Ultrasonic Class Reference

#include <Ultrasonic.h>

Inheritance diagram for Ultrasonic:

Collaboration diagram for Ultrasonic:

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List of all members.

Public Member Functions

Ultrasonic (DigitalOutput *pingChannel, DigitalInput *echoChannel)

Ultrasonic (unsigned pingChannel, unsigned echoChannel)

Ultrasonic (unsigned pingSlot, unsigned pingChannel, unsigned echoSlot, unsigned echoChannel)

~Ultrasonic (void)

void Ping (void)

bool IsRangeValid (void)

void SetAutomaticMode (bool enabling)

unsigned long GetRangeInches (void)

unsigned long GetRangeMM (void)

Detailed Description

Ultrasonic rangefinder class. The Ultrasonic rangefinder measures absolute distance based on the round-trip time of a ping generated by the controller. These sensors use two transducers, a speaker and a microphone both tuned to the ultrasonic range. A common ultrasonic sensor, the Daventech SRF04 requires a short pulse to be generated on a digital channel. This causes the chirp to be emmitted. A second line becomes high as the ping is transmitted and goes low when the echo is received. The time that the line is high determines the round trip distance (time of flight).

Constructor & Destructor Documentation

Ultrasonic::Ultrasonic	(	DigitalOutput *	pingChannel,
		DigitalInput *	echoChannel
	)

Create an instance of an Ultrasonic Sensor from a DigitalInput for the echo channel and a DigitalOutput for the ping channel.

Parameters:

	pingChannel	The digital output object that starts the sensor doing a ping. Requires a 10uS pulse to start.
	echoChannel	The digital input object that times the return pulse to determine the range.

Ultrasonic::Ultrasonic	(	unsigned	pingChannel,
		unsigned	echoChannel
	)

Create an instance of the Ultrasonic Sensor using the default module. This is designed to supchannel the Daventech SRF04 and Vex ultrasonic sensors. This constructor assumes that both digital I/O channels are in the default digital module.

Parameters:

	pingChannel	The digital output channel that sends the pulse to initiate the sensor sending the ping.
	echoChannel	The digital input channel that receives the echo. The length of time that the echo is high represents the round trip time of the ping, and the distance.

Ultrasonic::Ultrasonic	(	unsigned	pingSlot,
		unsigned	pingChannel,
		unsigned	echoSlot,
		unsigned	echoChannel
	)

Create an instance of the Ultrasonic sensor using specified modules. This is designed to supchannel the Daventech SRF04 and Vex ultrasonic sensors. This constructors takes the channel and module slot for each of the required digital I/O channels.

Parameters:

	pingSlot	The digital module that the pingChannel is in.
	pingChannel	The digital output channel that sends the pulse to initiate the sensor sending the ping.
	echoSlot	The digital module that the echoChannel is in.
	echoChannel	The digital input channel that receives the echo. The length of time that the echo is high represents the round trip time of the ping, and the distance.

Ultrasonic::~Ultrasonic ( void )

Destructor for the ultrasonic sensor. Delete the instance of the ultrasonic sensor by freeing the allocated digital channels. If the system was in automatic mode (round robin), then it is stopped, then started again after this sensor is removed (provided this wasn't the last sensor).

Member Function Documentation

void Ultrasonic::Ping ( void )

Single ping to ultrasonic sensor. Send out a single ping to the ultrasonic sensor. This only works if automatic (round robin) mode is disabled. A single ping is sent out, and the counter should count the semi-period when it comes in. The counter is reset to make the current value invalid.

bool Ultrasonic::IsRangeValid ( void )

Check if there is a valid range measurement. The ranges are accumulated in a counter that will increment on each edge of the echo (return) signal. If the count is not at least 2, then the range has not yet been measured, and is invalid.

void Ultrasonic::SetAutomaticMode ( bool enabling )

Turn Automatic mode on/off. When in Automatic mode, all sensors will fire in round robin, waiting a set time between each sensor.

Parameters:

enabling

Set to true if round robin scheduling should start for all the ultrasonic sensors. This scheduling method assures that the sensors are non-interfering because no two sensors fire at the same time. If another scheduling algorithm is preffered, it can be implemented by pinging the sensors manually and waiting for the results to come back.

unsigned long Ultrasonic::GetRangeInches ( void )

Get the range in inches from the ultrasonic sensor.

Returns:: unsigned Range in inches of the target returned from the ultrasonic sensor. If there is no valid value yet, i.e. at least one measurement hasn't completed, then return 0.

unsigned long Ultrasonic::GetRangeMM ( void )

Get the range in millimeters from the ultrasonic sensor.

Returns:: unsigned Range in millimeters of the target returned by the ultrasonic sensor. If there is no valid value yet, i.e. at least one measurement hasn't complted, then return 0.

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

C:/WindRiver/workspace/WPILib/Ultrasonic.h
C:/WindRiver/workspace/WPILib/Ultrasonic.cpp


Public Member Functions
	Ultrasonic (DigitalOutput pingChannel, DigitalInput echoChannel)
	Ultrasonic (unsigned pingChannel, unsigned echoChannel)
	Ultrasonic (unsigned pingSlot, unsigned pingChannel, unsigned echoSlot, unsigned echoChannel)
	~Ultrasonic (void)
void	Ping (void)
bool	IsRangeValid (void)
void	SetAutomaticMode (bool enabling)
unsigned long	GetRangeInches (void)
unsigned long	GetRangeMM (void)