BMP180 barometric temperature and pressure sensor (I2C), also deriving altitude from the measured pressure. More...

#include <BMP180.h>

Inheritance diagram for RumPi::BMP180:

Collaboration diagram for RumPi::BMP180:

Public Member Functions
	BMP180 (int bmpI2CAddress, const char *i2cDeviceFilePath)
	Builds a BMP180 bound to the given I2C address, copying the provided i2c device file path. More...

virtual	~BMP180 ()
	Destroys the sensor, turning it off and freeing the copied device file path. More...

virtual void	TurnOn () override
	Opens the i2c device, binds the slave address, and reads the sensor's EPROM calibration coefficients, reporting progress and any failures through the AlertManager. More...

virtual void	TurnOff () override
	Closes the i2c device and frees the copied device file path, reporting any close failure through the AlertManager. More...

virtual std::string	ToString () const override
	Serializes the most recently calculated temperature, pressure, and altitude to a string. More...

virtual void	ProcessRawValues () override
	Recomputes and caches the temperature, pressure, and altitude from fresh sensor reads. More...

float	CalculateTemperature ()
	Calculates the compensated temperature (in Celsius) from a raw read using the sensor's calibration coefficients. More...

long	CalculatePressure ()
	Calculates the compensated pressure (in pascal) from raw reads using the sensor's calibration coefficients. More...

float	CalculateAltitude ()
	Approximates the altitude (in meters) from the measured pressure relative to average sea-level pressure. More...

int	GetFileDescriptor () const
	Gets the open i2c device file descriptor. More...

int	GetI2CAddress () const
	Gets the sensor's I2C address. More...

int	GetOversamplingMode () const
	Gets the sensor's oversampling mode. More...

char *	GetI2CDeviceFilePath () const
	Gets the i2c device file path. More...

int32_t	GetAC1 () const
	Gets the AC1 calibration coefficient. More...

int32_t	GetAC2 () const
	Gets the AC2 calibration coefficient. More...

int32_t	GetAC3 () const
	Gets the AC3 calibration coefficient. More...

int32_t	GetAC4 () const
	Gets the AC4 calibration coefficient. More...

int32_t	GetAC5 () const
	Gets the AC5 calibration coefficient. More...

int32_t	GetAC6 () const
	Gets the AC6 calibration coefficient. More...

int32_t	GetB1 () const
	Gets the B1 calibration coefficient. More...

int32_t	GetB2 () const
	Gets the B2 calibration coefficient. More...

int32_t	GetMB () const
	Gets the MB calibration coefficient. More...

int32_t	GetMC () const
	Gets the MC calibration coefficient. More...

int32_t	GetMD () const
	Gets the MD calibration coefficient. 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	ReadSingleEpromFromRegister (int32_t *store, uint8_t reg, int32_t sign)
	Reads a single calibration coefficient from the BMP180 EPROM, byte-swapping it from the chip's ordering and applying two's-complement sign correction when the coefficient is signed. More...

void	ReadEprom ()
	Reads all eleven calibration coefficients from the BMP180 EPROM into their member variables. More...

int32_t	ReadRawTemperature ()
	Reads the raw (uncompensated) temperature value from the sensor, byte-swapped to host ordering. More...

int32_t	ReadRawPressure (uint8_t oversamplingMode)
	Reads the raw (uncompensated) pressure value from the sensor at the given oversampling mode. More...

Private Attributes
int	myFileDescriptor
	File descriptor. More...

int	myI2CAddress
	I2C device address. More...

int	myOversamplingMode
	BMP180 oversampling mode. More...

char *	myI2CDeviceFilePath
	i2c device file path. More...

int32_t	myAC1
	EPROM calibration coefficients. More...

int32_t	myAC2

int32_t	myAC3

int32_t	myAC4

int32_t	myAC5

int32_t	myAC6

int32_t	myB1

int32_t	myB2

int32_t	myMB

int32_t	myMC

int32_t	myMD

float	myRecentlyCalculatedTemperatureInC
	Most recently calculated values. More...

long	myRecentlyCalculatedPressureInHPA

float	myRecentlyCalculatedAltitudeInM

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

BMP180 barometric temperature and pressure sensor (I2C), also deriving altitude from the measured pressure.

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ BMP180()

RumPi::BMP180::BMP180	(	int	bmpI2CAddress,
		const char *	i2cDeviceFilePath
	)

Builds a BMP180 bound to the given I2C address, copying the provided i2c device file path.

Author: Eddie O'Hagan

Date: 8/13/2026

BMP180 barometer(0x77, "/dev/i2c-1");

RumPi::BMP180::BMP180

BMP180(int bmpI2CAddress, const char *i2cDeviceFilePath)

Builds a BMP180 bound to the given I2C address, copying the provided i2c device file path.

Definition: BMP180.cpp:19

Parameters

[in]	bmpI2CAddress	The sensor's I2C address.
[in]	i2cDeviceFilePath	The i2c device file path (copied internally; may be nullptr).

◆ ~BMP180()

RumPi::BMP180::~BMP180 ( )

virtual

Destroys the sensor, turning it off and freeing the copied device file path.

Author: Eddie O'Hagan

Date: 8/13/2026

BMP180* barometer = new BMP180(0x77, "/dev/i2c-1");

delete barometer;

Member Function Documentation

◆ CalculateAltitude()

float RumPi::BMP180::CalculateAltitude ( )

Approximates the altitude (in meters) from the measured pressure relative to average sea-level pressure.

Author: Eddie O'Hagan

Date: 8/13/2026

float altitude = barometer.CalculateAltitude();

Returns: The approximate altitude, in meters.

◆ CalculatePressure()

long RumPi::BMP180::CalculatePressure ( )

Calculates the compensated pressure (in pascal) from raw reads using the sensor's calibration coefficients.

Author: Eddie O'Hagan

Date: 8/13/2026

long pressure = barometer.CalculatePressure();

Returns: The measured pressure, in pascal.

◆ CalculateTemperature()

float RumPi::BMP180::CalculateTemperature ( )

Calculates the compensated temperature (in Celsius) from a raw read using the sensor's calibration coefficients.

Author: Eddie O'Hagan

Date: 8/13/2026

float temperature = barometer.CalculateTemperature();

Returns: The measured temperature, in Celsius.

◆ GetAC1()

int32_t RumPi::BMP180::GetAC1 ( ) const

Gets the AC1 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac1 = barometer.GetAC1();

Returns: The AC1 coefficient.

◆ GetAC2()

int32_t RumPi::BMP180::GetAC2 ( ) const

Gets the AC2 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac2 = barometer.GetAC2();

Returns: The AC2 coefficient.

◆ GetAC3()

int32_t RumPi::BMP180::GetAC3 ( ) const

Gets the AC3 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac3 = barometer.GetAC3();

Returns: The AC3 coefficient.

◆ GetAC4()

int32_t RumPi::BMP180::GetAC4 ( ) const

Gets the AC4 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac4 = barometer.GetAC4();

Returns: The AC4 coefficient.

◆ GetAC5()

int32_t RumPi::BMP180::GetAC5 ( ) const

Gets the AC5 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac5 = barometer.GetAC5();

Returns: The AC5 coefficient.

◆ GetAC6()

int32_t RumPi::BMP180::GetAC6 ( ) const

Gets the AC6 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t ac6 = barometer.GetAC6();

Returns: The AC6 coefficient.

◆ GetB1()

int32_t RumPi::BMP180::GetB1 ( ) const

Gets the B1 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t b1 = barometer.GetB1();

Returns: The B1 coefficient.

◆ GetB2()

int32_t RumPi::BMP180::GetB2 ( ) const

Gets the B2 calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t b2 = barometer.GetB2();

Returns: The B2 coefficient.

◆ GetFileDescriptor()

int RumPi::BMP180::GetFileDescriptor ( ) const

Gets the open i2c device file descriptor.

Author: Eddie O'Hagan

Date: 8/13/2026

int fd = barometer.GetFileDescriptor();

Returns: The file descriptor.

◆ GetI2CAddress()

int RumPi::BMP180::GetI2CAddress ( ) const

Gets the sensor's I2C address.

Author: Eddie O'Hagan

Date: 8/13/2026

int address = barometer.GetI2CAddress();

Returns: The I2C address.

◆ GetI2CDeviceFilePath()

char * RumPi::BMP180::GetI2CDeviceFilePath ( ) const

Gets the i2c device file path.

Author: Eddie O'Hagan

Date: 8/13/2026

char* path = barometer.GetI2CDeviceFilePath();

Returns: The i2c device file path.

◆ GetMB()

int32_t RumPi::BMP180::GetMB ( ) const

Gets the MB calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t mb = barometer.GetMB();

Returns: The MB coefficient.

◆ GetMC()

int32_t RumPi::BMP180::GetMC ( ) const

Gets the MC calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t mc = barometer.GetMC();

Returns: The MC coefficient.

◆ GetMD()

int32_t RumPi::BMP180::GetMD ( ) const

Gets the MD calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t md = barometer.GetMD();

Returns: The MD coefficient.

◆ GetOversamplingMode()

int RumPi::BMP180::GetOversamplingMode ( ) const

Gets the sensor's oversampling mode.

Author: Eddie O'Hagan

Date: 8/13/2026

int mode = barometer.GetOversamplingMode();

Returns: The oversampling mode.

◆ ProcessRawValues()

void RumPi::BMP180::ProcessRawValues ( )

overridevirtual

Recomputes and caches the temperature, pressure, and altitude from fresh sensor reads.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.ProcessRawValues();

Implements RumPi::BaseComponent.

◆ ReadEprom()

void RumPi::BMP180::ReadEprom ( )

private

Reads all eleven calibration coefficients from the BMP180 EPROM into their member variables.

Author: Eddie O'Hagan

Date: 8/13/2026

ReadEprom();

RumPi::BMP180::ReadEprom

void ReadEprom()

Reads all eleven calibration coefficients from the BMP180 EPROM into their member variables.

Definition: BMP180.cpp:265

◆ ReadRawPressure()

int32_t RumPi::BMP180::ReadRawPressure ( uint8_t oversamplingMode )

private

Reads the raw (uncompensated) pressure value from the sensor at the given oversampling mode.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t rawPressure = ReadRawPressure(BMP180_PRE_OSS0);

RumPi::BMP180::ReadRawPressure

int32_t ReadRawPressure(uint8_t oversamplingMode)

Reads the raw (uncompensated) pressure value from the sensor at the given oversampling mode.

Definition: BMP180.cpp:335

RumPi::BMP180_PRE_OSS0

constexpr int BMP180_PRE_OSS0

Definition: BMP180.h:25

Parameters

[in] oversamplingMode The oversampling mode (BMP180_PRE_OSS0 through BMP180_PRE_OSS3).

Returns: The raw pressure reading.

◆ ReadRawTemperature()

int32_t RumPi::BMP180::ReadRawTemperature ( )

private

Reads the raw (uncompensated) temperature value from the sensor, byte-swapped to host ordering.

Author: Eddie O'Hagan

Date: 8/13/2026

int32_t rawTemperature = ReadRawTemperature();

RumPi::BMP180::ReadRawTemperature

int32_t ReadRawTemperature()

Reads the raw (uncompensated) temperature value from the sensor, byte-swapped to host ordering.

Definition: BMP180.cpp:309

Returns: The raw temperature reading.

◆ ReadSingleEpromFromRegister()

void RumPi::BMP180::ReadSingleEpromFromRegister	(	int32_t *	store,
		uint8_t	reg,
		int32_t	sign
	)

private

Reads a single calibration coefficient from the BMP180 EPROM, byte-swapping it from the chip's ordering and applying two's-complement sign correction when the coefficient is signed.

Author: Eddie O'Hagan

Date: 8/13/2026

ReadSingleEpromFromRegister(&myAC1, BMP180_REG_AC1_H, 1);

RumPi::BMP180::ReadSingleEpromFromRegister

void ReadSingleEpromFromRegister(int32_t *store, uint8_t reg, int32_t sign)

Reads a single calibration coefficient from the BMP180 EPROM, byte-swapping it from the chip's orderi...

Definition: BMP180.cpp:238

RumPi::BMP180::myAC1

int32_t myAC1

EPROM calibration coefficients.

Definition: BMP180.h:121

RumPi::BMP180_REG_AC1_H

constexpr int BMP180_REG_AC1_H

Definition: BMP180.h:43

Parameters

[out]	store	The coefficient to write.
[in]	reg	The register address to read from.
[in]	sign	Non-zero if the coefficient is signed.

◆ ToString()

std::string RumPi::BMP180::ToString ( ) const

overridevirtual

Serializes the most recently calculated temperature, pressure, and altitude to a string.

Author: Eddie O'Hagan

Date: 8/13/2026

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

Returns: A string describing the sensor's most recent readings.

Implements RumPi::BaseComponent.

◆ TurnOff()

void RumPi::BMP180::TurnOff ( )

overridevirtual

Closes the i2c device and frees the copied device file path, reporting any close failure through the AlertManager.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.TurnOff();

Implements RumPi::BaseComponent.

◆ TurnOn()

void RumPi::BMP180::TurnOn ( )

overridevirtual

Opens the i2c device, binds the slave address, and reads the sensor's EPROM calibration coefficients, reporting progress and any failures through the AlertManager.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.TurnOn();

Implements RumPi::BaseComponent.

Member Data Documentation

◆ myAC1

int32_t RumPi::BMP180::myAC1

private

EPROM calibration coefficients.

◆ myAC2

int32_t RumPi::BMP180::myAC2

private

◆ myAC3

int32_t RumPi::BMP180::myAC3

private

◆ myAC4

int32_t RumPi::BMP180::myAC4

private

◆ myAC5

int32_t RumPi::BMP180::myAC5

private

◆ myAC6

int32_t RumPi::BMP180::myAC6

private

◆ myB1

int32_t RumPi::BMP180::myB1

private

◆ myB2

int32_t RumPi::BMP180::myB2

private

◆ myFileDescriptor

int RumPi::BMP180::myFileDescriptor

private

File descriptor.

◆ myI2CAddress

int RumPi::BMP180::myI2CAddress

private

I2C device address.

◆ myI2CDeviceFilePath

char* RumPi::BMP180::myI2CDeviceFilePath

private

i2c device file path.

◆ myMB

int32_t RumPi::BMP180::myMB

private

◆ myMC

int32_t RumPi::BMP180::myMC

private

◆ myMD

int32_t RumPi::BMP180::myMD

private

◆ myOversamplingMode

int RumPi::BMP180::myOversamplingMode

private

BMP180 oversampling mode.

◆ myRecentlyCalculatedAltitudeInM

float RumPi::BMP180::myRecentlyCalculatedAltitudeInM

private

◆ myRecentlyCalculatedPressureInHPA

long RumPi::BMP180::myRecentlyCalculatedPressureInHPA

private

◆ myRecentlyCalculatedTemperatureInC

float RumPi::BMP180::myRecentlyCalculatedTemperatureInC

private

Most recently calculated values.

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

Source/Headers/RumPi/Components/BMP180.h
Source/Implementations/RumPi/Components/BMP180.cpp

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BMP180()

◆ ~BMP180()

Member Function Documentation

◆ CalculateAltitude()

◆ CalculatePressure()

◆ CalculateTemperature()

◆ GetAC1()

◆ GetAC2()

◆ GetAC3()

◆ GetAC4()

◆ GetAC5()

◆ GetAC6()

◆ GetB1()

◆ GetB2()

◆ GetFileDescriptor()

◆ GetI2CAddress()

◆ GetI2CDeviceFilePath()

◆ GetMB()

◆ GetMC()

◆ GetMD()

◆ GetOversamplingMode()

◆ ProcessRawValues()

◆ ReadEprom()

◆ ReadRawPressure()

◆ ReadRawTemperature()

◆ ReadSingleEpromFromRegister()

◆ ToString()

◆ TurnOff()

◆ TurnOn()

Member Data Documentation

◆ myAC1

◆ myAC2

◆ myAC3

◆ myAC4

◆ myAC5

◆ myAC6

◆ myB1

◆ myB2

◆ myFileDescriptor

◆ myI2CAddress

◆ myI2CDeviceFilePath

◆ myMB

◆ myMC

◆ myMD

◆ myOversamplingMode

◆ myRecentlyCalculatedAltitudeInM

◆ myRecentlyCalculatedPressureInHPA

◆ myRecentlyCalculatedTemperatureInC