A standard rotary encoder. More...

#include <RotaryEncoder.h>

Inheritance diagram for RumPi::RotaryEncoder:

Collaboration diagram for RumPi::RotaryEncoder:

Public Member Functions
	RotaryEncoder (unsigned int clkPinNumber, unsigned int dtPinNumber, unsigned int swPinNumber)
	Builds a rotary encoder on the given CLK/DT/SW pins, sets them as inputs, registers this as the active encoder for the interrupt callback, and hooks a falling-edge interrupt on the push-button pin. More...

virtual	~RotaryEncoder ()
	Destroys the encoder, stopping and joining its listener thread first. More...

virtual void	TurnOn () override
	Turns the encoder on: starts the background listener thread that watches the pins and updates the value. More...

virtual void	TurnOff () override
	Turns the encoder off: signals the listener thread to stop and waits for it to finish. More...

virtual void	ProcessRawValues () override
	Processes the encoder's raw values. More...

virtual std::string	ToString () const override
	Serializes the encoder's pins, value, and pressed state to a string. More...

unsigned int	GetCLKPinNumber () const
	Gets the CLK (clock) pin number. More...

unsigned int	GetDTPinNumber () const
	Gets the DT (data) pin number. More...

unsigned int	GetSWPinNumber () const
	Gets the SW (switch / push-button) pin number. More...

unsigned char	GetCurrentDTStatus () const
	Gets the DT pin's current reading. More...

unsigned char	GetLastDTStatus () const
	Gets the DT pin's previous reading. More...

int	GetValue () const
	Gets the encoder's running value (increases/decreases as the knob turns). More...

bool	ConsumePressed ()
	Gets whether the push button has been pressed since the last call, then clears the pressed state so each press is reported exactly once. More...

void	SetCurrentDTStatus (char currentDTStatus)
	Sets the DT pin's current reading. More...

void	SetLastDTStatus (char lastDTStatus)
	Sets the DT pin's previous reading. More...

void	SetValue (int val)
	Sets the encoder's running value. More...

Public Member Functions inherited from RumPi::BaseComponent
	BaseComponent ()
	Builds a base component with an unknown type and an empty name. More...

virtual	~BaseComponent ()
	Virtual destructor so deleting a component through a BaseComponent* also cleans up the concrete subclass. More...

virtual void	TurnOn ()=0
	Turns the component on (e.g. More...

virtual void	TurnOff ()=0
	Turns the component off. More...

virtual std::string	ToString () const =0
	Serializes the component's current readings to a string (usually JSON). More...

virtual void	ProcessRawValues ()=0
	Reads and processes the component's latest raw values (called once per poll). More...

virtual EComponentType	GetComponentType () const
	Gets the component's type. More...

const std::string &	GetName () const
	Gets the component's unique per-instance name. More...

void	SetName (const std::string &name)
	Sets the component's unique per-instance name. More...

Private Member Functions
void	Update ()
	The listener-thread loop: watches the CLK/DT pins and increments or decrements the value based on the rotation direction, until the encoder is turned off. More...

Static Private Member Functions
static void	OnButtonPressedInterrupt ()
	Interrupt callback for the push-button pin. More...

Private Attributes
std::thread	myListenerThread
	The background thread that watches the encoder pins and updates the value. More...

std::atomic< bool >	myIsRunning
	Whether the listener thread should keep running. More...

unsigned int	myCLKPinNumber
	The CLK (clock) pin. More...

unsigned int	myDTPinNumber
	The DT (data) pin. More...

unsigned int	mySWPinNumber
	The SW (switch / push-button) pin. More...

std::atomic< unsigned char >	myCurrentDTStatus
	The DT pin's current reading (used to detect rotation direction). More...

std::atomic< unsigned char >	myLastDTStatus
	The DT pin's previous reading (used to detect rotation direction). More...

std::atomic< int >	myValue
	The running value, incremented or decremented as the knob turns. More...

std::atomic< bool >	myHasBeenPressed
	Whether the push button has been pressed since the last read (set by the interrupt callback, cleared on read). More...

Static Private Attributes
static std::atomic< RotaryEncoder * >	theActiveEncoderForISR = nullptr
	The most recently constructed encoder, so the static interrupt callback (wiringPiISR carries no user data) can reach an instance. More...

Additional Inherited Members
Static Public Member Functions inherited from RumPi::BaseComponent
static std::string	ComponentTypeToString (const EComponentType theComponentTypeToConvert)
	Maps an EComponentType to its string name. More...

static EComponentType	StringToComponentType (const std::string &theComponentTypeName)
	Maps a type name back to its EComponentType (the inverse of ComponentTypeToString), so the client can turn the type carried on the wire back into a value it can look an icon up with. More...

Protected Attributes inherited from RumPi::BaseComponent
EComponentType	myComponentType
	The kind of component this is (set by each concrete subclass). More...

std::string	myName
	A unique per-instance name, assigned when the component is added to the manager. More...

Detailed Description

A standard rotary encoder.

A background listener thread watches the CLK/DT pins and updates a running value (turned up or down as the knob rotates); the SW pin is a push button.

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ RotaryEncoder()

RumPi::RotaryEncoder::RotaryEncoder	(	unsigned int	clkPinNumber,
		unsigned int	dtPinNumber,
		unsigned int	swPinNumber
	)

Builds a rotary encoder on the given CLK/DT/SW pins, sets them as inputs, registers this as the active encoder for the interrupt callback, and hooks a falling-edge interrupt on the push-button pin.

Author: Eddie O'Hagan

Date: 8/13/2026

RotaryEncoder encoder(PIN_GPIO_17, PIN_GPIO_18, PIN_GPIO_27);

encoder.TurnOn();

RumPi::RotaryEncoder::RotaryEncoder

RotaryEncoder(unsigned int clkPinNumber, unsigned int dtPinNumber, unsigned int swPinNumber)

Builds a rotary encoder on the given CLK/DT/SW pins, sets them as inputs, registers this as the activ...

Definition: RotaryEncoder.cpp:25

RumPi::PIN_GPIO_17

constexpr unsigned int PIN_GPIO_17

BCM GPIO pin 17.

Definition: Common.h:43

RumPi::PIN_GPIO_18

constexpr unsigned int PIN_GPIO_18

BCM GPIO pin 18.

Definition: Common.h:44

RumPi::PIN_GPIO_27

constexpr unsigned int PIN_GPIO_27

BCM GPIO pin 27.

Definition: Common.h:53

Parameters

[in]	clkPinNumber	The CLK (clock) pin.
[in]	dtPinNumber	The DT (data) pin.
[in]	swPinNumber	The SW (switch / push-button) pin.

◆ ~RotaryEncoder()

RumPi::RotaryEncoder::~RotaryEncoder ( )

virtual

Destroys the encoder, stopping and joining its listener thread first.

Author: Eddie O'Hagan

Date: 8/13/2026

RotaryEncoder* encoder = new RotaryEncoder(17, 18, 27);

delete encoder;

Member Function Documentation

◆ ConsumePressed()

bool RumPi::RotaryEncoder::ConsumePressed ( )

Gets whether the push button has been pressed since the last call, then clears the pressed state so each press is reported exactly once.

Author: Eddie O'Hagan

Date: 8/13/2026

if (encoder.ConsumePressed() == true)
{
  //button was pressed...
}

Returns: true if the button was pressed since the last call; false otherwise. Reading clears the pressed state.

◆ GetCLKPinNumber()

unsigned int RumPi::RotaryEncoder::GetCLKPinNumber ( ) const

Gets the CLK (clock) pin number.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned int clk = encoder.GetCLKPinNumber();

Returns: The CLK pin number.

◆ GetCurrentDTStatus()

unsigned char RumPi::RotaryEncoder::GetCurrentDTStatus ( ) const

Gets the DT pin's current reading.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned char dtNow = encoder.GetCurrentDTStatus();

Returns: The DT pin's current reading.

◆ GetDTPinNumber()

unsigned int RumPi::RotaryEncoder::GetDTPinNumber ( ) const

Gets the DT (data) pin number.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned int dt = encoder.GetDTPinNumber();

Returns: The DT pin number.

◆ GetLastDTStatus()

unsigned char RumPi::RotaryEncoder::GetLastDTStatus ( ) const

Gets the DT pin's previous reading.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned char dtPrev = encoder.GetLastDTStatus();

Returns: The DT pin's previous reading.

◆ GetSWPinNumber()

unsigned int RumPi::RotaryEncoder::GetSWPinNumber ( ) const

Gets the SW (switch / push-button) pin number.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned int sw = encoder.GetSWPinNumber();

Returns: The SW pin number.

◆ GetValue()

int RumPi::RotaryEncoder::GetValue ( ) const

Gets the encoder's running value (increases/decreases as the knob turns).

Author: Eddie O'Hagan

Date: 8/13/2026

int value = encoder.GetValue();

Returns: The current running value.

◆ OnButtonPressedInterrupt()

void RumPi::RotaryEncoder::OnButtonPressedInterrupt ( )

staticprivate

Interrupt callback for the push-button pin.

Reports that a push was detected and latches it on the active encoder so ConsumePressed() reports it.

Author: Eddie O'Hagan

Date: 8/13/2026

//Hooked in the constructor:

wiringPiISR(mySWPinNumber, INT_EDGE_FALLING, &OnButtonPressedInterrupt);

RumPi::RotaryEncoder::OnButtonPressedInterrupt

static void OnButtonPressedInterrupt()

Interrupt callback for the push-button pin.

Definition: RotaryEncoder.cpp:151

RumPi::RotaryEncoder::mySWPinNumber

unsigned int mySWPinNumber

The SW (switch / push-button) pin.

Definition: RotaryEncoder.h:35

◆ ProcessRawValues()

void RumPi::RotaryEncoder::ProcessRawValues ( )

overridevirtual

Processes the encoder's raw values.

The listener thread already keeps the value current, so there is nothing to do here each poll - this is a no-op.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.ProcessRawValues(); //no-op; the listener thread does the work.

Implements RumPi::BaseComponent.

◆ SetCurrentDTStatus()

void RumPi::RotaryEncoder::SetCurrentDTStatus ( char currentDTStatus )

Sets the DT pin's current reading.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.SetCurrentDTStatus((char)digitalRead(dtPin));

Parameters

[in] currentDTStatus The DT pin's current reading.

◆ SetLastDTStatus()

void RumPi::RotaryEncoder::SetLastDTStatus ( char lastDTStatus )

Sets the DT pin's previous reading.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.SetLastDTStatus((char)digitalRead(dtPin));

Parameters

[in] lastDTStatus The DT pin's previous reading.

◆ SetValue()

void RumPi::RotaryEncoder::SetValue ( int val )

Sets the encoder's running value.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.SetValue(0); //reset the value.

Parameters

[in] val The new running value.

◆ ToString()

std::string RumPi::RotaryEncoder::ToString ( ) const

overridevirtual

Serializes the encoder's pins, value, and pressed state to a string.

Author: Eddie O'Hagan

Date: 8/13/2026

std::string data = encoder.ToString();

Returns: A multi-line string describing the encoder.

Implements RumPi::BaseComponent.

◆ TurnOff()

void RumPi::RotaryEncoder::TurnOff ( )

overridevirtual

Turns the encoder off: signals the listener thread to stop and waits for it to finish.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.TurnOff();

Implements RumPi::BaseComponent.

◆ TurnOn()

void RumPi::RotaryEncoder::TurnOn ( )

overridevirtual

Turns the encoder on: starts the background listener thread that watches the pins and updates the value.

Author: Eddie O'Hagan

Date: 8/13/2026

encoder.TurnOn();

Implements RumPi::BaseComponent.

◆ Update()

void RumPi::RotaryEncoder::Update ( )

private

The listener-thread loop: watches the CLK/DT pins and increments or decrements the value based on the rotation direction, until the encoder is turned off.

Runs on its own thread.

Author: Eddie O'Hagan

Date: 8/13/2026

//Launched on its own thread by TurnOn():

myListenerThread = std::thread(&RotaryEncoder::Update, this);

RumPi::RotaryEncoder::myListenerThread

std::thread myListenerThread

The background thread that watches the encoder pins and updates the value.

Definition: RotaryEncoder.h:23

RumPi::RotaryEncoder::Update

void Update()

The listener-thread loop: watches the CLK/DT pins and increments or decrements the value based on the...

Definition: RotaryEncoder.cpp:176

Member Data Documentation

◆ myCLKPinNumber

unsigned int RumPi::RotaryEncoder::myCLKPinNumber

private

The CLK (clock) pin.

◆ myCurrentDTStatus

std::atomic<unsigned char> RumPi::RotaryEncoder::myCurrentDTStatus

private

The DT pin's current reading (used to detect rotation direction).

◆ myDTPinNumber

unsigned int RumPi::RotaryEncoder::myDTPinNumber

private

The DT (data) pin.

◆ myHasBeenPressed

std::atomic<bool> RumPi::RotaryEncoder::myHasBeenPressed

private

Whether the push button has been pressed since the last read (set by the interrupt callback, cleared on read).

◆ myIsRunning

std::atomic<bool> RumPi::RotaryEncoder::myIsRunning

private

Whether the listener thread should keep running.

◆ myLastDTStatus

std::atomic<unsigned char> RumPi::RotaryEncoder::myLastDTStatus

private

The DT pin's previous reading (used to detect rotation direction).

◆ myListenerThread

std::thread RumPi::RotaryEncoder::myListenerThread

private

The background thread that watches the encoder pins and updates the value.

◆ mySWPinNumber

unsigned int RumPi::RotaryEncoder::mySWPinNumber

private

The SW (switch / push-button) pin.

◆ myValue

std::atomic<int> RumPi::RotaryEncoder::myValue

private

The running value, incremented or decremented as the knob turns.

◆ theActiveEncoderForISR

std::atomic< RotaryEncoder * > RumPi::RotaryEncoder::theActiveEncoderForISR = nullptr

staticprivate

The most recently constructed encoder, so the static interrupt callback (wiringPiISR carries no user data) can reach an instance.

Single active instance: a newer encoder replaces an older one.

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

Source/Headers/RumPi/Components/RotaryEncoder.h
Source/Implementations/RumPi/Components/RotaryEncoder.cpp

Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ RotaryEncoder()

◆ ~RotaryEncoder()

Member Function Documentation

◆ ConsumePressed()

◆ GetCLKPinNumber()

◆ GetCurrentDTStatus()

◆ GetDTPinNumber()

◆ GetLastDTStatus()

◆ GetSWPinNumber()

◆ GetValue()

◆ OnButtonPressedInterrupt()

◆ ProcessRawValues()

◆ SetCurrentDTStatus()

◆ SetLastDTStatus()

◆ SetValue()

◆ ToString()

◆ TurnOff()

◆ TurnOn()

◆ Update()

Member Data Documentation

◆ myCLKPinNumber

◆ myCurrentDTStatus

◆ myDTPinNumber

◆ myHasBeenPressed

◆ myIsRunning

◆ myLastDTStatus

◆ myListenerThread

◆ mySWPinNumber

◆ myValue

◆ theActiveEncoderForISR