INTRODUCTION TO WIRELESS SENSOR NETWORKS. This powerpoint generally defines Wireless Sensor Networks, the advantages, disadvantages and the general types.

1. Introduction toWireless
Sensor Networks
By God’spower Pius Agbulu (Research Fellow Electronics
and Instrumentation Engineering)

3. INTRODUCTION
• A Wireless Sensor Network(WSN)is a distributed network and it comprises a large number of
distributed, self-directed, tiny, low powered devices called sensor nodes
• WSN naturally encompasses a large number of spatially dispersed, petite, battery-operated,
embedded devices that are networked to supportively collect, process, and convey data to the
users, and it has restricted computing and processing capabilities.
• Now a days wireless network is the most popular services utilized in industrial and commercial
applications, because of its technical advancement in processor, communication, and usage of
low power embedded computing devices.

4. INTRO …….
• WSN is a wireless network that consists of base stations and numbers of nodes (wireless
sensors).
• A wireless sensor network is a group of specialized transducers with a communications
infrastructure for monitoring and recording conditions at diverse locations.
• Commonly monitored parameters are temperature, humidity, pressure, wind direction and
speed, illumination intensity, vibration intensity, sound intensity, power-line voltage,
chemical concentrations, pollutant levels and vital body functions.

5. INTRO…..
• Wireless sensor nodes are equipped with sensing unit, a processing unit,
communication unit and power unit. Each and every node is capable to perform
data gathering, sensing, processing and communicating with other nodes.The
sensing unit senses the environment, the processing unit computes the confined
permutations of the sensed data, and the communication unit performs exchange
of processed information among
• A sink or base station acts like an interface between users and the network. One
can retrieve required information from the network by injecting queries and
gathering results from the sink.

6. COMPONENTS OFWSNs
• Sensors are sophisticated devices that are frequently used to detect and respond
to electrical or optical signals.
• Transducers are devices that converts variations in a physical quantity, such as
pressure or brightness, into an electrical signal, or vice versa.
• Base stations are one or more components of the WSN with much more
computational, energy and communication resources. They act as a gateway
between sensor nodes and the end user as they typically forward data from the
WSN on to a server.
• A sensor node, also known as a mote (chiefly in North America), is a node in a
sensor network that is capable of performing some processing, gathering sensory
information and communicating with other connected nodes in the network.

7. Example ofWSN

8. EXAMPLES OF WSNTOPOLOGIES
StarTopologies
• Star topology is a communication topology, where each node connects directly to a
gateway. A single gateway can send or receive a message to a number of remote nodes.
In star topologies, the nodes are not permitted to send messages to each other. This
allows low-latency communications between the remote node and the gateway (base
station)
TreeTopologies
• Tree topology is also called as cascaded star topology. In tree topologies, each node
connects to a node that is placed higher in the tree, and then to the gateway. The main
advantage of the tree topology is that the expansion of a network can be easily
possible, and also error detection becomes easy. The disadvantage with this network is
that it relies heavily on the bus cable; if it breaks, all the network will collapse.

9. EXAMPLES OF WSNTOPOLOGIES
MeshTopologies
• The Mesh topologies allow transmission of data from one node to another,
which is within its radio transmission range. If a node wants to send a
message to another node, which is out of radio communication range, it
needs an intermediate node to forward the message to the desired node.
The advantage with this mesh topology includes easy isolation and
detection of faults in the network. The disadvantage is that the network is
large and requires huge investment.

10. Limitations ofWireless Sensor Networks
• Possess very little storage capacity – a few hundred kilobytes
• Possess modest processing power-8MHz
• Works in short communication range – consumes a lot of power
• Requires minimal energy – constrains protocols
• Have batteries with a finite life time
• Passive devices provide little energy

11. APPLICATIONS

12. APPLICATIONS
• Potential applications of sensor networks include:
• Industrial automation
• Automated and smart homes
• Video surveillance
• Traffic monitoring
• Medical device monitoring
• Monitoring of weather conditions
• Air traffic control
• Robot control.

13. APPLICATIONS
• Military applications:Wireless sensor networks be likely an integral part of military
command, control, communications, computing, intelligence, battlefield
surveillance, reconnaissance and targeting systems.
• Area monitoring: In area monitoring, the sensor nodes are deployed over a region
where some phenomenon is to be monitored.When the sensors detect the event
being monitored (heat, pressure etc), the event is reported to one of the base
stations, which then takes appropriate action.
• Transportation: Real-time traffic information is being collected byWSNs to later
feed transportation models and alert drivers of congestion and traffic problems.

14. APPLICATIONS
• Health applications: Some of the health applications for sensor networks are
supporting interfaces for the disabled, integrated patient monitoring,
diagnostics, and drug administration in hospitals, tele-monitoring of human
physiological data, and tracking & monitoring doctors or patients inside a
hospital.
• Environmental sensing:The term Environmental Sensor Networks has
developed to cover many applications ofWSNs to earth science research.
This includes sensing volcanoes, oceans, glaciers, forests etc