Remote controls use infrared signals.
A remote control is a hand-held device with buttons. The user points the remote control at the device to be controlled while pressing buttons to issue a command. Infrared remote controls operate over short distances and require a line of sight.
Function
Infrared remote controls shine a beam of light which is picked up by a sensor on the controlled device. The light is generated by a light emitting diode (LED). The light is actually "near infrared." It cannot be seen by the naked eye but can be picked up by digital camcorders.
Features
The wavelength that the diode emits varies between 850 and 950 nm (nanometers). The wavelength varies depending on the device being controlled and the manufacturer's preference. There is little variation in capabilities within this bandwidth; that is, a 950 nm wavelength does not empower a controller any more than an 860 nm wavelength.
Applications
Infrared remote controls are used to control consumer electronics like televisions, stereos and DVD players. The technology is appropriate to the application. Low frequency light uses little power to generate and so can be fueled by small batteries that last an acceptable length of time.
Tags: Infrared remote, Infrared remote controls, remote control, remote controls
