Early lessons from building Sensor.Network: an open data exchange for the web of things

An increasing number of embedded devices of all sorts (sensors, mobile phones, cameras, smart meters, traffic lights, home appliances etc.) are now capable of communicating and sharing data over the Internet. We have developed a web-based infrastructure called Sensor.Network for storing, sharing, searching, visualizing and analyzing data from heterogeneous devices and facilitating easy interaction amongst devices and with end users through an open, REST-based API. Such a data-exchange can enhance our understanding of the world around us and offer valuable insights for tackling a wide range of issues-from global ones like sustainable resource management to local ones like improving rush-hour traffic flow. The design and implementation of a service like this raises several questions: What are the right data abstractions? How should one balance ease of sharing with privacy concerns? What are effective mechanisms for searching, visualizing and analyzing data? How can one facilitate data-centric collaboration and the composition of loosely-coupled ¿mashups¿ between sensors and actuators (e.g. a humidity sensor from one vendor controlling a sprinkler system from another). This paper describes the design choices we made in addressing many of these questions and the rationale behind them. We also provide a brief survey of other comparable projects and evaluate them against a set of common criteria.