Gas data (its response curve and danger level) used by the MQ gas sensors. More...

#include <GasData.h>

Public Member Functions
	GasData ()
	Builds an empty GasData with all curve values sentinel-initialized to INT_MIN. More...

	GasData (const EGasType &gasType, const double &gasSlope, const double &gasYIntercept, const double &startX, const double &startY, const double &middleX, const double &middleY, const double &lastX, const double &lastY, const double &dangerLevel, const bool &isUsingDataCache)
	Builds a GasData from an explicit slope and y-intercept plus its three graph points. More...

	GasData (const EGasType &gasType, const double &startX, const double &startY, const double &middleX, const double &middleY, const double &lastX, const double &lastY, const double &dangerLevel, const bool &isUsingDataCache)
	Builds a GasData from its three graph points, computing the slope and y-intercept from them. More...

	GasData (const EGasType &gasType, const double &gasSlope, const double &gasYIntercept, const double &dangerLevel, const bool &isUsingDataCache)
	Builds a GasData from an explicit slope and y-intercept, leaving the graph points sentinel-initialized. More...

virtual	~GasData ()
	Destroys the GasData. More...

double	CalculateSlope ()
	Computes the response curve's slope (m) from the first and last graph points, using base-10 logs. More...

double	CalculateYIntercept ()
	Computes the response curve's y-intercept (b) from the middle graph point, calculating the slope first if needed. More...

std::string	ToString () const
	Serializes the gas name, slope, and y-intercept to a string. More...

const char *	GetGasName () const
	Gets the human-readable name of this data's gas type. More...

EGasType	GetGasType () const
	Gets the gas type this data describes. More...

double	GetGasSlope ()
	Gets the response curve's slope (m), calculating it first if it has not been computed yet. More...

double	GetGasYIntercept () const
	Gets the response curve's y-intercept (b). More...

double	GetFirstX () const
	Gets the x of the first graph point. More...

double	GetFirstY () const
	Gets the y of the first graph point. More...

double	GetMiddleX () const
	Gets the x of the middle graph point. More...

double	GetMiddleY () const
	Gets the y of the middle graph point. More...

double	GetLastX () const
	Gets the x of the last graph point. More...

double	GetLastY () const
	Gets the y of the last graph point. More...

double	GetDangerLevel () const
	Gets the concentration (ppm) considered dangerous for this gas. More...

double	GetDataCacheValueAtIndex (const int &index) const
	Gets a cached value at the given raw-analog index, or 0 if the index is out of range. More...

bool	GetIsUsingDataCache () const
	Gets whether this gas sensor uses the data cache for its calculations. More...

void	SetGasSlope (const double &slope)
	Sets the response curve's slope (m). More...

void	SetGasYIntercept (const double &yIntercept)
	Sets the response curve's y-intercept (b). More...

void	SetFirstX (const double &firstX)
	Sets the x of the first graph point. More...

void	SetFirstY (const double &firstY)
	Sets the y of the first graph point. More...

void	SetMiddleX (const double &middleX)
	Sets the x of the middle graph point. More...

void	SetMiddleY (const double &middleY)
	Sets the y of the middle graph point. More...

void	SetLastX (const double &lastX)
	Sets the x of the last graph point. More...

void	SetLastY (const double &lastY)
	Sets the y of the last graph point. More...

void	SetDangerLevel (const double &dangerLevel)
	Sets the concentration (ppm) considered dangerous for this gas. More...

void	SetDataCacheValueAtIndex (const int &index, const double &value)
	Sets a cached value at the given raw-analog index, ignoring out-of-range indices. More...

void	SetIsUsingDataCache (const bool &isUsingDataCache)
	Sets whether this gas sensor uses the data cache for its calculations. More...

Static Public Member Functions
static const char *	GetGasName (const EGasType &gasType)
	Gets the human-readable name for a given gas type. More...

Static Public Attributes
static const int	MAX_ANALOG_VALUE = 1023
	The maximum 10-bit raw analog reading. More...

Private Attributes
EGasType	myGasType
	The type of gas this data corresponds to. More...

double	myGasSlope
	The m in "y = mx + b". More...

double	myGasYIntercept
	The b in "y = mx + b". More...

double	myFirstX
	The x in the first point on the graph. More...

double	myFirstY
	The y in the first point on the graph. More...

double	myMiddleX
	The x in-between the start and last. More...

double	myMiddleY
	The y in-between the start and last. More...

double	myLastX
	The x for the last point on the graph. More...

double	myLastY
	The y for the last point on the graph. More...

double	myDangerLevel
	The amount considered dangerous for this gas in ppm. More...

double	myDataCache [MAX_ANALOG_VALUE+1] = {}
	Cache of expensive calculations (e.g. BAC in the MQ-3). Zero-initialized; filled by cache-using sensors. More...

bool	myIsUsingDataCache
	True if this gas sensor uses the data cache for calculations instead of slope and intercept. More...

Detailed Description

Gas data (its response curve and danger level) used by the MQ gas sensors.

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ GasData() [1/4]

RumPi::GasData::GasData ( )

Builds an empty GasData with all curve values sentinel-initialized to INT_MIN.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData data;

RumPi::GasData::GasData

GasData()

Builds an empty GasData with all curve values sentinel-initialized to INT_MIN.

Definition: GasData.cpp:15

◆ GasData() [2/4]

RumPi::GasData::GasData	(	const EGasType &	gasType,
		const double &	gasSlope,
		const double &	gasYIntercept,
		const double &	startX,
		const double &	startY,
		const double &	middleX,
		const double &	middleY,
		const double &	lastX,
		const double &	lastY,
		const double &	dangerLevel,
		const bool &	isUsingDataCache
	)

Builds a GasData from an explicit slope and y-intercept plus its three graph points.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData data(EGasType::E_Smoke, 1.5, 2.0, 200.0, 1.75, 1000.0, 0.99, 10000.0, 0.44, 1000.0, true);

RumPi::E_Smoke

@ E_Smoke

Definition: GasData.h:29

Parameters

[in]	gasType	The type of gas this data describes.
[in]	gasSlope	The slope (m) of the response curve.
[in]	gasYIntercept	The y-intercept (b) of the response curve.
[in]	startX	The x of the first graph point.
[in]	startY	The y of the first graph point.
[in]	middleX	The x of the middle graph point.
[in]	middleY	The y of the middle graph point.
[in]	lastX	The x of the last graph point.
[in]	lastY	The y of the last graph point.
[in]	dangerLevel	The concentration (ppm) considered dangerous for this gas.
[in]	isUsingDataCache	True if the sensor uses a cache instead of slope/intercept.

◆ GasData() [3/4]

RumPi::GasData::GasData	(	const EGasType &	gasType,
		const double &	startX,
		const double &	startY,
		const double &	middleX,
		const double &	middleY,
		const double &	lastX,
		const double &	lastY,
		const double &	dangerLevel,
		const bool &	isUsingDataCache
	)

Builds a GasData from its three graph points, computing the slope and y-intercept from them.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData data(EGasType::E_Smoke, 200.0, 1.75, 1000.0, 0.99, 10000.0, 0.44, 1000.0, true);

Parameters

[in]	gasType	The type of gas this data describes.
[in]	startX	The x of the first graph point.
[in]	startY	The y of the first graph point.
[in]	middleX	The x of the middle graph point.
[in]	middleY	The y of the middle graph point.
[in]	lastX	The x of the last graph point.
[in]	lastY	The y of the last graph point.
[in]	dangerLevel	The concentration (ppm) considered dangerous for this gas.
[in]	isUsingDataCache	True if the sensor uses a cache instead of slope/intercept.

◆ GasData() [4/4]

RumPi::GasData::GasData	(	const EGasType &	gasType,
		const double &	gasSlope,
		const double &	gasYIntercept,
		const double &	dangerLevel,
		const bool &	isUsingDataCache
	)

Builds a GasData from an explicit slope and y-intercept, leaving the graph points sentinel-initialized.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData data(EGasType::E_Alcohol, 2.2984, 0.5302, 1000.0, true);

RumPi::E_Alcohol

@ E_Alcohol

Definition: GasData.h:15

Parameters

[in]	gasType	The type of gas this data describes.
[in]	gasSlope	The slope (m) of the response curve.
[in]	gasYIntercept	The y-intercept (b) of the response curve.
[in]	dangerLevel	The concentration (ppm) considered dangerous for this gas.
[in]	isUsingDataCache	True if the sensor uses a cache instead of slope/intercept.

◆ ~GasData()

RumPi::GasData::~GasData ( )

virtual

Destroys the GasData.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData* data = new GasData();

delete data;

Member Function Documentation

◆ CalculateSlope()

double RumPi::GasData::CalculateSlope ( )

Computes the response curve's slope (m) from the first and last graph points, using base-10 logs.

Author: Eddie O'Hagan

Date: 8/13/2026

double slope = data.CalculateSlope();

Returns: The computed slope (m), which is also cached in the object.

◆ CalculateYIntercept()

double RumPi::GasData::CalculateYIntercept ( )

Computes the response curve's y-intercept (b) from the middle graph point, calculating the slope first if needed.

Author: Eddie O'Hagan

Date: 8/13/2026

double yIntercept = data.CalculateYIntercept();

Returns: The computed y-intercept (b), which is also cached in the object.

◆ GetDangerLevel()

double RumPi::GasData::GetDangerLevel ( ) const

Gets the concentration (ppm) considered dangerous for this gas.

Author: Eddie O'Hagan

Date: 8/13/2026

double dangerLevel = data.GetDangerLevel();

Returns: The danger level, in ppm.

◆ GetDataCacheValueAtIndex()

double RumPi::GasData::GetDataCacheValueAtIndex ( const int & index ) const

Gets a cached value at the given raw-analog index, or 0 if the index is out of range.

Author: Eddie O'Hagan

Date: 8/13/2026

double ppm = data.GetDataCacheValueAtIndex(512);

Parameters

[in] index The raw analog value (0 to MAX_ANALOG_VALUE) to look up.

Returns: The cached value, or 0 if the index is out of range.

◆ GetFirstX()

double RumPi::GasData::GetFirstX ( ) const

Gets the x of the first graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double firstX = data.GetFirstX();

Returns: The x of the first graph point.

◆ GetFirstY()

double RumPi::GasData::GetFirstY ( ) const

Gets the y of the first graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double firstY = data.GetFirstY();

Returns: The y of the first graph point.

◆ GetGasName() [1/2]

const char * RumPi::GasData::GetGasName ( ) const

Gets the human-readable name of this data's gas type.

Author: Eddie O'Hagan

Date: 8/13/2026

const char* name = data.GetGasName();

Returns: The gas name (e.g. "Propane (C3H8)").

◆ GetGasName() [2/2]

const char * RumPi::GasData::GetGasName ( const EGasType & gasType )

static

Gets the human-readable name for a given gas type.

Author: Eddie O'Hagan

Date: 8/13/2026

const char* name = GasData::GetGasName(EGasType::E_Propane);

RumPi::GasData::GetGasName

const char * GetGasName() const

Gets the human-readable name of this data's gas type.

Definition: GasData.cpp:216

RumPi::E_Propane

@ E_Propane

Definition: GasData.h:28

Output: Propane (C3H8)

Parameters

[in] gasType The gas type to name.

Returns: The gas name, or "UNKNOWN" if the type is unrecognized.

◆ GetGasSlope()

double RumPi::GasData::GetGasSlope ( )

Gets the response curve's slope (m), calculating it first if it has not been computed yet.

Author: Eddie O'Hagan

Date: 8/13/2026

double slope = data.GetGasSlope();

Returns: The slope (m) of the response curve.

◆ GetGasType()

EGasType RumPi::GasData::GetGasType ( ) const

Gets the gas type this data describes.

Author: Eddie O'Hagan

Date: 8/13/2026

EGasType type = data.GetGasType();

RumPi::EGasType

EGasType

The types of gas the MQ sensor family can detect.

Definition: GasData.h:13

Returns: The gas type.

◆ GetGasYIntercept()

double RumPi::GasData::GetGasYIntercept ( ) const

Gets the response curve's y-intercept (b).

Author: Eddie O'Hagan

Date: 8/13/2026

double yIntercept = data.GetGasYIntercept();

Returns: The y-intercept (b) of the response curve.

◆ GetIsUsingDataCache()

bool RumPi::GasData::GetIsUsingDataCache ( ) const

Gets whether this gas sensor uses the data cache for its calculations.

Author: Eddie O'Hagan

Date: 8/13/2026

bool usingCache = data.GetIsUsingDataCache();

Returns: True if the data cache is used instead of slope/intercept.

◆ GetLastX()

double RumPi::GasData::GetLastX ( ) const

Gets the x of the last graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double lastX = data.GetLastX();

Returns: The x of the last graph point.

◆ GetLastY()

double RumPi::GasData::GetLastY ( ) const

Gets the y of the last graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double lastY = data.GetLastY();

Returns: The y of the last graph point.

◆ GetMiddleX()

double RumPi::GasData::GetMiddleX ( ) const

Gets the x of the middle graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double middleX = data.GetMiddleX();

Returns: The x of the middle graph point.

◆ GetMiddleY()

double RumPi::GasData::GetMiddleY ( ) const

Gets the y of the middle graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

double middleY = data.GetMiddleY();

Returns: The y of the middle graph point.

◆ SetDangerLevel()

void RumPi::GasData::SetDangerLevel ( const double & dangerLevel )

Sets the concentration (ppm) considered dangerous for this gas.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetDangerLevel(1000.0);

Parameters

[in] dangerLevel The danger level, in ppm.

◆ SetDataCacheValueAtIndex()

void RumPi::GasData::SetDataCacheValueAtIndex	(	const int &	index,
		const double &	value
	)

Sets a cached value at the given raw-analog index, ignoring out-of-range indices.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetDataCacheValueAtIndex(512, 42.0);

Parameters

[in]	index	The raw analog value (0 to MAX_ANALOG_VALUE) to write.
[in]	value	The value to cache at that index.

◆ SetFirstX()

void RumPi::GasData::SetFirstX ( const double & firstX )

Sets the x of the first graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetFirstX(200.0);

Parameters

[in] firstX The x of the first graph point.

◆ SetFirstY()

void RumPi::GasData::SetFirstY ( const double & firstY )

Sets the y of the first graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetFirstY(1.75);

Parameters

[in] firstY The y of the first graph point.

◆ SetGasSlope()

void RumPi::GasData::SetGasSlope ( const double & slope )

Sets the response curve's slope (m).

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetGasSlope(1.5);

Parameters

[in] slope The slope (m) to set.

◆ SetGasYIntercept()

void RumPi::GasData::SetGasYIntercept ( const double & yIntercept )

Sets the response curve's y-intercept (b).

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetGasYIntercept(2.0);

Parameters

[in] yIntercept The y-intercept (b) to set.

◆ SetIsUsingDataCache()

void RumPi::GasData::SetIsUsingDataCache ( const bool & isUsingDataCache )

Sets whether this gas sensor uses the data cache for its calculations.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetIsUsingDataCache(true);

Parameters

[in] isUsingDataCache True to use the data cache instead of slope/intercept.

◆ SetLastX()

void RumPi::GasData::SetLastX ( const double & lastX )

Sets the x of the last graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetLastX(10000.0);

Parameters

[in] lastX The x of the last graph point.

◆ SetLastY()

void RumPi::GasData::SetLastY ( const double & lastY )

Sets the y of the last graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetLastY(0.44);

Parameters

[in] lastY The y of the last graph point.

◆ SetMiddleX()

void RumPi::GasData::SetMiddleX ( const double & middleX )

Sets the x of the middle graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetMiddleX(1000.0);

Parameters

[in] middleX The x of the middle graph point.

◆ SetMiddleY()

void RumPi::GasData::SetMiddleY ( const double & middleY )

Sets the y of the middle graph point.

Author: Eddie O'Hagan

Date: 8/13/2026

data.SetMiddleY(0.99);

Parameters

[in] middleY The y of the middle graph point.

◆ ToString()

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

Serializes the gas name, slope, and y-intercept to a string.

Author: Eddie O'Hagan

Date: 8/13/2026

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

Returns: A string describing the gas data.

Member Data Documentation

◆ MAX_ANALOG_VALUE

const int RumPi::GasData::MAX_ANALOG_VALUE = 1023

static

The maximum 10-bit raw analog reading.

◆ myDangerLevel

double RumPi::GasData::myDangerLevel

private

The amount considered dangerous for this gas in ppm.

◆ myDataCache

double RumPi::GasData::myDataCache[MAX_ANALOG_VALUE+1] = {}

private

Cache of expensive calculations (e.g. BAC in the MQ-3). Zero-initialized; filled by cache-using sensors.

◆ myFirstX

double RumPi::GasData::myFirstX

private

The x in the first point on the graph.

◆ myFirstY

double RumPi::GasData::myFirstY

private

The y in the first point on the graph.

◆ myGasSlope

double RumPi::GasData::myGasSlope

private

The m in "y = mx + b".

◆ myGasType

EGasType RumPi::GasData::myGasType

private

The type of gas this data corresponds to.

◆ myGasYIntercept

double RumPi::GasData::myGasYIntercept

private

The b in "y = mx + b".

◆ myIsUsingDataCache

bool RumPi::GasData::myIsUsingDataCache

private

True if this gas sensor uses the data cache for calculations instead of slope and intercept.

◆ myLastX

double RumPi::GasData::myLastX

private

The x for the last point on the graph.

◆ myLastY

double RumPi::GasData::myLastY

private

The y for the last point on the graph.

◆ myMiddleX

double RumPi::GasData::myMiddleX

private

The x in-between the start and last.

◆ myMiddleY

double RumPi::GasData::myMiddleY

private

The y in-between the start and last.

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

Source/Headers/RumPi/Data/GasData.h
Source/Implementations/RumPi/Data/GasData.cpp

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ GasData() [1/4]

◆ GasData() [2/4]

◆ GasData() [3/4]

◆ GasData() [4/4]

◆ ~GasData()

Member Function Documentation

◆ CalculateSlope()

◆ CalculateYIntercept()

◆ GetDangerLevel()

◆ GetDataCacheValueAtIndex()

◆ GetFirstX()

◆ GetFirstY()

◆ GetGasName() [1/2]

◆ GetGasName() [2/2]

◆ GetGasSlope()

◆ GetGasType()

◆ GetGasYIntercept()

◆ GetIsUsingDataCache()

◆ GetLastX()

◆ GetLastY()

◆ GetMiddleX()

◆ GetMiddleY()

◆ SetDangerLevel()

◆ SetDataCacheValueAtIndex()

◆ SetFirstX()

◆ SetFirstY()

◆ SetGasSlope()

◆ SetGasYIntercept()

◆ SetIsUsingDataCache()

◆ SetLastX()

◆ SetLastY()

◆ SetMiddleX()

◆ SetMiddleY()

◆ ToString()

Member Data Documentation

◆ MAX_ANALOG_VALUE

◆ myDangerLevel

◆ myDataCache

◆ myFirstX

◆ myFirstY

◆ myGasSlope

◆ myGasType

◆ myGasYIntercept

◆ myIsUsingDataCache

◆ myLastX

◆ myLastY

◆ myMiddleX

◆ myMiddleY