Code In The Air: Simplifying Sensing on Smartphones

Modern smartphones are equipped with a wide variety of sensors including GPS, WiFi and cellular radios capable of positioning, accelerometers, magnetic compasses and gyroscopes, light and proximity sensors, and cameras. These sensors have made smartphones an attractive platform for collaborative sensing (aka crowdsourcing) applications where phones cooperatively collect sensor data to perform various tasks. Researchers and mobile application developers have developed a wide variety of such applications. Examples of such systems include BikeTastic [4] and BikeNet [1] which allow bicyclists to collaboratively map and visualize biking trails, SoundSense [3] for collecting and analyzing microphone data, iCartel [2] which crowdsources driving tracks from users to monitor road traffic in real time, and Transitgenie [5], which cooperatively tracks buses and trains. What do all these applications have in common? Today, anyone who wants to develop a mobile phone crowdsourcing application needs to: 1. Write and debug low-level application software for one or more phone platforms (iPhone OS, Android, Symbian, etc.). 2. Publish the application on an official distribution channel like the iPhone App Store or the Android Market, and incentivize enough volunteers with phones to use the application, a challenging task. 3. Deal with issues of privacy, energy and intermittent network connectivity. For example, a traffic monitoring app that always collects GPS location samples once a second would drain the battery, and users would not want to install it. 4. Filter out irrelevant portions of sensor traces from phones that do not apply to the problem at hand. For example, Transitgenie, which cooperatively tracks public transit, filters out location traces when the user is stationary, walking or indoors. What if we had a platform with a large pre-existing installed base of phone users that enabled researchers and developers to instantly develop and deploy their own applications without having to worry about any of the above concerns? To realise this vision, we are building Code in the Air, a platform for developing mobile crowdsourcing applications that deals with all the low-level details