Remote control

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A remote control is an electronic device used for the remote operation of a machine.

The term remote control can be contracted to remote or controller. It is known by many other names as well, such as clicker and also the changer. It however, is also known commonly by the button, mainly in North England. Commonly, remote controls are Consumer IR devices used to issue commands from a distance to televisions or other consumer electronics 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.

Contents 1 History 1.1 Television Remote Controls 1.2 Social Effects of the Early Television Remote Control 1.3 Other Remote Controls 2 Technique 2.1 The opto components, circuits and mathematics 2.2 Improving an IR remote controls shooting distance 2.3 IR remote controls for roadside bombs 3 Usage 3.1 Industry 3.2 Emergency 3.3 Military 3.3.1 Military history 3.4 Space 3.5 Video games 3.6 PC control 3.7 Toys 4 Standby power 5 See also 5.1 Products and standards 6 External links 7 References

[edit] History

One of the earliest examples of remote control was developed in 1898 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 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,^[1] thus making it the first wireless remote control for a consumer electronics device.

[edit] Television Remote Controls

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 that the remote control be pointed very accurately at the receiver.^[2]

In 1956 Robert Adler developed "Zenith Space Command", a wireless remote.^[3] 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.^[4]

[edit] Social Effects of the Early Television Remote Control

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In the 1950s remotes were extra upgrades options to TV sets. As previously mentioned, Zenith was ready to change the lives of "lazy" people for good.^[5] The initial purpose to the TV remote was to turn off the TV set from afar, and to change the channels or mute commercials. People were told that the remote could turn off the TV while they were still laying in their LaZBoy and thus could drift off to sleep without interruption. A common complaint was that people tripped on the cable that was attached to the first remotes. It was not until 1955 that Zenith created the “Flash-matic” or their first wireless remote. While it helped keep the flow of traffic without tripping people along the way, the “Flash-matic” was not flawless. It frustrated people when the sun would hit the TV set, thus changing the channel.

The remote gave viewers an opportunity to “arm” themselves. Viewers no longer watched a show because they did not want to get up to turn the channel.^[6]

Audiences were “armed” with the ability to change their minds about what they were watching. It allowed audiences, for the first time, to interact with their TV.. The remote’s technology and buzz started something the first of its kind for the everyday TV viewer: the Joystick.^[7] The Joystick allowed people to interact with their TV, liberating the kinds of interaction they had with their television. Pong- the game in which people first used joysticks- was a basic game that was based on ping-pong. This new technology gave the average TV owner the ability to manipulate his or her own pixel on the TV screen for the first time.^[8]

The invention of the remote control has led to several different changes in television programming. One thing that the remote control led to was the creation of split screen credits. According to James Gleick, an NBC research team discovered that when the credits started rolling after a program, 25% of its viewers would change the channel before it was over. Because of this, the NBC 2000 unit invented the “squeeze and tease” which squeezed the credits onto one third of the screen while the final minutes of the broadcast aired simultaneously.^[9]

The remote control also led to an adjustment in commercial airings. Networks began to feel that they could not afford to have commercials between programs because it would detract viewers from staying tuned in on their channel. Programmers decided to place commercials in the middle of programs in order to transition into the next show directly.^[10]

With networks keeping in mind that people were equipped with remotes, thirty-second advertisement spots were cut down into segments of eight seconds or less. MTV was made up of this high-speed and broken cutting style, which aired music videos that were around three-minutes and each shot no more than two or three seconds. But MTV felt that even these three-minute segments were too long, so they created an animated series called Beavis and Butthead, to keep their viewer’s attention.^[11] In the show, they would show segments of music videos and then switch back to the characters and offer dialogue and action while the music video played in the background.^[12] Beavis and Butthead was purposefully stagnant, with slow dialogue and depending on reaction shots, but animation takes the most management and the pacing is everything. The last fraction of a second of sound track overlaid with the first fraction of a second of the visual track for the next scene.^[13]

[edit] 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 which could operate multiple electronic devices. The CORE unit as it was named (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 other different devices. It also had the ability to perform specific or multiple functions at various times with its built in clock. It was also the first remote control which could be linked to a computer and loaded with updated software code as needed. The CORE unit never made a huge impact of the market. It was much too cumbersome for the average user to program, but it received rave reviews from those who could figure out how to program it. These obstacles eventually lead 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.^[14]

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,^[15] a renowned usability specialist and Robert Adler, the inventor of the modern remote, note how confusing, unwieldy and frustrating the multiplying remotes have become.

[edit] Technique

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[edit] The opto components, circuits and mathematics

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

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 sophisticated 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 digital 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.

[edit] Improving an IR remote controls shooting distance

Remote controls used for TV and other home electronics work at a short distance below 30 meters. But for military use for roadsidebombs (both trigging the bomb or steering the disarming robot) improvements in shooting distance is necessary. The improvement in distance is also necessary if using IR to steer model airplanes.

There are five different techniques that can be used to extend the shooting distance up to above 20 km.

1A Using convex lenses:
A lens or a simple magnifying glass in front of the transmitters LED can extend the distance 5 to 25 times dependent on the lens burn width. And it's possible to extend the distance further with a lens at the receiver side.
The disadvantage is the narrow beam of light. And it is necessary to use a sight for aiming.
The projected light spots diameter from a 5 mm LED at 100 meters distance is between 1 to 7 meters, which means that this type of remote control can be handheld. (That is not possible if using a laser that projects a light spot with a 0.1 meter diameter.)

Diameter of light spot = LED diameter * Shooting distance / Burn width of the lens

Times improvement in shooting distance = Lens diameter / LED diameter

Thumb rule for a wide angle LED

The light that is shining outside the lens is lost and wasted. (Use a narrow beam LED instead.)

Times improvement in shooting distance = 2 * Burn width * tan(a/2) / LED diameter

Approximative thumb rule for a narrow angle LED, a is the LED's beam angle.

This thumb rule is used when the lens is wider than the beam of light.

Times improvement in shooting distance = SQR (lens area / photodiode sensitive area)

Thumb rule if also using a lens at the receiver side.

The burn width of the receivers lens is often below 20mm because the aiming becomes more complicated with longer burn widths.

The burn width of a lens is the distance from the center of the lens to the target when you try to ignite fire from the sunlight. The same as the distance between the center of the lens and a screen when you have projected a picture of something very far away. It differs less than a nanometer from the theoretical focal length value. Focal length, Lens (optics)

1B Using multiple LEDs in parallel, and no lens in the transmitter.
The improvement in distance is proportional to the square root of the number of LEDs.
100 LEDs for example means 10 times longer shooting distance.
High intensity LEDs with a narrow beam angle improves the shooting distance.
The advantage of this type of transmitter is that it has a wider beam of light, and you need no sight to aim.

This technique is also used in some TV remote controls which have two or more LEDs in parallel. If the LEDs are not aimed in parallel, then the intention is instead to create a wider beam of light.
This technique is also used in multiple LED IR illumination for TV-cameras to illuminate the target with invisible light at improved long distance.

2A High electric current pulses to the LED
A LED can survive short impulses of 10 to 200 times higher current than it can survive continuously. The shorter the pulse, and the longer time it can rest and cool down before the next pulse, the higher the current it can survive.
The shooting distance is almost proportional to the square root of the current to the LED. (except for extremely low or high current or too long pulses where the LED becomes hot and unlinear. See LED datasheets.) 100 times more current means 10 times longer shooting distance.
The advantage of this technique is that it is cheap and simple, which explains why it is used in many IR remote controls. Some extreme transmitters (for roadside bombs) can be designed for a few seconds lifetime for the LED, and the current can be increased 2 to 10 times beyond the LED manufacturers recommended maximum value.

2B Extremely narrow band tone modulated system.
The noise Voltage Thermal noise is proportional to the square root of the bandwidth which means that the noise is very low in a narrow band receiver. Low noise means that the gain and sensitivity can be increased to improve the shooting distance.
This device is built like a radio of the superheterodyne type, mixing down the received frequency with the help of a crystal reference. The use of a crystal is necessary to improve the receivers possible Q-value up to 10000.

Q = Centerfrequency / Bandwidth.

An alternative simplified solution is to skip the crystal and only use an ordinary electronic bandpass filter, but these are not temperature stable enough for higher Q-values than 100 to 200 for outdoor use. Which also means more noise and a shorter shooting distance, and more sensitive to jammers.
The disadvantage is that a tone selective system is a complicated and expensive device, which also consumes more current and are a bit slower. The advantage is that this system is more difficult to jam, especially if two or more tones are used in combination.

Tone modulation is used in some IR remote controls to make them less sensitive to disturbance from lamps and other twinkling light sources.

For military use, a non ringing filter design (simple RC filters) at the input makes the receiver more immune against laser impulse jammers. The Impulse response for a BP filter is a ringing (like a bell that you strike with a hammer) with the amplitude damped Q times unless you sabotage that by placing a low-Q filter before that filter stage. The superheterodyne receiver itself has a Q value up to 10000. Another alternative is to adjust the input filters ringing frequency at an offset from the center frequency.

3 Connecting multiple transmitters and receivers in a chain.
No limit to how much the distance can be improved, but the delay time is proportional to the number of links. This technique can be used with all types of remote control media, radio, IR or sound.

[edit] IR remote controls for roadside bombs

Remote controlled roadside bombs are used by the resistance to kill the mobility of a military occupation and scare the enemy away from using the roads.

Why is an optical system better than a radio system:
It's easy to shield away light from unwanted directions, while that is not possible for radio waves because the antenna must be kept small and simple.

The attenuation of radio power (for frequencies above 2 MHz) is proportional to the inverse of the fourth power of the distance between the transmitter and the receiver, 1/R⁴. (because this is not free space propagation, 1/R²). See Ground plane reflection Radio propagation.
Since the resistance's transmitter is located at least 20 times further away from the receiver than the enemy's jammer, it can be estimated that the resistance's transmitter must emit 160000 times more radio power to generate the same signal strength in the receiver. If the resistance instead use an optical system then the opposite is true. The enemy need 100 to 100000 times more power than the resistance. Because the war has changed from being focused on the distance to the receiver to a question about free sight.
This means that the enemy has lost it's main advantage in the jammer war against the resistance's remote controls.
The optical system is also extremely easy to build and very cheap compared to a radio system. It's possible to take electronic parts from a computer mouse and a TVs remote control to build the device. Electronic parts which are easy to find in any occupied nation.

The immunity against jammers can be improved further with tone selective systems, or narrow band 20nm color filters, or microprocessors and pulse distance coding. Optical systems can also be made immune to impulse weapons, High-energy radio-frequency weapons and EMP Electromagnetic pulse from nuclear weapons, by using optic fibres or glass bars, and explosives filled tubing instead of electric cables or antennas. And is also invisible to radar if there are no visible metal.

Special improvements to the resistance's remote controls:
Unwanted signals can be damped if limiting the view angle of the photodiode. If the view angle is 10 degrees instead of 120 degrees then the daylight DC and AC from wide angle jammer light are 1/100 of the original values. A simple solution is to put the photodiode inside a tube that is painted black inside to damp the reflected light. The damping of unwanted DC and AC means that the receiver becomes more immune to jammers, and also that it becomes possible for the resistance to use cheap 3pin-double-phototransistors from a PC mouse.

Photodiodes are the best choice in a receiver circuit because they work well in any light condition, while phototransistors give trouble in extreme daylight or darkness. Phototransistors are used by the resistance which must take what they can find at home.

How to fix the trouble with the phototransistors:
Phototransistors have too high daylight DC that can paralyze the receiver. (The transistor is stuck in an endpoint short circuit position.)
If the phototransistor has 3 pins then it's possible to only use the photodiode between the base and collector pins, or as an alternative compensate for the high DC with a simple external circuit. But that's not possible for a 2-pin phototransistor because it has no base pin. But a 2-pin phototransistor can still be used in daylight if placed inside a tube that limits the view angle and shields away 99% of the daylight.
Phototransistors also become dead in darkness if there is no bias current (from daylight) to establish a working point for the transistor stage. A trouble that can be fixed with a bias resistor for a 3-pin phototransistor, or an extra LED in the receiver that illuminates the 2-pin phototransistor.

[edit] Usage

[edit] 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.

[edit] Emergency

Remotely controlled machinery is used in radioactive or toxic environments to avoid human casualties and damage to human health. For example, remotely controlled robots were used during liquidation of circumstances of Chernobyl disaster.These are also used on Police vans, ambulances and firetrucks to change lights to green in that lane.

[edit] Military

Only in the military field of use of remote controls can you find the jammers and the countermeasures against the jammers.
Jammers are used to disable or sabotage the enemy's use of remote controls. IED jamming systems, Radio jamming, Electronic warfare
The distances for military remote controls also tend to be much longer, up to intercontinental distance satellite linked remote controls used by the U.S. for their unmanned airplanes (drones) in Afghanistan, Iraq and Pakistan.

Remote controls are used by the resistance in Iraq and Afghanistan to kill occupation troops with roadside bombs Improvised explosive device, Explosively formed penetrator.
The arms race and the fact that the enemy is many times closer to the receiver has made it more complicated and too expensive to build radio remote controls for roadside bombs that are immune to jammers. The simplest types of radio remote controls have been almost entirely disabled by the advanced jammers. But are still in use against unprotected Iraqi and Afghan national troops and civilian targets. One of the simplest solutions against the radio jammers is to fool the jammer itself to ignite the bomb.

Optical types of remote controls that uses light instead of radio are still immune to the jammers. The resistance in Iraq is reported in the media to use modified TV remote controls to ignite the bombs.^[16]

[edit] Military history

In World War I, the Imperial German Navy employed FL-boats (Fernlenkboote) 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 to the shore station. EMBs carried a high explosive charge in the bow and traveled at speeds of thirty knots.^[17]

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 Patriotic War. There were also remotely controlled cutters and experimental remotely controlled planes in the Red Army.

[edit] 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.

[edit] 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.

[edit] 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. An example can be found here: BobRemote

[edit] Toys

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Main article: Radio-controlled model

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

Planes

Remote controlled planes serves as a great hobby for all ages, it has the same fuselage as a real plane and it flies just as well. If the wing of the remote controlled plane is in an airfoil form and it creates a high and low pressure and creates lift, the plane would fly. This is helped by a small electric motor that creates thrust and the plane flies. you get different types of channels that controls the plane. 2 Channel is mostly for beginners and you control the plane through its rudder and elevators. 3 channel is also for beginners and experienced pilots because you have control over the motor speed as well, the motor will set your pitch. Higher speed: faster climbing, lower speed: fast descents. 4 channel radio's is normally for all of above including ailerons which lets you turn smoother, were as your rudder turns makes the turn slower and it slows the plane's airspeed. 5-8 channel radios is things like gear up and down etc. but its things that you don't need.

The rudder, ailerons, elevators etc. is controlled by servos which is connected to the receiver, the receiver gives the commands that the transmitter (radio) sends it, you have control over the transmitter.

Types

You get different types of remote controlled planes, but they all operate in the same way. You get biplanes, fixed wing, jets, turbine jets etc. The turbine planes is powered by a small turbine that works the same way as a real turbine but its much smaller. These "mini-turbines" are very powerful. The more common RC planes are the ones with an electric or nitro powered planes.

You can get RC planes of all sizes. The smallest has a wingspan of 8 cm and the biggest one is over 5 metres long.

Although remote controlled planes are very fun, there is a trick in how to fly it and people who want to begin this hobby has to read the forums on which plane to buy and how to fly it.

[edit] Standby power

To be turned on by a wireless remote, the controlled appliance must always be partly on, consuming standby power. Studies indicate that around 5-10% of domestic electricity is consumed by appliances when they are off. In the average home, 75% of the electricity used to power home electronics is consumed while the products are turned off.^[18]

[edit] See also

• Consumer IR
• Universal remote
• Channel surfing
• Radio control
• Domotics
• Audience response
• Remote keyless system
• Telecommand
• Remote-controlled animal
• Control Car Remote Control Locomotive
• Garage door opener

[edit] Products and standards

• INSTEON
• LIRC
• X10 (industry standard)
• TV-B-Gone
• JP1 remote, a common interface that allows ad-hoc reprogramming of some remote controls

[edit] External links

• Description of infrared remote protocols
• Infra-red Remote Control Theory
• Five Decades of Channel Surfing: History of the TV Remote Control at the Internet Archive
• New Remote's History of the Remote Control

[edit] References