{"id":27200,"date":"2016-10-14T09:38:26","date_gmt":"2016-10-14T09:38:26","guid":{"rendered":"http:\/\/randomnerdtutorials.com\/?p=27200"},"modified":"2019-04-02T10:23:30","modified_gmt":"2019-04-02T10:23:30","slug":"guide-for-bmp180-barometric-sensor-with-arduino","status":"publish","type":"post","link":"https:\/\/randomnerdtutorials.com\/guide-for-bmp180-barometric-sensor-with-arduino\/","title":{"rendered":"Guide for BMP180 Barometric Sensor with Arduino"},"content":{"rendered":"

This post is about how to use the BMP180 barometric sensor with the Arduino. It is also applicable for\u00a0other similar barometric sensors.<\/p>\n

<\/p>\n

Introducing the BMP180 barometric sensor<\/h2>\n

The BMP180 barometric sensor<\/a> (model GY-68) is the one in \u00a0the following figure (front and back view). It is a very small module\u00a0with 1mm x 1.1mm (0.039in x 0.043in).<\/p>\n

\"sensor\"<\/p>\n

It measures the absolute pressure of the air around it. It has a measuring range from 300 to 1100hPa with an accuracy down to 0.02 hPa. It can also measure altitude and temperature.<\/p>\n

The BMP180 barometric sensor communicates via I2C interface. This means that it communicates with the Arduino using just 2 pins.<\/p>\n

Where to buy?<\/h2>\n

This sensor is very cheap. You can buy one for approximately $3. Find the best price on Maker Advisor<\/a>.<\/p>\n

You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p>

<\/a><\/p>\n

Pin wiring<\/h2>\n

Wiring the sensor to the Arduino is pretty straightforward:<\/p>\n\n\n\n\n\n\n\n
Pin<\/strong><\/td>\nWiring to Arduino Uno<\/strong><\/td>\n<\/tr>\n
Vin<\/span><\/td>\n5V<\/span><\/td>\n<\/tr>\n
GND<\/span><\/td>\nGND<\/span><\/td>\n<\/tr>\n
SCL<\/span><\/td>\nA5<\/span><\/td>\n<\/tr>\n
SDA<\/span><\/td>\nA4<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Schematics<\/h2>\n

Wire your sensor to the Arduino as shown in the schematics below.<\/p>\n

\"bmp180-barometris-sensor_bb\"<\/p>\n

Code<\/h2>\n

To control the BMP180 barometric sensor, you need to install the\u00a0SFE_BMP180 Library.<\/strong><\/p>\n

Installing the SFE_BMP180 Library<\/strong><\/h3>\n
    \n
  1. Click here to download the SFE_BMP180 library<\/a>. You should have a .zip folder in your Downloads folder<\/li>\n
  2. Unzip the .zip folder and you should get\u00a0BMP180_Breakout_Arduino_Library-master<\/strong> folder<\/li>\n
  3. Rename your folder from BMP180_Breakout_Arduino_Library-master<\/strong><\/del>\u00a0to BMP180_Breakout_Arduino_Library<\/strong>\u00a0<\/strong><\/li>\n
  4. Move the BMP180_Breakout_Arduino_Library\u00a0<\/strong>folder to your Arduino IDE installation libraries folder<\/li>\n
  5. Finally, re-open your Arduino IDE<\/li>\n<\/ol>\n

    Go to File > Examples >SparkfunBMP180 > SFE_BMP180_example.<\/span><\/span><\/p>\n

    This example is very well commented and explained on how the sensor reads the pressure, temperature and computes the altitude.<\/p>\n

    \/* SFE_BMP180 library example sketch\n\nThis sketch shows how to use the SFE_BMP180 library to read the\nBosch BMP180 barometric pressure sensor.\nhttps:\/\/www.sparkfun.com\/products\/11824\n\nLike most pressure sensors, the BMP180 measures absolute pressure.\nThis is the actual ambient pressure seen by the device, which will\nvary with both altitude and weather.\n\nBefore taking a pressure reading you must take a temparture reading.\nThis is done with startTemperature() and getTemperature().\nThe result is in degrees C.\n\nOnce you have a temperature reading, you can take a pressure reading.\nThis is done with startPressure() and getPressure().\nThe result is in millibar (mb) aka hectopascals (hPa).\n\nIf you'll be monitoring weather patterns, you will probably want to\nremove the effects of altitude. This will produce readings that can\nbe compared to the published pressure readings from other locations.\nTo do this, use the sealevel() function. You will need to provide\nthe known altitude at which the pressure was measured.\n\nIf you want to measure altitude, you will need to know the pressure\nat a baseline altitude. This can be average sealevel pressure, or\na previous pressure reading at your altitude, in which case\nsubsequent altitude readings will be + or - the initial baseline.\nThis is done with the altitude() function.\n\nHardware connections:\n\n- (GND) to GND\n+ (VDD) to 3.3V\n\n(WARNING: do not connect + to 5V or the sensor will be damaged!)\n\nYou will also need to connect the I2C pins (SCL and SDA) to your\nArduino. The pins are different on different Arduinos:\n\nAny Arduino pins labeled:  SDA  SCL\nUno, Redboard, Pro:        A4   A5\nMega2560, Due:             20   21\nLeonardo:                   2    3\n\nLeave the IO (VDDIO) pin unconnected. This pin is for connecting\nthe BMP180 to systems with lower logic levels such as 1.8V\n\nHave fun! -Your friends at SparkFun.\n\nThe SFE_BMP180 library uses floating-point equations developed by the\nWeather Station Data Logger project: http:\/\/wmrx00.sourceforge.net\/\n\nOur example code uses the "beerware" license. You can do anything\nyou like with this code. No really, anything. If you find it useful,\nbuy me a beer someday.\n\nV10 Mike Grusin, SparkFun Electronics 10\/24\/2013\n*\/\n\n\/\/ Your sketch must #include this library, and the Wire library.\n\/\/ (Wire is a standard library included with Arduino.):\n\n#include <SFE_BMP180.h>\n#include <Wire.h>\n\n\/\/ You will need to create an SFE_BMP180 object, here called "pressure":\n\nSFE_BMP180 pressure;\n\n#define ALTITUDE 1655.0 \/\/ Altitude of SparkFun's HQ in Boulder, CO. in meters\n\nvoid setup()\n{\n  Serial.begin(9600);\n  Serial.println("REBOOT");\n\n  \/\/ Initialize the sensor (it is important to get calibration values stored on the device).\n\n  if (pressure.begin())\n    Serial.println("BMP180 init success");\n  else\n  {\n    \/\/ Oops, something went wrong, this is usually a connection problem,\n    \/\/ see the comments at the top of this sketch for the proper connections.\n\n    Serial.println("BMP180 init fail\\n\\n");\n    while(1); \/\/ Pause forever.\n  }\n}\n\nvoid loop()\n{\n  char status;\n  double T,P,p0,a;\n\n  \/\/ Loop here getting pressure readings every 10 seconds.\n\n  \/\/ If you want sea-level-compensated pressure, as used in weather reports,\n  \/\/ you will need to know the altitude at which your measurements are taken.\n  \/\/ We're using a constant called ALTITUDE in this sketch:\n  \n  Serial.println();\n  Serial.print("provided altitude: ");\n  Serial.print(ALTITUDE,0);\n  Serial.print(" meters, ");\n  Serial.print(ALTITUDE*3.28084,0);\n  Serial.println(" feet");\n  \n  \/\/ If you want to measure altitude, and not pressure, you will instead need\n  \/\/ to provide a known baseline pressure. This is shown at the end of the sketch.\n\n  \/\/ You must first get a temperature measurement to perform a pressure reading.\n  \n  \/\/ Start a temperature measurement:\n  \/\/ If request is successful, the number of ms to wait is returned.\n  \/\/ If request is unsuccessful, 0 is returned.\n\n  status = pressure.startTemperature();\n  if (status != 0)\n  {\n    \/\/ Wait for the measurement to complete:\n    delay(status);\n\n    \/\/ Retrieve the completed temperature measurement:\n    \/\/ Note that the measurement is stored in the variable T.\n    \/\/ Function returns 1 if successful, 0 if failure.\n\n    status = pressure.getTemperature(T);\n    if (status != 0)\n    {\n      \/\/ Print out the measurement:\n      Serial.print("temperature: ");\n      Serial.print(T,2);\n      Serial.print(" deg C, ");\n      Serial.print((9.0\/5.0)*T+32.0,2);\n      Serial.println(" deg F");\n      \n      \/\/ Start a pressure measurement:\n      \/\/ The parameter is the oversampling setting, from 0 to 3 (highest res, longest wait).\n      \/\/ If request is successful, the number of ms to wait is returned.\n      \/\/ If request is unsuccessful, 0 is returned.\n\n      status = pressure.startPressure(3);\n      if (status != 0)\n      {\n        \/\/ Wait for the measurement to complete:\n        delay(status);\n\n        \/\/ Retrieve the completed pressure measurement:\n        \/\/ Note that the measurement is stored in the variable P.\n        \/\/ Note also that the function requires the previous temperature measurement (T).\n        \/\/ (If temperature is stable, you can do one temperature measurement for a number of pressure measurements.)\n        \/\/ Function returns 1 if successful, 0 if failure.\n\n        status = pressure.getPressure(P,T);\n        if (status != 0)\n        {\n          \/\/ Print out the measurement:\n          Serial.print("absolute pressure: ");\n          Serial.print(P,2);\n          Serial.print(" mb, ");\n          Serial.print(P*0.0295333727,2);\n          Serial.println(" inHg");\n\n          \/\/ The pressure sensor returns abolute pressure, which varies with altitude.\n          \/\/ To remove the effects of altitude, use the sealevel function and your current altitude.\n          \/\/ This number is commonly used in weather reports.\n          \/\/ Parameters: P = absolute pressure in mb, ALTITUDE = current altitude in m.\n          \/\/ Result: p0 = sea-level compensated pressure in mb\n\n          p0 = pressure.sealevel(P,ALTITUDE); \/\/ we're at 1655 meters (Boulder, CO)\n          Serial.print("relative (sea-level) pressure: ");\n          Serial.print(p0,2);\n          Serial.print(" mb, ");\n          Serial.print(p0*0.0295333727,2);\n          Serial.println(" inHg");\n\n          \/\/ On the other hand, if you want to determine your altitude from the pressure reading,\n          \/\/ use the altitude function along with a baseline pressure (sea-level or other).\n          \/\/ Parameters: P = absolute pressure in mb, p0 = baseline pressure in mb.\n          \/\/ Result: a = altitude in m.\n\n          a = pressure.altitude(P,p0);\n          Serial.print("computed altitude: ");\n          Serial.print(a,0);\n          Serial.print(" meters, ");\n          Serial.print(a*3.28084,0);\n          Serial.println(" feet");\n        }\n        else Serial.println("error retrieving pressure measurement\\n");\n      }\n      else Serial.println("error starting pressure measurement\\n");\n    }\n    else Serial.println("error retrieving temperature measurement\\n");\n  }\n  else Serial.println("error starting temperature measurement\\n");\n\n  delay(5000);  \/\/ Pause for 5 seconds.\n}\n<\/code><\/pre>\n\t
    View raw code<\/a><\/p>\n
    Set the altitude<\/h3>\n
    Before uploading the code, you need to set up your current altitude.\u00a0Go to elevationmap.net<\/a>, insert your address and check your altitude’s location. Set your altitude in the code. The place where you should write your altitude is commented.<\/p>\n
    \"set-the-altitude\"<\/p>\n
    Demonstration<\/h2>\n
    After uploading the code, open your serial monitor at a baud rate of 9600.<\/p>\n
    You’ll be able to see your sensor readings.<\/p>\n
    \"serial-monitor\"<\/p>\n
    Wrapping up<\/h2>\n
    The BMP180 is an interesting sensor to be used in your own weather station.<\/p>\n
    Because the pressure changes with the altitude, this sensor is also able to compute the altitude.<\/p>\n
    If you would like to build a complete weather station, here’s some recommended guides:<\/p>\n