Evolving shapes in wireless sensor networks

We present an implementation of a system for managing evolving shapes in Wireless Sensor Networks (WSN). A shape is a contiguous region in which the measurements of the sensors detect values above a given threshold. Our system, in its current version, solves two important problems: (1) Detecting and tracking the changes of boundaries; (2) Detecting an occurrence of within distance predicate for two (or more) shapes. A centralized approach (transmitting raw measurements to a dedicated sink) incurs communication overhead, so we developed distributed algorithms for managing the predicates related to evolving shapes. This demo will present the implementation of our solutions in a heterogeneous WSN consisting of TelosB and SunSPOT motes. It will also illustrate the end-user tools: interface for specifying the parameters of the predicates, along with real-time visualization of their evaluation.