I tested & corrected and this code really works.<\/p>\n
\/\/ DANGER: The BMP08 accepts 1.8 to 3.6 Volts \u2013 so no chance to connect it directly to 5 Volts.<\/p>\n \/\/ Connect VCC to VCC and GND to GND, SCL goes to analogue pin 5, SDA to analogue pin4. \/\/ References: http:\/\/interactive-matter.org\/2009\/12\/arduino-barometric-pressure-sensor-bmp085\/ and http:\/\/news.jeelabs.org\/2009\/02\/19\/hooking-up-a-bmp085-sensor\/ #include \"Wire.h\"<\/p>\n #define I2C_ADDRESS 0x77 <\/p>\n const unsigned char oversampling_setting = 3; \/\/oversamplig for measurement \/\/just taken from the BMP085 datasheet void setup() bmp085_read_temperature_and_pressure(&temperature,&pressure); void bmp085_read_temperature_and_pressure(int* temperature, long* pressure) { \/\/calculate the temperature \/\/calculate the pressure \/\/b3 = (((int32_t) ac1 * 4 + x3)< if (oversampling_setting == 3) b3 = ((int32_t) ac1 * 4 + x3 + 2) << 1;\n if (oversampling_setting == 2) b3 = ((int32_t) ac1 * 4 + x3 + 2); \n if (oversampling_setting == 1) b3 = ((int32_t) ac1 * 4 + x3 + 2) >> 1; x1 = ac3 * b6 >> 13; }<\/p>\n unsigned int bmp085_read_ut() { void bmp085_get_cal_data() { long bmp085_read_up() { void write_register(unsigned char r, unsigned char v) char read_register(unsigned char r) Wire.requestFrom(I2C_ADDRESS, 1); \/\/ read a byte int read_int_register(unsigned char r) Wire.requestFrom(I2C_ADDRESS, 2); \/\/ read a byte
\n\/\/ BMP08 with Arduino<\/p>\n
\n\/\/ Notice! Sparkfun breakoutboard contains already 4.7K pull ups,
\n\/\/ If not using pre-built pull-ups:
\n\/\/ --> Add some pull up resistors (1K to 20K, most often something like 4.7K) between SDA, SCL and VCC finishes the setup.<\/p>\n
\n\/\/ Specification: http:\/\/www.bosch-sensortec.com\/content\/language1\/downloads\/BST-BMP085-DS000-05.pdf
\n\/\/ SparkFun breakout board: http:\/\/www.sparkfun.com\/commerce\/product_info.php?products_id=9694<\/p>\n
\nconst unsigned char pressure_waittime[4] = { 5, 8, 14, 26 };<\/p>\n
\nint ac1;
\nint ac2;
\nint ac3;
\nunsigned int ac4;
\nunsigned int ac5;
\nunsigned int ac6;
\nint b1;
\nint b2;
\nint mb;
\nint mc;
\nint md;<\/p>\n
\n{
\n Serial.begin(9600); \/\/ start serial for output
\n Serial.println(\"Setting up BMP085\");
\n Wire.begin();
\n bmp085_get_cal_data();
\n}
\nvoid bmp085_read_temperature_and_pressure(int& temperature, long& pressure);
\nvoid loop()
\n{
\n int temperature = 0;
\n long pressure = 0;<\/p>\n
\n Serial.print(temperature,DEC);
\n Serial.print(\" \");
\n Serial.print(pressure,DEC);
\n Serial.println();
\n delay(100);
\n}<\/p>\n
\n int ut= bmp085_read_ut();
\n long up = bmp085_read_up();
\n long x1, x2, x3, b3, b5, b6, p;
\n unsigned long b4, b7;<\/p>\n
\n x1 = ((long)ut - ac6) * ac5 >> 15;
\n x2 = ((long) mc << 11) \/ (x1 + md);\n b5 = x1 + x2;\n *temperature = (b5 + 8) >> 4;<\/p>\n
\n b6 = b5 - 4000;
\n x1 = (b2 * (b6 * b6 >> 12)) >> 11;
\n x2 = ac2 * b6 >> 11;
\n x3 = x1 + x2;<\/p>\n
\n if (oversampling_setting == 0) b3 = ((int32_t) ac1 * 4 + x3 + 2) >> 2;<\/p>\n
\n x2 = (b1 * (b6 * b6 >> 12)) >> 16;
\n x3 = ((x1 + x2) + 2) >> 2;
\n b4 = (ac4 * (uint32_t) (x3 + 32768)) >> 15;
\n b7 = ((uint32_t) up - b3) * (50000 >> oversampling_setting);
\n p = b7 < 0x80000000 ? (b7 * 2) \/ b4 : (b7 \/ b4) * 2;\n \n x1 = (p >> 8) * (p >> 8);
\n x1 = (x1 * 3038) >> 16;
\n x2 = (-7357 * p) >> 16;
\n *pressure = p + ((x1 + x2 + 3791) >> 4);<\/p>\n
\n write_register(0xf4,0x2e);
\n delay(5); \/\/longer than 4.5 ms
\n return read_int_register(0xf6);
\n}<\/p>\n
\n Serial.println(\"Reading Calibration Data\");
\n ac1 = read_int_register(0xAA);
\n Serial.print(\"AC1: \");
\n Serial.println(ac1,DEC);
\n ac2 = read_int_register(0xAC);
\n Serial.print(\"AC2: \");
\n Serial.println(ac2,DEC);
\n ac3 = read_int_register(0xAE);
\n Serial.print(\"AC3: \");
\n Serial.println(ac3,DEC);
\n ac4 = read_int_register(0xB0);
\n Serial.print(\"AC4: \");
\n Serial.println(ac4,DEC);
\n ac5 = read_int_register(0xB2);
\n Serial.print(\"AC5: \");
\n Serial.println(ac5,DEC);
\n ac6 = read_int_register(0xB4);
\n Serial.print(\"AC6: \");
\n Serial.println(ac6,DEC);
\n b1 = read_int_register(0xB6);
\n Serial.print(\"B1: \");
\n Serial.println(b1,DEC);
\n b2 = read_int_register(0xB8);
\n Serial.print(\"B2: \");
\n Serial.println(b1,DEC);
\n mb = read_int_register(0xBA);
\n Serial.print(\"MB: \");
\n Serial.println(mb,DEC);
\n mc = read_int_register(0xBC);
\n Serial.print(\"MC: \");
\n Serial.println(mc,DEC);
\n md = read_int_register(0xBE);
\n Serial.print(\"MD: \");
\n Serial.println(md,DEC);
\n}<\/p>\n
\n write_register(0xf4,0x34+(oversampling_setting<<6));\n delay(pressure_waittime[oversampling_setting]);\n \n unsigned char msb, lsb, xlsb;\n Wire.beginTransmission(I2C_ADDRESS);\n Wire.send(0xf6); \/\/ register to read\n Wire.endTransmission();\n\n Wire.requestFrom(I2C_ADDRESS, 3); \/\/ read a byte\n while(!Wire.available()) {\n \/\/ waiting\n }\n msb = Wire.receive();\n while(!Wire.available()) {\n \/\/ waiting\n }\n lsb |= Wire.receive();\n while(!Wire.available()) {\n \/\/ waiting\n }\n xlsb |= Wire.receive();\n return (((long)msb<<16) | ((long)lsb<<8) | ((long)xlsb)) >>(8-oversampling_setting);
\n}<\/p>\n
\n{
\n Wire.beginTransmission(I2C_ADDRESS);
\n Wire.send(r);
\n Wire.send(v);
\n Wire.endTransmission();
\n}<\/p>\n
\n{
\n unsigned char v;
\n Wire.beginTransmission(I2C_ADDRESS);
\n Wire.send(r); \/\/ register to read
\n Wire.endTransmission();<\/p>\n
\n while(!Wire.available()) {
\n \/\/ waiting
\n }
\n v = Wire.receive();
\n return v;
\n}<\/p>\n
\n{
\n unsigned char msb, lsb;
\n Wire.beginTransmission(I2C_ADDRESS);
\n Wire.send(r); \/\/ register to read
\n Wire.endTransmission();<\/p>\n
\n while(!Wire.available()) {
\n \/\/ waiting
\n }
\n msb = Wire.receive();
\n while(!Wire.available()) {
\n \/\/ waiting
\n }
\n lsb = Wire.receive();
\n return (((int)msb<<8) | ((int)lsb));\n}\n<\/code><\/p>\n