Disney knows who’s touching what

Regular touch interfaces don’t discriminate, treating all fleshy finger contact alike. They generally detect a single change in electrical current, or light / sound waves regardless of who is swiping or pinching. However, that could be about to change thanks to new work by a team at Disney Research, which involves identifying touch users through unique properties of the individual.

Everyone is different down to bone density, muscular mass, blood volume and water content. The device, which forms part of the ongoing Touché research project, sends a variety of harmless electrical currents through the body. This resists them depending on the various physiological properties of the individual. The Touché system measures the unique capacitive signature to identify individuals.
The top later is made of transparent Indium Tin Oxide. It acts as an electrode transmitting an electric current into the user’s fingertips. 
The sensor board layer injects tiny currents into the ITO layer. When a user touches the screen, current flows from the sensor board, through the ITO and into the body of the user. The sensor then measures the impedance of the person to a variety of frequencies.
Disney’s latest prototype takes around a second to calibrate for a new user, but it can recognise an existing user in around 500 milliseconds.
The bottom layer is a standard LCD which provides the GUI.