Remote control

In consumer electronics, a remote control can be used to operate devices such as a television set, DVD player or other digital home media appliance.

In some cases, remote controls allow a person to operate a device that they otherwise would not be able to reach, as when a garage door opener is triggered from outside.

They control functions such as power, volume, channels, playback, track change, energy, fan speed, and various other features.

[2][3] Remote controls for 2010s onward Smart TVs may feature a standalone keyboard on the rear side to facilitate typing, and be usable as a pointing device.

Unlike previous “on/off” techniques, the Telekino was able to execute a finite but not limited set of different mechanical actions using a single communication channel.

[12] The first remote-controlled model airplane flew in 1932,[citation needed] and the use of remote control technology for military purposes was worked on intensively during the Second World War, one result of this being the German Wasserfall missile.

[22][21] When the user pushed a button on the remote control, it struck a bar and clicked, hence they were commonly called "clickers", and the mechanics were similar to a pluck.

[21][23] Each of the four bars emitted a different fundamental frequency with ultrasonic harmonics, and circuits in the television detected these sounds and interpreted them as channel-up, channel-down, sound-on/off, and power-on/off.

[24] Later, the rapid decrease in price of transistors 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.

Some problems with this method were that the receiver could be triggered accidentally by naturally occurring noises or deliberately by metal against glass, for example, and some people could hear the lower ultrasonic harmonics.

In 1970, RCA introduced an all-electronic remote control that uses digital signals and metal–oxide–semiconductor field-effect transistor (MOSFET) memory.

[25] The impetus for a more complex type of television remote control came in 1973, with the development of the Ceefax teletext service by the BBC.

[26] In 1980, the most popular remote control was the Starcom Cable TV Converter (from Jerrold Electronics, a division of General Instrument)[15] which used 40-kHz sound to change channels.

Then, a Canadian company, Viewstar, Inc., was formed by engineer Paul Hrivnak and started producing a cable TV converter with an infrared remote control.

[27][28] The Blab-off was a wired remote control created in 1952 that turned a TV's (television) sound on or off so that viewers could avoid hearing commercials.

[citation needed] These obstacles eventually led to the demise of CL 9, but two of its employees continued the business under the name Celadon.

[citation needed] 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 (DVR/PVR), DVD player, TV and audio amplifier.

In the early 2010s, many smartphone manufacturers began incorporating infrared emitters into their devices, thereby enabling their use as universal remotes via an included or downloadable app.

[32] Most remote controls for electronic appliances use a near infrared diode to emit a beam of light that reaches the device.

For multi-channel (normal multi-function) remote controls more sophisticated procedures are necessary: one consists of modulating the carrier with signals of different frequencies.

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.

Since infrared (IR) remote controls use light, they require line of sight to operate the destination device.

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.

The superheterodyne receiver is used because of its stability, high sensitivity and it has relatively good anti-interference ability, a small package and lower price.

[36][37] Archibald Low was known as the "father of radio guidance systems" for his pioneering work on guided rockets and planes during the First World War.

As head of the secret RFC experimental works at Feltham, A. M. Low was the first person to use radio control successfully on an aircraft, an "Aerial Target".

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.

[42] In the winter of 1971, the Soviet Union explored the surface of the Moon with the lunar vehicle Lunokhod 1, the first roving remote-controlled robot to land on another celestial body.

Many space exploration rovers can be remotely controlled, though vast distance to a vehicle results in a long time delay between transmission and receipt of a command.

Many action cameras such as the GoPros [45] as well as standard DSLRs including Sony's Alpha series [46] incorporate Wi-Fi based remote control systems.