Wiimote

39.73 U.S. dollars = 53.2660123 Singapore dollars

IR Pen

firstly, modify a current LED light pen: http://www.youtube.com/watch?v=I568NyZLJkY

wiimote

buy a wiimote

build wiimote whiteboard with mac

• http://mkeadle.org/wiiboard/
• http://macapper.com/2007/04/27/how-to-control-your-mac-with-a-wii-remote/
• http://johnnylee.net/projects/wii/