wireless devices

8/7/2019 wireless devices

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BLUETOOTH

INTRODUCTION

Bluetooth is a wireless technology that allows computers, phones and other devices

to talk to each other over short distances (up to 100 meters). Bluetooth uses radio waves (inthe 2.4 Gigahertz range), and is designed to be a secure and inexpensive way of connecting

and exchanging information between devices without wires.

You'll find Bluetooth in many of the newer mobile phones, handheld computers, laptops,

printers, handheld organizers, as well as in all sorts of products.


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BASIC USES OF BLUETOOTH

sending photos from your mobile

exchanging business cards

sending voice from a headset to a mobile phone and real-time satellite navigation using GPS [The Global Positioning

System (GPS) is a space-based global navigation satellite

system that provides reliable location and time information in all

weather and at all times and anywhere on or near the Earth.]


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USING BLUETOOTH

Here's an example of some of the things you can do with

Bluetooth:

Transfer files (such as mp3s and photos) to and from your mobile

A wire-free headset for your mobile

Backup your PDA or mobile to your PC

Use a Bluetooth GPS device for satellite navigation on your mobile phone, PDA orlaptop.


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BLUETOOTH PRODUCTS

MOBILE HANDSET HANDHELD PDA PHONE HEADSET USB DONGLES

AND ADAPTERS

GPS NAVIGATION MODEM/ACCESS POINT PRINTER/PRINT ADAPTER


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WIRELESS LAN

INTRODUCTION

A wireless local area network (WLAN) links two or more devices

using some wireless distribution method, and usually providing a

connection through an access point to the wider internet. This gives

users the mobility to move around within a local coverage area andstill be connected to the network.


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WLAN TYPES

The private home or small business WLANCommonly, a home or business WLAN employs one or two access points to broadcast

signal around a 100- to 200-foot radius.

The enterprise class WLANThis type employs a large number of individual access points to broadcast the signal to a

wide area.

Wireless WAN (wide area network)

WANs used to exist in order to connect LANs in different geographical areas.Now, cellular phone companies offer WWAN technology that the end user can

access directly.


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ADVANTAGES OF WIRELESS LAN

Easy set-up

Easy access

More users of the same

network


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Reasons to choose wireless networking over

traditional wired networks include:

- Easy set up-Flexibility of location and data ports is required

-Roaming capability

Network access is desired outdoors; e.g., outside a home or office

building


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Wi-Fi

INTRODUCTION Wi-Fiis the industry name for wireless LAN (WLAN) communication

technology . Wi-Fi is a particular type of wireless local area network

(WLAN) - i.e. it is not necessary to plug a computer into a phone network

via a cable. There are many types of WLAN but all of them allow two or more

computers to form a network using radio frequency (RF) signals.


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DISADVANTAGES OF USING Wi-Fi

Password and Security

Signal Strength Sensitivity

Effect of Climatic Conditions


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IsBluetooth the sameasWi-Fi?

Bluetooth isnottobemistaken for Wi-Fi (wirelessnetworking) - Bluetoothrunsatalower

speed and powerthan Wi-Fi.

IsBluetooth& Wi-FiCompatable?

Bluetooth and Wi-Fi arebothradiotechnologies, butthey differin the frequenciesand

protocolsthatthey use. They don'tinterferewitheachother, butthetwodon'ttalk toeachothereither- in other wordsyoucan'tgetadevicewithBluetoothtocommunicate

toadevicethatonly supportsWi-Fi.


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'Infrared' (IR) light is electromagnetic radiationwith awavelength

between0.7 and300 micrometres, which equates to afrequency rangebetweenapproximately 1 and430 THz.

IR wavelengths are longer than that ofvisible light, but shorterthan that

ofterahertz radiationmicrowaves. Bright sunlight provides an irradiance

ofjust over1 kilowatt persquaremeterat sea level. Ofthis energy, 527

watts is infraredradiation, 445 watts is visible light, and32 watts isultraviolet radiation.

DEFINITION


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Infrared is used in night vision equipment when there is insufficient

visible light to see. Night vision devices operate through a process

involving the conversion of ambient light photons into electrons

which are then amplified by a chemical and electrical process andthen converted back into visible light. Infrared light sources can be

used to augment the available ambient light for conversion by

night vision devices, increasing in-the-dark visibility without

actually using a visible light source.

The use of infrared light and night vision devices should not be

confused with thermal imaging which creates images based ondifferences in surface temperature by detecting infrared radiation

(heat) that emanates from objects and their surrounding

environment.

Night Vision

Active-infrared night vision : the camera

illuminates the scene at infrared wavelengths

invisible to the human eye. Despite a dark

back-lit scene, active-infrared night vision

delivers identifying details, as seen on the

display monitor.


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The Earth's surface and the clouds absorb visible and invisible

radiation from the sun and re-emit much of the energy as infrared

back to the atmosphere. Certain substances in the atmosphere,chiefly cloud droplets and water vapor, but also carbon dioxide,

methane, nitrous oxide, sulfur hexafluoride, and

chlorofluorocarbons,absorb this infrared, and re-radiate it in all

directions including back to Earth. Thus the greenhouse effectkeeps the atmosphere and surface much warmer than if the

infrared absorbers were absent from the atmosphere.

The Earth as an infrared emitter


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PRESENTATION DONE BY :

GIRISHROHRA

38

DHWANIL SHROFF

54

VIDUR SURI55


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