Wireless sensor networks (WSNs) refer to networks of
spatially dispersed and dedicated sensors that monitor
and record the physical conditions of the environment
and forward the collected data to a central location.
.
.Components of WSN:
1)Sensors: Sensors in WSN are used to capture the environmental variables and which is used for data
acquisition. Sensor signals are converted into electrical signals.
2)Radio Nodes: It is used to receive the data produced by the Sensors and sends it to the WLAN
access point. It consists of a microcontroller, transceiver, external memory, and power source.
3)WLAN Access Point: It receives the data which is sent by the Radio nodes wirelessly, generally
through the internet.
4)Evaluation Software: The data received by the WLAN Access Point is processed by a software called
as Evaluation Software for presenting the report to the users for further processing of the data which
can be used for processing, analysis, storage, and mining of the data.
Application
1)Air quality monitoring
Experiments have shown that personal exposure to air pollution in cities
can vary a lot.[12] Therefore, it is of interest to have higher temporal and
spatial resolution of pollutants and particulates. For research purposes,
wireless sensor networks have been deployed to monitor the
concentration of dangerous gases for citizens (e.g., in London).[13]
However, sensors for gases and particulate matter suffer from high unit-tounit variability, cross-sensitivities, and (concept) drift.
2)Forest fire detection
A network of Sensor Nodes can be installed in a forest to detect when a
fire has started. The nodes can be equipped with sensors to measure
temperature, humidity and gases which are produced by fire in the trees or
vegetation. The early detection is crucial for a successful action of the
firefighters; With the usage of Wireless Sensor Networks, the fire brigade
will be able to know when a fire is started and how it is spreading.
3)Transportation: Real-time traffic information is being collected by WSNs
to later feed transportation models and alert drivers of congestion and
traffic problems.
4)Structural monitoring: Wireless sensors can be utilized to monitor the
movement within buildings and infrastructure such as bridges, flyovers,
embankments, tunnels etc enabling Engineering practices to monitor
assets remotely with out the need for costly site visits.
Inefficiency of WSN
1)Scalability: Sensor networks vary in scale from several
nodes to potentially several hundred thousand. In addition,
the deployment density is also variable. For collecting highresolution data, the node density might reach the level
where a node has several thousand neighbours in their
transmission range. The protocols deployed in sensor
networks need to be scalable to these levels and be able to
maintain adequate performance.