  Today's smartphones come equipped with a range of advanced sensors capable of
sensing motion, orientation, audio as well as environmental data with high
accuracy. With the existence of application distribution channels such as the
Apple App Store and the Google Play Store, researchers can distribute
applications and collect large scale data in ways that previously were not
possible. Motivated by the lack of a universal, multi-platform sensing library,
in this work we present the design and implementation of SensingKit, an
open-source continuous sensing system that supports both iOS and Android mobile
devices. One of the unique features of SensingKit is the support of the latest
beacon technologies based on Bluetooth Smart (BLE), such as iBeaconand
Eddystone. We evaluate and compare the power consumption of each supported
sensor individually, using an iPhone 5S device running on iOS 9. We believe
that this platform will be beneficial to all researchers and developers who
plan to use mobile sensing technology in large-scale experiments.
