Touchscreen 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. 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 that selects Teletext pages would need buttons for each numeral from zero to nine, as well as other control functions, such as switching from text to picture, and the normal television controls of volume, channel, brightness, color intensity, etc. 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 1977–1978 that could control many more functions. ITT was one of the companies and later gave its name to the ITT protocol of infrared communication.

In 1980, the most popular remote control was the ''Starcom Cable TV Converter'' (from Jerrold Electronics, a division of General Instrument) 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. The product was sold through Philips for approximately $190 CAD. The Viewstar converter was an immediate success, the millionth converter being sold on March 21, 1985, with 1.6 million sold by 1989.

Other remote controls

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. 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 two of its employees continued the business under the name Celadon. This was one of the first computer-controlled learning remote controls on the market.

In the 1990s, cars were increasingly sold with electronic remote control door locks. These remotes transmit a signal to the car which locks or unlocks the door locks or unlocks the trunk. An aftermarket device sold in some countries is the remote starter. This enables a car owner to remotely start their car. This feature is most associated with countries with winter climates, where users may wish to run the car for several minutes before they intend to use it, so that the car heater and defrost systems can remove ice and snow from the windows.

Proliferation

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 US 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 (DVR/PVR), DVD player, TV and audio amplifier. Several of these remotes may need to be used sequentially for some programs or services to work properly. However, as there are no accepted interface guidelines, the process is increasingly cumbersome. One solution used to reduce the number of remotes that have to be used is the universal remote, a remote control that is programmed with the operation codes for most major brands of TVs, DVD players, etc. 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.

Technique

The main technology used in home remote controls is infrared (IR) light. The signal between a remote control handset and the device it controls consists of pulses of infrared light, which is invisible to the human eye but can be seen through a digital camera, video camera or phone camera. The transmitter in the remote control handset sends out a stream of pulses of infrared light when the user presses a button on the handset. A transmitter is often a light emitting diode (LED) which is built into the pointing end of the remote control handset. The infrared light pulses form a pattern unique to that button. The receiver in the device recognizes the pattern and causes the device to respond accordingly.

Opto components and circuits

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 not visible 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 frequencies. After the receiver demodulates the received signal, it applies the appropriate frequency filters to separate the respective signals. 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. Today, IR remote controls almost always use a pulse width modulated code, encoded and decoded by a digital computer: a command from a remote control consists of a short train of pulses of carrier-present and carrier-not-present of varying widths.

Consumer electronics infrared protocols

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, the carrier is 36 kHz. Other consumer infrared protocols include the various versions of SIRCS used by Sony, the RC-6 from Philips, the Ruwido R-Step, and the NEC TC101 protocol.

Infrared, line of sight and operating angle

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.

Radio remote control systems

Radio remote control (RF remote control) is used to control distant objects using a variety of radio signals transmitted by the remote control device. As a complementary method to infrared remote controls, the radio remote control is used with electric garage door or gate openers, automatic barrier systems, burglar alarms and industrial automation systems. Standards used for RF remotes are: Bluetooth AVRCP, ZigBee (RF4CE), Z-Wave. Most remote controls use their own coding, transmitting from 8 to 100 or more pulses, fixed or Rolling code, using OOK or FSK modulation. Also, transmitters or receivers can be ''universal'', meaning they are able to work with many different codings. In this case, the transmitter is normally called a ''universal remote control duplicator'' because it is able to copy existing remote controls, while the receiver is called a ''universal receiver'' because it works with almost any remote control in the market.

A radio remote control system commonly has two parts: transmit and receive. The transmitter part is divided into two parts, the RF remote control and the transmitter module. This allows the transmitter module to be used as a component in a larger application. The transmitter module is small, but users must have detailed knowledge to use it; combined with the RF remote control it is much simpler to use.

The receiver is generally one of two types: a super-regenerative receiver or a superheterodyne. The super-regenerative receiver works like that of an intermittent oscillation detection circuit. The superheterodyne works like the one in a radio receiver. 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.

Usage

Industry

A 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.

Garage and gate

Garage and gate remote controls are very common, especially in some countries such as the US, Australia, and the UK, where garage doors, gates and barriers are widely used. Such a remote is very simple by design, usually only one button, and some with more buttons to control several gates from one control. Such remotes can be divided into two categories by the encoder type used: fixed code and rolling code. If you find dip-switches in the remote, it is likely to be fixed code, an older technology which was widely used. However, fixed codes have been criticized for their (lack of) security, thus rolling code has been more and more widely used in later installations.

Military

Remotely operated torpedoes were demonstrated in the late 19th century in the form of several types of remotely controlled torpedoes. The early 1870s saw remotely controlled torpedoes by John Ericsson ( pneumatic), John Louis Lay (electric wire guided), and Victor von Scheliha (electric wire guided).Edwyn Gray, Nineteenth-century torpedoes and their inventors, page 18

The Brennan torpedo, invented by Louis Brennan in 1877 was powered by two contra-rotating propellers that were spun by rapidly pulling out wires from drums wound inside the torpedo. Differential speed on the wires connected to the shore station allowed the torpedo to be guided to its target, making it "the world's first ''practical'' guided missile". In 1898 Nikola Tesla

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