ustd::PressTempBMP280 Class Reference

mupplet-sensor temperature and pressure with Bosch BMP280 More...

#include <mup_presstemp_bmp280.h>

Public Types
enum	BMPSampleMode {   ULTRA_LOW_POWER = 1 , LOW_POWER = 2 , STANDARD = 3 , HIGH_RESOLUTION = 4 ,   ULTRA_HIGH_RESOLUTION = 5 }

Public Member Functions
	PressTempBMP280 (String name, FilterMode filterMode=FilterMode::MEDIUM, uint8_t i2cAddress=0x76)
void	setReferenceAltitude (double _referenceAltitudeMeters)
void	startRelativeAltitude ()
double	getTemperature ()
double	getPressure ()
double	getPressureNN (double _pressure)

Detailed Description

mupplet-sensor temperature and pressure with Bosch BMP280

The mup_presstemp_bmp280 mupplet measures temperature and pressure using BMP280 sensor.

This mupplet is a fully asynchronous state-machine with no delay()s, so it never blocks.

Messages sent by presstemp_bmp280 mupplet:

messages are prefixed by omu/<hostname>:

topic	message body	comment
<mupplet-name>/sensor/temperature	temperature in degree celsius	Float value encoded as string, sent periodically as available
<mupplet-name>/sensor/pressure	pressure in hPA for current altitude	Float value encoded as string, sent periodically as available
<mupplet-name>/sensor/pressureNN	pressure in hPA adjusted for sea level (requires setReferenceAltitude() to be called)	Float value encoded as string, sent periodically as available
<mupplet-name>/sensor/calibrationdata	a string with values of all internal calibration variables	descriptive string
<mupplet-name>/sensor/referencealtitude	altitude above sea level as set with setReferenceAltitude()	Float value encoded as string
<mupplet-name>/sensor/relativealtitude	current altitude in meters	Current altitude in comparison to the set reference in meters, requires referencealtitude/set and relativealtitude/set msgs being sent.
<mupplet-name>/sensor/deltaaltitude	current altitude in meters	Current altitude delta in meters, requirements as with relativealtitude
<mupplet-name>/sensor/oversampling	ULTRA_LOW_POWER, STANDARD, HIGH_RESOLUTION, ULTRA_HIGH_RESOLUTION	Internal sensor oversampling mode (sensor hardware)
<mupplet-name>/sensor/mode	FAST, MEDIUM, or LONGTERM	Integration time for sensor values, external, additional integration

Messages received by presstemp_bmp280 mupplet:

Need to be prefixed by <hostname>/:

topic	message body	comment
<mupplet-name>/sensor/temperature/get	-	Causes current value to be sent.
<mupplet-name>/sensor/pressure/get	-	Causes current value to be sent.
<mupplet-name>/sensor/pressureNN/get	-	Causes current value to be sent.
<mupplet-name>/sensor/referencealtitude/get	-	Causes current value to be sent.
<mupplet-name>/sensor/referencealtitude/set	float encoded as string of current altitude in meters	Once the reference altitude is set, pressureNN values can be calculated.
<mupplet-name>/sensor/relativealtitude/set	-	Save current pressureNN values as reference, start generating relative altitude-change messages, requires reference altitude to be set
<mupplet-name>/sensor/relativealtitude/get	-	Get current altitude in comparison to the set reference and an altitude delta in meters
<mupplet-name>/sensor/calibrationdata/get	-	Causes current values to be sent.
<mupplet-name>/sensor/oversampling/get	-	Returns samplemode: ULTRA_LOW_POWER, LOW_POWER, STANDARD, HIGH_RESOLUTION, ULTRA_HIGH_RESOLUTION
<mupplet-name>/sensor/oversampling/set	ULTRA_LOW_POWER, LOW_POWER, STANDARD, HIGH_RESOLUTION, ULTRA_HIGH_RESOLUTION	Set internal sensor oversampling mode
<mupplet-name>/sensor/mode/get	-	Returns filterMode: FAST, MEDIUM, or LONGTERM
<mupplet-name>/sensor/mode/set	FAST, MEDIUM, or LONGTERM	Set external additional filter values

Sample code

For a complete examples see the muwerk/examples project.

#include "ustd_platform.h"
#include "scheduler.h"
#include "net.h"
#include "mqtt.h"
 
#include "mup_presstemp_bmp280.h"
 
void appLoop();
 
ustd::Scheduler sched(10, 16, 32);
ustd::Net net(LED_BUILTIN);
ustd::Mqtt mqtt;
 
ustd::PressTempBMP280 bmp("myBMP280");
 
void sensorUpdates(String topic, String msg, String originator) {
    // data is in topic, msg
}
 
void setup() {
#ifdef USE_SERIAL_DBG
    Serial.begin(115200);
#endif  // USE_SERIAL_DBG
    net.begin(&sched);
    mqtt.begin(&sched);
    ota.begin(&sched);
    int tID = sched.add(appLoop, "main", 1000000);
 
    // sensors start measuring pressure and temperature
    bmp.setReferenceAltitude(518.0); // 518m above NN, now we also receive PressureNN values for sea level.
    bmp.begin(&sched, ustd::PressTempBMP280::BMPSampleMode::ULTRA_HIGH_RESOLUTION);
 
    sched.subscribe(tID, "myBMP280/sensor/temperature", sensorUpdates);
}
 
void appLoop() {
}
 
// Never add code to this loop, use appLoop() instead.
void loop() {
    sched.loop();
}

Member Enumeration Documentation

BMPSampleMode

enum ustd::PressTempBMP280::BMPSampleMode

Hardware accuracy modes of BMP280, while the sensor can have different pressure- and temperature oversampling, we use same for both temp and press.

Enumerator
ULTRA_LOW_POWER	1 samples, pressure resolution 16bit / 2.62 Pa, rec temperature oversampling: x1
LOW_POWER	2 samples, pressure resolution 17bit / 1.31 Pa, rec temperature oversampling: x1
STANDARD	4 samples, pressure resolution 18bit / 0.66 Pa, rec temperature oversampling: x1
HIGH_RESOLUTION	8 samples, pressure resolution 19bit / 0.33 Pa, rec temperature oversampling: x1
ULTRA_HIGH_RESOLUTION	16 samples, pressure resolution 20bit / 0.16 Pa, rec temperature oversampling: x2

Constructor & Destructor Documentation

PressTempBMP280()

ustd::PressTempBMP280::PressTempBMP280 ( String  name, FilterMode  filterMode = FilterMode::MEDIUM, uint8_t  i2cAddress = 0x76  )

inline

Instantiate an BMP sensor mupplet

Parameters

name	Name used for pub/sub messages
filterMode	FAST, MEDIUM or LONGTERM filtering of sensor values
i2cAddress	Should always be 0x76 or 0x77 for BMP280, depending on SDO pin.

Member Function Documentation

getPressure()

double ustd::PressTempBMP280::getPressure ( )

inline

Get current pressure

Returns

Pressure (in hPa)

getPressureNN()

double ustd::PressTempBMP280::getPressureNN ( double  _pressure )

inline

Get current pressure at sea level (NN)

Once a reference altitude is defined (see setReferenceAltitude()), pressure at sea level NN can be calculated with this function.

Returns

Pressure at sea level (in hPa)

getTemperature()

double ustd::PressTempBMP280::getTemperature ( )

inline

Get current temperature

Returns

Temperature (in degrees celsius)

setReferenceAltitude()

void ustd::PressTempBMP280::setReferenceAltitude ( double  _referenceAltitudeMeters )

inline

Set the altitude at current sensor location as reference

Parameters

_referenceAltitudeMeters

The current altitude above sea level in meters

startRelativeAltitude()

void ustd::PressTempBMP280::startRelativeAltitude ( )

inline

Store current pressure for a reference altitude to start relative altitude measurement

Once a reference altitude is defined (see setReferenceAltitude()), measurement of relative altitude can be started by calling this function.

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

• src/mup_presstemp_bmp280.h