Base class for the MQ-series gas sensors (MQ2, MQ7, ...). More...

#include <GasSensor.h>

Inheritance diagram for RumPi::GasSensor:

Collaboration diagram for RumPi::GasSensor:

Public Member Functions
virtual void	CalculateInitialR0 ()
	Calibrates the sensor: computes and stores its clean-air resistance (R0). More...

	GasSensor ()
	Builds a default gas sensor with zeroed calibration values and no ADC or digital pin. More...

	GasSensor (IAnalogDigitalConverterComponent *analogToDigitalConverter, const EComponentType &gasSensorType, const unsigned int &analogToDigitalConverterIndex, const unsigned int &digitalOutputPinNumber)
	Builds an analog gas sensor that reads through an ADC and also exposes a digital threshold pin. More...

	GasSensor (IAnalogDigitalConverterComponent *analogToDigitalConverter, const EComponentType &gasSensorType, const unsigned int &analogToDigitalConverterIndex)
	Builds an analog-only gas sensor that reads through an ADC (no digital threshold pin). More...

	GasSensor (const EComponentType &gasSensorType, const unsigned int &digitalOutputPinNumber)
	Builds a digital-only gas sensor that reports only its threshold-output pin (no ADC). More...

virtual	~GasSensor ()
	Destroys the gas sensor, turning it off first. More...

virtual void	TurnOn ()
	Turns the sensor on. More...

virtual void	TurnOff ()
	Turns the sensor off. More...

virtual void	Initialize ()
	Initializes the sensor's datasheet values. More...

int	ReadRawAnalogValue () const
	Reads the raw analog value from the sensor's ADC channel. More...

int	ReadDigitalValue ()
	Reads the sensor's digital threshold-output pin (1 when the configured gas threshold is exceeded). More...

virtual double	ReadGasValue () const
	Gets the most recently processed gas value. More...

virtual void	ProcessRawValues () override
	Reads the sensor and computes the current gas value (PPM) from the RS/R0 ratio using the datasheet's log-log curve. More...

virtual std::string	ToString () const override
	Serializes the sensor's current gas value (PPM), a rough percentage, and the raw reading to a string. More...

unsigned int	GetAnalogToDigitalConverterIndex () const
	Gets the ADC channel index this sensor reads from. More...

unsigned int	GetDigitalOutputPinNumber () const
	Gets the digital threshold-output pin (UINT_MAX if unused). More...

double	GetInitialValueR0 () const
	Gets the sensor's clean-air resistance (R0) from calibration. More...

double	GetResistorValueRL () const
	Gets the load resistor value (RL) from the sensor's datasheet. More...

double	GetCurrentValueRS () const
	Gets the sensor's current resistance (RS). More...

const char *	GetDetectibleConcentration () const
	Gets a human-readable detectable-concentration range for this sensor. More...

EComponentType	GetGasSensorType () const
	Gets this sensor's component type (which MQ sensor it is). More...

const char *	GetGasSensorTypeAsString () const
	Gets this sensor's type as a display string (e.g. More...

const char *	GetGasSensorTypeAsString (const EComponentType &gasSensorType) const
	Maps a gas-sensor component type to its display string (e.g. More...

IAnalogDigitalConverterComponent *	GetAnalogDigitalConverter () const
	Gets the ADC this sensor reads its analog value through. More...

const GasData &	GetGasData () const
	Gets the per-gas curve data (slope/intercept and concentration points) for this sensor. 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...

Static Public Attributes
static constexpr double	GAS_SENSOR_VOLTAGE = 5.0
	The supply voltage the gas sensor runs on. More...

static const int	CALIBRATION_SAMPLE_TIMES = 200
	The number of samples taken during the calibration phase. More...

static const int	CALIBRATION_SAMPLE_INTERVAL = 250
	Milliseconds between samples during the calibration phase. More...

static const int	READ_SAMPLE_INTERVAL = 250
	Milliseconds between samples during normal operation. More...

Protected Member Functions
virtual double	CalculateR0 ()
	Samples the sensor many times in clean air, averages the reading, converts it to resistance (RS), and divides by the clean-air factor to get R0. More...

virtual double	CalculateRS (const double &sensorValueInVolts) const
	Computes the sensor's resistance (RS) from its output voltage, using the load resistor RL and supply voltage. More...

virtual double	CalculateRSR0Ratio (const double &sensorValueInVolts) const
	Computes the RS/R0 ratio (used to look up PPM on the datasheet curve) from the sensor's output voltage. More...

double	ConvertRawSensorValueToVolts (const double &rawGasSensorValue) const
	Converts a raw analog reading to its equivalent voltage (using the sensor's supply voltage and the ADC's maximum value). More...

double	ConvertVoltsToRawSensorValue (const double &volts) const
	Converts a voltage back to its equivalent raw analog value (the inverse of ConvertRawSensorValueToVolts). More...

double	GetAnalogToDigitalConverterMaxRawValue () const
	Gets the ADC's full-scale raw count for scaling raw readings to volts (PCF8591 = 255 8-bit, MCP3008 = 1023 10-bit), falling back to the 10-bit convention when no ADC is wired. More...

double	GetAnalogToDigitalConverterVoltage () const
	Gets the ADC's reference voltage for scaling raw readings to volts (defined by the wired ADC, e.g. More...

Protected Attributes
unsigned int	myAnalogToDigitalConverterIndex
	The ADC channel index this sensor reads its analog value from. More...

unsigned int	myDigitalOutputPinNumber
	The digital output (threshold) pin, or UINT_MAX if unused. More...

double	myInitialValueR0
	The sensor's resistance in clean air (R0), from calibration. More...

double	myResistorValueRL
	The load resistor value (RL) from the sensor's datasheet. More...

double	myCurrentValueRS
	The sensor's current resistance (RS). More...

double	myCleanAirFactor
	The clean-air factor (RS/R0 in clean air) from the datasheet. More...

double	myRawGasSensorValue
	The most recent raw analog reading. More...

double	myCurrentGasValue
	The most recent computed gas value (PPM). More...

const char *	myDetectibleConcentration
	A human-readable detectable-concentration range for this sensor. More...

IAnalogDigitalConverterComponent *	myAnalogToDigitalConverter
	The ADC this sensor reads its analog value through. More...

GasData	myGasData
	Per-gas curve data (slope/intercept) used to convert the RS/R0 ratio to PPM. 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...

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...

Detailed Description

Base class for the MQ-series gas sensors (MQ2, MQ7, ...).

An MQ sensor's value only reflects the approximate trend of gas concentration within a permissible error range - it does NOT represent an exact concentration. The R0/RL/RS/CleanAirFactor references come from the various MQ-X datasheets (https://www.mysensors.org/build/gas/).

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ GasSensor() [1/4]

RumPi::GasSensor::GasSensor ( )

Builds a default gas sensor with zeroed calibration values and no ADC or digital pin.

Subclasses (e.g. MQ2) fill in their datasheet values via Initialize().

Author: Eddie O'Hagan

Date: 8/13/2026

//Called by a subclass's default constructor, e.g. MQ2().

◆ GasSensor() [2/4]

RumPi::GasSensor::GasSensor	(	IAnalogDigitalConverterComponent *	analogToDigitalConverter,
		const EComponentType &	gasSensorType,
		const unsigned int &	analogToDigitalConverterIndex,
		const unsigned int &	digitalOutputPinNumber
	)

Builds an analog gas sensor that reads through an ADC and also exposes a digital threshold pin.

Author: Eddie O'Hagan

Date: 8/13/2026

//Called by a subclass, e.g. MQ2(adc, index, digitalPin).

Parameters

[in]	analogToDigitalConverter	The ADC the sensor reads its analog value through.
[in]	gasSensorType	The concrete sensor type (e.g. E_MQ2).
[in]	analogToDigitalConverterIndex	The ADC channel index to read.
[in]	digitalOutputPinNumber	The digital threshold-output pin.

◆ GasSensor() [3/4]

RumPi::GasSensor::GasSensor	(	IAnalogDigitalConverterComponent *	analogToDigitalConverter,
		const EComponentType &	gasSensorType,
		const unsigned int &	analogToDigitalConverterIndex
	)

Builds an analog-only gas sensor that reads through an ADC (no digital threshold pin).

Author: Eddie O'Hagan

Date: 8/13/2026

//Called by a subclass, e.g. MQ2(adc, index).

Parameters

[in]	analogToDigitalConverter	The ADC the sensor reads its analog value through.
[in]	gasSensorType	The concrete sensor type (e.g. E_MQ2).
[in]	analogToDigitalConverterIndex	The ADC channel index to read.

◆ GasSensor() [4/4]

RumPi::GasSensor::GasSensor	(	const EComponentType &	gasSensorType,
		const unsigned int &	digitalOutputPinNumber
	)

Builds a digital-only gas sensor that reports only its threshold-output pin (no ADC).

Author: Eddie O'Hagan

Date: 8/13/2026

//Called by a subclass, e.g. MQ2(digitalPin).

Parameters

[in]	gasSensorType	The concrete sensor type (e.g. E_MQ2).
[in]	digitalOutputPinNumber	The digital threshold-output pin.

◆ ~GasSensor()

RumPi::GasSensor::~GasSensor ( )

virtual

Destroys the gas sensor, turning it off first.

Author: Eddie O'Hagan

Date: 8/13/2026

GasSensor* sensor = new MQ2();

delete sensor;

RumPi::GasSensor::GasSensor

GasSensor()

Builds a default gas sensor with zeroed calibration values and no ADC or digital pin.

Definition: GasSensor.cpp:17

Member Function Documentation

◆ CalculateInitialR0()

void RumPi::GasSensor::CalculateInitialR0 ( )

virtual

Calibrates the sensor: computes and stores its clean-air resistance (R0).

Run this once in clean air before reading, so the RS/R0 ratio has a valid baseline. Public so callers can (re)calibrate after warm-up.

Author: Eddie O'Hagan

Date: 8/13/2026

sensor.CalculateInitialR0(); //call once in clean air to calibrate.

Run this in clean air.

Author: Eddie O'Hagan

Date: 8/13/2026

sensor.CalculateInitialR0(); //call once in clean air to calibrate.

◆ CalculateR0()

double RumPi::GasSensor::CalculateR0 ( )

protectedvirtual

Samples the sensor many times in clean air, averages the reading, converts it to resistance (RS), and divides by the clean-air factor to get R0.

Author: Eddie O'Hagan

Date: 8/13/2026

double r0 = sensor.CalculateR0();

Returns: The computed clean-air resistance (R0).

Reimplemented in RumPi::MQ135.

◆ CalculateRS()

double RumPi::GasSensor::CalculateRS ( const double & sensorValueInVolts ) const

protectedvirtual

Computes the sensor's resistance (RS) from its output voltage, using the load resistor RL and supply voltage.

Author: Eddie O'Hagan

Date: 8/13/2026

double rs = sensor.CalculateRS(sensorValueInVolts);

Parameters

[in] sensorValueInVolts The sensor's output voltage.

Returns: The sensor resistance (RS).

◆ CalculateRSR0Ratio()

double RumPi::GasSensor::CalculateRSR0Ratio ( const double & sensorValueInVolts ) const

protectedvirtual

Computes the RS/R0 ratio (used to look up PPM on the datasheet curve) from the sensor's output voltage.

Author: Eddie O'Hagan

Date: 8/13/2026

double ratio = sensor.CalculateRSR0Ratio(sensorValueInVolts);

Parameters

[in] sensorValueInVolts The sensor's output voltage.

Returns: The RS/R0 ratio.

◆ ConvertRawSensorValueToVolts()

double RumPi::GasSensor::ConvertRawSensorValueToVolts ( const double & rawGasSensorValue ) const

protected

Converts a raw analog reading to its equivalent voltage (using the sensor's supply voltage and the ADC's maximum value).

Converts a raw analog reading to its equivalent voltage (using the ADC's reference voltage and the ADC's maximum value).

Author: Eddie O'Hagan

Date: 8/13/2026

double volts = sensor.ConvertRawSensorValueToVolts(rawValue);

Parameters

[in] rawGasSensorValue The raw analog reading.

Returns: The equivalent voltage.

◆ ConvertVoltsToRawSensorValue()

double RumPi::GasSensor::ConvertVoltsToRawSensorValue ( const double & volts ) const

protected

Converts a voltage back to its equivalent raw analog value (the inverse of ConvertRawSensorValueToVolts).

Author: Eddie O'Hagan

Date: 8/13/2026

double raw = sensor.ConvertVoltsToRawSensorValue(volts);

Parameters

[in] volts The voltage to convert.

Returns: The equivalent raw analog value.

◆ GetAnalogDigitalConverter()

IAnalogDigitalConverterComponent * RumPi::GasSensor::GetAnalogDigitalConverter ( ) const

Gets the ADC this sensor reads its analog value through.

Author: Eddie O'Hagan

Date: 8/13/2026

IAnalogDigitalConverterComponent* adc = sensor.GetAnalogDigitalConverter();

Returns: The sensor's ADC (may be nullptr for a digital-only sensor).

◆ GetAnalogToDigitalConverterIndex()

unsigned int RumPi::GasSensor::GetAnalogToDigitalConverterIndex ( ) const

Gets the ADC channel index this sensor reads from.

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned int channel = sensor.GetAnalogToDigitalConverterIndex();

Returns: The ADC channel index.

◆ GetAnalogToDigitalConverterMaxRawValue()

double RumPi::GasSensor::GetAnalogToDigitalConverterMaxRawValue ( ) const

protected

Gets the ADC's full-scale raw count for scaling raw readings to volts (PCF8591 = 255 8-bit, MCP3008 = 1023 10-bit), falling back to the 10-bit convention when no ADC is wired.

Author: Eddie O'Hagan

Date: 8/13/2026

double fullScale = sensor.GetAnalogToDigitalConverterMaxRawValue();

Returns: The ADC's full-scale raw count, or GasData::MAX_ANALOG_VALUE if no ADC is set.

◆ GetAnalogToDigitalConverterVoltage()

double RumPi::GasSensor::GetAnalogToDigitalConverterVoltage ( ) const

protected

Gets the ADC's reference voltage for scaling raw readings to volts (defined by the wired ADC, e.g.

Gets the ADC's reference voltage for scaling raw readings to volts, falling back to the gas sensor's supply voltage when no ADC is wired.

the PCF8591's configured "adcVoltage"), falling back to the gas sensor's supply voltage when no ADC is wired.

Author: Eddie O'Hagan

Date: 8/13/2026

double vref = sensor.GetAnalogToDigitalConverterVoltage();

Returns: The ADC's reference voltage, or the gas sensor's supply voltage if no ADC is set.

Author: Eddie O'Hagan

Date: 8/13/2026

double vref = sensor.GetAnalogToDigitalConverterVoltage();

Returns: The ADC's reference voltage, or the gas sensor's supply voltage if no ADC is set.

◆ GetCurrentValueRS()

double RumPi::GasSensor::GetCurrentValueRS ( ) const

Gets the sensor's current resistance (RS).

Author: Eddie O'Hagan

Date: 8/13/2026

double rs = sensor.GetCurrentValueRS();

Returns: The RS value.

◆ GetDetectibleConcentration()

const char * RumPi::GasSensor::GetDetectibleConcentration ( ) const

Gets a human-readable detectable-concentration range for this sensor.

Author: Eddie O'Hagan

Date: 8/13/2026

const char* range = sensor.GetDetectibleConcentration();

Returns: The detectable-concentration range string.

◆ GetDigitalOutputPinNumber()

unsigned int RumPi::GasSensor::GetDigitalOutputPinNumber ( ) const

Gets the digital threshold-output pin (UINT_MAX if unused).

Author: Eddie O'Hagan

Date: 8/13/2026

unsigned int pin = sensor.GetDigitalOutputPinNumber();

Returns: The digital output pin number.

◆ GetGasData()

const GasData & RumPi::GasSensor::GetGasData ( ) const

Gets the per-gas curve data (slope/intercept and concentration points) for this sensor.

Author: Eddie O'Hagan

Date: 8/13/2026

GasData data = sensor.GetGasData();

Returns: The sensor's gas curve data.

◆ GetGasSensorType()

EComponentType RumPi::GasSensor::GetGasSensorType ( ) const

Gets this sensor's component type (which MQ sensor it is).

Author: Eddie O'Hagan

Date: 8/13/2026

EComponentType type = sensor.GetGasSensorType();

RumPi::EComponentType

EComponentType

Identifies each kind of component the library supports.

Definition: BaseComponent.h:14

Returns: The sensor's component type.

◆ GetGasSensorTypeAsString() [1/2]

const char * RumPi::GasSensor::GetGasSensorTypeAsString ( ) const

Gets this sensor's type as a display string (e.g.

"MQ-2").

Author: Eddie O'Hagan

Date: 8/13/2026

const char* name = sensor.GetGasSensorTypeAsString();

Returns: The sensor's type as a string.

◆ GetGasSensorTypeAsString() [2/2]

const char * RumPi::GasSensor::GetGasSensorTypeAsString ( const EComponentType & gasSensorType ) const

Maps a gas-sensor component type to its display string (e.g.

E_MQ2 -> "MQ-2").

Author: Eddie O'Hagan

Date: 8/13/2026

const char* name = sensor.GetGasSensorTypeAsString(EComponentType::E_MQ7); //"MQ-7"

RumPi::EComponentType::E_MQ7

@ E_MQ7

Parameters

[in] gasSensorType The gas-sensor type to convert.

Returns: The type's display string, or "UNKNOWN" if it is not a gas sensor.

◆ GetInitialValueR0()

double RumPi::GasSensor::GetInitialValueR0 ( ) const

Gets the sensor's clean-air resistance (R0) from calibration.

Author: Eddie O'Hagan

Date: 8/13/2026

double r0 = sensor.GetInitialValueR0();

Returns: The R0 value.

◆ GetResistorValueRL()

double RumPi::GasSensor::GetResistorValueRL ( ) const

Gets the load resistor value (RL) from the sensor's datasheet.

Author: Eddie O'Hagan

Date: 8/13/2026

double rl = sensor.GetResistorValueRL();

Returns: The RL value.

◆ Initialize()

void RumPi::GasSensor::Initialize ( )

virtual

Initializes the sensor's datasheet values.

The base does nothing; each MQ subclass overrides this to set its RL, clean-air factor, detectable concentration, and gas curve.

Author: Eddie O'Hagan

Date: 8/13/2026

//Overridden by subclasses, e.g. MQ2::Initialize().

Reimplemented in RumPi::MQ135, RumPi::MQ2, RumPi::MQ3, RumPi::MQ4, RumPi::MQ5, RumPi::MQ6, RumPi::MQ7, RumPi::MQ8, and RumPi::MQ9.

◆ ProcessRawValues()

void RumPi::GasSensor::ProcessRawValues ( )

overridevirtual

Reads the sensor and computes the current gas value (PPM) from the RS/R0 ratio using the datasheet's log-log curve.

Warns and reports zero if the gas curve slope is zero (which would divide by zero).

Author: Eddie O'Hagan

Date: 8/13/2026

sensor.ProcessRawValues(); //call each poll to refresh the gas value.

Implements RumPi::BaseComponent.

◆ ReadDigitalValue()

int RumPi::GasSensor::ReadDigitalValue ( )

Reads the sensor's digital threshold-output pin (1 when the configured gas threshold is exceeded).

Author: Eddie O'Hagan

Date: 8/13/2026

int triggered = sensor.ReadDigitalValue();

Returns: The digital pin reading.

◆ ReadGasValue()

double RumPi::GasSensor::ReadGasValue ( ) const

virtual

Gets the most recently processed gas value.

MQ subclasses may override this to compute a gas-specific value.

Author: Eddie O'Hagan

Date: 8/13/2026

double ppm = sensor.ReadGasValue();

Returns: The current gas value (PPM).

Reimplemented in RumPi::MQ135, RumPi::MQ3, RumPi::MQ4, RumPi::MQ5, RumPi::MQ6, RumPi::MQ7, RumPi::MQ8, and RumPi::MQ9.

◆ ReadRawAnalogValue()

int RumPi::GasSensor::ReadRawAnalogValue ( ) const

Reads the raw analog value from the sensor's ADC channel.

Author: Eddie O'Hagan

Date: 8/13/2026

int raw = sensor.ReadRawAnalogValue();

Returns: The raw analog reading, or -1 if the sensor has no ADC.

◆ ToString()

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

overridevirtual

Serializes the sensor's current gas value (PPM), a rough percentage, and the raw reading to a string.

Author: Eddie O'Hagan

Date: 8/13/2026

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

Returns: A string describing the sensor's current reading.

Implements RumPi::BaseComponent.

Reimplemented in RumPi::MQ135, RumPi::MQ3, RumPi::MQ4, RumPi::MQ5, RumPi::MQ6, RumPi::MQ7, RumPi::MQ8, and RumPi::MQ9.

◆ TurnOff()

void RumPi::GasSensor::TurnOff ( )

virtual

Turns the sensor off.

No active teardown is needed, so this is a no-op.

Author: Eddie O'Hagan

Date: 8/13/2026

sensor.TurnOff();

Implements RumPi::BaseComponent.

◆ TurnOn()

void RumPi::GasSensor::TurnOn ( )

virtual

Turns the sensor on.

If a digital threshold pin is configured, sets it as an input.

Author: Eddie O'Hagan

Date: 8/13/2026

sensor.TurnOn();

Implements RumPi::BaseComponent.

Member Data Documentation

◆ CALIBRATION_SAMPLE_INTERVAL

const int RumPi::GasSensor::CALIBRATION_SAMPLE_INTERVAL = 250

static

Milliseconds between samples during the calibration phase.

◆ CALIBRATION_SAMPLE_TIMES

const int RumPi::GasSensor::CALIBRATION_SAMPLE_TIMES = 200

static

The number of samples taken during the calibration phase.

◆ GAS_SENSOR_VOLTAGE

constexpr double RumPi::GasSensor::GAS_SENSOR_VOLTAGE = 5.0

staticconstexpr

The supply voltage the gas sensor runs on.

◆ myAnalogToDigitalConverter

IAnalogDigitalConverterComponent* RumPi::GasSensor::myAnalogToDigitalConverter

protected

The ADC this sensor reads its analog value through.

◆ myAnalogToDigitalConverterIndex

unsigned int RumPi::GasSensor::myAnalogToDigitalConverterIndex

protected

The ADC channel index this sensor reads its analog value from.

◆ myCleanAirFactor

double RumPi::GasSensor::myCleanAirFactor

protected

The clean-air factor (RS/R0 in clean air) from the datasheet.

◆ myCurrentGasValue

double RumPi::GasSensor::myCurrentGasValue

protected

The most recent computed gas value (PPM).

◆ myCurrentValueRS

double RumPi::GasSensor::myCurrentValueRS

protected

The sensor's current resistance (RS).

◆ myDetectibleConcentration

const char* RumPi::GasSensor::myDetectibleConcentration

protected

A human-readable detectable-concentration range for this sensor.

◆ myDigitalOutputPinNumber

unsigned int RumPi::GasSensor::myDigitalOutputPinNumber

protected

The digital output (threshold) pin, or UINT_MAX if unused.

◆ myGasData

GasData RumPi::GasSensor::myGasData

protected

Per-gas curve data (slope/intercept) used to convert the RS/R0 ratio to PPM.

◆ myInitialValueR0

double RumPi::GasSensor::myInitialValueR0

protected

The sensor's resistance in clean air (R0), from calibration.

◆ myRawGasSensorValue

double RumPi::GasSensor::myRawGasSensorValue

protected

The most recent raw analog reading.

◆ myResistorValueRL

double RumPi::GasSensor::myResistorValueRL

protected

The load resistor value (RL) from the sensor's datasheet.

◆ READ_SAMPLE_INTERVAL

const int RumPi::GasSensor::READ_SAMPLE_INTERVAL = 250

static

Milliseconds between samples during normal operation.

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

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

Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ GasSensor() [1/4]

◆ GasSensor() [2/4]

◆ GasSensor() [3/4]

◆ GasSensor() [4/4]

◆ ~GasSensor()

Member Function Documentation

◆ CalculateInitialR0()

◆ CalculateR0()

◆ CalculateRS()

◆ CalculateRSR0Ratio()

◆ ConvertRawSensorValueToVolts()

◆ ConvertVoltsToRawSensorValue()

◆ GetAnalogDigitalConverter()

◆ GetAnalogToDigitalConverterIndex()

◆ GetAnalogToDigitalConverterMaxRawValue()

◆ GetAnalogToDigitalConverterVoltage()

◆ GetCurrentValueRS()

◆ GetDetectibleConcentration()

◆ GetDigitalOutputPinNumber()

◆ GetGasData()

◆ GetGasSensorType()

◆ GetGasSensorTypeAsString() [1/2]

◆ GetGasSensorTypeAsString() [2/2]

◆ GetInitialValueR0()

◆ GetResistorValueRL()

◆ Initialize()

◆ ProcessRawValues()

◆ ReadDigitalValue()

◆ ReadGasValue()

◆ ReadRawAnalogValue()

◆ ToString()

◆ TurnOff()

◆ TurnOn()

Member Data Documentation

◆ CALIBRATION_SAMPLE_INTERVAL

◆ CALIBRATION_SAMPLE_TIMES

◆ GAS_SENSOR_VOLTAGE

◆ myAnalogToDigitalConverter

◆ myAnalogToDigitalConverterIndex

◆ myCleanAirFactor

◆ myCurrentGasValue

◆ myCurrentValueRS

◆ myDetectibleConcentration

◆ myDigitalOutputPinNumber

◆ myGasData

◆ myInitialValueR0

◆ myRawGasSensorValue

◆ myResistorValueRL

◆ READ_SAMPLE_INTERVAL