The difficulty of developing wireless sensor systems is widely recognized. Problems associated with testing, debugging, and profiling are key contributing factors. While network simulators have proven useful, they are unable to capture the subtleties of underlying hardware, nor the dynamics of wireless signal propagation and interference; and physical experimentation remains a necessity. To this end, developers increasingly rely on shared deployments exposed for physical experimentation. Sensor network testbeds are under development across the world.

We present a complementary testbed architecture that derives its novelty from three characteristics. First, the system is interactive; users can profile source and network level components across a network in real time, as well as inject transient state faults and external network traffic. Second, the system is source-centric; it enables automated source code analysis, instrumentation, and compilation. Finally, the design is open; developers can extend the set of exposed inter faces as appropriate to particular projects without modifying the underlying middleware. We present the testbed design and implementation, a graphical user interface, a shell-based macro programming interface, example scenarios that illustrate their use, and discuss the testbed's application in the research and teaching activities at client institutions.