Rangefinder objects wrap a FreeRTOS thread with pin change interrupts to read trigger/echo style ultrasonic sensors. More...

#include <Rangefinder.h>

Collaboration diagram for Rangefinder:

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Public Member Functions
	Rangefinder ()

void	attach (int trigger, int echo)
	Attach 2 pins to be used as triger and echo. More...

long	getRoundTripTimeMicroSeconds ()
	get the time of latest round trip in microseconds More...

float	getDistanceCM ()
	get the distance of an object from the sensor in centimeters More...

void	sensorISR ()
	The method called from the ISR indicating the echo pin changed state. More...

Static Public Member Functions
static void	checkTimeout ()
	check the current state of timeout and fire if its time to do so More...

static void	fire ()
	fire a strobe of the trig pin More...

static int	getTimeoutState ()
	Function used by the timeout check thread to determine if this object has timed out. More...

Data Fields
portMUX_TYPE	synch = portMUX_INITIALIZER_UNLOCKED

int	echoPin

int	triggerPin

volatile unsigned long	startTime

volatile unsigned long	roundTripTime

Static Public Attributes
static int	numberOfFinders = 0

static bool	timoutThreadStarted = false

static int	pingIndex = 0

static bool	forceFire = false

static Rangefinder *	list [MAX_POSSIBLE_INTERRUPT_RANGEFINDER] = { NULL, }
	list of attached rangefinders More...

Detailed Description

Rangefinder objects wrap a FreeRTOS thread with pin change interrupts to read trigger/echo style ultrasonic sensors.

Rangefinder objects can be declared statically

Range is calculated continuously and the current measurement is retrieved with getDistanceCM()

Many objects can be declared, and they are pinged one at a time in a round-robbin configuration to prevent echo and cross-talk.

When pins are attached, the thread is started. The thread checks for timeouts and re sets the round-robbin.

This library supports up to 4 range finders

Definition at line 21 of file Rangefinder.h.

Constructor & Destructor Documentation

◆ Rangefinder()

Rangefinder::Rangefinder ( )

Definition at line 136 of file Rangefinder.cpp.

Member Function Documentation

◆ attach()

void Rangefinder::attach	(	int	trigger,
		int	echo
	)

Attach 2 pins to be used as triger and echo.

The trigger pin needs to be an output, and the echo pin needs to have CHANGE interrupts.

Interrupts are managed through Arduio attachInterrupt()

Definition at line 92 of file Rangefinder.cpp.

References complexHandlerTaskUS, echoPin, MAX_POSSIBLE_INTERRUPT_RANGEFINDER, numberOfFinders, onTimer(), sensorISR0(), sensorISR1(), sensorISR2(), sensorISR3(), timoutThreadStarted, and triggerPin.

Referenced by setup().

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◆ checkTimeout()

void Rangefinder::checkTimeout ( )

static

check the current state of timeout and fire if its time to do so

Definition at line 44 of file Rangefinder.cpp.

References fire(), and getTimeoutState().

Referenced by onTimer().

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◆ fire()

void Rangefinder::fire ( )

static

fire a strobe of the trig pin

this will initiate a chirp and wait for the echo to come back

Definition at line 66 of file Rangefinder.cpp.

References forceFire, numberOfFinders, pingIndex, threadTimeout, and triggerPin.

Referenced by checkTimeout(), and onTimer().

◆ getDistanceCM()

float Rangefinder::getDistanceCM ( )

get the distance of an object from the sensor in centimeters

Returns: the distance in centimeters

Definition at line 153 of file Rangefinder.cpp.

References getRoundTripTimeMicroSeconds().

Referenced by loop(), and updateDashboard().

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◆ getRoundTripTimeMicroSeconds()

long Rangefinder::getRoundTripTimeMicroSeconds ( )

get the time of latest round trip in microseconds

Returns: the time in microseconds

Definition at line 143 of file Rangefinder.cpp.

References roundTripTime, and synch.

Referenced by getDistanceCM().

◆ getTimeoutState()

int Rangefinder::getTimeoutState ( )

static

Function used by the timeout check thread to determine if this object has timed out.

Definition at line 40 of file Rangefinder.cpp.

References threadTimeout.

Referenced by checkTimeout().

◆ sensorISR()

void Rangefinder::sensorISR ( )

The method called from the ISR indicating the echo pin changed state.

This method is called by the static method for the associated interrupt.

Definition at line 82 of file Rangefinder.cpp.

References echoPin, forceFire, roundTripTime, startTime, and synch.

Referenced by sensorISR0(), sensorISR1(), sensorISR2(), and sensorISR3().

Field Documentation

◆ echoPin

int Rangefinder::echoPin

GPIO pin number for the echo

Definition at line 55 of file Rangefinder.h.

Referenced by attach(), and sensorISR().

◆ forceFire

bool Rangefinder::forceFire = false

static

flag to force a fire from the timeout thread

Definition at line 47 of file Rangefinder.h.

Referenced by fire(), onTimer(), and sensorISR().

◆ list

Rangefinder * Rangefinder::list = { NULL, }

static

list of attached rangefinders

when attach completes, a pointer to the object being attahced is added to this list. THis list is read from the timeout thread and Fire in order to run the round-robbin of all sensors.

Definition at line 80 of file Rangefinder.h.

◆ numberOfFinders

int Rangefinder::numberOfFinders = 0

static

running count of attached range finders

Definition at line 35 of file Rangefinder.h.

Referenced by attach(), and fire().

◆ pingIndex

int Rangefinder::pingIndex = 0

static

which index in the round robbin to ping

Definition at line 43 of file Rangefinder.h.

Referenced by fire().

◆ roundTripTime

volatile unsigned long Rangefinder::roundTripTime

the cached time of the latest sensor read.

Definition at line 67 of file Rangefinder.h.

Referenced by getRoundTripTimeMicroSeconds(), and sensorISR().

◆ startTime

volatile unsigned long Rangefinder::startTime

Time the pulse started

Definition at line 63 of file Rangefinder.h.

Referenced by sensorISR().

◆ synch

portMUX_TYPE Rangefinder::synch = portMUX_INITIALIZER_UNLOCKED

synchronization object to lock out access to volitile memory

Definition at line 51 of file Rangefinder.h.

Referenced by getRoundTripTimeMicroSeconds(), and sensorISR().

◆ timoutThreadStarted

bool Rangefinder::timoutThreadStarted = false

static

flag to keep track of the state of the thread, started or not

Definition at line 39 of file Rangefinder.h.

Referenced by attach().

◆ triggerPin

int Rangefinder::triggerPin

GPIO pin for the trigger

Definition at line 59 of file Rangefinder.h.

Referenced by attach(), and fire().

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

src/Rangefinder.h
src/Rangefinder.cpp

Public Member Functions

Static Public Member Functions

Data Fields

Static Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Rangefinder()

Member Function Documentation

◆ attach()

◆ checkTimeout()

◆ fire()

◆ getDistanceCM()

◆ getRoundTripTimeMicroSeconds()

◆ getTimeoutState()

◆ sensorISR()

Field Documentation

◆ echoPin

◆ forceFire

◆ list

◆ numberOfFinders

◆ pingIndex

◆ roundTripTime

◆ startTime

◆ synch

◆ timoutThreadStarted

◆ triggerPin