The touch sensors and the speakers are applied to the paper using conductive inks, which imprint them onto the material. These inks contain silver particles, which allow a current to flow through them – controlling the billboard. The touch of a human hand, pressuring an area on the surface, causes the billboard to respond in a previously programmed way. The inks are re-applied according to the command, and a new image can immediately show on the sheet, while electromagnets can vibrate in order to play a sound. Still, surprisingly, the billboards presented at Mid Sweden University, were made almost entirely from regular paper and therefore, in addition to the fact that they were cheaper than what one might expect, could be easily recycled. 

The researchers behind this project call their invention “Paper Four”. This fourth generation of paper, they say, is the next step in using it after printed books, packaging, and hygiene. Because the smart paper contains three layers – an outer layer with the printed design and text, a middle layer containing the conductive inks, connected to a power supply, and a third one made of thick cardboard material – one can easily replace the middle layer, thus changing the billboard’s functionality, and making it respond differently.   

These kinds of responsive, smart-paper billboards can be applied to a number of industries: think about an advertisement to any store, on which you can explore the specific item you are interested in, or billboards for movie theatres, shifting their patterns, playing music and repainting themselves once triggered by a human touch. The scientists themselves are already talking about using the paper for interactive packaging of various products. A chocolate begging you to eat it, when your hand reaches out for the box…Could it be the next big thing in advertising?