Disney researchers develop finger-powered energy-harvesting technology

Disney researchers have developed an energy harvesting system that can generate enough electric current by finger-tapping a paper or plastic surface to light LEDs or trigger actions within games.The Paper Generator involves a thin, flexible sheet of Teflon between two…

Disney researchers have developed an energy harvesting system

that can generate enough electric current by finger-tapping a paper
or plastic surface to light LEDs or trigger actions within
games.The
Paper Generator involves a thin, flexible sheet of Teflon
between two conductive layers of metallized polyester, which serve
as electrodes. Electrical charge accumulates on the Teflon sheet
when paper is rubbed against it. Then if the electrodes are made to
move relative to each other against the sheet, it generates a tiny
alternating current. This can then be used to power LED displays,
e-ink displays, sound buzzers and infrared communications
devices.The idea came about from a collaboration between interaction
designer Ivan Poupyrev and electrical engineer Mustafa Emre
Karagozler. “We were discussing new ways of harvesting energy and
thought it would be cool to collect the electrostatic charge from
rubbing materials,” Poupyrev told Wired.co.uk.

Disney Research
The system relies on electrets — electrostatic equivalents of
permanent magnets, which carry a quasi-permanent electric charge.
Polytetrafluoroethylene (PTFE), aka Teflon, is one such electret,
quartz is another. These special electrical properties mean that
electrets are already used in microphones and tiny MEMS
devices.“The Teflon has to be charged, and it can be sandwiched between
any two conductive objects — this can be two layers of Mylar
[plastic] or polyester. Or one layer can be a human hand. The
charge is produced every time the electrodes move in relation to
the Teflon. Either the Teflon is moved or the electrode is moved.
It can move horizontally, vertically, or rotate. Any movement
creates charge,” explains Ivan Poupyrev to Wired.co.uk.Researchers have already demonstrated how to use electrets to
convert finger tapping into power to light LEDs using expensive,
microfabricated structures. However, the researchers at Disney have
found a way to do so in a low-tech, cheap way. The technology could
be used to create new types of interactive books, posters and other
printed materials without the need for batteries.The devices produce only a small current (just a few hundred
microamperes) but up to 1,000 volts, which is ideal for triggering
e-ink paper displays.Disney has created a few demonstrations of the technology, such
as a picture of a spaceship with LEDs in the rocket which can be
made to light up by tapping the paper. In another demonstration, an
e-ink face of a cat astronaut (catstronaut?) can be revealed by
rubbing a “button” on a piece of Teflon material. Another example
pits two people against each other to tap fast enough to turn on an
LED first. The energy can also be stored in a capacitor to trigger
a buzzer sound when enough power is generated. Similarly it can be
used to send an infrared signal to trigger action by a
computer.Poupyrev said that in the early stages of the project the duo
tried to over-engineer things. “We went into clean rooms and used
vacuum positioning techniques to deposit thin layers of aluminium
on Teflon. We then decided to try a thin layer of Mylar, slowly we
were simplifying it until we got to the design we have now.”The biggest challenge was trying to find specific scenarios
where the small charge would power devices. “By accident we found
that e-ink was an amazing display for this technology. One of our
co-workers had a sheet of pure e-ink film, so we tried it,”
Poupyrev said. “We also tried lots of other displays including a
low-power LCD, but nothing worked except for e-ink, which worked
really well.” The team plans to improve the technology. “There’s a
lot of optimisation that could be done. We are collecting tiny
amounts of power. We can significantly step up the amount of power
we can produce. Our goal is to see if we can optimise it to the
point that we can charge a simple device like a smartwatch or a
simple e-ink reader.”Also on the topic of fingers, Disney researchers recently also
developed a microphone that lets a user record a voice message and
then relay that message to another person simply by touching them with a finger.