As cool as it is to be sending data over sound, its only $25 for some of the cheaper wireless modules over at sparkfun: http://www.sparkfun.com/commerce/categor

As cool as it is to be sending data over sound, its only $25 for some of the cheaper wireless modules over at sparkfun: http://www.sparkfun.com/commerce/categories.php?c=16 http://www.sparkfun.com/commerce/categories.php?c=16 That would be impossibly more practical, and you wouldn't really have to have them wired together to sync them. You could have a master transmitter that sends out a sync bit that everyone syncs with (or something...).