frc::Ultrasonic Class Reference

Ultrasonic rangefinder class. More...

#include <frc/Ultrasonic.h>

Inheritance diagram for frc::Ultrasonic:

Public Member Functions
	Ultrasonic (int pingChannel, int echoChannel)
	Create an instance of the Ultrasonic Sensor. More...
	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. More...
	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. More...
	Ultrasonic (std::shared_ptr< DigitalOutput > pingChannel, std::shared_ptr< DigitalInput > echoChannel)
	Create an instance of an Ultrasonic Sensor from a DigitalInput for the echo channel and a DigitalOutput for the ping channel. More...
	~Ultrasonic () override
	Ultrasonic (Ultrasonic &&)=default
Ultrasonic &	operator= (Ultrasonic &&)=default
int	GetEchoChannel () const
void	Ping ()
	Single ping to ultrasonic sensor. More...
bool	IsRangeValid () const
	Check if there is a valid range measurement. More...
units::meter_t	GetRange () const
	Get the range from the ultrasonic sensor. More...
bool	IsEnabled () const
void	SetEnabled (bool enable)
void	InitSendable (wpi::SendableBuilder &builder) override
	Initializes this Sendable object. More...
Public Member Functions inherited from wpi::Sendable
virtual	~Sendable ()=default
virtual void	InitSendable (SendableBuilder &builder)=0
	Initializes this Sendable object. More...
Public Member Functions inherited from wpi::SendableHelper< Ultrasonic >
	SendableHelper (const SendableHelper &rhs)=default
	SendableHelper (SendableHelper &&rhs)
SendableHelper &	operator= (const SendableHelper &rhs)=default
SendableHelper &	operator= (SendableHelper &&rhs)

Static Public Member Functions
static void	SetAutomaticMode (bool enabling)
	Turn Automatic mode on/off. More...

Additional Inherited Members
Protected Member Functions inherited from wpi::SendableHelper< Ultrasonic >
	SendableHelper ()=default
	~SendableHelper ()

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 emitted. 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() [1/5]

frc::Ultrasonic::Ultrasonic	(	int	pingChannel,
		int	echoChannel
	)

Create an instance of the Ultrasonic Sensor.

This is designed to support the Daventech SRF04 and Vex ultrasonic sensors.

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() [2/5]

frc::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() [3/5]

frc::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() [4/5]

frc::Ultrasonic::Ultrasonic	(	std::shared_ptr< DigitalOutput >	pingChannel,
		std::shared_ptr< 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()

frc::Ultrasonic::~Ultrasonic ( )

override

Ultrasonic() [5/5]

frc::Ultrasonic::Ultrasonic ( Ultrasonic &&  )

default

Member Function Documentation

GetEchoChannel()

int frc::Ultrasonic::GetEchoChannel

(

)

const

GetRange()

units::meter_t frc::Ultrasonic::GetRange

(

)

const

Get the range from the ultrasonic sensor.

Returns

Range 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.

InitSendable()

void frc::Ultrasonic::InitSendable ( wpi::SendableBuilder &  builder )

overridevirtual

Initializes this Sendable object.

Parameters

builder

sendable builder

Implements wpi::Sendable.

IsEnabled()

bool frc::Ultrasonic::IsEnabled

(

)

const

IsRangeValid()

bool frc::Ultrasonic::IsRangeValid

(

)

const

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.

operator=()

Ultrasonic & frc::Ultrasonic::operator= ( Ultrasonic &&  )

default

Ping()

void frc::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.

SetAutomaticMode()

static void frc::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 preferred, it can be implemented by pinging the sensors manually and waiting for the results to come back.

SetEnabled()

void frc::Ultrasonic::SetEnabled

(

bool

enable

)

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

• frc/Ultrasonic.h