Tabula: trackable tangibles on multi-touch displays
Objects placed on capacitive multi-touch surfaces are usually only detected when the user is touching them. As soon as the user lets go of the object the system cannot tell if the object was only released or if it was removed as well. The Tabula project uses tangible objects on interactive table-tops in computer science education. To make this work, persistent capacitive (PERC) tangibles that ‘know’ whether they are currently on a capacitive touch surface or not, have been developed.