This German hacker created a desktop VR rig with 6DOF (degrees of freedom) tracking, using two Wiimotes and a stereo monitor. I like when he put the glasses on and then says: "Don't laugh. This is serious cutting-edge technology." (I laughed anyway.)
Three of the four LEDs are aligned in a line with only slightly different height. The fourth LED is mounted above the line with more height. This special order of the lights is needed by the algorithm to be able to assign the IR-points recognized by the Wiimote to the original LEDs of the beacon. It is also important that the fourth LED has not the same height, so that the LEDs are not so planar. Please see picture 4 for a schematic layout of the beacon. For power supply I just us on AAA battery and connect all LEDs in parallel to the battery poles. For easy handling I use a battery holder which are also available at electronic components supply stores.
VRHome [via Hack a Wii]
Source: Blog.makezine.com