ORBIT: A Smartphone-Based System Platform for Embedded Sensing Applications

Owing to the rich processing, multi-modal sensing, and versatile networking capabilities, smartphones are increasingly used to build data-intensive embedded sensing applications. However, various challenges must be systematically addressed before smartphones can be used as a generic embedded sensing platform, including high power consumption, lack of real-time functionality and embedded programming support. This paper presents ORBIT, a smartphone-based system platform for embedded sensing applications. ORBIT features a tiered architecture, in which smartphone is interfaced to an energy efficient peripheral board and a cloud server. Time-critical tasks, such as high-rate sensor sampling and lightweight signal processing, are executed on the peripheral board, while computationintensive tasks are offloaded to the smartphone or cloud. By intelligently dispatching the processing tasks among the peripheral board, smartphone, and cloud, ORBIT minimizes the system energy consumption, subject to upper-bounded processing delays. ORBIT also includes a signal processing library that supports such task partition through new embedded programming primitives. Microbenchmark evaluation and three case studies, which include seismic sensing, visual tracking using an ORBIT robot, and multi-camera 3D reconstruction, validate the design of ORBIT.