Putting Everything Together: Part 3: Barometric Pressure Sensor

Last week, as I was also working on the BMP085 Barometric Pressure/Temperature Sensor. As this sensor came with calibration values issued by the factory, it was a bit harder to set up. It also seems to have some compatibility issues with the Arduino Mega ADK/Arduino Mega, where as it did not seem to have any problem with the Arduino Duemilanove.**



Though we also have a temperature/humidity sensor, it's a good check to have a temperature sensor on this one as well. Temperature on this one is measured in ... uh... deci-degrees C? That is, the number 277 means 27.7 degrees, which is actually rather uncomfortably warm for my room. Barometric pressure is measured in Pa.

Here's an example of the readout:

Temperature: 277 * 0.1 deg C
Pressure: 98218 Pa


Temperature: 277 * 0.1 deg C
Pressure: 98218 Pa


Temperature: 277 * 0.1 deg C
Pressure: 98221 Pa


Temperature: 277 * 0.1 deg C
Pressure: 98224 Pa


Temperature: 277 * 0.1 deg C
Pressure: 98224 Pa

The current output is 1 reading/second, though that can be easily changed.

**It seems that the Arduino Mega/Mega ADK both have trouble reading the calibration values from the device at certain times. The Duemilanove has no such issue and is always able to display data on the terminal. The Mega/Mega ADK sometimes gets "stuck".