Update BMP085 library.

And additional pressure sensor problems repoted by @magkas.
http://forum.mysensors.org/topic/631/pressure-sensor-arduino-low-memory

Author: henrikekblad

libraries/Adafruit_BMP085/Adafruit_BMP085.cpp

@@ -1,8 +1,9 @@
 /*************************************************** 
-  This is a library for the BMP085 Barometric Pressure & Temp Sensor
+  This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
 
-  Designed specifically to work with the Adafruit BMP085 Breakout 
-  ----> https://www.adafruit.com/products/391
+  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
@@ -15,7 +16,6 @@
  ****************************************************/
 
 #include "Adafruit_BMP085.h"
-#include <util/delay.h>
 
 Adafruit_BMP085::Adafruit_BMP085() {
 }
@@ -59,11 +59,19 @@ boolean Adafruit_BMP085::begin(uint8_t mode) {
   Serial.print("mc = "); Serial.println(mc, DEC);
   Serial.print("md = "); Serial.println(md, DEC);
 #endif
+
+  return true;
+}
+
+int32_t Adafruit_BMP085::computeB5(int32_t UT) {
+  int32_t X1 = (UT - (int32_t)ac6) * ((int32_t)ac5) >> 15;
+  int32_t X2 = ((int32_t)mc << 11) / (X1+(int32_t)md);
+  return X1 + X2;
 }
 
 uint16_t Adafruit_BMP085::readRawTemperature(void) {
   write8(BMP085_CONTROL, BMP085_READTEMPCMD);
-  _delay_ms(5);
+  delay(5);
 #if BMP085_DEBUG == 1
   Serial.print("Raw temp: "); Serial.println(read16(BMP085_TEMPDATA));
 #endif
@@ -76,13 +84,13 @@ uint32_t Adafruit_BMP085::readRawPressure(void) {
   write8(BMP085_CONTROL, BMP085_READPRESSURECMD + (oversampling << 6));
 
   if (oversampling == BMP085_ULTRALOWPOWER) 
-    _delay_ms(5);
+    delay(5);
   else if (oversampling == BMP085_STANDARD) 
-    _delay_ms(8);
+    delay(8);
   else if (oversampling == BMP085_HIGHRES) 
-    _delay_ms(14);
+    delay(14);
   else 
-    _delay_ms(26);
+    delay(26);
 
   raw = read16(BMP085_PRESSUREDATA);
 
@@ -129,10 +137,7 @@ int32_t Adafruit_BMP085::readPressure(void) {
   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;
+  B5 = computeB5(UT);
 
 #if BMP085_DEBUG == 1
   Serial.print("X1 = "); Serial.println(X1);
@@ -189,9 +194,13 @@ int32_t Adafruit_BMP085::readPressure(void) {
   return p;
 }
 
+int32_t Adafruit_BMP085::readSealevelPressure(float altitude_meters) {
+  float pressure = readPressure();
+  return (int32_t)(pressure / pow(1.0-altitude_meters/44330, 5.255));
+}
 
 float Adafruit_BMP085::readTemperature(void) {
-  int32_t UT, X1, X2, B5;     // following ds convention
+  int32_t UT, B5;     // following ds convention
   float temp;
 
   UT = readRawTemperature();
@@ -205,11 +214,8 @@ float Adafruit_BMP085::readTemperature(void) {
   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);
+  B5 = computeB5(UT);
+  temp = (B5+8) >> 4;
   temp /= 10;
 
   return temp;

libraries/Adafruit_BMP085/Adafruit_BMP085.h

@@ -1,8 +1,9 @@
 /*************************************************** 
-  This is a library for the BMP085 Barometric Pressure & Temp Sensor
+  This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
 
-  Designed specifically to work with the Adafruit BMP085 Breakout 
-  ----> https://www.adafruit.com/products/391
+  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
@@ -14,6 +15,9 @@
   BSD license, all text above must be included in any redistribution
  ****************************************************/
 
+#ifndef ADAFRUIT_BMP085_H
+#define ADAFRUIT_BMP085_H
+
 #if (ARDUINO >= 100)
  #include "Arduino.h"
 #else
@@ -54,11 +58,13 @@ class Adafruit_BMP085 {
   boolean begin(uint8_t mode = BMP085_ULTRAHIGHRES);  // by default go highres
   float readTemperature(void);
   int32_t readPressure(void);
+  int32_t readSealevelPressure(float altitude_meters = 0);
   float readAltitude(float sealevelPressure = 101325); // std atmosphere
   uint16_t readRawTemperature(void);
   uint32_t readRawPressure(void);
 
  private:
+  int32_t computeB5(int32_t UT);
   uint8_t read8(uint8_t addr);
   uint16_t read16(uint8_t addr);
   void write8(uint8_t addr, uint8_t data);
@@ -69,3 +75,5 @@ class Adafruit_BMP085 {
   uint16_t ac4, ac5, ac6;
 };
 
+
+#endif //  ADAFRUIT_BMP085_H

libraries/Adafruit_BMP085/README.txt

@@ -1,7 +1,8 @@
-This is a library for the Adafruit BMP085 Barometric Pressure + Temp sensor
+This is a library for the Adafruit BMP085/BMP180 Barometric Pressure + Temp sensor
 
-Designed specifically to work with the Adafruit BMP085 Breakout 
-  ----> https://www.adafruit.com/products/391
+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, 
@@ -17,6 +18,11 @@ products from Adafruit!
 Written by Limor Fried/Ladyada for Adafruit Industries.  
 BSD license, all text above must be included in any redistribution
 
-To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder Adafruit_BMP085. Check that the Adafruit_BMP085 folder contains Adafruit_BMP085.cpp and Adafruit_BMP085.h
+To download. click the DOWNLOAD ZIP button, rename the uncompressed folder Adafruit_BMP085. 
+Check that the Adafruit_BMP085 folder contains Adafruit_BMP085.cpp and Adafruit_BMP085.h
 
-Place the Adafruit_BMP085 library folder your <arduinosketchfolder>/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE.
+Place the Adafruit_BMP085 library folder your arduinosketchfolder/libraries/ folder. 
+You may need to create the libraries subfolder if its your first library. Restart the IDE.
+
+We also have a great tutorial on Arduino library installation at:
+http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use

libraries/MySensors/examples/PressureSensor/PressureSensor.ino

@@ -44,7 +44,7 @@ void setup() {
 }
 
 void loop() {
-  float pressure = bmp.readPressure()/100;
+  float pressure = bmp.readSealevelPressure(205)/100; // 205 meters above sealevel
   float temperature = bmp.readTemperature();
 
   if (!metric) {
@@ -95,7 +95,7 @@ void loop() {
 int sample(float pressure) {
 	// Algorithm found here
 	// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
-	if (minuteCount > 180)
+	if (minuteCount == 180)
 		minuteCount = 5;
 
 	pressureSamples[minuteCount] = pressure;