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Remote control

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Remote Control
Remote Control


A remote control is a component of an electronics device, most commonly a television set, used for operating the device wirelessly from a short line-of-sight distance.

The remote control can be contracted to remote or controller. It is known by many other names as well, such as converter clicker, didge, flipper, the tuner or the changer. Commonly, remote controls are Consumer IR devices used to issue commands from a distance to televisions or other consumer electronics such as stereo systems, DVD players and dimmers. 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. Television IR signals can be mimicked by a universal remote, which is able to emulate the functionality of most major brand television remote controls. They are usually powered by small AAA or AA size batteries.

Contents

History

One of the earliest examples of remote control was developed in 1898 by Nikola Tesla, and described in his patent, named Method of an Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles. In 1898, he demonstrated a radio-controlled boat to the public during an electrical exhibition at Madison Square Garden. Tesla called his boat a "teleautomaton".[1]

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 time he obtained a patent in France, Spain, Great Britain, and the United States. The Telekino consisted of a robot that executed commands transmitted by 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, he 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 intensively 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,[2] thus making it the first wireless remote control for a consumer electronics device.

Television remote controls

The first remote intended to control a television was developed by Zenith Electronics Corporation|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 Solar cell|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.[3]

In 1956 Robert Adler developed "Zenith Space Command", a wireless remote.[4] 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 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 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.

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 channel, 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 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 the 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 functions. ITT was one of the companies and later gave its name to the ITT protocol of infrared communication.[5]

Other remote controls

In the 1980s Steve Wozniak of Apple, started a company named CL 9. The purpose of this company was to create a remote control that could operate multiple electronic devices. The CORE unit (Controller Of Remote Equipment) was introduced in the fall of 1987. The advantage to this remote controller was that it could “learn” remote signals from different devices. It had the ability to perform specific or multiple functions at various times with its built-in clock. It was the first remote control that could be linked to a computer and loaded with updated software code as needed.

The CORE unit never made a huge impact on the market. It was much too cumbersome for the average user to program, but it received rave reviews from those who could. These obstacles eventually led to the demise of CL 9, but one of its employees continued the business under the name Celadon. This was one of the first computer-controlled learning remote controls on the market.[6]

The proliferation of remote controls

By the early 2000s, the number of consumer electronic devices in most homes greatly increased, along with the number of remotes to control those devices. According to the Consumer Electronics Association, an average American home has four remotes. To operate a home theater as many as five or six remotes may be required, including one for cable or satellite receiver, VCR or digital video recorder, DVD player, TV and audio amplifier. Several of these remotes may need to be used sequentially but, as there are no accepted interface guidelines, the process is increasingly cumbersome.

Many specialists, including Jakob Nielsen,[7] a renowned usability specialist and Robert Adler, the inventor of the modern remote, note how confusing, unwieldy and frustrating the multiplying remotes have become. Because of this proliferation of remote controls, universal remote controls that manage multiple devices are becoming increasingly popular.


Infrared Technology

Most remote controls 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 picked up by sensors on the receiving device. Video cameras see the diode as if it produces visible purple light.

Different manufacturers of infrared remote controls use different protocols to transmit the infrared commands. The RC-5 protocol that has its origins within Philips, uses, for instance, a total of 14 bits for each button press. The bit pattern is modulated onto a carrier frequency that, again, can be different for different manufacturers and standards, in the case of RC-5, a 36 kHz carrier is being used. Other consumer infrared protocols are, for instance, the different SIRCS versions used by Sony, the RC-6 from Philips, or the NEC TC101 protocol.

Since infrared (IR) remote controls use light, they require line of sight to operate the destination device. The signal can, however, be reflected by mirrors, just like any other light source.

If operation is required where no line of sight is possible, for instance when controlling equipment in another room or installed in a cabinet, many brands of IR extenders are available for this on the market. Most of these have an IR receiver, picking up the IR signal and relaying it via radio waves to the remote part, which has an IR transmitter mimicking the original IR control.

Infrared receivers also tend to have a more or less limited operating angle, which mainly depends on the optical characteristics of the phototransistor. However, it’s easy to increase the operating angle using a matte transparent object in front of the receiver. A description can be found here.


Usage Within the Home

Video games

Video game consoles had not used wireless controllers until recently, mainly because of the difficulty involved in playing the game while keeping the infrared transmitter pointed at the console. Early wireless controllers 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, 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.

PC control

Existing infrared remote controls can be used to control PC applications. Any application that supports shortcut keys can be controlled via IR remote controls from other home devices (TV, VCR, AC, ...). This is widely used with multimedia applications for PC based Home Theatre systems. For this to work, you need a device that decodes IR remote control data signals and a PC application that communicates to this device connected to PC. Connection can be made via serial port, USB port or motherboard IrDA connector. Such devices are commercially available or it can be home made using low cost microcontrollers.
LIRC(linux IR Remote control) and Win-LIRC(for windows) softwares are developed for the purpose of controlling pc using TV remote and can be also used for home brew remote with lesser modification.They support almost all TV remotes. Examples of many pc remote control ckts are available here [1]


Standby power

To be turned on by a wireless remote, the controlled appliance must always be partly on, consuming standby power.[8]


References

  1. Jonnes, Jill. Empires of Light ISBN 0-375-75884-4. Page 355, referencing O'Neill, John J., Prodigal Genius: The Life of Nikola Tesla (New York: David McKay, 1944), p. 167.
  2. http://www.philcorepairbench.com/mystery/index.htm|
  3. http://www.zenith.com/sub_about/about_remote.html
  4. Farhi, Paul. "The Inventor Who Deserves a Sitting Ovation." Washington Post. February 17, 2007.
  5. http://www.sbprojects.com/knowledge/ir/itt.htm
  6. http://www.celadon.com/Profile/Profile.html
  7. http://www.useit.com/alertbox/20040607.html
  8. http://www1.eere.energy.gov/consumer/tips/home_office.html


External Links