The BMP180 is the improved version of the BMP085. This chip is able to measure the air pressure and temperature very efficiently and precisely. The data is easy to read with the built-in I2C interface.
Voltage: 1.8V to 3.6V
Consumption: 0.5uA at 1Hz
Max I2C Speed: 3.5 MHz
Noise: 0.02hPa (17cm)
Measuring range: 300hPa to 1100hPa (+ 9000m to -500m)