Measuring the absolute pressure of the enviroment using a digital barometer such as this has some interesting applications. By converting the pressure measured into altitude, you have a reliable sensor for determining the height of your robot, plane or projectile!
Using a sensor as capable as the BMP180 you can achieve accurary of 1m, with noise of only 17cm in ultra high resolution noise. The device will operate at only 0.3uA meaning low current draw for battery powered applications.
The BMP180 comes fully calibrated and ready to use. As the device operates over I2C we've added optional I2C pull ups that can be enabled using the PU (pull up) jumper on the board for your convenience and ease during breadboarding.
Using I2C, the device provides pressure and temperature as 16bit values, which are used along with calibration data within the device are used to provide a temperature compensated altitude calculation.

Features:

• 1.8V to 3.6V Supply Voltage
  
• Low power consumption - 0.5uA at 1Hz
  
• I2C interface
  
• Max I2C Speed: 3.5Mhz
  
• Very low noise - up to 0.02hPa (17cm)
  
• Full calibrated
  
• Pressure Range: 300hPa to 1100hPa (+9000m to -500m)