The conclusion is they are not, so I guess it's good someone did the study then [7] I'm not sure there's any real purpose to doing this since proper machines c

The conclusion is they are not, so I guess it's good someone did the study then [7] I'm not sure there's any real purpose to doing this since proper machines can record it. Unlike earthquakes for instance were local data might be useful. Using the magnetometers for geo-location is a more interesting use I've heard about. Given a GPS location using local interference with the magnetometer as beacons to further pinpoint where you stand. Are you near the metal door. Or if you could create a beacon to mess with it. [7] "The conclusion from this study is that some smartphone models are indeed capable of detecting and measuring geomagnetic storms with a high enough fidelity to be of some value to studies of actual major storm events spanning a wide range of latiudes. When taken under environmental conditions where the temperature is stable, where the smartphone is situated on a level, vibration-free, non-magnetic tabletop, and where no external electromagnetic interference (motors, air conditioners etc) are present, sensitivity levels can closely approach the ±0.2 µT noise limit of the electronics and allow the detection of the stronger geomagnetic storms. [8] "When you go out for a walk, run, or other outdoor activities, use CrowdMag to measure the magnetic data along your path and save the data as a “magtivity”. " - https://www.ngdc.noaa.gov/geomag/crowdmag.shtml https://www.ngdc.noaa.gov/geomag/crowdmag.shtml