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Added .readAltitude function

This commit is contained in:
Kevin Townsend 2015-09-01 07:23:33 +02:00
parent 59079b6d37
commit 11ad05a034
3 changed files with 74 additions and 48 deletions
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82
Adafruit_BME280.cpp
View File

@ -1,17 +1,17 @@
/***************************************************************************
This is a library for the BME280 humidity, temperature & pressure sensor
Designed specifically to work with the Adafruit BME280 Breakout
Designed specifically to work with the Adafruit BME280 Breakout
----> http://www.adafruit.com/products/2650
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
to interface.
Adafruit invests time and resources providing this open source code,
please support Adafruit andopen-source hardware by purchasing products
from Adafruit!
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
BSD license, all text above must be included in any redistribution
***************************************************************************/
#include "Arduino.h"
@ -19,23 +19,23 @@
#include <SPI.h>
#include "Adafruit_BME280.h"
static bme280_calib_data bme280_calib;
static bme280_calib_data bme280_calib;
/***************************************************************************
PRIVATE FUNCTIONS
***************************************************************************/
Adafruit_BME280::Adafruit_BME280()
: _cs(-1), _mosi(-1), _miso(-1), _sck(-1)
Adafruit_BME280::Adafruit_BME280()
: _cs(-1), _mosi(-1), _miso(-1), _sck(-1)
{ }
Adafruit_BME280::Adafruit_BME280(int8_t cspin)
: _cs(cspin), _mosi(-1), _miso(-1), _sck(-1)
Adafruit_BME280::Adafruit_BME280(int8_t cspin)
: _cs(cspin), _mosi(-1), _miso(-1), _sck(-1)
{ }
Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin, int8_t sckpin)
: _cs(cspin), _mosi(mosipin), _miso(misopin), _sck(sckpin)
Adafruit_BME280::Adafruit_BME280(int8_t cspin, int8_t mosipin, int8_t misopin, int8_t sckpin)
: _cs(cspin), _mosi(mosipin), _miso(misopin), _sck(sckpin)
{ }
@ -70,9 +70,9 @@ bool Adafruit_BME280::begin(uint8_t a) {
}
uint8_t Adafruit_BME280::spixfer(uint8_t x) {
if (_sck == -1)
if (_sck == -1)
return SPI.transfer(x);
// software spi
//Serial.println("Software SPI");
uint8_t reply = 0;
@ -81,7 +81,7 @@ uint8_t Adafruit_BME280::spixfer(uint8_t x) {
digitalWrite(_sck, LOW);
digitalWrite(_mosi, x & (1<<i));
digitalWrite(_sck, HIGH);
if (digitalRead(_miso))
if (digitalRead(_miso))
reply |= 1;
}
return reply;
@ -119,7 +119,7 @@ void Adafruit_BME280::write8(byte reg, byte value)
uint8_t Adafruit_BME280::read8(byte reg)
{
uint8_t value;
if (_cs == -1) {
Wire.beginTransmission((uint8_t)_i2caddr);
Wire.write((uint8_t)reg);
@ -173,7 +173,7 @@ uint16_t Adafruit_BME280::read16(byte reg)
uint16_t Adafruit_BME280::read16_LE(byte reg) {
uint16_t temp = read16(reg);
return (temp >> 8) | (temp << 8);
}
/**************************************************************************/
@ -217,8 +217,8 @@ void Adafruit_BME280::readCoefficients(void)
bme280_calib.dig_H1 = read8(BME280_REGISTER_DIG_H1);
bme280_calib.dig_H2 = readS16_LE(BME280_REGISTER_DIG_H2);
bme280_calib.dig_H3 = read8(BME280_REGISTER_DIG_H3);
bme280_calib.dig_H4 = (read8(BME280_REGISTER_DIG_H4) << 4) | (read8(BME280_REGISTER_DIG_H4+1) & 0xF);
bme280_calib.dig_H5 = (read8(BME280_REGISTER_DIG_H5+1) << 4) | (read8(BME280_REGISTER_DIG_H5) >> 4);
bme280_calib.dig_H4 = (read8(BME280_REGISTER_DIG_H4) << 4) | (read8(BME280_REGISTER_DIG_H4+1) & 0xF);
bme280_calib.dig_H5 = (read8(BME280_REGISTER_DIG_H5+1) << 4) | (read8(BME280_REGISTER_DIG_H5) >> 4);
bme280_calib.dig_H6 = (int8_t)read8(BME280_REGISTER_DIG_H6);
}
@ -230,17 +230,17 @@ void Adafruit_BME280::readCoefficients(void)
float Adafruit_BME280::readTemperature(void)
{
int32_t var1, var2;
int32_t adc_T = read16(BME280_REGISTER_TEMPDATA);
adc_T <<= 8;
adc_T |= read8(BME280_REGISTER_TEMPDATA+2);
adc_T >>= 4;
var1 = ((((adc_T>>3) - ((int32_t)bme280_calib.dig_T1 <<1))) *
var1 = ((((adc_T>>3) - ((int32_t)bme280_calib.dig_T1 <<1))) *
((int32_t)bme280_calib.dig_T2)) >> 11;
var2 = (((((adc_T>>4) - ((int32_t)bme280_calib.dig_T1)) *
((adc_T>>4) - ((int32_t)bme280_calib.dig_T1))) >> 12) *
var2 = (((((adc_T>>4) - ((int32_t)bme280_calib.dig_T1)) *
((adc_T>>4) - ((int32_t)bme280_calib.dig_T1))) >> 12) *
((int32_t)bme280_calib.dig_T3)) >> 14;
t_fine = var1 + var2;
@ -256,7 +256,7 @@ float Adafruit_BME280::readTemperature(void)
/**************************************************************************/
float Adafruit_BME280::readPressure(void) {
int64_t var1, var2, p;
int32_t adc_P = read16(BME280_REGISTER_PRESSUREDATA);
adc_P <<= 8;
adc_P |= read8(BME280_REGISTER_PRESSUREDATA+2);
@ -269,7 +269,7 @@ float Adafruit_BME280::readPressure(void) {
var1 = ((var1 * var1 * (int64_t)bme280_calib.dig_P3)>>8) +
((var1 * (int64_t)bme280_calib.dig_P2)<<12);
var1 = (((((int64_t)1)<<47)+var1))*((int64_t)bme280_calib.dig_P1)>>33;
if (var1 == 0) {
return 0; // avoid exception caused by division by zero
}
@ -295,17 +295,39 @@ float Adafruit_BME280::readHumidity(void) {
v_x1_u32r = (t_fine - ((int32_t)76800));
v_x1_u32r = (((((adc_H << 14) - (((int32_t)bme280_calib.dig_H4) << 20) -
(((int32_t)bme280_calib.dig_H5) * v_x1_u32r)) + ((int32_t)16384)) >> 15) *
(((((((v_x1_u32r * ((int32_t)bme280_calib.dig_H6)) >> 10) *
(((v_x1_u32r * ((int32_t)bme280_calib.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) +
v_x1_u32r = (((((adc_H << 14) - (((int32_t)bme280_calib.dig_H4) << 20) -
(((int32_t)bme280_calib.dig_H5) * v_x1_u32r)) + ((int32_t)16384)) >> 15) *
(((((((v_x1_u32r * ((int32_t)bme280_calib.dig_H6)) >> 10) *
(((v_x1_u32r * ((int32_t)bme280_calib.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) +
((int32_t)2097152)) * ((int32_t)bme280_calib.dig_H2) + 8192) >> 14));
v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) *
v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) *
((int32_t)bme280_calib.dig_H1)) >> 4));
v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
v_x1_u32r = (v_x1_u32r > 419430400) ? 419430400 : v_x1_u32r;
float h = (v_x1_u32r>>12);
float h = (v_x1_u32r>>12);
return h / 1024.0;
}
/**************************************************************************/
/*!
Calculates the altitude (in meters) from the specified atmospheric
pressure (in hPa), and sea-level pressure (in hPa).
@param seaLevel Sea-level pressure in hPa
@param atmospheric Atmospheric pressure in hPa
*/
/**************************************************************************/
float Adafruit_BME280::readAltitude(float seaLevel)
{
// Equation taken from BMP180 datasheet (page 16):
// http://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf
// Note that using the equation from wikipedia can give bad results
// at high altitude. See this thread for more information:
// http://forums.adafruit.com/viewtopic.php?f=22&t=58064
float atmospheric = readPressure() / 100.0F;
return 44330.0 * (1.0 - pow(atmospheric / seaLevel, 0.1903));
}

12
Adafruit_BME280.h
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@ -1,17 +1,17 @@
/***************************************************************************
This is a library for the BME280 humidity, temperature & pressure sensor
Designed specifically to work with the Adafruit BME280 Breakout
Designed specifically to work with the Adafruit BME280 Breakout
----> http://www.adafruit.com/products/2650
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
to interface.
Adafruit invests time and resources providing this open source code,
please support Adafruit andopen-source hardware by purchasing products
from Adafruit!
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
BSD license, all text above must be included in any redistribution
***************************************************************************/
#ifndef __BME280_H__
@ -113,7 +113,7 @@ class Adafruit_BME280_Unified : public Adafruit_Sensor
{
public:
Adafruit_BME280_Unified(int32_t sensorID = -1);
bool begin(uint8_t addr = BME280_ADDRESS);
void getTemperature(float *temp);
void getPressure(float *pressure);
@ -140,9 +140,7 @@ class Adafruit_BME280
float readTemperature(void);
float readPressure(void);
float readHumidity(void);
// float pressureToAltitude(float seaLevel, float atmospheric, float temp);
// float seaLevelForAltitude(float altitude, float atmospheric, float temp);
float readAltitude(float seaLevel);
private:

28
examples/bme280test/bme280test.ino
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@ -1,17 +1,17 @@
/***************************************************************************
This is a library for the BME280 humidity, temperature & pressure sensor
Designed specifically to work with the Adafruit BME280 Breakout
Designed specifically to work with the Adafruit BME280 Breakout
----> http://www.adafruit.com/products/2650
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
to interface.
Adafruit invests time and resources providing this open source code,
please support Adafruit andopen-source hardware by purchasing products
from Adafruit!
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
BSD license, all text above must be included in any redistribution
***************************************************************************/
@ -22,36 +22,42 @@
#define BME_SCK 13
#define BME_MISO 12
#define BME_MOSI 11
#define BME_MOSI 11
#define BME_CS 10
#define SEALEVELPRESSURE_HPA (1013.25)
Adafruit_BME280 bme; // I2C
//Adafruit_BME280 bme(BME_CS); // hardware SPI
//Adafruit_BME280 bme(BME_CS, BME_MOSI, BME_MISO, BME_SCK);
void setup() {
Serial.begin(9600);
Serial.println(F("BME280 test"));
if (!bme.begin()) {
if (!bme.begin()) {
Serial.println("Could not find a valid BME280 sensor, check wiring!");
while (1);
}
}
void loop() {
Serial.print("Temperature = ");
Serial.print(bme.readTemperature());
Serial.println(" *C");
Serial.print("Pressure = ");
Serial.print(bme.readPressure() / 100.0F);
Serial.println(" hPa");
Serial.print("Approx. Altitude = ");
Serial.print(bme.readAltitude(SEALEVELPRESSURE_HPA));
Serial.println(" m");
Serial.print("Humidity = ");
Serial.print(bme.readHumidity());
Serial.println(" %");
Serial.println();
delay(500);
}