Package lejos.hardware.sensor

Class NXTUltrasonicSensor

java.lang.Object

lejos.hardware.Device

lejos.hardware.sensor.BaseSensor

lejos.hardware.sensor.I2CSensor

lejos.hardware.sensor.NXTUltrasonicSensor

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, SensorConstants, SensorMode, SensorModes, SampleProvider

public class NXTUltrasonicSensor
extends I2CSensor

NXT Ultrasonic sensor
The NXT Ultrasonic sensor generates sound waves and reads their echoes to detect and measure distance from objects.

Supported modes
Mode name	Description	unit(s)	Getter
Distance	Measures the distance to the nearest object in front of the sensor	meter	getDistanceMode()
Ping	Measures the distance to the nearest 8 objects in front of the sensor	meter	getPingMode()

See Mindstorms NXT HDK/SDK See The leJOS sensor framework See leJOS conventions for SampleProviders

Author:

Aswin

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	NXTUltrasonicSensor.DistanceMode
class	NXTUltrasonicSensor.PingMode

Field Summary

Fields

Modifier and Type	Field	Description
protected static byte	MODE_CONTINUOUS
protected static byte	MODE_OFF
protected static byte	MODE_PING

Fields inherited from class lejos.hardware.sensor.I2CSensor

address, DEFAULT_I2C_ADDRESS, port, REG_PRODUCT_ID, REG_VENDOR_ID, REG_VERSION, retryCount

Fields inherited from class lejos.hardware.sensor.BaseSensor

modes

Fields inherited from class lejos.hardware.Device

closeList

Fields inherited from interface lejos.hardware.sensor.SensorConstants

BLACK, BLANK_INDEX, BLUE, BLUE_INDEX, BROWN, GREEN, GREEN_INDEX, MAX_TYPE, MIN_TYPE, MODE_RAW, NXT_ADC_RES, RED, RED_INDEX, TYPE_ANGLE, TYPE_COLORBLUE, TYPE_COLORFULL, TYPE_COLORGREEN, TYPE_COLORNONE, TYPE_COLORRED, TYPE_CUSTOM, TYPE_HIGHSPEED, TYPE_HIGHSPEED_9V, TYPE_HISPEED, TYPE_LIGHT_ACTIVE, TYPE_LIGHT_INACTIVE, TYPE_LOWSPEED, TYPE_LOWSPEED_9V, TYPE_NO_SENSOR, TYPE_REFLECTION, TYPE_SOUND_DB, TYPE_SOUND_DBA, TYPE_SWITCH, TYPE_TEMPERATURE, WHITE, YELLOW

Constructor Summary

Constructors

Constructor	Description
NXTUltrasonicSensor(I2CPort port)
NXTUltrasonicSensor(Port port)

Method Summary

Modifier and Type	Method	Description
void	disable()
void	enable()
void	getData(int register, byte[] buf, int off, int len)	Executes an I2C read transaction and waits for the result.
SampleProvider	getDistanceMode()	Gives a SampleProvider representing the sensor in distance mode.
SampleProvider	getPingMode()	Gives a SampleProvider representing the sensor in ping mode.
boolean	isEnabled()
void	sendData(int register, byte[] buf, int off, int len)	Executes an I2C write transaction.
protected boolean	setMode(byte mode)	Sets the sensor to CONTINUOUS, PING or OFF

Methods inherited from class lejos.hardware.sensor.I2CSensor

fetchString, getAddress, getData, getPort, getProductID, getRetryCount, getVendorID, getVersion, sendData, sendData, setAddress, setRetryCount

Methods inherited from class lejos.hardware.sensor.BaseSensor

fetchSample, getAvailableModes, getCurrentMode, getMode, getMode, getModeCount, getName, sampleSize, setCurrentMode, setCurrentMode, setModes

Methods inherited from class lejos.hardware.Device

close, releaseOnClose

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MODE_OFF

protected static final byte MODE_OFF

See Also:

Constant Field Values

MODE_PING

protected static final byte MODE_PING

See Also:

Constant Field Values

MODE_CONTINUOUS

protected static final byte MODE_CONTINUOUS

See Also:

Constant Field Values

Constructor Detail

NXTUltrasonicSensor

public NXTUltrasonicSensor(I2CPort port)

NXTUltrasonicSensor

public NXTUltrasonicSensor(Port port)

Method Detail

getData

public void getData(int register,
                    byte[] buf,
                    int off,
                    int len)

Description copied from class: I2CSensor

Executes an I2C read transaction and waits for the result.

Overrides:

getData in class I2CSensor

Parameters:

register - I2C register, e.g 0x41

buf - Buffer to return data

off - Offset of the start of the data

len - Length of the return data

sendData

public void sendData(int register,
                     byte[] buf,
                     int off,
                     int len)

Description copied from class: I2CSensor

Executes an I2C write transaction.

Overrides:

sendData in class I2CSensor

Parameters:

register - I2C register, e.g 0x42

buf - Buffer containing data to send

off - Offset of the start of the data

len - Length of data to send

getDistanceMode

public SampleProvider getDistanceMode()

Gives a SampleProvider representing the sensor in distance mode. In this mode the sensor scans the surrounding continuously and reports the distance to the nearest object in sight. The sensor reports the distance to the nearest object in meters. The theoretical range of the sensor is 0,04 to 2.54 meter. If there is no object detected within this range the sensor reports Float.POSITIVE_INFINITY.
Samples can only be provided every 30 ms. If samples are fetched more often the SampleProvider will pause until the 30ms have passed.

Returns:

A SamplePrivider

getPingMode

public SampleProvider getPingMode()

Gives a SampleProvider representing the sensor in ping mode. In this mode the sensor only scans the surrounding upon request, ie by calling fetchSample method. The sensor reports the distance, expressed in meters, to the eight nearest objects in sight. The theoretical range of the sensor is 0,04 to 2.54 meter. If there are less then eight objects within the sensors range the sensor will reports Float.POSITIVE_INFINITY. Fetching a sample in ping mode takes about 70 ms.

Returns:

the sample provider

enable

public void enable()

disable

public void disable()

isEnabled

public boolean isEnabled()

setMode

protected boolean setMode(byte mode)

Sets the sensor to CONTINUOUS, PING or OFF

Parameters:

mode -

Returns:

True, if the mode was changed.
False, if the mode was already in the requested state.