adafruit/Adafruit_BMP085_Unified
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Fixed temp calculations

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KTOWN
2013-06-18 17:40:11 +02:00
parent 491d1375e7
commit 123b6711ec
2 changed files with 36 additions and 13 deletions
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26
Adafruit_BMP085.cpp
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@ -311,14 +311,28 @@ void Adafruit_BMP085::getPressure(float *pressure)
/**************************************************************************/ /**************************************************************************/
void Adafruit_BMP085::getTemperature(float *temp) void Adafruit_BMP085::getTemperature(float *temp)
{ {
int32_t ut, x1, x2; int32_t UT, X1, X2, B5; // following ds convention
float t;
readRawTemperature(&ut); readRawTemperature(&UT);
x1 = (ut - _bmp085_coeffs.ac6) * _bmp085_coeffs.ac5 >> 15; #if BMP085_USE_DATASHEET_VALS
x2 = (_bmp085_coeffs.mc << 11) / (x1 + _bmp085_coeffs.md); // use datasheet numbers!
*temp = (x1+x2+8) >> 4; UT = 27898;
*temp /= 10; _bmp085_coeffs.ac6 = 23153;
_bmp085_coeffs.ac5 = 32757;
_bmp085_coeffs.mc = -8711;
_bmp085_coeffs.md = 2868;
#endif
// step 1
X1 = (UT - (int32_t)_bmp085_coeffs.ac6) * ((int32_t)_bmp085_coeffs.ac5) / pow(2,15);
X2 = ((int32_t)_bmp085_coeffs.mc * pow(2,11)) / (X1+(int32_t)_bmp085_coeffs.md);
B5 = X1 + X2;
t = (B5+8)/pow(2,4);
t /= 10;
*temp = t;
} }
/**************************************************************************/ /**************************************************************************/

23
examples/sensorapi/sensorapi.pde
View File

@ -89,7 +89,9 @@ void loop(void)
if (event.pressure) if (event.pressure)
{ {
/* Display atmospheric pressue in hPa */ /* Display atmospheric pressue in hPa */
Serial.print(event.pressure); Serial.print(" hPa"); Serial.print("Pressure: ");
Serial.print(event.pressure);
Serial.println(" hPa");
/* Calculating altitude with reasonable accuracy requires pressure * /* Calculating altitude with reasonable accuracy requires pressure *
* sea level pressure for your position at the moment the data is * * sea level pressure for your position at the moment the data is *
@ -106,19 +108,26 @@ void loop(void)
* For example, for Paris, France you can check the current mean * * For example, for Paris, France you can check the current mean *
* pressure and sea level at: http://bit.ly/16Au8ol */ * pressure and sea level at: http://bit.ly/16Au8ol */
float seaLevelPressure = SENSORS_PRESSURE_SEALEVELHPA; /* First we get the current temperature from the BMP085 */
float temperature; float temperature;
bmp.getTemperature(&temperature); bmp.getTemperature(&temperature);
Serial.print("Temperature: ");
Serial.print(" ("); Serial.print(temperature);
Serial.print(bmp.pressureToAltitude(seaLevelPressure, Serial.println(" C");
/* Then convert the atmospheric pressure, SLP and temp to altitude */
/* Update this next line with the current SLP for better results */
float seaLevelPressure = SENSORS_PRESSURE_SEALEVELHPA;
Serial.print("Altitude: ");
Serial.print(bmp.pressureToAltitude(seaLevelPressure,
event.pressure, event.pressure,
temperature)); temperature));
Serial.println(" m)"); Serial.println(" m");
Serial.println("");
} }
else else
{ {
Serial.println("Sensor error"); Serial.println("Sensor error");
} }
delay(250); delay(1000);
} }