wireless infrared communication

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INFRARED wireless technology

Batch no: 21

K.Bharath Reddy

10881A0464

Supervisor- Mrs M.srilatha

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contents

• Introduction

• History

• Wireless Communication

• Projection Keyboard• Infrared Data Association

• Advantages

•Disadvantages

• Health Risks

• References

I

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Electromagnetic radiation spectrum

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History of wireless communication

• Guglielmo Marconi invented the wirelesstelegraph in 1896

Sent telegraphic signals across the Atlantic

Ocean• 1914  – first voice communication over radio

waves

• Communications satellites launched in 1960s

• Advances in wireless technology – Radio, television, mobile telephone,

communication satellites

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What is Wireless 

Communication?

• Transmitting voice and data using

electromagnetic waves in open space

(atmosphere)

• Electromagnetic waves

• Travel at speed of light (c = 3x108 m/s)

•

Has a frequency (f) and wavelength (l

)»c = f x l 

• Higher frequency means higher energy

photons

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Types of electromagnetic carriers

• when the distance between the sender andreceiver is short (e.g. TV box and a remote control)infrared waves are used

• for long range distances between sender and

receiver (e.g. TV broadcasting and cellular service)both microwaves and radio waves are used

 – radio waves are ideal when large areas need tobe coverd and obstacles exist in the transmissionpath

 – microwaves are good when large areas need tobe coverd and no obstacles exist in thetransmission path

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Wireless Communication(cont.)

• Place two infrared devices within a few feet

(no more than 5 meters).

• Infrared network signals cannot penetrate

walls or other obstructions and work only in

the direct "line of sight.“ 

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Wireless Communication(cont.)

• Why we use Infrared System ???

• The electromagnetic spectrum, the infrared wave

is higher frequency and therefore shorter

wavelength than the radio wave. Conversely, theradio wave is lower frequency and therefore

longer wavelength than the infrared wave. The

infrared energy wave completes nearly 5 and ahalf cycles in the time that the radio frequency

wave completes 2 cycles.

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Wireless Communication(cont.)

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Projection Keyboard

• A projection keyboard is a virtual keyboardthat can be projected and touched on anysurface. The keyboard watches finger

movements and translates them intokeystrokes in the device.

• A proposed system called the P-ISM willcombine the technology with a small videoprojector to create a portable computer thesize of a fountain pen.

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Projection Keyboard(cont.)

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Projection Keyboard(cont.)

• How a projection keyboard generally works??

• 1 . An invisible infrared beam is projected above the virtualkeyboard

• 2 . Finger makes keystroke on virtual keyboard. This breaks

infrared beam and infrared light is reflected back toprojector

• 3 . Reflected infrared beam passes through infrared filter tocamera

• 4 . Camera photographs angle of incoming infrared light

• 5 . Sensor chip determines where infrared beam wasbroken

• 6 . detected coordinates determine actions or characters tobe generated

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Infrared Data Association

• The Infrared Data Association (IrDA) defines

physical specifications communication

protocol standards for the short-range

exchange of data over infrared light, for usessuch as personal area networks (PANs).

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Infrared Data Association(cont.)

IrDA via USB IrDA in mobile phone

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Infrared Data Association(cont.)

• For the devices to communicate via IrDA they

must have a direct line of sight similar to a TV

remote control.

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Mobile infrared system

• Infrared, related to mobile phones is a short

beam of radiation used to send, receive and

make connections between mobile phones.

• Infrared works by sending a short infrared

beam from a mobile to another to create a

connection.

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Send and receive pictures

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Disadvantages

• Line of sight

• Blocked by common materials

•

 Short range• Light, weather sensitive

• Speed

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Health Risks

• Point-to-point lasers which can cause burns or

blindness

• Prolonged microwave exposure which has

been linked to cancer and leukemia

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References

• www.wikipedia.org/wiki/infrred 

• www.schnozberry.com 

•

http://en.wikipedia.org/wiki/Infrared_Data_Association