Introduction to Wireless Sensor Actuator Networks Pritee Parwekar

Introduction to Wireless Sensor Actuator Networks Pritee Parwekar 1

Terminology n Mote : A sensor node also known as a mote (North America) Processing+gathering sensory info+communicating Pritee Parwekar 2

Terminology (Cont) n Tiny. OS: n An open source, Berkley Software Distribution n licensed operating system designed for low-power wireless devices, those used in sensor networks, ubiquitous computing, personal area networks, smart buildings. Pritee Parwekar 3

Terminology (Cont) n GCC: GNU compiler collection, a compiler system produced by the GNU Project supporting various programming languages. n GNU is a UNIX-compatible operating system Pritee Parwekar 4

Terminology (Cont) n Basestation: n The head of a wireless sensor network. This is the Mote that sends the data back to a computer for analysis. Moteview compiles the data from the network into an SQL database. Pritee Parwekar 5

Basestation Pritee Parwekar 6

Basestation Pritee Parwekar 7

Mobile Basestation Pritee Parwekar 8

Terminology (Cont) n Gateway: n An intermediate node that performs data aggregation from the sensor nodes. It ‘sniffs’ for packets from the radio transmissions of the sensor nodes. Pritee Parwekar 9

Gateway Pritee Parwekar 10

Gateway-sms Pritee Parwekar 11

Terminology (Cont) n Node: Most general term for a device in the wireless sensor network. n This nomenclature is also used when assigning the number to a device during compilation. n The base station must be compiled using node 0. Pritee Parwekar 12

Common Sensor Types Tensio n Humidity Temperature Acceleration Inclination Light Pritee Parwekar EMF 13

Terminology (cont) n. Sink n. It is similar to head node which gather, control data collected by other sensor node. Pritee Parwekar 14

Sink Pritee Parwekar 15

Query scenario-Sink Node Sink Select temp from Pritee Parwekar 16

Wireless Sensors Tiny sensing devices capable of wireless communication Pritee Parwekar 17

WSAN n. A wireless sensor/actuator network (WSAN) is a group of sensors and actuators that are geographically distributed and interconnected by wireless networks. Sensors gather information about the state of physical world. Actuators react to this information by performing appropriate actions. Pritee Parwekar 18

Sensor n. Sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. Pritee Parwekar 19

WSAN Pritee Parwekar 20

Definition n Wireless Sensor Networks (WSNs): n Highly distributed networks of small, lightweight wireless nodes, n Deployed in large numbers, n Monitors the environment or system by measuring physical parameters such as temperature, pressure, humidity. Pritee Parwekar 21

Node n sensing + processing + communication n WSAN is built of nodes-from few to several hundereds, thousands. n The cost of the nodes varies depending on complexities. n Sensor nodes varies in size (from shoebox size to grain of dust). Pritee Parwekar 22

WSAN n The development of wireless sensor network was motivated by military applications such as battlefield surveillance n Now a days this technology is used in industrial and consumer applications. Pritee Parwekar 23

Components of sensor node n. Microcontroller n. Transceiver(with internal antenna or connection to external antenna) n. Memory n. Power Source n. Sensors Pritee Parwekar 24

Controller n Processes the data n Controls the functionality of other components in sensor nodes Pritee Parwekar 25

Transceiver n The device that has both transmitter and receiver n They are called as MAU(medium access units) in IEEE 802. 3 Pritee Parwekar 26

Antenna n An antenna is a transducer that transmits or receives electromagnetic waves. n Antenna converts electromagnetic radiation into electrical signal and vice versa. Pritee Parwekar 27

Power Source n The sensor nodes consumes power for sensing , communicating and data processing. n More energy is required for data communication than any other process. n Power is stored either in batteries or capacitors n Batteries are both rechargeable and non rechargeable Pritee Parwekar 28

WSN Architecture Pritee Parwekar WSN General Block Diagram 29

Applications of WSNs n Constant monitoring & detection of specific events n Military, battlefield surveillance n Forest fire & flood detection n Habitat exploration of animals n Patient monitoring n Home appliances Pritee Parwekar 30

Comparison with Ad Hoc Wireless Networks n Both consist of wireless nodes but they are different. The number of nodes is very large n Being more prone to failure, energy drain n Not having unique global IDs n Data-centric, query-based addressing vs. address-centric n Resource limitations: memory, power, processing n Pritee Parwekar 31

Design Issues & Challenges n Random deployment autonomous setup & maintenance n Infrastructure-less networks distributed routing n Energy, the major constraint trading off network lifetime n n n for fault tolerance or accuracy of results Hardware energy efficiency Distributed synchronization Adapting to changes in connectivity Real-time communication, Qo. S Security Pritee Parwekar 32

Design Factors n Scalability n Fault tolerance n Power consumption n Sensor network architectures: n Layered n Clustered Pritee Parwekar 33