Researchers at Mid Sweden University, Sundsvall, Sweden have created paper that is interactive and plays sounds when it is touched. “Paper Four” responds to a users' touch, by playing clips from music albums or spoken audio (in their current billboard examples).
In order to make the paper interactive the billboard is made in layers; a paper screen printed with conductive ink is placed on a base and a top layer showing the design is placed on top. The middle conductive layer is connected to a power supply and microelectronics that are used to play the sounds. The touch sensors are activated when the user touches the paper and alters the current flow (similar to a laptop touchpad). The billboards also contain speakers which “are made by printing electromagnets out of conductive ink and stretching the paper over a cavity like a speaker cone behind the billboard. The electromagnets vibrate in response to a current, creating a sound.”
Check out the video here
The video shows some cool uses of this technology and opens the door to such things as talking maps, interactive street signs etc...
Source: New Scientist