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24 Νοε 2013 (πριν από 4 χρόνια και 7 μήνες)

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e 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 conne
ctions 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
", "

energy transfer
", etc. rega
rdless 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 dev
ices that directed German naval vessels to
crash into Allied boats during 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, so
me of us spend an hour looking for the remote before we

there are buttons on the


The term wireless is normally used to refer to any type of electrical o
r 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 "wires". 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 b
ranch of

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 keybo
ards, 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.

Wireless operations permits services,

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, remote c
ontrols, 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
transferred i
n this manner over both short and long distances.

Wireless communication may be via:


radio frequency communication,


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


Infrared (
IR) short
range communication, for example from remote controls or via

Applications may involve point
point communication, point
communication, broadcasting, cellular networks and other wireless networks.

The term "wireless" should
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 cordl
ess 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

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 technol
ogy innovations.

Applications of wireless technology

Remote control

A pile of various remote controls

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" or "
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 electronics s
uch 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) sig
nals and a few via radio signals. They are
usually powered by small AAA or AA size batteries


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

at the Paris Academy of
Science, accompanied by a brief, and mak
ing an experimental demonstration. In the same
year, he obtained a patent in France, Spain, Great Britain, and the United States. The


consisted of a robot that executed commands transmitted by electromagnetic
waves. It constituted the world's firs
t 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, he wo
uld try to apply the

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 intensivel
y 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
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


Some televisions were previously manufact
ured 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

and DVD
devices sho
wn 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 con
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 that
the remote
control be pointed very accurately at the receiver.

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 volume.
When the user pushed a
button on the remote control it 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 elec
tronic 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 circuit

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 even
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.


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
, 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 well a
s 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 the r
emote 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
that could control a much larger number of functions
. ITT was one of the companies and
later gave its name to the ITT protocol of infrared communication.


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

The modulation of the IR diode varies by button.

ost 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 appl
iance, 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 sophi
sticated 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

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 take 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 control y
ou can see that there is really just 1 part visible: a
printed circuit

that contains the electronics and the battery contacts.

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

(also known as a
labeled "TA11835". The chip is packaged in what is known
as an
18 pin Dual Inline Package
, or a
. To the right of the chip you can see a diode, a
transistor (black, with three leads), a resonator (yellow), two resistors (green) and a
capacitor (dark blu
e). 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 di
key. The chip sends that signal out to the transistor to amplify the signal and make it

The 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 th
in copper "wires" etched onto its surface. Electronic parts
are assembled on printed circuit boards because they 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 t
o "print" copper wires onto a sheet of fiber glass. It is also easy to have a
machine drop the parts (the chips, 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 the 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.

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
button you pressed. It produces a

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" the signal
reacts appropriately.



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


Remotely controlled machinery is used in radio
active 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


In World War I the Imperial German Navy emp
loyed FL
boats (Fernlenkbootes) against
coastal shipping. These were driven by internal combustion engines, and controlled
remotely from a shore station through several miles of wire wound on a spool on the boat.
An aircraft was used to signal directions t
o 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 W
ar. 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 Patriotic War. There were also rem
otely controlled cutters and
experimental remotely controlled planes in the Red Army.


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 involved in playing the game whil
e 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 were produced by third parties, i
n 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 fo
r 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.


Remote control toys, such as racing cars, boats and even ai
rcraft are a favorite pastime of
many people.


Audience response


Remote keyless system




controlled animal


Control Car Remote Control Locomotive


Garage door opener


Wireless 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 certain range by passing signals th
rough 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.




ATIS Committee T1A1 Performance and Signal Processing. ANS T1.523
2001, Telecom
Glossary 2000


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


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


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


United Kingdom National Physics Laboratory report.


Bees Van
ish, and Scientists Race for Reasons. New York Times. Retrieved on 2007