Science Tuesday: Power Up an Interactive Display Without a Battery

By Sanah Faroke, Staff Writer
@sanahfaroke

Let’s face it, nearly everything we do, we do it with the use of a battery or an outside electrical source. Writing a paper? Hello—you need to charge that laptop with 5 percent battery. And you can’t heat up that mac and cheese over an open wood fire, so microwave that bad boy. Putting on makeup? Have you ever tried that in the dark? I’m telling you, it won’t give you that Cover Girl look.

So, when I think back to the last time I heard a story without the aid of a battery, I recall my mom’s tales about climbing trees and playing marbles and I probably couldn’t deal. The newest thing now though is the powering through energy harvesting. Disney Researchers in Pittsburgh have come up with a way to power things like interactive books and lighting up LEDs all with just a paper generator—no battery required.

In a Discovery article, researchers at the ACM Symposium on User Interface Software and Technology (UIST), in St. Andrews, Scotland, found two techniques that show that a paper generator can be activated with hand rubbing and tapping so this voltage can actually control displays, e-ink and send signals to other devices like a laptop.

This sheet called polytetrafluoroethylene (PTFE), typically known as Teflon, and another material that can be used as an electrode are the only two things needed. I kind of wish this study came out when I was participating in the fourth grade science fair; partly because it’s pretty awesome AND because it sounds like such an easy science experiment (and I was that kid in the science fair who tried to create enough energy to power a light bulb with lemons…it didn’t work and now I hate citrus).

UIST researchers proved, however, that with two techniques, the paper generator can be powered. In one approach, they used the Teflon sheet that will be used to create a static charge and then put it in between two silver-coated polyester sheets. It kind of looks like a mini sandwich that could shock you if you try to eat it, so don’t, but if you tap the polyester, it generates a voltage and a small current.  The second approach is to rub the conductive sheet on the Teflon, which also creates a voltage.

While the current, produced by the rubbing or tapping, is relatively low, the voltage is high; up to 1,000 volts which can trigger e-paper displays. So for example, the Disney Researchers created a cartoon of a rocket ship with the rocket ship’s fire outlined with LED lights. When the paper was tapped, the LEDs lit up. In another demonstration, there was a cartoon of astronauts and aliens, so when the conductive sheet was rubbed on the Teflon, the e-paper revealed the word ‘Hello.’

So, how does this work? Well, the materials, including the Teflon, have a permanent static charge, so when researchers moved a conductive material through an electric field, it gives you a current. The system is fairly easy to make considering that almost anything can be an electrode, as long as it conducts electricity– it’s easy to build and you could even print a paper generator from your laptop. All the demonstrations were produced without a battery and yet it’s still interactive. Crazy, huh? Well, I suspect that intellectual light bulbs are going off around the world, so although we’re simplifying things without batteries, the days of playing jacks and marbles are way behind us (oh, and science fair projects with lemons).

To see more watch the video below:

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