Sensorcope: A Urban Environmental Monitoring Network

The SensorScope project is a collaboration between environmental scientists and hardware/software engineers at Ecole Polytechnique Fédérale de Lausanne (EPFL) that aims to study the energy exchanges and balances at the earth/atmosphere boundary. It consists in a large scale Wireless Sensor Network (WSN) deployed in the EPFL campus that measures key environmental quantities at high spatial resolution for the purpose of modeling and understanding this energy exchange. A broad environmental sensing platform has been developed for this project. The design considers the entire chain of requirements for a scientific atmospheric measurement campaign, including packaging, energy autonomy, sensor placement, and a diverse set of sensors. This sensing unit is centered around a TinyNode module, consisting of a TI MSP430 microcontroller running TinyOS, and a Xemics XE1205 radio. Around this core module we have designed an autonomous solar energy power system. The system has bi-directional multi-hop communication allowing for automatic re-configuration of the network and over-the-air reprogramming. A data base and web interface were developed to organize and present the data. The station includes also a sensor interface board accommodating seven external sensors, which makes the station capable of measuring nine different data inputs: ambient temperature and humidity, IR surface temperature, solar radiation, wind speed and direction, precipitation, soil moisture, and soil pressure. The system has been tested with external multiplexers which allow for multi-sensor configurations for each parameter. The system is mounted on an aluminum frame with a weatherproof housing containing the core module, solar energy board, and interface board. This weather station has been deployed at over one hundred locations distributed over the EPFL campus as part of a high-resolution measurement and modeling campaign with a goal of better understanding urban environmental processes. This system will be employed for non-urban observations in the coming year. The team developed the system to be flexible for a wide range of applications and encourages collaboration with other scientists interested in adoption such a mote-database-web system.