Boxes that sense the weight of their contents and books that talk back when pages are turned could be developed using technology being tested by researchers at MIT in the US.
They are making paper with wires, sensors, and computer chips embedded, a technology dubbed 'Pulp-based' computing.
Marcelo Coelho, now at MIT's Media Lab in Boston, US, presented progress on the project this week at the International Conference on Ubiquitous Computing in Innsbruck, Austria.
Swedish researchers have previously used a slightly different technique have made interactive paper for billboard adverts.
Other research groups are also working on so-called electronic paper - flexible displays designed to make computer screens more like traditional paper. But Coelho and Patti Maes at MIT and colleagues at Concordia University in Montreal, Canada, are instead blending traditional paper-making skills with electronic components (see a video of the production process and some applications).
Although paper-making is an ancient process, "only now we have developed the material technology to make paper sheets that are responsive and interactive," says Coelho.
To make electronically-enhanced paper the team produces a layer of paper pulp and lays down wires or patterns of conductive ink on top. Adding another layer of pulp, pressing and drying it leaves electronics embedded within the paper.
This can give the paper a range of new abilities. For example, a spiral of conductive ink can act as either a speaker or a touch sensor, the researchers show. Watch this video clip to see paper speakers, LEDs and sensors in action.
Current running through the speaker spiral makes the paper vibrate and produce sound. The quality is not yet good enough to produce speech, but Coelho says it "works well enough for feedback sounds and simple melodies."
The same spirals can also work as sensors to detect the touch or proximity of a finger, using the same technology behind laptop touch-pads. Touching the paper or holding a hand close to its surface changes the way electricity flows through the spiral.
Adding two layers of conductive ink allows the paper to sense when it bends. If incorporated in a book, such pages "could play sounds or light up as they are turned, supporting more interactive forms of storytelling," Coelho suggests. They could also allow cardboard boxes to sense the weight inside them by measuring the stresses on their walls, he adds.
"The advantage of paper over other materials is that we can make interactive objects that still look and behave like paper," Coelho says. People can interact with pulp-based computers as they would with paper, he adds, folding or writing on it, or even ripping it up.
Jean-Baptiste Labrune of the University of Paris-Sud in Orsay, France, says pulp-based computing could be useful.
"Paper-based computation is an expression of one future area for electronics - flexible and stretchable circuits," Labrune adds. "This means that we could think about computational objects without the traditional limits of electronics."
One of the outstanding products of TL8 science is Smart Paper, a material that looks and feels very much like thick, glossy paper, but is actually a controllable display surface. It combines the advantages of paper and screen, and has countless applications. There are several ways to make Smart Paper. Some manufacturers use thousands of tiny spheres with one dark and one bright hemisphere embedded between thin polymer foils, others make sheets out of crystal particles that can assume a certain color and level of brightness and maintain it without power.
There are two versions of Smart Paper: Normal and Advanced.
Normal Smart Paper is early TL8 and cannot change very quickly. Its surface can change many times per second, but not quick enough for video applications. The resolution of Normal Smart Paper is equal to that of a 20th century newspaper.
Normal Smart Paper has only very crude sensors to detect stylus movements on its surface. It can function as a simple touch screen, but writing can only be recognized with a Smart Pen, and it does not react very quickly. Users scribble on a small writing pad at the bottom of the page, which offers a quicker response.
Advanced Smart Paper is available at late TL8 or early TL9. Its resolution is like that of a modern high-quality art book, and it can change so quickly that it can be used to display video images in perfect quality.
Advanced Smart Paper has a fine latticework of sensors that can detect the movements on a stylus with a special electrically conductive tip (a dozen cost $50) or a Smart Pen. The overall quality of handwriting recognition depends on the Computer attached to the Smart Paper sheet. See Handwriting Recognition below.
Smart paper requires only minute amounts of energy, and all this comes from a tiny solar cell in one of the corners of a page or on the cover. Smart Paper can maintain its content without energy, but the quality of the image degrades after a few months. GMs take note: The good old barely-legible treasure map, the mainstay of many adventure stories, makes its comeback in the computer age as Smart Paper that has been in a dark corner for too long.
Smart Paper Products
Smart paper is available in several forms. The GM should use this list only as a rough set of guidelines, as the possibilities are endless. All Smart Paper items can be mistaken for normal paper, and are normally clearly marked with logos or colorful borders to prevent accidental destruction.
Datacloth (p. UTII32) is a single sheet of Advanced Smart Paper with a set of processors.
Single sheets of Smart Paper cost $5 for a 8" x 11" sheet. A "ring binder" with a reader for small storage media and a cable plug-in Connector that can load data into the pages cost $30 and weighs 1 pound empty. Note that complete books are cheaper because much of the technology can be put into the covers.
A Smart Book is a book whose sheets and cover are Smart Paper. These books have a data cable, but no real processing power. They can be linked to a computer, but the book itself is just a display device. It comes in several sizes: