Sensor network

A sensor network is a computer network of many, spatially distributed devices using sensors to monitor conditions at different locations, such as temperature, sound, vibration, pressure, motion or pollutants. Usually these devices are small and inexpensive, so that they can be produced and deployed in large numbers, and so their resources in terms of energy, memory, computational speed and bandwidth are severely constrained. Each device is equipped with a radio transceiver, a small microcontroller, and an energy source, usually a battery. The devices use each other to transport data to a monitoring computer.

Sensor networks involve three areas: sensing, communications, and computation (hardware, software, algorithms). Very useful technologies are wireless database technology such as queries, used in a wireless sensor network, and network technology to communicate with other sensors, especially multihop routing protocols. For example, Zigbee is a wireless protocol used by Motorola in home control systems.

Applications

Sensor networks are applied in a wide variety of areas, such as video surveillance, traffic monitoring, air traffic control, robotics, cars, home and health monitoring and manufacturing and industrial automation. One typical application in environmental monitoring is Sensor Web. Sensor networks are an up-and-coming technology in the aerospace sector, notably for structural and system health monitoring, where it is particularly advantageous to have a distribution of sensors around the airframe, especially in inaccessible areas.

Operation

The networks usually self-organize in order to cope with changes. Data from the sensors is usually aggregated and analyzed by a computer outside the network. This computer is connected to the network by a special network node called a gateway node or sink or base station.

History

The early sensor networks were designed for military purposes, like the Sound Surveillance System (SOSUS) during the Cold War. Modern research on sensor networks started around 1980 at the Defense Advanced Research Projects Agency (DARPA): Distributed Sensor Networks (DSN) program. Smaller computing chips, more capable sensors, wireless networks, and other new IT technologies are pushing the development of sensor networks.

See also

• Wireless sensor networks
• Sensor Web
• Smartdust
• TinyOS
• Contiki
• BTnodes
• Particle Computer
• TinyMaCLaS

External references

• Akyildiz, I.F., W. Su, Y. Sankarasubramaniam, E. Cayirci, "A Survey on Sensor Networks", IEEE Communications Magazine, August, 102–114 (2002). PDF version
• Chee-Yee Chong; Kumar, S.P., "Sensor networks: Evolution, opportunities, and challenges," Proc. IEEE, August 2003. (PDF version)
• Lecture on sensor networks
• OGC Standards work for web accessible sensor networks
• Textbook on sensor networks under the GNU FDL
• TECO Particle Web Site.