Disney Research presents a new energy harvesting technology that generates electrical energy from a user’s interactions with paper-like materials. The energy harvesters are flexible, light, and inexpensive, and they utilize a user’s gestures such as tapping, touching, rubbing and sliding to generate energy. The harvested energy is then used to actuate LEDs, e-paper displays and other devices to create interactive applications for books and other printed media.
This new approach to energy harvesting uses electrets, materials with special electrical properties that already are used in microphones and in tiny MEMS devices. This latest application, developed by researchers at Disney Research, Pittsburgh and at Carnegie Mellon University, could make possible new types of interactive applications involving books, posters and other printed materials that require no batteries or external power.
The design of a Paper Generator is simple: one approach is to sandwich a thin, flexible sheet of polytetrafluoroethylene, or PTFE – best known by the brand name Teflon® –between two conductive layers, such as sheets of metallized polyester, that serve as electrodes. Electrical charge accumulates on the PTFE sheet when paper is rubbed against it. Then, if the electrodes are made to move relative to each other against the PTFE, a tiny, alternating electrical current is generated. This electrical current can be used to power a broad variety of devices such as LED arrays, e-ink displays, sound buzzers and infrared communication devices.
“Though the fundamental principles of operation remain the same, it’s possible to build Paper Generators that respond to a number of different gestures, such as tapping, touching, rubbing or sliding,” said Ivan Poupyrev, director of Disney Research, Pittsburgh’s Interaction Group. “We can imagine any number of ways to use this to add sights, sounds and other interactivity to books and other printed materials inexpensively and without having to worry about power sources.”