3. Introduction
It was noted that routing data from one sensor to the central
controller required a costly and cumbersome cabling
The progress made in microelectronics and wireless communication
technologies, have produced a reasonable cost components called
micro-sensors
The deployment of several micro-sensors to collect and transmit
environmental data to one or more collection points, is a network of
wireless sensors.
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5. What’s a Wireless Sensor networks ?
A special Capture and
type of ad transmit
hoc environmental
networks data
autonomously
A large
number of
micro-
sensors 5/24
6. What’s the environmental data?
Temperature
Pressure
Luminosity Environmental
data
sound
vibration
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7. How it works the sensor networks
Phase 1 Phase 2 Phase 3
The data are Routing data This
captured by through a collection of
different multi-hop to a "skin" is
nodes. collection connected to
point called the user via
“sink”. web or
satellite
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12. Architecture of a mote
The Control Unit of Energy
The Transmission Unit
The Processing Unit
The Control Unit
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13. Architecture of a micro-sensor (1/2)
The capture unit : generally composed of two sub-units: the sensor and an
Analog / Digital. The sensor is responsible for providing analog signals
based on the phenomenon observed in Analog / Digital. This converts the
signals into a digital signal understood by the processing unit.
The processing unit :includes a processor generally associated with a
small storage unit and works using an operating system designed for micro-
sensors. This unit is responsible for implementing the communications
protocols that allow the node to collaborate with other network nodes. It can
also analyze data collected to reduce the workload of the node wells.
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14. Architecture of a micro-sensor (2/2)
The transmission unit : This unit is responsible for conducting all
transmitting and receiving data over a wireless medium. It can be either
optical or radio-frequency type.
The control unit of Energy : She is responsible for distributing the energy
available to other modules and reduce expenses by pausing the active
components for example. This unit can also handle systems of charging
energy from the observed environment such as solar cells, to extend the
total lifetime of the network.
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16. Applications Domain
Detect movements of the •Report a possible
earth to predict earthquake outbreak of fire
Location of
•Detect dry areas
combatants, vehicles 2:Security
and weapons on the application 3:Environmen
battlefield
tal
application
1: Military
4:Medical
applications
Application
5:Commercial application
It may be used to
monitor patients from a
Facilitate stock distance
management
www.them
egallery.co
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20. Protocol
The protocol exploited in wireless sensor networks is Zigbee:
ZigBee is a protocol for high-level communications of small radio
stations (with reduced consumption), based on the IEEE 802.15.4
networks for personal dimension (Wireless Personal Area Networks:
WPAN).
We find this protocol in "embedded systems" where consumption is
a criterion of selection. It is known by his reduced consumption.
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21. ZigBee stack
The ZigBee
application layer The NWK layer has been
consists of layers designed to allow the
sublayer Application network to expand with
Support (APS), transmitters at low power
ZigBee Device Object consumption and to manage
(ZDO) and the a large number of nodes with
Application a very low latency.
Framework defined
by the manufacturers.
The MAC (Media Access
Control) has been designed to
integrate multiple topologies
without complexity.
The PHY layer has been
designed for high integration
needs at low cost.
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23. Conclusion
A problem related to the location is the placement of
nodes in a sensor network, that mean how to position the
nodes to each other.
With the new technology, it has found the best way to
improve the environment.
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