Smart Paper, a New Digital Interactive Interface

There are countless digital tools that can enhance our recreational, leisure and professional activities. But we sometimes involuntarily return to our old habits. For example, we often tend to take notes on a piece of paper lying on the desk and then forget that we have done so. Researchers have developed a solution that combines work habits acquired in the real world with digital solutions.

Yang Zhang and Chris Harrison of the Human-Computer Interaction Institute at Carnegie Mellon University in Pittsburgh, United States, created a touch-sensing paper, a plain sheet of paper sensitive to touch that communicates with computer devices. Both researchers are working on human-machine interaction and detection technologies.

Their paper samples were presented at the Conference on Human Factors in Computing Systems 2018 held at the Palais des congrès in Montreal, from April 21 to 26. Their presentation is entitled “Pulp Nonfiction: Low-Cost Touch Tracking for Paper.”

Dubbed “Pulp Nonfiction”, this paper has three advantages:

• It is inexpensive
• It can be discarded or stored like plain paper
• It retains the graphic properties of sketches and writing done on its surface by relaying them instantly to a computer

Materials, Manufacturing Technique and System

To make the paper sensitive to touch, the team coated the surface with a conductive material called Velostat, a thin resistant film used as covering, as packaging and in electronic components. It is made of polymeric foil (polyolefins) impregnated with carbon particles that make it conductive. The researchers point out that there are other materials that possess this property, for example, by applying a conductive sprayed-on layer and other coatings used in Zhang’s Electrick project.

The Electrick project

The sheet’s sensitive surface is connected to an electrode-based signal receiver linked to a computer. This manufacturing technique will later be replaced by a more efficient process that work together to increase the opacity of the paper, reduce its thickness and make it touch-sensitive on both sides. Consequently, the relay device will be simpler, as shown in the video. In fact, the sheet coating will be replaced by grids made of conductive materials printed directly on the sheet.

Operation of the Touch-Sensing Surface

The technique is based on electrical tomography, a method that generates images of 2D and 3D electrical resistivity variations on a surface. Electrodes emit a small electric current that spreads over the entire surface. They also make it possible to measure electrical voltage on different points of the paper. When the finger (or pencil) touches the conductive coating, this reduces the electrodes voltage, which relay this information to the computer. A tomographic reconstruction algorithm translates changes in the electrical flow into lines and points, which can also indicate the pressure exerted on the sensitive surface. The device also makes it possible to simultaneously represent remote contact points.

 Applications

In addition to applications in design and the arts, touch-sensing paper can be used in complex human-machine interfaces. It can reinvent the use of digital education and entertainment devices or allow newspaper and magazine readers to share articles and their comments on social networks. In their presentation, the researchers listed other interactive applications for office, education and entertainment activities.