It’s true that LEDs can help illuminate your life in all kinds of ways. You can use them to light your home, your garden, your pool; they’re used in cars, on planes, streetlamps and in almost every civic application you can think of. But LEDs can also emit light waves that are invisible to the human eye: infrared waves. Infrared (IR) LEDs are most often the types of lights used in remote control devices and in security systems across the globe, including covert devices used by the US Military.
Infrared LEDs are typically used in security cameras, to allow cameras to capture both day and nighttime images. Infrared light waves are invisible to the human eye, but are emitted by anything that gives off heat, such as a human body or a still-warm car engine. As opposed to night vision goggles, which simply detect infrared light, Infrared cameras both detect and emit infrared light according to the ambient light available. Infrared cameras usually have a sensor system that can monitor the light level in the recorded area. As the natural light level drops, the sensor will calculate how much infrared light is needed to illuminate the picture, and infrared LEDs will turn on accordingly. The power of the IR LED strips will increase gradually until it is fully dark out, at which point the image will be viewed in 100 percent IR light. The only drawback to IR technology is that images shot in IR can only be viewed in black and white.
Infrared LEDs are also used in most remote-control devices; an infrared beam carrying instructions in binary code is sent from the remote control to the device (your television or your child’s Tonka truck), which receives these commands and performs the action given.