This post is about how to use the BMP180 barometric sensor with the Arduino. It is also applicable for other similar barometric sensors.
Introducing the BMP180 barometric sensor
The BMP180 barometric sensor (model GY-68) is the one in the following figure (front and back view). It is a very small module with 1mm x 1.1mm (0.039in x 0.043in).
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.
The BMP180 barometric sensor communicates via I2C interface. This means that it communicates with the Arduino using just 2 pins.
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Step 1: Where to Buy?
This sensor is very cheap. You can buy one for approximately $3BMP180
Step 2: Pin Wiring
Wiring the sensor to the Arduino is pretty straightforward:
PinWiring to Arduino Uno
Step 3: Code
To control the BMP180 barometric sensor, you need to install the SFE_BMP180 Library.
Installing the SFE_BMP180 Library
1.Click here to download the SFE_BMP180 libraryYou should have a .zip folder in your Downloads folder.
2.Unzip the .zip folder and you should get BMP180_Breakout_Arduino_Library-master folder.
3.Rename your folder from BMP180_Breakout_Arduino_Library-master to BMP180_Breakout_Arduino_Library.
4.Move the BMP180_Breakout_Arduino_Library folder to your Arduino IDE installation libraries folder
5.Finally, re-open your Arduino IDE
Go to File > Examples >SparkfunBMP180 > SFE_BMP180_example.
This example is very well commented and explained on how the sensor reads the pressure, temperature and computes the altitude.
Step 4: Set the Altitude
Before uploading the code, you need to set up your current altitude. Go tohttps://elevationmap.net/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.
Step 5: Demonstration
After uploading the code, open your serial monitor at a baud rate of 9600.
You’ll be able to see your sensor readings.
Step 6: Wrapping Up
The BMP180 is an interesting sensor to be used in your own weather station.
Because the pressure changes with the altitude, this sensor is also able to compute the altitude.