BMP180 Barometric Pressure Sensor Hookup
This Tutorial is Retired!
This tutorial covers concepts or technologies that are no longer current. It's still here for you to read and enjoy, but may not be as useful as our newest tutorials.
MikeGrusin 
Under Pressure!
The BMP180 Breakout is a barometric pressure sensor with an I2C ("Wire") interface.
Barometric pressure sensors measure the absolute pressure of the air around them. This pressure varies with both the weather and altitude. Depending on how you interpret the data, you can monitor changes in the weather, measure altitude, or any other tasks that require an accurate pressure reading.
Covered in this Tutorial
We will show you how to connect this sensor to an Arduino microcontroller and use the included software library to get measurements out of the sensor. (If you're using a different type of microcomputer these instructions and source code may still help.) We'll also show you how to interpret the readings for both monitoring the weather and showing changes in altitude.
Suggested Reading
This part is easy to use. But before you start, we recommend the following background knowledge: