Embedded Web Services : Making Sense out of Diverse Sensors

How many times have you heard, “I just want to connect a collection of different sensors together and have them JUST WORK”? As providers of sensor related technology, this seemingly naïve statement should give us pause. Why is ease of integration such an increasingly common expectation? And, why is it so hard to achieve in practice? In part, the expectation is natural given the increasingly sophisticated interconnects that are built into our instruments, meters, and gauges, making them a source of physical information, rather than just a measurement device. However, the design space of sensors is so diverse with so many subtle specializations that it very difficult to represent the information that they produce in anything like a plug-and-play fashion, much less to describe how these devices must be utilized in order for that information to be meaningful. Starting from the observation that sensors have become embedded physical information servers, we may draw insights from IT community’s long standing efforts to cope with integrating diverse sources of distributed information. Today, every large enterprise, major supply chain, and significant Web portal integrates many different kinds of data sources from physically distributed dynamic processes. After many attempts, the key was to simplify the approach into a Service Oriented Architecture built upon a relatively straightforward foundation of Web Services. In this article, we translate these lessons to Embedded Web Services as a framework for integrating diverse sensor networks.