Light Class Reference

API for the Light Sensor. More...

Detailed Description

• ID: light
• Name: Analog Light Sensor
• Category: light
• Manufacturer: seeed
• Connection: analog
• Kit: gsk

The light sensor detects the intensity of the ambient light. As the light intensity of the environment increases, the resistance of the sensor decreases. This means the raw value from the analog pin is larger in bright light and smaller in the dark. A very approximate lux value can also be returned.

    // Create the light sensor object using AIO pin 0
    upm::Light* light = new upm::Light(0);

    // Read the input and print both the normalized ADC value and a
    // rough lux value, waiting one second between readings
    while( 1 ) {
        std::cout << light->name() << " normalized value is "
                  << light->getNormalized() <<
            ", which is roughly " << light->value() << " lux" << std::endl;
        sleep(1);
    }

    // Delete the light sensor object
    delete light;

Public Member Functions
	Light (unsigned int pin)
	~Light ()
float	raw_value ()
int	value ()
void	setAref (float aref)
void	setScale (float scale)
void	setOffset (float offset)
float	getAref ()
float	getScale ()
float	getOffset ()
float	getNormalized ()
float	getRawVolts ()
std::string	name ()

Protected Attributes
light_context	m_light

Constructor & Destructor Documentation

Light

(

unsigned int

pin

)

analog light sensor constructor

Parameters

pin	Analog pin to use

Exceptions

std::runtime_error

on initialization error

~Light

(

)

Light destructor

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Member Function Documentation

float raw_value

(

)

Gets the raw value from the AIO pin

Deprecated:

This function is deprecated use getNormalized() instead.

Returns

Raw value from the ADC

Exceptions

std::runtime_error

on error

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int value

(

)

Gets an approximate light value in lux from the sensor

Returns

Approximate light reading in lux

Exceptions

std::runtime_error

on error

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void setAref

(

float

aref

)

Set ADC reference voltage

Parameters

aref	ADC reference voltage

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void setScale

(

float

scale

)

Set sensor scale. This scale is applied to the return value: counts = counts * scale

Parameters

scale

count scale value used

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void setOffset

(

float

offset

)

Set sensor offset. This offset is applied to the return value: value = value + offset

Parameters

offset

count offset value used

Returns

Function result code

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float getAref

(

)

Get sensor aref

Parameters

dev	sensor context pointer

Returns

Sensor ADC reference voltage

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float getScale

(

)

Get sensor scale

Parameters

dev	sensor context pointer

Returns

Sensor scale

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float getOffset

(

)

Get sensor offset

Parameters

dev	sensor context pointer

Returns

Sensor offset

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float getNormalized

(

)

Read normalized value for sensor

Parameters

dev	sensor context pointer
*value	Normalized value (0.0 -> 1.0)

Returns

Function result code

Exceptions

std::runtime_error

on error

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float getRawVolts

(

)

Read raw voltage from the sensor

Parameters

dev	sensor context pointer
*value	Raw sensor voltage

Returns

Function result code

Exceptions

std::runtime_error

on error

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Collaboration diagram for Light:

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The documentation for this class was generated from the following files:

• src/light/light.hpp
• src/light/light.cxx