Wireless sensor networks consist of distributed autonomous devices that use sensors to cooperatively monitor physical conditions like temperature, pressure, and motion. Sensor nodes contain sensors, a processor, memory, a transceiver, and a power supply. They face design challenges due to power constraints, node failures, mobility, heterogeneity, and scalability to large deployments. Applications of wireless sensor networks include military monitoring, environmental monitoring, health monitoring, home/office automation, automotive uses, and commercial uses.

1. WIRELESS SENSOR NETWORKS

2. INTRODUCTION
• A wireless sensor network (WSN) is a wireless
network consisting of spatially distributed
autonomous devices using sensors to cooperatively
monitor physical or environmental conditions, such
as temperature, sound, vibration, pressure, motion
or pollutants, at different locations.
• A collection of sensing devices that can communicate
wirelessly.

3. Wireless Sensor Networks (WSN)
• Even though wireless sensors has limited resources in
memory, computation power, bandwidth, and energy,
With small physical size. It Can be embedded in the
physical environment.
• Self-organizing multi-hop ad-doc networks.

4. Wireless Sensor Network Architecture

5. Special addressing requirement
• Local unique addresses
• Data-centric
• Example: Each node has an unique number.
Attribute-based naming architecture
• Data is named by one or more attributes.
• Example: Each node is distinguished by an attribute-GPS sensors are practical
for this.
Architecture for a WSN

6. Architecture of Sensor Node

7. Sensors are used by wireless sensor nodes to capture data from their environment. They
are hardware devices that produce a measurable response to a change in a physical
condition like temperature or pressure. Sensors measure physical data of the parameter
to be monitored and have specific characteristics such as accuracy, sensitivity etc. The
continual analog signal produced by the sensors is digitized by an analog-to-digital
converter and sent to controllers for further processing. Some sensors contain the
necessary electronics to convert the raw signals into readings which can be retrieved via
a digital link (e.g. I2C, SPI) and many convert to units such as °C. Most sensor nodes
are small in size, consume little energy, operate in high volumetric densities, be
autonomous and operate unattended, and be adaptive to the environment. As wireless
sensor nodes are typically very small electronic devices, they can only be equipped with
a limited power source of less than 0.5-2 ampere-hour and 1.2-3.7 volts.

8. • Sensor
- A transducer
converts physical phenomenon e.g. heat, light, motion, vibration, and sound
into electrical signals
• Sensor node
- basic unit in sensor network
- contains on-board sensors, processor, memory, transceiver, and power supply
• Sensor network
- consists of a large number of sensor nodes
-nodes deployed either inside or very close to the sensed phenomenon
Wireless Sensor Node

9. Characteristics
 Power consumption constraints for nodes using
batteries or energy harvesting
 Ability to cope with node failures (resilience)
 Mobility of nodes
 Heterogeneity of nodes
 Scalability to large scale of deployment
 Ability to withstand harsh environmental
conditions
 Ease of use
 Cross-layer design

10.  Fault tolerance
 Scalability
 Production costs
 Hardware constraints
 Sensor network topology
 Environment
 Transmission media
 Power Consumption
- Sensing
-Communication
-Data processing
Factors Influencing WSN Design

11.  Military Applications
 Environmental Applications
 Health Applications
 Home and Office Applications
 Automotive Applications
 Other Commercial Applications
APPLICATIONS OF WIRELESS COMMUNICATIONS

12. It is scalable and hence can accommodate any new
nodes or devices at any time.
It is flexible and hence open to physical partitions.
All the WSN nodes can be accessed through
centralized monitoring system.
As it is wireless in nature, it does not require wires or
cables.
Advantages of WSN

13.  Lower speed compared to wired network.
 Less secure because hacker's laptop can act as Access Point. If you connected to
their laptop, they'll read all your information (username, password.. etc).
 More complex to configure than wired network.
 Gets distracted by various elements like Blue-tooth.
 Still Costly at large.
 It does not make sensing quantities in buildings easier.
 It does not reduce costs for installation of sensors.
 It does not allow us to do more than can be done with a wired system
Disadvantages of WSN

14. • Heterogeneity
-The devices deployed may be of various types
and need to collaborate with each other.
• Distributed Processing
-The algorithms need to be centralized as the processing
is carried out on different nodes.
• Low Bandwidth Communication
- The data should be transferred efficiently between
sensors
Design Challenges

15.  Large Scale Coordination
- The sensors need to coordinate with each
other to produce required results.
 Utilization of Sensors
-The sensors should be utilized in a ways
that produce the maximum performance and
use less energy.
 Real Time Computation
- The computation should be done quickly
as new data is always being generated.

17. 1.Quality of Service
2.Security Issue
3.Energy Efficiency
4.Network Throughput
5.Performance
6.Ability to cope with node failure
7.Cross layer optimization
8.Scalability to large scale of
deployment
Operational Challenges of Wireless Sensor Networks

18.  WSNS possible today due to technological advancement in various
domains . Envisioned to become an essential part of our lives .
 Design Constraints need to be satisfied for realization of sensor
networks.
 Tremendous research efforts being made in different layers of WSNs
protocol stack.
Conclusion

20. Computers, communication, and sensing technologies are converging to change the
way we live, interact, and conduct business. Wireless sensor networks reflect such
convergence. These networks are based on collaborative efforts of a large number of
sensor nodes. They should be low-cost, low-power, and multifunction. These nodes
have the capabilities of sensing, data processing, and communicating. Sensor
networks have a wide range of applications, from monitoring sensors in industrial
facilities to control and management of energy applications to military and security
fields. Because of the special features of these networks, new network technologies
are needed for cost effective, low power, and reliable communication. These network
protocols and architectures should take into consideration the special features of
sensor networks such as: the large number of nodes, their failure rate, limited power,
high density, etc. In this talk the impact of wireless sensor networks will be addressed,
several of the design and communication issues will be discussed, and a case study of
a current project of using such networks in drilling and management off-shore oil and
natural gas in the gulf region will be given.