #

The optical class is used to access data from the EXP Optical Sensor. It uses reflected light to detect objects, identify colors, and measure brightness and hue.

Class Constructors #

optical(
    int32_t index );

Class Destructor #

Destroys the optical object and releases associated resources.

virtual ~optical();

Parameters #

Parameter	Type	Description
`index`	`int32_t`	The Smart Port that the Optical Sensor is connected to, written as `PORTx`, where `x` is the port number (for example, `PORT1`).

Examples #

// Create an optical instance in Port 1
optical Optical1 = optical(PORT1);

Member Functions #

The optical class includes the following member functions:

setLight — Turns the Optical Sensor’s LED on or off.
setLightPower — Sets the Optical Sensor’s light power level.
isNearObject — Returns whether the Optical Sensor detects an object within range.
color — Returns the color detected by the Optical Sensor.
brightness — Returns the amount of light reflected from the object.
hue — Returns the hue detected by the Optical Sensor.
objectDetected — Registers a function to be called when the Optical Sensor detects an object.
objectLost — Registers a function to be called when the Optical Sensor loses an object.

Before calling any optical member functions, an optical instance must be created, as shown below:

/* This constructor is required when using VS Code.
Optical Sensor configuration is generated automatically
in VEXcode using the Device Menu. Replace the values
as needed. */

// Create an optical instance
optical Optical1 = optical(
    PORT1);   // Smart Port 1

setLight #

Sets Optical Sensor’s LED to on or off. The light can help the Optical Sensor detect objects and colors more clearly.

Available Functions

void  setLight(ledState state);

Parameters

Parameter	Type	Description
`state`	`ledState`	Sets the LED on or off. `ledState::on` turns the LED on at 100% brightness. `ledState::off` turns it off.

Return Values

This function does not return a value.

Examples

// Turn on LED with previous intensity.
Optical.setLight(ledState::on);

setLightPower #

Sets the brightness of the Optical Sensor’s LED. The light can help the Optical Sensor detect objects and colors more clearly.

If the Optical Sensor’s light is off, setting the light power above 0% will turn the light on.

If the Optical Sensor’s light is on, setting the light power at 0% will turn the light off.

A higher percentage makes the light brighter. A lower percentage makes the light dimmer.

Available Functions

void setLightPower( 
      int32_t      intensity, 
      percentUnits units = percent );

Parameters

Parameter	Type	Description
`intensity`	`int32_t`	The power level to set the light from 0 – 100.
`units`	`percentUnits`	The unit that represents the light intensity: `percent` / `pct` — percent

Return Values

This function does not return a value.

Examples

// Set the light power to 50 percent.
Optical.setLightPower(50, percent);

isNearObject #

Returns if the Optical Sensor detects a nearby object.

Available Functions

bool  isNearObject();

Parameters

This function does not accept any parameters.

Return Values

This function returns a Boolean indicating if a nearby object is detected:

true – The Optical Sensor detects an object.
false – The Optical Sensor does not detect an object.

Examples

// If an object is detected by the Optical Sensor, print
// "near object".
if (Optical.isNearObject()){
  Brain.Screen.print("near object");
}

color #

Returns the color detected by the Optical Sensor.

Available Functions

vex::color  color();

Parameters

This function does not accept any parameters.

Return Values

The color detected by the Optical Sensor as an instance of the color class.

Possible colors are:

black
white
red - A hue value between 340° - 20°
green - A hue value between 80° - 140°
blue - A hue value between 200° - 240°
yellow - A hue value between 40° - 60°
orange - A hue value between 20° - 40°
purple - A hue value between 240° - 280°
cyan - A hue value between 140° - 200°

Examples

// Set a variable, detectColor, to the color detected by the
// Optical Sensor
color detectColor = Optical.color();

// Print the color detected by the Optical Sensor
// to the Brain's screen
Brain.Screen.print(detectColor);

brightness #

Returns the amount of light reflected from the object.

A higher percentage means more light is reflected back to the Optical Sensor. A lower percentage means less light is reflected back.

Available Functions

double  brightness(bool bRaw = false);

Parameters

Parameter	Type	Description
`bRaw`	`bool`	A Boolean value to read raw brightness data instead of percentage. The default is `false`.

Return Values

A double representing the brightness detected by the Optical Sensor as a double in the range 0 - 100%, or a double representing the raw data detected by the sensor.

Examples

// Set a variable, brightness, to the value of the brightness
// detected by the Optical Sensor
double brightness = Optical.brightness();

// Print the brightness detected by the Optical Sensor to the
// Brain's screen
Brain.Screen.print(brightness);

hue #

Returns the hue value of the detected color.

Hue is a way to describe color using numbers around a color wheel.

The VEX Color Wheel showing the degrees of colors around a circle, with red at 0 degrees and transitioning through the rainbow as the value increases.

Available Functions

double hue();

Parameters

This function does not accept any parameters.

Return Values

A double representing the value of the hue detected by the Optical Sensor in the range 0 — 359.99.

Examples

// Set a variable, hue, to the value of the hue detected
// by the Optical Sensor.
double hue = Optical.hue();

objectDetected #

Registers a callback function for when an object is detected.

Available Functions

void objectDetected(void (* callback)(void));

Parameters

Parameter	Type	Description
`callback`	`void (*)(void)`	A previously defined function that executes when the Optical Sensor detects a new object.

Return Values

This function does not return a value.

Examples

Define the callback function (outside of int main())

// Called when the Optical Sensor detects an object
void detected() {
  // The Brain will print that the Optical Sensor detected an
  // object to the Brain's screen.
  Brain.Screen.print("object detected");
}

/* vexcodeInit() is only required when using VEXcode.
Remove vexcodeInit() if compiling in VS Code. */
int main() {

  // Run when the Optical Sensor detects an object.
  Optical.objectDetected(detected);
}

objectLost #

Registers a callback function for when an object is lost.

Available Functions

void objectLost(void (* callback)(void));

Parameters

Parameter	Type	Description
`callback`	`void (*)(void)`	A previously defined function that executes when the Optical Sensor loses a detected object.

Return Values

This function does not return a value.

Examples

Define the callback function (outside of int main())

// Called when the Optical Sensor loses an object
void lost() {
  // The Brain will print that the Optical Sensor lost an
  // object to the Brain's screen.
  Brain.Screen.print("object lost");
}

/* vexcodeInit() is only required when using VEXcode.
Remove vexcodeInit() if compiling in VS Code. */
int main() {

  // Run lost when the Optical Sensor loses an object.
  Optical.objectLost(lost);
}