com.sun.spot.sensorboard.peripheral
Class LightSensor

java.lang.Object
  com.sun.spot.resources.Resource
      com.sun.spot.sensorboard.io.ScalarInput
          com.sun.spot.sensorboard.peripheral.LightSensor

All Implemented Interfaces:

IResource, ILightSensor, IMeasurementInfo, ITransducer, IScalarInput

public class LightSensor
extends ScalarInput
implements ILightSensor, ILightSensor, IMeasurementInfo

Simple extension of ScalarInput.

Author:

arshan & Ron Goldman

Field Summary

Fields inherited from class com.sun.spot.sensorboard.io.ScalarInput

index, myController, range, thIsolates, thListeners

Constructor Summary

LightSensor(PinDescriptor pidx, int r, IADCController cntrl)
Creates a new instance of LightSensor

Method Summary

void	addILightSensorThresholdListener(ILightSensorThresholdListener who) Adds the specified light sensor threshold listener to receive callbacks from this light sensor.
SensorEvent	createSensorEvent() Create a SensorEvent of the appropriate type for this sensor.
double	getAccuracy() Returns the accuracy of the sensor (in the current measurement range) as a percentage of reading (=data value).
int	getAverageValue() Take 17 readings, one every 1 msec and average them.
int	getAverageValue(int n) To deal with light sources that change rapidly over time, such as fluorescent light bulbs, it is necessary to take multiple readings and average them.
ILightSensorThresholdListener[]	getILightSensorThresholdListeners() Returns an array of all the light sensor threshold listeners registered on this light sensor.
double	getMaxValue() Returns the current maximum value of the sensor (in the current measurement range).
double	getMinValue() Returns the current minimum value of the sensor (in the current measurement range).
double	getResolution() Returns the resolution of the range (in the current measurement range).
void	removeILightSensorThresholdListener(ILightSensorThresholdListener who) Removes the specified light sensor threshold listener so that it no longer receives callbacks from this light sensor.
void	saveEventState(SensorEvent evt) Save the current sensor state in the specified event.

Methods inherited from class com.sun.spot.sensorboard.io.ScalarInput

addIADT7411ThresholdListener, addIScalarInputThresholdListener, areThresholdEventsEnabled, enableThresholdEvents, getDescription, getHighThreshold, getIADT7411ThresholdListeners, getIndex, getIScalarInputThresholdListeners, getLowThreshold, getMaxSamplingRate, getRange, getValue, getVoltage, removeIADT7411ThresholdListener, removeIScalarInputThresholdListener, setThresholds, supportsThresholdEvents, thresholdChanged, thresholdExceeded, toString

Methods inherited from class com.sun.spot.resources.Resource

addTag, getTags, getTagValue, hasTag, removeTag

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.sun.spot.sensorboard.io.IScalarInput

addIScalarInputThresholdListener, areThresholdEventsEnabled, enableThresholdEvents, getHighThreshold, getIndex, getIScalarInputThresholdListeners, getLowThreshold, getRange, getValue, removeIScalarInputThresholdListener, setThresholds, supportsThresholdEvents

Methods inherited from interface com.sun.spot.resources.transducers.ITransducer

getDescription, getMaxSamplingRate

Methods inherited from interface com.sun.spot.resources.IResource

addTag, getTags, getTagValue, hasTag, removeTag

Methods inherited from interface com.sun.spot.resources.transducers.ILightSensor

getValue

Methods inherited from interface com.sun.spot.resources.transducers.ITransducer

getDescription, getMaxSamplingRate

Methods inherited from interface com.sun.spot.resources.IResource

addTag, getTags, getTagValue, hasTag, removeTag

Constructor Detail

LightSensor

public LightSensor(PinDescriptor pidx,
                   int r,
                   IADCController cntrl)

Creates a new instance of LightSensor

Parameters:

pidx - PinDescriptor that the lightsensor is connected to

r - Range of the mask for the above pin

cntrl - the ADC controller to use

Method Detail

getAverageValue

public int getAverageValue(int n)
                    throws IOException

To deal with light sources that change rapidly over time, such as fluorescent light bulbs, it is necessary to take multiple readings and average them. This method sleeps for 1 millisecond between readings. At least one reading is always taken, even if n <= 0.

Specified by:

getAverageValue in interface ILightSensor

Parameters:

n - the number of readings to take.

Returns:

the averaged light intensity.

Throws:

IOException

getAverageValue

public int getAverageValue()
                    throws IOException

Take 17 readings, one every 1 msec and average them. Equivalent to getAverageValue(17);

Specified by:

getAverageValue in interface ILightSensor

Returns:

the averaged light intensity.

Throws:

IOException

addILightSensorThresholdListener

public void addILightSensorThresholdListener(ILightSensorThresholdListener who)

Adds the specified light sensor threshold listener to receive callbacks from this light sensor. Callbacks occur when the light sensor reading falls below or equal to the low threshold value, or when it rises above or equal to the high threshold value.

Parameters:

who - the light sensor threshold listener to add.

removeILightSensorThresholdListener

public void removeILightSensorThresholdListener(ILightSensorThresholdListener who)

Removes the specified light sensor threshold listener so that it no longer receives callbacks from this light sensor. This method performs no function, nor does it throw an exception, if the listener specified by the argument was not previously added to this light sensor.

Parameters:

who - the light sensor threshold listener to remove.

getILightSensorThresholdListeners

public ILightSensorThresholdListener[] getILightSensorThresholdListeners()

Returns an array of all the light sensor threshold listeners registered on this light sensor.

Returns:

all of this light sensor's ILightSensorThresholdListener or an empty array if no light sensor threshold listeners are currently registered.

getMinValue

public double getMinValue()

Returns the current minimum value of the sensor (in the current measurement range).

Specified by:

getMinValue in interface IMeasurementInfo

Overrides:

getMinValue in class ScalarInput

Returns:

the min value of the sensor

getMaxValue

public double getMaxValue()

Returns the current maximum value of the sensor (in the current measurement range).

Specified by:

getMaxValue in interface IMeasurementInfo

Overrides:

getMaxValue in class ScalarInput

Returns:

the max value of the sensor

getResolution

public double getResolution()

Returns the resolution of the range (in the current measurement range). The resolution is the minimum amount of change in the input of a sensor that can be detected as a change in the output. Resolution is a property of the transducer of a sensor but the input and output ranges and word length of the A/D converter usually set the limitations for the resolution of a digital sensor.

Specified by:

getResolution in interface IMeasurementInfo

Overrides:

getResolution in class ScalarInput

Returns:

resolution of the sensor

getAccuracy

public double getAccuracy()

Returns the accuracy of the sensor (in the current measurement range) as a percentage of reading (=data value). Because this accuracy value describes the relative measurement error, greater values indicate a less accurate sensor. The accuracy value is within: 0 ≤ accuracy < 1

Specified by:

getAccuracy in interface IMeasurementInfo

Overrides:

getAccuracy in class ScalarInput

Returns:

the accuracy of the sensor. If the accuracy is not known, a value of -1 is returned.

createSensorEvent

public SensorEvent createSensorEvent()

Description copied from interface: ITransducer

Create a SensorEvent of the appropriate type for this sensor.

Specified by:

createSensorEvent in interface ITransducer

Overrides:

createSensorEvent in class ScalarInput

Returns:

a SensorEvent of the appropriate type for this sensor.

saveEventState

public void saveEventState(SensorEvent evt)

Description copied from interface: ITransducer

Save the current sensor state in the specified event.

Specified by:

saveEventState in interface ITransducer

Overrides:

saveEventState in class ScalarInput

Parameters:

evt - the event to store the sensor state in