SPAN: A Sensor Processing and Acquisition Network
In recent years, advances in sensor network technology have shown great potential to revolutionize environmental data collection. Still, these systems have remained the purview of the engineers and computer scientists who design them, rather than useful tools for the field scientists who need them. Today, there are many data logging options for basic data collection in the field, but scientists are still required to travel to their sites to collect data, and to manually import data into spreadsheets. Few end-to-end systems that can automatically collect and transfer data to a database in the lab exist, and these tend to be overly complex, usually only working with specific sensor hardware. We have designed and built a robust and flexible sensor network called Sensor Processing and Acquisition Network (SPAN). SPAN is hardware agnostic in that it uses commercially available hardware to create a turnkey solution for environmental observation systems. While developing SPAN, our goal was to create an end-to-end system that enabled data collection from various types of sensors in the field and provided a simple way to transfer those data in real-time to a database where they could be shared and analyzed.
We developed SPAN using extensible building blocks that can be integrated to meet specific scientific requirements. As an open-source and flexible data acquisition architecture, not tied to a particular sensor brand or application, SPAN works with several commonly used data loggers in conjunction with analog, digital, and complex sensors (e.g. imagers and robotic sensors). SPAN allows real-time data access, and provides various options for long haul communication, including cellular and satellite links. This real-time communication enables field scientists to reconfigure sensors remotely and to monitor their status. SPAN offers intuitive user interfaces to configure, control, and monitor deployments from a lab desktop, or in the field, using a laptop or PDA. As such, the system facilitates sensor calibration and system tuning in the field. We employed a deployment driven design, build, and test approach in close collaboration with scientists, who provide requirements and technology verification to drive the design. SPAN has been used for diverse scientific applications throughout the world: from studying mercury cycling in rice paddies in China, to ecological research in the neotropical rainforests of Costa Rica, to monitoring the contamination of salt lakes in Argentina. In this poster we describe the SPAN architecture, deployment activities and experiences working with different scientific applications.