WIRELESS COMMUNICATIONS - Technical symposium.

safflowerpepperoniMobile - Wireless

Nov 24, 2013 (3 years and 7 months ago)

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1


REMOTE CONTROLLING


A SHORT RANGE APPLICATION IN WIRELESS













Ab
stract
T
he term "wireless" came into public use
to refer to a radio receiver or
transceiver

(a dual purpose receiver and transmitter
device), establishing its usage in the field
of wireless telegraphy early on; now the
term is used to describe modern wireless
conn
ections such as in cellular networks
and

wireless broadband Internet. It is also
used in a general sense to refer to any
type of operation that is implemented
without the use of wires, such as
"
wireless remote control
", "
wireless

energy transfer
", etc. reg
ardless of the
specific technology (e.g.,
radio
,
infrared
,
ultrasonic
, etc.) that is used to accomplish
the operation.

Remote control is an
electronic device used for a remote
operation of a device.

The world's first
remote controls were radio
-
frequency
de
vices that directed German naval
vessels to crash into Allied boats during

2

WWI. In WWII, remote controls
detonated bombs for the first time. The
end of the great wars left scientists with a
brilliant technology and nowhere to apply
it. Sixty years later, s
ome of us spend an
hour looking for the remote before we
remember

there are buttons on the
TV
.








Introduction

The term wireless is normally used to refer
to any type of
electrica
l

or
electronic

operation which is accomplished without the
use of a "hard wired" connection. Wireless
communication is the transfer of information
over a distance without the use of electrical
conductors or "
wire
s
". The distances
involved may be short (a
few meters as in
television remote control) or very long
(thousands or even millions of kilometers
for radio communications). When the
context is clear the term is often simply
shortened to "wireless". Wireless
communications is generally considered to
be
a branch of
telecommunications
.

It encompasses
cellular telephones
,
personal
digital assistants

(PDAs), and
wireless
networking
. Other examples of wireless
technology include
GPS

units,
garage door
openers and or garage doors
, wireless
computer mice

and
ke
yboards
,
satellite

television

and cordless
telephones
.



Handheld wireless radios such as this
Maritime VHF radio transceiver use

electromagnetic waves to implement a form
of wireless communications technology.




3

Wireless operations permits servic
es, such
as long range communications, that are
impossible or impractical to implement with
the use of wires. The term is commonly used
in the telecommunications industry to refer
to telecommunications systems (e.g., radio
transmitters and receivers, remot
e controls,
computer networks, network terminals, etc.)
which use some form of energy (e.g.
radio
frequency (
RF),
infrared

light,
laser

light,
visible light, acoustic energy, etc.) to
transfer information without the use of
wires. Information is transferre
d in this
manner over both short and long distances.

Wireless communication may be via:



radio

frequency communication,



microwave

communication, for
example long
-
range line
-
of
-
sight via
highly directional antennas, or short
-
range communication, or



I
nfrare
d

(IR) short
-
range
communication, for example from
remote controls

or via
IRDA
,

Applications may involve
point
-
to
-
point
communication
,
point
-
to
-
multipoint
communication
,
broadcasting
,
cellular
networks

and other
wireless networks
.

The term "wireless" shou
ld not be confused
with the term "
cordless
", which is generally
used to refer to powered electrical or
electronic devices that are able to operate
from a portable power source (e.g., a battery
pack) without any cable or cord to limit the
mobility of the co
rdless device through a
connection to the mains power supply. Some
cordless devices, such as cordless
telephones, are also wireless in the sense
that information is transferred from the
cordless telephone to the telephone's base
unit via some type of wirel
ess
communications link
. This has caused some
disparity in the usage of the term "cordless",
for example in
Digital Enhanced Cordless
Telecommunications
.

In the last 50 years, wireless
communications industry experienced
drastic changes driven by many tech
nology
innovations.



4


Applications of wireless
technology

Remote control

A pile of various remote controls

A
remote control

is an
electronic

device
used for the remote operation of a
machine
.


The term remote control can be also
referred to as "remote" o
r "controller" when
abbreviated. It is known by many other
names as well, such as the "clicker",
"channel
-
changer", "splat", "magic hand",
etc. Commonly, remote controls are used to
issue commands from a distance to
televisions

or other
consumer electronic
s

such as
stereo

systems and
DVD

players.
Remote controls for these devices are
usually small wireless handheld objects with
an array of buttons for adjusting various
settings such as
television channel
, track
number, and
volume
. In fact, for the
majority
of modern devices with this kind of
control, the remote contains all the function
controls while the controlled device itself
only has a handful of essential primary
controls. Most of these remotes
communicate to their respective devices via
infrared

(IR)
signals and a few via
radio
signals
. They are usually powered by small
AAA

or
AA

size
batteries
.


History

One of the earliest examples of remote
control was developed in 1893 by
Nikola
Tesla
, and described in
his patent
,
U.S.
Patent 613,809

, named
Method of an
Apparatus for Controlling Mechanism of
Moving Vehicle or Vehicles
.

In
1903
,
Leonardo Torres Quevedo

presented the
Telekino

at the Paris Academy
of Science, accompanied by a brief, and

making an experimental demonstration. In
the same year, he obtained a patent in
France, Spain, Great Britain, and the
United
States
. The
Telekino

consisted of a
robot

that
executed commands transmitted by

5

electromagnetic waves. It constituted the
world's
first apparatus for radio control and
was a pioneer in the field of remote control.
In
1906
, in the presence of the king and
before a great crowd, Torres successfully
demonstrated the invention in the
port of
Bilbao
, guiding a boat from the shore. Later,
h
e would try to apply the
Telekino

to
projectiles and torpedoes, but had to
abandon the project for lack of financing.

The first remote
-
controlled model aeroplane
flew in 1932, and the use of remote control
technology for military purposes was
worked intens
ively during the Second World
War, one result of this being the German
Wasserfall missile
.


By the late 1930s, several radio
manufacturers offered remote controls for
some of their higher
-
end models. Most of
these were connected to the set being
controlled

by wires, but the
Philco

Mystery
Control (
1939
) was a battery
-
operated low
-
frequency radio transmitter
,

thus making it
the first wireless remote control for a
consumer electronics device.


Television Remote

Controls


Some televisions were previously
manu
factured with hard wired remote
controls which plugged in to a receptacle or
jack in the television whereas more modern
televisions use wireless (generally infrared)
remote control units



There are 11

various remote controls for
TV
-
,
VHS
-

and
DVD
-
devices

shown here


The first remote intended to control a
television was developed by
Zenith Radio
Corporation

in 1950. The remote


officially called "Lazy Bones" was
connected to the
television

set by a wire. To
improve the cumbersome setup, a wireless
remote

control called "Flashmatic" was
developed in 1955 which worked by shining
a beam of light onto a
photoelectric cell
.
Unfortunately, the cells did not distinguish
between light from the remote and light
from other sources and the Flashmatic also
required t
hat the remote control be pointed
very accurately at the receiver.

The
Zenith Space Commander 600

remote
control

In 1956
Robert Adler

developed "Zenith
Space Command", a wireless remote.

It was
mechanical and used ultrasound to change
the channel and volu
me. When the user
pushed a button on the remote control it

6

clicked and struck a bar, hence the term
"clicker". Each bar emitted a different
frequency and circuits in the television
detected this noise. The invention of the
transistor

made possible cheaper
electronic
remotes that contained a
piezoelectric

crystal that was fed by an
oscillating

electric
current at a
frequency

near or above the
upper threshold of
human hearing
, though
still audible to
dogs
. The receiver contained
a
microphone

attached to a cir
cuit that was
tuned to the same frequency. Some
problems with this method were that the
receiver could be triggered accidentally by
naturally occurring noises, and some people,
especially young women, could hear the
piercing ultrasonic signals. There was e
ven a
noted incident in which a toy
xylophone

changed the channels on these types of TVs
since some of the
overtones

from the
xylophone matched the remote's ultrasonic
frequency.

Jerrold

remote control by
General
Instrument

from the late 1970s

The impetus

for a more complex type of
television remote control came in the late
1970s with the development of the
Ceefax

teletext

service by the
BBC
. Most
commercial remote controls at that time had
a limited number of functions, sometimes as
few as three: next cha
nnel, previous channel,
and volume/off. This type of control did not
meet the needs of teletext sets where pages
were identified with three
-
digit numbers. A
remote control to select teletext pages would
need buttons for each number from zero to
nine, as we
ll as other control functions, such
as switching from text to picture, and the
normal television controls of volume,
station, brightness, colour intensity and so
on. Early teletext sets used wired remote
controls to select pages but the continuous
use of t
he remote control required for
teletext quickly indicated the need for a
wireless device. So BBC engineers began
talks with one or two television
manufacturers which led to early prototypes
in around 1977
-
78 that could control a much
larger number of funct
ions.
ITT

was one of
the companies and later gave its name to the
ITT protocol

of infrared communication.



7

Technique


The emission spectrum of a typical sound
system remote control is in the near infrared.

The modulation of the IR diode varies by
button
.

Most control remotes for electronic
appliances use a near infrared diode to emit
a beam of light that reaches the device. A
940 nm wavelength LED is typical. This
infrared light is invisible to the human eye
but carries signals that are detected by the
appliance, as well as by the sensor of a
digital camera.

With a single channel (single
-
function, one
-
button) remote control the presence of a
carrier signal can be used to trigger a
function. For multi
-
channel (normal multi
-
function) remote controls more s
ophisticated
procedures are necessary: one consists of
modulating the carrier with signals of
different frequency. After the demodulation
of the received signal, the appropriate
frequency filters are applied to separate the
respective signals. Nowadays dig
ital
procedures are more commonly used. One
can often hear the signals being modulated
on the infrared carrier by operating a remote
control in very close proximity to an AM
radio not tuned to a station.



Working
of a television
remote

control
:

Let’s tak
e a normal television remote control

as in the figure



The remote control's job is to wait for you to
press a key, and then to translate that key
-
press into infrared light signals that are
received by the TV. When you take off the
back cover of the contr
ol you can see that
there is really just 1 part visible: a
printed
circuit board

that contains the electronics
and the battery contacts.


8


The components that you see here are
typical
for most remotes. You can see an
integrated circuit

(also known as a
chip
)
labeled "TA11835". The chip is packaged in
what is known as an
18 pin Dual Inline
Package
, or a
DIP
. To the right of the chip
you can see a diode, a transistor (black, with
three le
ads), a resonator (yellow), two
resistors (green) and a capacitor (dark blue).
Next to the battery contacts there is a
resistor (green) and a capacitor (tan disk). In
this circuit, the chip can detect when a key is
pressed. It then translates the key into
a
sequence something like morse code, with a
different sequence for each different key.
The chip sends that signal out to the
transistor to amplify the signal and make it
stronger.



T
he Circuit Board

When you unscrew the circuit board and
take it out, you can see that the circuit board
is a thin piece of fiber glass that has thin
copper "wires" etched onto its surface.
Electronic parts are assembled on printed
circuit boards because th
ey are easy to mass
produce and assemble. In the same way that
it is relatively inexpensive to print ink onto a
sheet of paper, it is inexensive to "print"
copper wires onto a sheet of fiber glass. It is
also easy to have a machine drop the parts
(the chip
s, transistors, etc.) onto the sheet of
fiberglass and then solder them on to
connect them to the copper wires.


When you look at the board, you can see a
set of contact points for th
e buttons. The
buttons themselves are made of a thin
rubbery sheet. For each button there is a
black conductive disk. When the disk
touches the contacts on the printed circuit
board, it connects them and the chip can
sense that connection.


9


At the end of the circuit board there is an
infrared LED
, or
Light Emitting Diode
.
You can think of an LED as a small light
bulb. Many LEDs produce visible light, but
a remote's LED produces infrared

light that
is invisible to the human eye. It is not
invisible to all eyes, however. For example,
if you have a camcorder it can see the
infrared light. Point your remote at the
camera and push a button. You will be able
to see the infrared light flashing
in the
viewfinder. The receptor in the TV is able to
see infrared light as well.

So the basic operation of the remote goes
like this: You press a button. When you do
that you complete a specific connection. The
chip senses that connection and knows what
b
utton you pressed. It produces a morse
-
code
-
line signal specific to that button.



The transistors amplify the signal and send
them to the LED, which translates the signal
into infrared light. The sensor in the TV can
see the infrared light and "seeing" t
he signal
reacts appropriately.



Applications


Industry

Remote control is used for controlling
substations, pump storage power stations
and HVDC
-
plants. For these systems often
PLC
-
systems working in the longwave
range are used.


Emergency

Remotely contr
olled machinery is used in
radioactive or toxic environments to avoid
human casualties and to prevent damage to
human health. For example, remotely
controlled robots were used during
liquidation of circumstances of
Chernobyl
disaster
.


Military

In
World Wa
r I

the
Imperial German Navy

employed
FL
-
boats

(Fernlenkbootes) against
coastal shipping. These were driven by
internal combustion

engines, and controlled

10

remotely from a shore station through
several miles of wire wound on a spool on
the boat. An aircraft

was used to signal
directions to the shore station. EMBs carried
a high explosive charge in the bow and
traveled at speeds of thirty knots.

The Soviet
Red Army

used remotely
controlled
teletanks

during 1930s in the
Winter War

against
Finland

and the early

stages of the
Great Patriotic War
. A teletank
is controlled by radio from a control tank at
a distance of 500

1,500 meters, the two
constituting a
telemechanical group
. The
Red Army fielded at least two teletank
battalions at the beginning of the
Great
Pa
triotic War
. There were also remotely
controlled cutters and experimental remotely
controlled planes in the Red Army.


Space

Remote control technology is also used in
space travel, for instance the Russian
Lunokhod

vehicles were remote
-
controlled
from the
ground. Direct remote control of
space vehicles at greater distances from the
earth is not practical due to increasing signal
delay times.


Video games

Video game consoles

had not used wireless
controllers until recently, mainly because of
the difficulty i
nvolved in playing the game
while keeping the infrared transmitter
pointed at the console. Early wireless
controlers were cumbersome and when
powered on alkaline batteries, lasted only a
few hours before they needed replacement.
Some wireless controllers w
ere produced by
third parties, in most cases using a radio link
instead of infrared. Even these were very
inconsistent, and in some cases, had
transmission delays, making them virtually
useless. The first official wireless controller
made by a first party
manufacturer was the
WaveBird

for
Nintendo Gamecube
. The
Wavebird changed the face of wireless
technology in video game consoles. In the
current generation

of gaming consoles,
wireless controllers have become the
standard.


Toys

Remote control toys, such a
s racing cars,
boats and even aircraft are a favorite pastime
of many people.



Audience response




Remote keyless system


11



Telecommand



Remote
-
controlled animal




Control Car Remote Control
Locomotive




Garage door opener




CONCLUSION:

W
ireless communication is
an electronic
operation which is accomplished without
any hardware connections has many
applications in our day to day life

Remote
control is a short range wireless technology
used

for operation of a machine i.e. one can
communicate with machines up to cer
tain
range by passing signals through the remote
control
.

. Most importantly remote control
has its own application in industry, space,
toys , vedio games..

By using keys present
on the remote control the infrared light can
be transmitted and is received
by the
machine.









REFERENCES:

1.

www.wikipedia.com

2.

ATIS Committee T1A1 Performance
and Signal Processing. ANS T1.523
-
2001, Telecom Glossary 2000
http://www.atis.org/tg2k/


3.

Story, Alfred Thomas (1904).
A story of
wireless telegraphy
. New York, D.
Appleto
n and Co..



4.

"Electromagnetic fields"
.
World Health
Organization
. Last retrieved September
24, 2007.

5.

"Consensus Statement on
Electromagnetic Radiation (Draft)"
.
Collaborative on Health and the
Environment. October 10, 2006.

6.


United Kingdom National Physi
cs
Laboratory report
.

7.


Bees Vanish, and Scientists Race for
Reasons
. New York Times. Retrieved
on
2007
-
10
-
23
.