BMP280 barometric temperature and pressure sensor (I2C), also deriving altitude from the measured pressure. More...

#include <BMP280.h>

Inheritance diagram for RumPi::BMP280:

Collaboration diagram for RumPi::BMP280:

Public Member Functions
	BMP280 (const int bmpI2CAddress)
	Builds a BMP280 bound to the given I2C address, computing its config/ctrl_meas bytes and opening the i2c device. More...

virtual	~BMP280 ()
	Destroys the sensor, turning it off first. More...

virtual void	TurnOn () override
	Reads the chip ID/version, soft-resets and configures the sensor, and reads its temperature/pressure calibration coefficients, reporting progress through the AlertManager. More...

virtual void	TurnOff () override
	No-op: the BMP280's only OS resource (the i2c file descriptor) is opened in the constructor and closed in the destructor, so a power-off releases nothing. More...

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

virtual void	ProcessRawValues () override
	Reads the raw temperature and pressure registers and applies the Bosch datasheet compensation formulas to update the cached temperature (C), pressure (hPa), and approximated altitude (m). More...

int	GetConfigsByte () const
	Gets the computed register config byte. More...

int	GetCtrlMeasByte () const
	Gets the computed register ctrl_meas byte. More...

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

int	GetChipID () const
	Gets the sensor's chip ID. More...

int	GetChipVersion () const
	Gets the sensor's chip version. More...

double	GetTemperature () const
	Gets the most recently calculated temperature, in Celsius. More...

double	GetPressure () const
	Gets the most recently calculated pressure, in hPa. More...

double	GetAltitude () const
	Gets the most recently calculated altitude, in meters. More...

int	GetDigT1 () const
	Gets the DigT1 temperature calibration coefficient. More...

int	GetDigT2 () const
	Gets the DigT2 temperature calibration coefficient. More...

int	GetDigT3 () const
	Gets the DigT3 temperature calibration coefficient. More...

int	GetDigP1 () const
	Gets the DigP1 pressure calibration coefficient. More...

int	GetDigP2 () const
	Gets the DigP2 pressure calibration coefficient. More...

int	GetDigP3 () const
	Gets the DigP3 pressure calibration coefficient. More...

int	GetDigP4 () const
	Gets the DigP4 pressure calibration coefficient. More...

int	GetDigP5 () const
	Gets the DigP5 pressure calibration coefficient. More...

int	GetDigP6 () const
	Gets the DigP6 pressure calibration coefficient. More...

int	GetDigP7 () const
	Gets the DigP7 pressure calibration coefficient. More...

int	GetDigP8 () const
	Gets the DigP8 pressure calibration coefficient. More...

int	GetDigP9 () const
	Gets the DigP9 pressure calibration coefficient. More...

void	SetTemperature (const double temp)
	Sets the cached temperature, in Celsius. More...

void	SetPressure (const double pressure)
	Sets the cached pressure, in hPa. More...

void	SetAltitude (const double alt)
	Sets the cached altitude, in meters. 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
int	WriteByteDataToRegister (const int reg, const int value)
	Writes a byte to a register over I2C. More...

int	ReadByteDataFromRegister (const int reg)
	Reads a byte from a register over I2C. More...

int	ReadWordDataFromRegisterUnsigned (const int reg)
	Reads an unsigned 16-bit word from a register over I2C. More...

int	ReadWordDataFromRegisterSigned (const int reg)
	Reads a signed 16-bit word from a register over I2C, applying two's-complement sign correction. More...

Private Attributes
int	CONFIGS
	Register config byte; computed in the ctor. More...

int	CTRL_MEAS
	Register ctrl_meas byte; computed in the ctor. More...

int	myFileDescriptor
	The open i2c device file descriptor. More...

int	myChipID
	The sensor's chip ID. More...

int	myChipVersion
	The sensor's chip version. More...

double	myTemperatureInC
	The most recently calculated temperature, in Celsius. More...

double	myPressureInHPA
	The most recently calculated pressure, in hPa. More...

double	myAltitudeInM
	The most recently calculated altitude, in meters. More...

int	myDigT1
	Temperature calibration coefficient. More...

int	myDigT2
	Temperature calibration coefficient. More...

int	myDigT3
	Temperature calibration coefficient. More...

int	myDigP1
	Pressure calibration coefficient. More...

int	myDigP2
	Pressure calibration coefficient. More...

int	myDigP3
	Pressure calibration coefficient. More...

int	myDigP4
	Pressure calibration coefficient. More...

int	myDigP5
	Pressure calibration coefficient. More...

int	myDigP6
	Pressure calibration coefficient. More...

int	myDigP7
	Pressure calibration coefficient. More...

int	myDigP8
	Pressure calibration coefficient. More...

int	myDigP9
	Pressure calibration coefficient. 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

BMP280 barometric temperature and pressure sensor (I2C), also deriving altitude from the measured pressure.

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ BMP280()

RumPi::BMP280::BMP280 ( const int bmpI2CAddress )

Builds a BMP280 bound to the given I2C address, computing its config/ctrl_meas bytes and opening the i2c device.

Author: Eddie O'Hagan

Date: 8/13/2026

BMP280 barometer(0x76);

RumPi::BMP280::BMP280

BMP280(const int bmpI2CAddress)

Builds a BMP280 bound to the given I2C address, computing its config/ctrl_meas bytes and opening the ...

Definition: BMP280.cpp:19

Parameters

[in] bmpI2CAddress The sensor's I2C address.

◆ ~BMP280()

RumPi::BMP280::~BMP280 ( )

virtual

Destroys the sensor, turning it off first.

Author: Eddie O'Hagan

Date: 8/13/2026

BMP280* barometer = new BMP280(0x76);

delete barometer;

Member Function Documentation

◆ GetAltitude()

double RumPi::BMP280::GetAltitude ( ) const

Gets the most recently calculated altitude, in meters.

Author: Eddie O'Hagan

Date: 8/13/2026

double altitude = barometer.GetAltitude();

Returns: The altitude, in meters.

◆ GetChipID()

int RumPi::BMP280::GetChipID ( ) const

Gets the sensor's chip ID.

Author: Eddie O'Hagan

Date: 8/13/2026

int id = barometer.GetChipID();

Returns: The chip ID.

◆ GetChipVersion()

int RumPi::BMP280::GetChipVersion ( ) const

Gets the sensor's chip version.

Author: Eddie O'Hagan

Date: 8/13/2026

int version = barometer.GetChipVersion();

Returns: The chip version.

◆ GetConfigsByte()

int RumPi::BMP280::GetConfigsByte ( ) const

Gets the computed register config byte.

Author: Eddie O'Hagan

Date: 8/13/2026

int config = barometer.GetConfigsByte();

Returns: The config byte.

◆ GetCtrlMeasByte()

int RumPi::BMP280::GetCtrlMeasByte ( ) const

Gets the computed register ctrl_meas byte.

Author: Eddie O'Hagan

Date: 8/13/2026

int ctrlMeas = barometer.GetCtrlMeasByte();

Returns: The ctrl_meas byte.

◆ GetDigP1()

int RumPi::BMP280::GetDigP1 ( ) const

Gets the DigP1 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP1 = barometer.GetDigP1();

Returns: The DigP1 coefficient.

◆ GetDigP2()

int RumPi::BMP280::GetDigP2 ( ) const

Gets the DigP2 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP2 = barometer.GetDigP2();

Returns: The DigP2 coefficient.

◆ GetDigP3()

int RumPi::BMP280::GetDigP3 ( ) const

Gets the DigP3 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP3 = barometer.GetDigP3();

Returns: The DigP3 coefficient.

◆ GetDigP4()

int RumPi::BMP280::GetDigP4 ( ) const

Gets the DigP4 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP4 = barometer.GetDigP4();

Returns: The DigP4 coefficient.

◆ GetDigP5()

int RumPi::BMP280::GetDigP5 ( ) const

Gets the DigP5 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP5 = barometer.GetDigP5();

Returns: The DigP5 coefficient.

◆ GetDigP6()

int RumPi::BMP280::GetDigP6 ( ) const

Gets the DigP6 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP6 = barometer.GetDigP6();

Returns: The DigP6 coefficient.

◆ GetDigP7()

int RumPi::BMP280::GetDigP7 ( ) const

Gets the DigP7 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP7 = barometer.GetDigP7();

Returns: The DigP7 coefficient.

◆ GetDigP8()

int RumPi::BMP280::GetDigP8 ( ) const

Gets the DigP8 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP8 = barometer.GetDigP8();

Returns: The DigP8 coefficient.

◆ GetDigP9()

int RumPi::BMP280::GetDigP9 ( ) const

Gets the DigP9 pressure calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digP9 = barometer.GetDigP9();

Returns: The DigP9 coefficient.

◆ GetDigT1()

int RumPi::BMP280::GetDigT1 ( ) const

Gets the DigT1 temperature calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digT1 = barometer.GetDigT1();

Returns: The DigT1 coefficient.

◆ GetDigT2()

int RumPi::BMP280::GetDigT2 ( ) const

Gets the DigT2 temperature calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digT2 = barometer.GetDigT2();

Returns: The DigT2 coefficient.

◆ GetDigT3()

int RumPi::BMP280::GetDigT3 ( ) const

Gets the DigT3 temperature calibration coefficient.

Author: Eddie O'Hagan

Date: 8/13/2026

int digT3 = barometer.GetDigT3();

Returns: The DigT3 coefficient.

◆ GetFileDescriptor()

int RumPi::BMP280::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.

◆ GetPressure()

double RumPi::BMP280::GetPressure ( ) const

Gets the most recently calculated pressure, in hPa.

Author: Eddie O'Hagan

Date: 8/13/2026

double pressure = barometer.GetPressure();

Returns: The pressure, in hPa.

◆ GetTemperature()

double RumPi::BMP280::GetTemperature ( ) const

Gets the most recently calculated temperature, in Celsius.

Author: Eddie O'Hagan

Date: 8/13/2026

double temperature = barometer.GetTemperature();

Returns: The temperature, in Celsius.

◆ ProcessRawValues()

void RumPi::BMP280::ProcessRawValues ( )

overridevirtual

Reads the raw temperature and pressure registers and applies the Bosch datasheet compensation formulas to update the cached temperature (C), pressure (hPa), and approximated altitude (m).

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.ProcessRawValues();

Implements RumPi::BaseComponent.

◆ ReadByteDataFromRegister()

int RumPi::BMP280::ReadByteDataFromRegister ( const int reg )

private

Reads a byte from a register over I2C.

Author: Eddie O'Hagan

Date: 8/13/2026

int msb = ReadByteDataFromRegister(BMP280_REGISTER_TEMPDATA_MSB);

RumPi::BMP280::ReadByteDataFromRegister

int ReadByteDataFromRegister(const int reg)

Reads a byte from a register over I2C.

Definition: BMP280.cpp:190

RumPi::BMP280_REGISTER_TEMPDATA_MSB

constexpr int BMP280_REGISTER_TEMPDATA_MSB

Definition: BMP280.h:69

Parameters

[in] reg The register to read from.

Returns: The byte value read.

◆ ReadWordDataFromRegisterSigned()

int RumPi::BMP280::ReadWordDataFromRegisterSigned ( const int reg )

private

Reads a signed 16-bit word from a register over I2C, applying two's-complement sign correction.

Author: Eddie O'Hagan

Date: 8/13/2026

int dig = ReadWordDataFromRegisterSigned(BMP280_REGISTER_DIG_T2);

RumPi::BMP280::ReadWordDataFromRegisterSigned

int ReadWordDataFromRegisterSigned(const int reg)

Reads a signed 16-bit word from a register over I2C, applying two's-complement sign correction.

Definition: BMP280.cpp:228

RumPi::BMP280_REGISTER_DIG_T2

constexpr int BMP280_REGISTER_DIG_T2

Definition: BMP280.h:52

Parameters

[in] reg The register to read from.

Returns: The signed 16-bit value read.

◆ ReadWordDataFromRegisterUnsigned()

int RumPi::BMP280::ReadWordDataFromRegisterUnsigned ( const int reg )

private

Reads an unsigned 16-bit word from a register over I2C.

Author: Eddie O'Hagan

Date: 8/13/2026

int dig = ReadWordDataFromRegisterUnsigned(BMP280_REGISTER_DIG_T1);

RumPi::BMP280::ReadWordDataFromRegisterUnsigned

int ReadWordDataFromRegisterUnsigned(const int reg)

Reads an unsigned 16-bit word from a register over I2C.

Definition: BMP280.cpp:209

RumPi::BMP280_REGISTER_DIG_T1

constexpr int BMP280_REGISTER_DIG_T1

Definition: BMP280.h:51

Parameters

[in] reg The register to read from.

Returns: The unsigned 16-bit value read.

◆ SetAltitude()

void RumPi::BMP280::SetAltitude ( const double alt )

Sets the cached altitude, in meters.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.SetAltitude(120.0);

Parameters

[in] alt The altitude to set, in meters.

◆ SetPressure()

void RumPi::BMP280::SetPressure ( const double pressure )

Sets the cached pressure, in hPa.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.SetPressure(1013.25);

Parameters

[in] pressure The pressure to set, in hPa.

◆ SetTemperature()

void RumPi::BMP280::SetTemperature ( const double temp )

Sets the cached temperature, in Celsius.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.SetTemperature(21.5);

Parameters

[in] temp The temperature to set, in Celsius.

◆ ToString()

std::string RumPi::BMP280::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::BMP280::TurnOff ( )

overridevirtual

No-op: the BMP280's only OS resource (the i2c file descriptor) is opened in the constructor and closed in the destructor, so a power-off releases nothing.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.TurnOff();

Implements RumPi::BaseComponent.

◆ TurnOn()

void RumPi::BMP280::TurnOn ( )

overridevirtual

Reads the chip ID/version, soft-resets and configures the sensor, and reads its temperature/pressure calibration coefficients, reporting progress through the AlertManager.

Author: Eddie O'Hagan

Date: 8/13/2026

barometer.TurnOn();

Implements RumPi::BaseComponent.

◆ WriteByteDataToRegister()

int RumPi::BMP280::WriteByteDataToRegister	(	const int	reg,
		const int	value
	)

private

Writes a byte to a register over I2C.

Author: Eddie O'Hagan

Date: 8/13/2026

WriteByteDataToRegister(BMP280_REGISTER_CONTROL, CTRL_MEAS);

RumPi::BMP280::WriteByteDataToRegister

int WriteByteDataToRegister(const int reg, const int value)

Writes a byte to a register over I2C.

Definition: BMP280.cpp:171

RumPi::BMP280::CTRL_MEAS

int CTRL_MEAS

Register ctrl_meas byte; computed in the ctor.

Definition: BMP280.h:86

RumPi::BMP280_REGISTER_CONTROL

constexpr int BMP280_REGISTER_CONTROL

Definition: BMP280.h:66

Parameters

[in]	reg	The register to write to.
[in]	value	The byte value to write.

Returns: The wiringPi write result.

Member Data Documentation

◆ CONFIGS

int RumPi::BMP280::CONFIGS

private

Register config byte; computed in the ctor.

◆ CTRL_MEAS

int RumPi::BMP280::CTRL_MEAS

private

Register ctrl_meas byte; computed in the ctor.

◆ myAltitudeInM

double RumPi::BMP280::myAltitudeInM

private

The most recently calculated altitude, in meters.

◆ myChipID

int RumPi::BMP280::myChipID

private

The sensor's chip ID.

◆ myChipVersion

int RumPi::BMP280::myChipVersion

private

The sensor's chip version.