T5403 Barometric Pressure Sensor Hookup Guide
CaseyTheRobot 
Installing the Arduino Library
Libraries are collections of software functions geared towards a single purpose, such as communicating with a specific device. Arduino comes with a number of built-in libraries that help you do advanced tasks. We've written an Arduino library called SFE_T5403 that allows you to easily talk to the T5403 sensor. This library is not included with the stock Arduino software, but don't worry, installing new libraries is easy.
If you'd like to interface the T5403 to a microcontroller other than an Arduino, the C++ source code in the library and the information in the datasheet may be helpful when writing your own code.
1. Install the Arduino IDE
If you don't already have the Arduino IDE (Integrated Development Environment) installed, download the version for your system (Windows, Mac, Linux) from http://arduino.cc/en/Main/Software and install it following the instructions on that site.
If you need help installing the IDE, check out our tutorial.
2. Install the SFE_T5403 Library
User-installed libraries live in a "libraries" folder within your personal Arduino sketch folder. On Windows systems your personal sketch folder is located in "My Documents/Arduino". On Mac computers, it's "~/Documents/Arduino". On Linux it is usually "~/Arduino/sketchbook". Locate your personal Arduino sketch folder and open it so you can drag new files into it.
Now download the latest T5403 software archive from this link: https://github.com/sparkfun/SparkFun_T5403_Barometric_Sensor_Arduino_Library/archive/V_1.0.zip. You can either save the file to your system and open it later, or open it directly.
(Note that you can find the .zip file for any Github repository by looking for the "Download ZIP" button on the main page:)
Open the .zip file you just downloaded. (On most systems you should be able to double-click it to show the included files.) Open the folder called "T5403_Barometric_Breakout-master", then "software", then "Arduino". You should now see a folder called "libraries". Drag the "libraries" folder from the .zip folder into your personal Arduino sketch folder. If you get a warning that there is already a libraries folder there, that's fine. It just means you've already installed some libraries, which is great! Just tell your system to go ahead and overwrite them, which sounds alarming but will only add the new library to the existing folder.
That's it! Now restart the Arduino IDE and you should be ready to go.
If any of these instructions are unclear, you can find more detailed instructions in our installing an arduino library tutorial.