What Is a Remote Control?
In electronics, a remote control is a component of an electronic device used to operate the device wirelessly from a distance. For example, in consumer electronics, a remote control can be used to operate devices such as a television set, DVD player, or other home appliance, from a short distance.
A remote control is primarily a convenience feature for the user, and can allow operation of devices that are out of convenient reach for direct operation of controls. 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 or when a Digital Light Processing projector that is mounted on a high ceiling is controlled by a person from the floor level.
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 to control functions such as power, volume, tuning, temperature set point, fan speed, or other features. 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.
For many devices, the remote control contains all the function controls while the controlled device itself has only a handful of essential primary controls. The remote control code, and thus the required remote control device, is usually specific to a product line, but there are universal remotes, which emulate the remote control made for most major brand devices.
Remote control has continually evolved and advanced in the 2000s to include Bluetooth connectivity, motion sensor-enabled capabilities and voice control.
Remote control has actually been around a long time. In both World War I and World War II, radio-frequency devices were used to control boats and explosive devices remotely. Eventually, scientists would figure out how to incorporate that technology into all sorts of electronic devices.
Today, remote control devices are usually based upon one of two main types of technology: infrared (IR) technology or radio frequency (RF) technology. Let’s look at how these types of technology help you control devices from afar.
When it comes to televisions and home theater devices, the dominant technology tends to be infrared. An IR remote (also called a transmitter) uses light to carry signals from the remote to the device it controls. It emits pulses of invisible infrared light that correspond to specific binary codes.
These codes represent commands, such as power on, volume up, or channel down. The controlled device (also called the receiver) decodes the infrared pulses of light into binary code that its internal microprocessor understands. Once the signal is decoded, the microprocessor executes the commands.
IR remotes use LED lights to transmit their infrared signals. This results in a few limitations of the technology. Since light is used to transmit the signal, IR remotes require line-of-sight, which means you need an open path between the transmitter and receiver. This means that IR remotes won’t work through walls or around corners. They also have a limited range of about 30 feet.
Radio-frequency remotes work in a similar way. Instead of using infrared light, though, they transmit binary codes to a receiver via radio waves.
This gives RF remotes a much greater range than IR remotes. RF remotes can work at distances of 100 feet or more. This makes them useful in applications such as garage door openers and car alarms. You can also now find RF remotes being used with some modern satellite television systems.
RF remotes aren’t without their own issues, however. Although range is greatly improved compared to IR remotes, interference can be an issue for RF remotes due to the large number of radio waves all around us nearly all the time. For example, wireless internet and cell phones both use radio signals.
To get around the issue of interference, many RF remotes only transmit at specific frequencies. They can also embed digital address codes in the radio signals to ensure that a receiver only responds to the correct radio signals.