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=== IR Sensor ===

=== IR Sensor ===

During R&D, Nintendo discovered the motion sensors were not accurate enough to use the remote to control an on-screen cursor. To correct this, they augmented the remote with an infrared image sensor on the front designed to locate two IR beacons within the controller's field of view. The beacons are housed within a device misleadingly called the sensor bar. The sensor bar is powered by the Wii base unit, and contains 2 groups of IR LEDs, spaced 7.5 inches apart. Each group is composed of 5 LEDs, but homemade sensor bars have been effective with fewer LEDs, so long as the intensity is sufficient. The cable from the Wii to the sensor bar only carries power. No information is passed either to or from the sensor bar, and the intensity is not modulated in any way.

During R&D, Nintendo discovered the motion sensors were not accurate enough to use the remote to control an on-screen cursor. To correct this, they augmented the remote with an infrared image sensor on the front designed to locate two IR beacons within the controller's field of view. The beacons are housed within a device misleadingly called the sensor bar. The sensor bar is powered by the Wii base unit, and contains 2 groups of IR LEDs, spaced 7.5 inches apart. Each group is composed of 5 LEDs, but homemade sensor bars have been effective with fewer LEDs, so long as the intensity is sufficient. There have been unconfirmed reports of people using two candles, which give off the same kind of infrared radiation. The cable from the Wii to the sensor bar only carries power. No information is passed either to or from the sensor bar, and the intensity is not modulated in any way.

These two sources of IR light are tracked by a [http://www.pixart.com.tw/ PixArt] sensor in the front of the Wiimote housing. By tracking the locations of these two points in the sensors 2D field of view, the system can derive more accurate pointing information. Not much is known about this feature yet, but circumstantial evidence from the [http://www.wiiregamers.com/news/2492 Nintendo/PixArt] press release suggests that Nintendo is using a PixArt System-on-a-Chip to process the images on-board the Wiimote and sends the minimum information needed for tracking back to the base unit. Transmitting full 2D images constantly would require a prohibitive amount of bandwidth, especially when multiple remotes are in use.

These two sources of IR light are tracked by a [http://www.pixart.com.tw/ PixArt] sensor in the front of the Wiimote housing. By tracking the locations of these two points in the sensors 2D field of view, the system can derive more accurate pointing information. Not much is known about this feature yet, but circumstantial evidence from the [http://www.wiiregamers.com/news/2492 Nintendo/PixArt] press release suggests that Nintendo is using a PixArt System-on-a-Chip to process the images on-board the Wiimote and sends the minimum information needed for tracking back to the base unit. Transmitting full 2D images constantly would require a prohibitive amount of bandwidth, especially when multiple remotes are in use.