[tschuy]

> Are there common devices out there with these?

Most Android devices since maybe late 2012 have had one. It's used for enhancing GPS lock, and whatever developers can dream up. All I've heard about it being used for is a distributed air pressure sensor network used for weather prediction, tracking, etc. [0[

0: https://www.pressurenet.io/

[dheera]

Yes. The barometric sensors in the iPhone 6 and most high-end Android phones of past 2 years are sensitive enough to determine +/-1 floor of building movement, among a whole lot of other things. Very useful if you're writing a hiking app, want to determine if the user is in an airplane or not, trying to do vertical geolocation in a vertical city like New York or Hong Kong (subtract user's barometric reading from the weather station and you'll have it accurate to +/-a few floors), and a whole lot of other endless possibilities.