Donsez: Created page with "https://www.sparkfun.com/products/retired/9694 * http://wiring.org.co/learning/libraries/bmp085.html * 3.3V * GND * PIN_SDL=8 * PIN_SDA=9 ==Arduino==
 #include 
2013-10-07T19:37:11Z
Created page with "https://www.sparkfun.com/products/retired/9694 * http://wiring.org.co/learning/libraries/bmp085.html  * 3.3V * GND * PIN_SDL=8 * PIN_SDA=9    ==Arduino== <pre> #include <Wire...."
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https://www.sparkfun.com/products/retired/9694

* http://wiring.org.co/learning/libraries/bmp085.html



* 3.3V

* GND

* PIN_SDL=8

* PIN_SDA=9







==Arduino==

<pre>

#include <Wire.h>



// From the datasheet the BMP module address LSB distinguishes

// between read (1) and write (0) operations, corresponding to 

// address 0xEF (read) and 0xEE (write).

// shift the address 1 bit right (0xEF or 0xEE), the Wire library only needs the 7

// most significant bits for the address 0xEF >> 1 = 0x77

// 0xEE >> 1 = 0x77



// http://wiring.org.co/learning/libraries/bmp085.html



// 3.3V

// GND

// PIN_SDL=8

// PIN_SDA=9





int I2C_ADDRESS = 0x77;  // sensor address



// oversampling setting

// 0 = ultra low power

// 1 = standard

// 2 = high

// 3 = ultra high resolution

const unsigned char oversampling_setting = 3; //oversampling for measurement

const unsigned char pressure_conversiontime[4] = { 

  5, 8, 14, 26 };  // delays for oversampling settings 0, 1, 2 and 3   



// sensor registers from the BOSCH BMP085 datasheet

int ac1;

int ac2; 

int ac3; 

unsigned int ac4;

unsigned int ac5;

unsigned int ac6;

int b1; 

int b2;

int mb;

int mc;

int md;



// variables to keep the values

int temperature = 0;

long pressure = 0;





void setup()

{  

  Serial.begin(9600);  

  Wire.begin();

  getCalibrationData();

}



void loop()

{

  readSensor();

  Serial.print("Temperature: ");

  Serial.print(temperature,DEC);

  Serial.print(" Pressure: ");

  Serial.println(pressure,DEC);

  delay(100);

}





// Below there are the utility functions to get data from the sensor.



// read temperature and pressure from sensor

void readSensor() {

  int  ut= readUT();

  long up = readUP();

  long x1, x2, x3, b3, b5, b6, p;

  unsigned long b4, b7;



  //calculate true temperature

  x1 = ((long)ut - ac6) * ac5 >> 15;

  x2 = ((long) mc << 11) / (x1 + md);

  b5 = x1 + x2;

  temperature = (b5 + 8) >> 4;



  //calculate true pressure

  b6 = b5 - 4000;

  x1 = (b2 * (b6 * b6 >> 12)) >> 11; 

  x2 = ac2 * b6 >> 11;

  x3 = x1 + x2;

  b3 = (((int32_t) ac1 * 4 + x3)<<oversampling_setting + 2) >> 2;

  x1 = ac3 * b6 >> 13;

  x2 = (b1 * (b6 * b6 >> 12)) >> 16;

  x3 = ((x1 + x2) + 2) >> 2;

  b4 = (ac4 * (uint32_t) (x3 + 32768)) >> 15;

  b7 = ((uint32_t) up - b3) * (50000 >> oversampling_setting);

  p = b7 < 0x80000000 ? (b7 * 2) / b4 : (b7 / b4) * 2;



  x1 = (p >> 8) * (p >> 8);

  x1 = (x1 * 3038) >> 16;

  x2 = (-7357 * p) >> 16;

  pressure = p + ((x1 + x2 + 3791) >> 4);

}



// read uncompensated temperature value

unsigned int readUT() {

  writeRegister(0xf4,0x2e);

  delay(5); // the datasheet suggests 4.5 ms

  return readIntRegister(0xf6);

}



// read uncompensated pressure value

long readUP() {

  writeRegister(0xf4,0x34+(oversampling_setting<<6));

  delay(pressure_conversiontime[oversampling_setting]);



  unsigned char msb, lsb, xlsb;

  Wire.beginTransmission(I2C_ADDRESS);

  Wire.write(0xf6);  // register to read

  Wire.endTransmission();



  Wire.requestFrom(I2C_ADDRESS, 3); // request three bytes

  while(!Wire.available()); // wait until data available

  msb = Wire.read();

  while(!Wire.available()); // wait until data available

  lsb |= Wire.read();

  while(!Wire.available()); // wait until data available

  xlsb |= Wire.read();

  return (((long)msb<<16) | ((long)lsb<<8) | ((long)xlsb)) >>(8-oversampling_setting);

}



void  getCalibrationData() {

  Serial.println("Reading Calibration Data");

  ac1 = readIntRegister(0xAA);

  Serial.print("AC1: ");

  Serial.println(ac1,DEC);

  ac2 = readIntRegister(0xAC);

  Serial.print("AC2: ");

  Serial.println(ac2,DEC);

  ac3 = readIntRegister(0xAE);

  Serial.print("AC3: ");

  Serial.println(ac3,DEC);

  ac4 = readIntRegister(0xB0);

  Serial.print("AC4: ");

  Serial.println(ac4,DEC);

  ac5 = readIntRegister(0xB2);

  Serial.print("AC5: ");

  Serial.println(ac5,DEC);

  ac6 = readIntRegister(0xB4);

  Serial.print("AC6: ");

  Serial.println(ac6,DEC);

  b1 = readIntRegister(0xB6);

  Serial.print("B1: ");

  Serial.println(b1,DEC);

  b2 = readIntRegister(0xB8);

  Serial.print("B2: ");

  Serial.println(b1,DEC);

  mb = readIntRegister(0xBA);

  Serial.print("MB: ");

  Serial.println(mb,DEC);

  mc = readIntRegister(0xBC);

  Serial.print("MC: ");

  Serial.println(mc,DEC);

  md = readIntRegister(0xBE);

  Serial.print("MD: ");

  Serial.println(md,DEC);

}



void writeRegister(unsigned char r, unsigned char v)

{

  Wire.beginTransmission(I2C_ADDRESS);

  Wire.write(r);

  Wire.write(v);

  Wire.endTransmission();

}



// read a 16 bit register

int readIntRegister(unsigned char r)

{

  unsigned char msb, lsb;

  Wire.beginTransmission(I2C_ADDRESS);

  Wire.write(r);  // register to read

  Wire.endTransmission();



  Wire.requestFrom(I2C_ADDRESS, 2); // request two bytes

  while(!Wire.available()); // wait until data available

  msb = Wire.read();

  while(!Wire.available()); // wait until data available

  lsb = Wire.read();

  return (((int)msb<<8) | ((int)lsb));

}



// read an 8 bit register

/*

unsigned char readRegister(unsigned char r)

{

  unsigned char v;

  Wire.beginTransmission(I2C_ADDRESS);

  Wire.send(r);  // register to read

  Wire.endTransmission();



  Wire.requestFrom(I2C_ADDRESS, 1); // request a byte

  while(!Wire.available()); // wait until data available

  v = Wire.receive();

  return v;

}

*/

</pre>
Capteur de pression BMP085 - Revision history
