Phone barometers can be used to get a pretty good idea which floor of a building you're on. https://www.popsci.com/gadgets/article/2011-10/so-um-why-does-new-g

Phone barometers can be used to get a pretty good idea which floor of a building you're on. https://www.popsci.com/gadgets/article/2011-10/so-um-why-does-new-google-phone-have-barometer-it/ https://www.popsci.com/gadgets/article/2011-10/so-um-why-doe... https://www.engadget.com/2012-09-06-stmicroelectronics-details-pressure-sensor-in-your-galaxy-s-iii.html https://www.engadget.com/2012-09-06-stmicroelectronics-detai...