Wiimote
From Wikicliki
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
wiimote 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/