Low-cost multi-touch whiteboard using the Wiimote

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.