Now using a Wii-mote and an Infra-red pen, and a few other things, you can have a complete touch screen, wall, desk, or anything else. Its pretty cool! Here is a little more Information.

Since the Wiimote can track sources of infrared (IR) light, you can track pens that have an IR led in the tip. By pointing a wiimote at a projection screen or LCD display, you can create very low-cost interactive whiteboards or tablet displays. Since the Wiimote can track upto 4 points, up to 4 pens can be used. It also works great with rear-projected displays.

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