An infrared (IR) light switch detects or receives infrared signals and responds with a programmed action. An IR motion sensor might respond by turning on a light after detecting motion by receiving infrared signals from people, living things, or any objects producing heat. IR sensors might also perform a task when triggered by a beam of infrared light aimed directly toward the sensor by a light emitting diode (LED). The IR light switch operates indoors or out to turn on lights, fans, or other electrical devices.
The shortest wavelength of invisible light contains the infrared spectrum. As the atoms in matter move constantly, they emit energy or photons, and some of this energy lies within the infrared spectrum. Sensors in an IR light switch detect this energy and translate the signal into electric current, causing a light to turn on. Some IR technology, a television remote control for example, requires signals transmitted from a beam of infrared light. When a button on the remote is depressed, current travels to and illuminates the LED, producing the infrared light beam.
When used for outdoor safety or security, the light producing device generally contains the IR light switch. Depending on the IR technology, lights may turn on and off automatically at dusk when sensors no longer receive heat signals from sunlight. Other appliances might require the infrared heat emitted by people or other living things before responding by turning on lights. These devices also contain timers that continue illumination for a specified period of time after an initial response is triggered.
Consumers may purchase relatively inexpensive motion detecting IR light switches for indoor use. The light switch usually screws into the light bulb socket and a light bulb screws into the outer end of the device. When people enter the room, the sensor detects the infrared signals and turns the light on. The drawbacks of this type of apparatus include the fact that the sensor cannot be covered with a lampshade or otherwise be obstructed.
Another type of IR light switch requires attaching the device to a live wire of a room wall switch or socket. The device appears as any other light switch or socket plate, but contains an IR sensor. Using the IR beam transmitted by a remote control device, consumers turn the lights, fans or other room appliances on and off. The more complex versions allow codes to be programmed into the remote to turn lights off after 15 minutes or even up to two hours later.