On Thursday, February 9, 2017 at 8:21:16 PM UTC+3, wrote:
Speaking of technology I just watched a seminar by Infineon - they make sensors. In the pressure transducer they make for exercise trackers can have high definition to tell that someone is climbing or descending stairs or help determine what kind of activity they are doing.
They can sense a air pressure difference of 50mm/2 inches!!!

Sure. I've used a couple of these in little projects. Dead easy to hook up to any Arduino, Raspberry Pi etc.

https://www.sparkfun.com/products/11824

Relative accuracy of 0.02 hPa means about 15 cm at sea level I think.

There are better ones available but this chip sells for 3.73 Euro for one, or 2.25 Euro if you buy 1000 of them http://eu.mouser.com/ProductDetail/B...sortec/BMP180/

The Sparkfun board is more because ... it not just the chip, it's the chip on a board, easy to use for amateurs or for prototyping.