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BMP085/BMP180 Barometric Pressure + Temp sensor for Spark Core
//-----------------------------------------------------------------
// BMP085/BMP180 Barometric Pressure + Temp sensor for Spark Core
//=================================================================
// Copy this into a new application at:
// https://www.spark.io/build and go nuts!
//-----------------------------------------------------------------
// Technobly / BDub - Jan 2014
//=================================================================
/***************************************************
This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
Designed specifically to work with the Adafruit BMP085 or BMP180 Breakout
----> http://www.adafruit.com/products/391
----> http://www.adafruit.com/products/1603
These displays use I2C to communicate, 2 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include <math.h>
#define boolean bool
#define BMP085_DEBUG 0
#define BMP085_I2CADDR 0x77
#define BMP085_ULTRALOWPOWER 0
#define BMP085_STANDARD 1
#define BMP085_HIGHRES 2
#define BMP085_ULTRAHIGHRES 3
#define BMP085_CAL_AC1 0xAA // R Calibration data (16 bits)
#define BMP085_CAL_AC2 0xAC // R Calibration data (16 bits)
#define BMP085_CAL_AC3 0xAE // R Calibration data (16 bits)
#define BMP085_CAL_AC4 0xB0 // R Calibration data (16 bits)
#define BMP085_CAL_AC5 0xB2 // R Calibration data (16 bits)
#define BMP085_CAL_AC6 0xB4 // R Calibration data (16 bits)
#define BMP085_CAL_B1 0xB6 // R Calibration data (16 bits)
#define BMP085_CAL_B2 0xB8 // R Calibration data (16 bits)
#define BMP085_CAL_MB 0xBA // R Calibration data (16 bits)
#define BMP085_CAL_MC 0xBC // R Calibration data (16 bits)
#define BMP085_CAL_MD 0xBE // R Calibration data (16 bits)
#define BMP085_CONTROL 0xF4
#define BMP085_TEMPDATA 0xF6
#define BMP085_PRESSUREDATA 0xF6
#define BMP085_READTEMPCMD 0x2E
#define BMP085_READPRESSURECMD 0x34
class Adafruit_BMP085 {
public:
Adafruit_BMP085();
boolean begin(uint8_t mode = BMP085_ULTRAHIGHRES); // by default go highres
float readTemperature(void);
int32_t readPressure(void);
float readAltitude(float sealevelPressure = 101325); // std atmosphere
uint16_t readRawTemperature(void);
uint32_t readRawPressure(void);
private:
uint8_t read8(uint8_t addr);
uint16_t read16(uint8_t addr);
void write8(uint8_t addr, uint8_t data);
uint8_t oversampling;
int16_t ac1, ac2, ac3, b1, b2, mb, mc, md;
uint16_t ac4, ac5, ac6;
};
/***************************************************
This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
Designed specifically to work with the Adafruit BMP085 or BMP180 Breakout
----> http://www.adafruit.com/products/391
----> http://www.adafruit.com/products/1603
These displays use I2C to communicate, 2 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
Adafruit_BMP085::Adafruit_BMP085() {
}
boolean Adafruit_BMP085::begin(uint8_t mode) {
if (mode > BMP085_ULTRAHIGHRES)
mode = BMP085_ULTRAHIGHRES;
oversampling = mode;
Wire.begin();
if (read8(0xD0) != 0x55) return false;
/* read calibration data */
ac1 = read16(BMP085_CAL_AC1);
ac2 = read16(BMP085_CAL_AC2);
ac3 = read16(BMP085_CAL_AC3);
ac4 = read16(BMP085_CAL_AC4);
ac5 = read16(BMP085_CAL_AC5);
ac6 = read16(BMP085_CAL_AC6);
b1 = read16(BMP085_CAL_B1);
b2 = read16(BMP085_CAL_B2);
mb = read16(BMP085_CAL_MB);
mc = read16(BMP085_CAL_MC);
md = read16(BMP085_CAL_MD);
#if (BMP085_DEBUG == 1)
Serial.print("ac1 = "); Serial.println(ac1, DEC);
Serial.print("ac2 = "); Serial.println(ac2, DEC);
Serial.print("ac3 = "); Serial.println(ac3, DEC);
Serial.print("ac4 = "); Serial.println(ac4, DEC);
Serial.print("ac5 = "); Serial.println(ac5, DEC);
Serial.print("ac6 = "); Serial.println(ac6, DEC);
Serial.print("b1 = "); Serial.println(b1, DEC);
Serial.print("b2 = "); Serial.println(b2, DEC);
Serial.print("mb = "); Serial.println(mb, DEC);
Serial.print("mc = "); Serial.println(mc, DEC);
Serial.print("md = "); Serial.println(md, DEC);
#endif
return true;
}
uint16_t Adafruit_BMP085::readRawTemperature(void) {
write8(BMP085_CONTROL, BMP085_READTEMPCMD);
delay(5);
#if BMP085_DEBUG == 1
Serial.print("Raw temp: "); Serial.println(read16(BMP085_TEMPDATA));
#endif
return read16(BMP085_TEMPDATA);
}
uint32_t Adafruit_BMP085::readRawPressure(void) {
uint32_t raw;
write8(BMP085_CONTROL, BMP085_READPRESSURECMD + (oversampling << 6));
if (oversampling == BMP085_ULTRALOWPOWER)
delay(5);
else if (oversampling == BMP085_STANDARD)
delay(8);
else if (oversampling == BMP085_HIGHRES)
delay(14);
else
delay(26);
raw = read16(BMP085_PRESSUREDATA);
raw <<= 8;
raw |= read8(BMP085_PRESSUREDATA+2);
raw >>= (8 - oversampling);
/* this pull broke stuff, look at it later?
if (oversampling==0) {
raw <<= 8;
raw |= read8(BMP085_PRESSUREDATA+2);
raw >>= (8 - oversampling);
}
*/
#if BMP085_DEBUG == 1
Serial.print("Raw pressure: "); Serial.println(raw);
#endif
return raw;
}
int32_t Adafruit_BMP085::readPressure(void) {
int32_t UT, UP, B3, B5, B6, X1, X2, X3, p;
uint32_t B4, B7;
UT = readRawTemperature();
UP = readRawPressure();
#if BMP085_DEBUG == 1
// use datasheet numbers!
UT = 27898;
UP = 23843;
ac6 = 23153;
ac5 = 32757;
mc = -8711;
md = 2868;
b1 = 6190;
b2 = 4;
ac3 = -14383;
ac2 = -72;
ac1 = 408;
ac4 = 32741;
oversampling = 0;
#endif
// do temperature calculations
X1=(UT-(int32_t)(ac6))*((int32_t)(ac5))/pow(2,15);
X2=((int32_t)mc*pow(2,11))/(X1+(int32_t)md);
B5=X1 + X2;
#if BMP085_DEBUG == 1
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B5 = "); Serial.println(B5);
#endif
// do pressure calcs
B6 = B5 - 4000;
X1 = ((int32_t)b2 * ( (B6 * B6)>>12 )) >> 11;
X2 = ((int32_t)ac2 * B6) >> 11;
X3 = X1 + X2;
B3 = ((((int32_t)ac1*4 + X3) << oversampling) + 2) / 4;
#if BMP085_DEBUG == 1
Serial.print("B6 = "); Serial.println(B6);
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B3 = "); Serial.println(B3);
#endif
X1 = ((int32_t)ac3 * B6) >> 13;
X2 = ((int32_t)b1 * ((B6 * B6) >> 12)) >> 16;
X3 = ((X1 + X2) + 2) >> 2;
B4 = ((uint32_t)ac4 * (uint32_t)(X3 + 32768)) >> 15;
B7 = ((uint32_t)UP - B3) * (uint32_t)( 50000UL >> oversampling );
#if BMP085_DEBUG == 1
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
Serial.print("B4 = "); Serial.println(B4);
Serial.print("B7 = "); Serial.println(B7);
#endif
if (B7 < 0x80000000) {
p = (B7 * 2) / B4;
} else {
p = (B7 / B4) * 2;
}
X1 = (p >> 8) * (p >> 8);
X1 = (X1 * 3038) >> 16;
X2 = (-7357 * p) >> 16;
#if BMP085_DEBUG == 1
Serial.print("p = "); Serial.println(p);
Serial.print("X1 = "); Serial.println(X1);
Serial.print("X2 = "); Serial.println(X2);
#endif
p = p + ((X1 + X2 + (int32_t)3791)>>4);
#if BMP085_DEBUG == 1
Serial.print("p = "); Serial.println(p);
#endif
return p;
}
float Adafruit_BMP085::readTemperature(void) {
int32_t UT, X1, X2, B5; // following ds convention
float temp;
UT = readRawTemperature();
#if BMP085_DEBUG == 1
// use datasheet numbers!
UT = 27898;
ac6 = 23153;
ac5 = 32757;
mc = -8711;
md = 2868;
#endif
// step 1
X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) / pow(2,15);
X2 = ((int32_t)mc * pow(2,11)) / (X1+(int32_t)md);
B5 = X1 + X2;
temp = (B5+8)/pow(2,4);
temp /= 10;
return temp;
}
float Adafruit_BMP085::readAltitude(float sealevelPressure) {
float altitude;
float pressure = readPressure();
altitude = 44330 * (1.0 - pow(pressure /sealevelPressure,0.1903));
return altitude;
}
/*********************************************************************/
uint8_t Adafruit_BMP085::read8(uint8_t a) {
uint8_t ret;
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.write(a); // sends register address to read from
Wire.endTransmission(); // end transmission
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.requestFrom(BMP085_I2CADDR, 1);// send data n-bytes read
ret = Wire.read(); // receive DATA
Wire.endTransmission(); // end transmission
return ret;
}
uint16_t Adafruit_BMP085::read16(uint8_t a) {
uint16_t ret;
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.write(a); // sends register address to read from
Wire.endTransmission(); // end transmission
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.requestFrom(BMP085_I2CADDR, 2);// send data n-bytes read
ret = Wire.read(); // receive DATA
ret <<= 8;
ret |= Wire.read(); // receive DATA
Wire.endTransmission(); // end transmission
return ret;
}
void Adafruit_BMP085::write8(uint8_t a, uint8_t d) {
Wire.beginTransmission(BMP085_I2CADDR); // start transmission to device
Wire.write(a); // sends register address to read from
Wire.write(d); // write data
Wire.endTransmission(); // end transmission
}
/***************************************************
This is an example for the BMP085 Barometric Pressure & Temp Sensor
Designed specifically to work with the Adafruit BMP085 Breakout
----> https://www.adafruit.com/products/391
These displays use I2C to communicate, 2 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
// SPARK CORE PINOUT ---------------------------------
// Connect VCC of the BMP085 sensor to 3.3* (NOT Vin!)
// Connect GND to GND
// Connect SCL to i2c clock - on Spark Core this is D1
// Connect SDA to i2c data - on Spark Core this is D0
// EOC is not used, it signifies an end of conversion
// XCLR is a reset pin, also not used here
Adafruit_BMP085 bmp;
void setup() {
Serial.begin(9600); // start Core with Serial terminal Closed, then open serial terminal
while(!Serial.available()) SPARK_WLAN_Loop(); // wait for user to press ENTER in serial terminal
if (!bmp.begin()) {
Serial.println("Could not find a valid BMP085 sensor, check wiring!");
while(1) SPARK_WLAN_Loop(); // Die, with the possibility of reincarnation
}
}
void loop() {
Serial.print("Temperature = ");
Serial.print(bmp.readTemperature());
Serial.println(" *C");
Serial.print("Pressure = ");
Serial.print(bmp.readPressure());
Serial.println(" Pa");
// Calculate altitude assuming 'standard' barometric
// pressure of 1013.25 millibar = 101325 Pascal
Serial.print("Altitude = ");
Serial.print(bmp.readAltitude());
Serial.println(" meters");
// you can get a more precise measurement of altitude
// if you know the current sea level pressure which will
// vary with weather and such. If it is 1015 millibars
// that is equal to 101500 Pascals.
Serial.print("Real altitude = ");
Serial.print(bmp.readAltitude(101500));
Serial.println(" meters");
Serial.println();
delay(500);
}
@dmiddlecamp
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Just used this at JSCONF, some guys here are build node rockets, I think we're going to hook a core up to a rocket tomorrow and see how far it goes!

@ecoffman
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ecoffman commented Dec 7, 2014

As a total newb to Spark Core, I am unsure about the wiring of the BMP180. SDA to D0 and SCL to D1. Then 3V to 3V3* and Gnd to Gnd. Is there anything else needed?

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