Ultrasonic Class Reference

#include <Ultrasonic.h>

Inheritance diagram for Ultrasonic:

Collaboration diagram for Ultrasonic:

List of all members.

Public Types
enum	DistanceUnit { kInches = 0, kMilliMeters = 1 }
Public Member Functions
	Ultrasonic (DigitalOutput *pingChannel, DigitalInput *echoChannel, DistanceUnit units=kInches)
	Ultrasonic (DigitalOutput &pingChannel, DigitalInput &echoChannel, DistanceUnit units=kInches)
	Ultrasonic (UINT32 pingChannel, UINT32 echoChannel, DistanceUnit units=kInches)
	Ultrasonic (UINT8 pingModuleNumber, UINT32 pingChannel, UINT8 echoModuleNumber, UINT32 echoChannel, DistanceUnit units=kInches)
virtual	~Ultrasonic ()
void	Ping ()
bool	IsRangeValid ()
double	GetRangeInches ()
double	GetRangeMM ()
bool	IsEnabled ()
void	SetEnabled (bool enable)
double	PIDGet ()
void	SetDistanceUnits (DistanceUnit units)
DistanceUnit	GetDistanceUnits ()
Static Public Member Functions
static void	SetAutomaticMode (bool enabling)

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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).

Definition at line 28 of file Ultrasonic.h.

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Constructor & Destructor Documentation

Ultrasonic::Ultrasonic	(	DigitalOutput *	pingChannel,
		DigitalInput *	echoChannel,
		DistanceUnit	units = kInches
	)

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.
	units	The units returned in either kInches or kMilliMeters

Definition at line 102 of file Ultrasonic.cpp.

Ultrasonic::Ultrasonic	(	DigitalOutput &	pingChannel,
		DigitalInput &	echoChannel,
		DistanceUnit	units = kInches
	)

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.
	units	The units returned in either kInches or kMilliMeters

Definition at line 123 of file Ultrasonic.cpp.

Ultrasonic::Ultrasonic	(	UINT32	pingChannel,
		UINT32	echoChannel,
		DistanceUnit	units = kInches
	)

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.
	units	The units returned in either kInches or kMilliMeters

Definition at line 86 of file Ultrasonic.cpp.

Ultrasonic::Ultrasonic	(	UINT8	pingModuleNumber,
		UINT32	pingChannel,
		UINT8	echoModuleNumber,
		UINT32	echoChannel,
		DistanceUnit	units = kInches
	)

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:

	pingModuleNumber	The digital module that the pingChannel is on.
	pingChannel	The digital output channel that sends the pulse to initiate the sensor sending the ping.
	echoModuleNumber	The digital module that the echoChannel is on.
	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.
	units	The units returned in either kInches or kMilliMeters

Definition at line 144 of file Ultrasonic.cpp.

Ultrasonic::~Ultrasonic

(

)

[virtual]

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).

Definition at line 160 of file Ultrasonic.cpp.

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Member Function Documentation

Ultrasonic::DistanceUnit Ultrasonic::GetDistanceUnits

(

)

Get the current DistanceUnit that is used for the PIDSource base object.

Returns:

The type of DistanceUnit that is being used.

Definition at line 322 of file Ultrasonic.cpp.

double Ultrasonic::GetRangeInches

(

)

Get the range in inches from the ultrasonic sensor.

Returns:

double 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.

Definition at line 271 of file Ultrasonic.cpp.

double Ultrasonic::GetRangeMM

(

)

Get the range in millimeters from the ultrasonic sensor.

Returns:

double 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.

Definition at line 284 of file Ultrasonic.cpp.

bool Ultrasonic::IsRangeValid

(

)

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.

Definition at line 261 of file Ultrasonic.cpp.

double Ultrasonic::PIDGet

(

)

[virtual]

Get the range in the current DistanceUnit for the PIDSource base object.

Returns:

The range in DistanceUnit

Implements PIDSource.

Definition at line 294 of file Ultrasonic.cpp.

void Ultrasonic::Ping

(

)

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.

Definition at line 247 of file Ultrasonic.cpp.

void Ultrasonic::SetAutomaticMode

(

bool

enabling

)

[static]

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.

Definition at line 208 of file Ultrasonic.cpp.

void Ultrasonic::SetDistanceUnits

(

DistanceUnit

units

)

Set the current DistanceUnit that should be used for the PIDSource base object.

Parameters:

units

The DistanceUnit that should be used.

Definition at line 312 of file Ultrasonic.cpp.

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

• Ultrasonic.h
• Ultrasonic.cpp