CitySee: not only a wireless sensor network

CitySee, an environment monitoring system with 1196 sensor nodes and 4 mesh nodes in an urban area, is mainly motivated by the needs of precise carbon emission measurement and real-time surveillance for CO² management in cities. Being one of the largest working wireless sensor networks, CitySee faces several challenges such as hardware design, software development, platforms, network protocols, and, most important, satisfactory services to users. We share some early lessons learned from this project, illustrate the potential benefits and risks of current solutions, and discuss the possible extensions of CitySee applications.