I enjoy using these breakouts. The I2C interface is simple and they are very powerful and accurate. In fact, they have resolution that is beyond my microprocessor and I have to drop a couple of low order bits to use them. I have made several styles of Barometers with them - they are very accurate. I used the Altimeter function that is included in the onboard data to indicate elevation (above MSL) and the system is sensitive enough to indicate the elevation changes from very small rises and dips along the highway! But on a trip to VA, it had no problem sensing the elevation of the Appalachian Trail at one point (2,157' MSL). Lots of fun! Photos show the Barometer and Elevation modes and a recent project showing just the Barometer and LED's showing the Tendency (Rising etc). The elevation unit has strips of tape over the display. You can just make out the breakout board in the unit on the right - look for red! It is a pretty compact enclosure. The Pressure was 30.19 and rising at the moment I took the shot (The green LED is lit).