The Wii Remote Sees the Bar, Not the Other Way Around
Despite its name, the Wii “sensor bar” does not detect the controller. It shines infrared light—light just beyond the range of human vision—from two clusters of LEDs. A small camera in the Wii Remote looks for those bright points.
Because the points sit apart at a known distance, their positions in the remote’s camera image give the system clues about where the controller is aimed and how it is tilted. The Wii can use that information to place the on-screen pointer. The bar itself sends no tracking data; it is simply a powered reference target.
Why Two Lights Are Enough
One bright point could show where the remote is looking, but it would provide little information about the controller’s angle. Two points create a recognizable pair. As the remote moves or rotates, that pair shifts and changes apparent spacing in the camera’s view, giving the tracking system more to work with.
The arrangement also explains the candle trick. A candle flame emits infrared light, so two flames placed apart can appear to the remote much like the bar’s two illuminated ends. They are not sending a signal to the console; the remote’s camera is simply seeing light in the right part of the spectrum.
A Simple Design with a Clear Tradeoff
Since the bar provides illumination rather than communication, it does not need complex electronics. But the remote must be able to see both points: anything blocking them, or moving them far from their expected arrangement, can make pointer tracking less reliable. The clever part is that a seemingly specialized console accessory is, at its core, a pair of visible-to-the-controller landmarks.
