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Wireless Sensor Networks

Using ZIGBEE

Submitted By

Kasif AliElectronics & Comm. Engineering

Engineering College Bikaner

Bikaner - Rajasthan

Contents

Applications

Overview of IEEE 802.15.4

Overview of ZigBee

Typical Wireless Sensor Hardware

Advantages of Wireless Sensors

Introduction

Introduction

A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location.

The WSN is built of "nodes“.

Each such sensor network node has typically several parts: a radio transceiver with an internal antenna or connection to an external antenna, a microcontroller, an electronic circuit for interfacing with the sensors and an energy source, usually a battery or an embedded form of energy harvesting

Advantages of Wireless Sensors

Traditional Sensing Method

Sensors do not have computation ability Sensors do not communicate

Advantages of Wireless Sensors

WSN Sensing Method

Now, sensors become sensor nodes Nodes process information and communicate it wirelessly

collected information

Sensor

Power Supply

Communication

Typical Wireless Sensor Hardware

Power Supply

Radio Transceiver

Microcontroller

Sensor

Typical Wireless Sensor Hardware

Microcontroller

Contains CPU, Memory and Peripherals on same chip Typically 8-bit or 16-bit Operate at less than 20MHz Memory less than 128kB Low power consumption to ensure long run times

Typical Wireless Sensor Hardware

Radio Transceiver

Typically operate in the ISM bands Use various modulation techniques

QPSK, BFSK, GFSK

Low Output Power 0dBm or 1mw Low Range around 10-300 feet

Typical Wireless Sensor Hardware

Sensors

Temperature Humidity Atmospheric Pressure Light Acceleration ( Accelerometer ) Angular Rate ( Gyroscope) Strain

Overview of ZIGBEE

Zigbee is a technology developed as a global standard to comply with the needs of low cost and low power wireless networks.

It has been designed with the facility to be able to provide an easy to use wireless solution which creates a secure and reliable network.

Ability to support multiple network functions like the point to point or multipoint to point and also the mesh networks as well.

It has the direct sequence spread spectrum as well. It also has the ability to run for years without any kind of

maintenance and with an automatic meter reading.

Why ZIGBEE ?

Regulated by the ZigBee

AllianceTopologies supported are Star,

Mesh and Cluster

Tree

simpler and less

expensive than

BluetoothHandles aspects such as

messaging, configuration, security and

application profile layers

Zigbee Device Classes

•Most capable device•Forms the root of the network tree•Acts as repository for security keys

Zigbee Coordinator

(ZC)

Zigbee Coordinator

(ZC)

Contains just enough functionality to talk to its parent node either ZC or ZR

Zigbee End

Device (ZED)

Zigbee End

Device (ZED)

Can pass data from one device to another

Zigbee Router (ZR)

Zigbee Router (ZR)

How ZigBee Works

-Active-Sleep

Full Function Devices(FFD’s)Reduced Function Devices (RFD’s)

- Beacon- Non-beacon

States of operation Devices

Modes of operation

Overview of IEEE 802.15.4

Part of the 802.15 wireless PAN standard Specifies the PHY and MAC layers Created for low data rate and multi-month or

multi-year battery life Targeted Applications

Sensors Interactive Toys Smart Badges Remote Controls Home Automation

Overview of IEEE 802.15.4

16 Channels in 2.4GHz band – 250kbps

DSSS used in all bands

2.4GHz band uses O-QPSK modulation

CSMA-CA channel access

Two addressing modes supported

IEEE 802.15.4 SpecificationsIEEE 802.15.4 Specifications

Wireless Technology Comparison

Standard Bandwidth Power

Consumption

Protocol Stack Size

Stronghold

Wi-Fi Up to 54Mbps

400+mA TX

Sleep 20mA

100+KB High Data Rate

Bluetooth 1Mbps 40mA TX

Sleep .2mA

100+KB Interoperability

Cable Replacement

Zigbee 250kbps 30mA TX

Sleep .003mA

32KB Long Battery Life, Low cost

Applications

Applications

HVAC SystemsAgricultural

Home Automation

Structural Monitoring ( Bridges, Buildings)

Monitoring condition of Machinery

Area Monitoring

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