Coding4Fun

Using the Wii Remote Infrared Camera

One of the ways we can track the location of a stylus to create an interactive display surface is to use a camera. A camera can see where the stylus is in an image, and we can extract those pixel coordinates to tell the computer where the cursor should be on the screen. Several interactive touch systems today use camera-based tracking for touch input, including the Microsoft Surface, the Perceptive Pixel display, and products from Smart Technologies. Often these systems use near infrared (IR) light illumination to highlight the location of touches. Near IR refers to wavelengths of light that are just outside the range of human visibility at the red end of the spectrum. IR light is commonly used in household remote controls to interact with televisions and stereos. Since this light is invisible to us, camera tracking systems can use specialized IR illumination to highlight the visibility of target objects.

Behind the black plastic in the tip of each Wii remote is an IR-sensitive camera. The camera provides pointing capability on the Wii game console by looking for the sensor bar placed near your television. The name "sensor bar" is actually a misnomer since it does not actually contain any sensors but rather two groups of IR emitters. The two groups of emitters appear as two bright dots in the camera image. Using the location of these two dots, the console can determine where you are pointing on the screen.

The camera chip is manufactured by a company ...