With a Simple Piece of Paper, Engineers Create Self-Powered, Wireless Keyboard

Scientists at Purdue University have found a way to make a piece of paper digitally interactive

Paper keypad next to laptop
As the researcher taps the page, numbers appear on screen. Purdue University

Engineers at Purdue University have developed a printing process that can turn an ordinary sheet of paper into a Bluetooth-connected, self-powered, wireless, interactive keyboard or keypad.

First, the team takes a plain old sheet of paper with a typical alphabetical keyboard, numeric keypad or even piano keys printed on it and places coats it with a neon-green, omniphobic solution, which repels just about everything, including dust, water and oil, reports Gizmodo's Victoria Song. The solution dries clear, and then the engineers can "print" circuit layers over the page without smearing the ink, according to a press release. The layers are constructed to be triboelectric, meaning friction generates its electricity. Essentially, each time a "key" is pressed, energy is produced, so the paper-based tablet is totally self-powered.

In a preprint paper published in the scientific journal Nano Energy, the researchers explain that those now triboelectric areas can then be used to relay “Bluetooth wireless communication,” much like a wireless keyboard relays letters, numbers and other data to a computer.

Moisture insensitivity and rapid cleaning of a flexible, wireless RF SPE keypad.

All-in-all, the printed device doesn’t need an external battery to operate, says Purdue University engineer Ramses Martinez, one of the paper’s authors.

“This is the first time a self-powered, paper-based electronic device is demonstrated,” Martinez says in the press release. “We developed a method to render paper repellent to water, oil and dust by coating it with highly fluorinated molecules. This omniphobic coating allows us to print multiple layers of circuits onto paper without getting the ink to smear from one layer to the next one.”

The new development relatively inexpensive to employ because it can be applied to a scrap of cardboard or any other paper-based surface. The team hopes that the technology can be used operationally by many different industries.

Triboelectric power generation & wireless data transmission on RF-SPE keypad during user interaction

“I envision this technology to facilitate the user interaction with food packaging, to verify if the food is safe to be consumed, or enabling users to sign the package that arrives at home by dragging their finger over the box to properly identify themselves as the owner of the package,” Martinez says. “Additionally, our group demonstrated that simple paper sheets from a notebook can be transformed into music player interfaces for users to choose songs, play them and change their volume.”

So, the next time you’re about to crumple up a piece of paper and pitch it into the trashcan, you might want to think twice. You could very well be tossing out an important piece of technology.

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