Remote control

In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as a television set, DVD player or other home appliance. A remote control can allow operation of devices that are out of convenient reach for direct operation of controls. They function best when used from a short distance. This is primarily a convenience feature for the user. 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.

Early television remote controls (1956–1977) used ultrasonic tones. Present-day remote controls are commonly consumer infrared devices which send digitally-coded pulses of infrared radiation. They control functions such as power, volume, channels, playback, track change, heat, fan speed, and various other features. Remote controls for these devices are usually small wireless handheld objects with an array of buttons. They are used to adjust various settings such as television channel, track number, and volume. The remote control code, and thus the required remote control device, is usually specific to a product line. However, there are universal remotes, which emulate the remote control made for most major brand devices.

Remote controls in the 2000s include Bluetooth or Wi-Fi connectivity, motion sensor-enabled capabilities and voice control. 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.

History

Wired and wireless remote control was developed in the latter half of the 19th century to meet the need to control unmanned vehicles (for the most part military torpedoes). These included a wired version by German engineer Werner von Siemens in 1870, and radio controlled ones by British engineer Ernest Wilson and C. J. Evans (1897) and a prototype that inventor Nikola Tesla demonstrated in New York in 1898. In 1903 Spanish engineer Leonardo Torres y Quevedo demonstrated a radio controlled boat using a system called "''Telekino''", which he hoped to use to control a dirigible airship of his own design. The first remote-controlled model airplane flew in 1932, 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.

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. Using pulse-count modulation, this also was the first digital wireless remote control.

Television remote controls

The first remote intended to control a television was developed by Zenith Radio Corporation in 1950. The remote, called "Lazy Bones," was connected to the television by a wire. A wireless remote control, the "Flashmatic," was developed in 1955 by Eugene Polley. It worked by shining a beam of light onto one of four photoelectric cells, but the cell did not distinguish between light from the remote and light from other sources. The Flashmatic also had to be pointed very precisely at one of the sensors in order to work.

In 1956, Robert Adler developed "Zenith Space Command," a wireless remote.Farhi, Paul
"The Inventor Who Deserves a Sitting Ovation."
''Washington Post''. February 17, 2007. It was mechanical and used ultrasound to change the channel and volume. When the user pushed a button on the remote control, it struck a bar and clicked, hence they were commonly called a "clicker," but it sounded like a "clink" and the mechanics were similar to a pluck. 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.

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. 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 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. This was widely adopted for color television, replacing motor-driven tuning controls.

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
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