All modern smartphones have at least an accelerometer, GPS, video camera and mic. More expensive models also include more weather sensors. This should make a great and free source of data but getting any of the many apps to work right turns out to be difficulty. | All modern smartphones have at least an accelerometer, GPS, video camera and mic. More expensive models also include more weather sensors. This should make a great and free source of data but getting any of the many apps to work right turns out to be difficulty. |