Infrared... what is it?|
Technically known as "infrared radiation", infrared light is part of the electromagnetic spectrum located just below the red portion of normal visible light Ė the opposite end to ultraviolet. Although invisible, infrared follows the same principles as regular light and can be reflected or pass through transparent objects, such as glass. Infrared remote controls use this invisible light as a form of communications between themselves and home theater equipment, all of which have infrared receivers positioned on the front. Essentially, each time you press a button on a remote, a small infrared diode at the front of the remote beams out pulses of light at high speed to all of your equipment. When the equipment recognizes the signal as its own, it responds to the command.
But much like a flashlight, infrared light can be focused or diffused, weak or strong. The type and number of emitters can affect the possible angles and range your remote control can be used from. Better remotes can be used up to thirty feet away and from almost any angle, while poorer remotes must be aimed carefully at the device being controlled.
It takes two to tango.
However, the operational effectiveness of a remote control is not solely determined by the remote itself Ė the aforementioned infrared receiver also plays a critical role. For instance, if the receiver is placed too far into the deviceís chassis it develops what is known as "tunnel vision": itís view of the world is severely reduced, thus making it harder to see off-angle infrared commands. As an example, cut a hole the size of a pea into a piece of paper. As long as you hold that hole right up to your eye, you can see much of the room around you. As the paper gets farther away from your eye, the visible portion of the room becomes much smaller.
Similar design considerations must be made on the remoteís side. Thatís why youíll find many remotes use emitters that are completely open, or placed in a plastic bubble that allows them protected but superior exposure. Room conditions can also affect infrared performance. Walls lined with absorbing materials such as brick or fabric will absorb infrared light rather than reflect it elsewhere.
Batteries matter too.
Just as low batteries in a flashlight will produce a dim beam, remote controls really operate best with a full power source. Even though a remote may appear to be working fine otherwise, if you find the range seems to have diminished over time you should replace the batteries with new ones. Chances are youíll see a marked improvement.
How we tested.
All remote controls were photographed in a darkened room using a digital camera with infrared sensitive CCD. All camera settings were manually maintained for each photograph, ensuring that no automatic compensations were used. Although this test was conducted in such a way as to ensure that all remote controls were photographed in the best possible conditions, it is not a scientifically accurate comparison.
Even though some remotes immediately stand out as having the strongest and brightest signals, itís important to remember that a more dispersed signal is sometimes more effective. And although the quantity of emitters can affect signal quality, many remotes using only two can, in actual usability tests, be the equals of those that employ four.