Georgia Institute of Technology

Using what they are calling "mechanical agitation," researchers out of the Georgia Institute of Technology say they've developed arrays that can sense touch with the same level of sensitivity as the human fingertip, which could result in better bots and prosthetics.

The transparent and flexible arrays use about 8,000 taxels, which are touch-sensitive transistors that can generate piezoelectric signals independently -- meaning they emit electricity when mechanically agitated. As the researchers report this week in the journal Science, each of those thousands of transistors comprises a bundle of some 1,500 zinc oxide nanowires, which connect to electrodes via a thin layer of gold, enabling the arrays to pick up on changes in pressure as low as 10 kilopascals -- which is what human skin can detect.

"Any mechanical motion, such as the movement of arms or the fingers of a robot, could be translated to control signals," lead author Zhong Lin Wang of Georgia Tech's School of Materials Science and Engineering said in a news release. "This could make artificial skin smarter and more like the human skin. It would allow the skin to feel activity on the surface."

Mimicking the sense of touch electronically has long been the dream of many a researcher, and has been accomplished by measuring changes in resistance. But the team at Georgia Tech experimented with a different approach, measuring tiny polarization changes when piezoelectric materials such as zinc oxide (in which current can accumulate) are placed under mechanical stress. In these transistors, then, piezoelectric charges control the flow of current through the nanowires.

"This is a fundamentally new technology that allows us to control electronic devices directly using mechanical agitation," Prof Wang said. "This could be used in a broad range of areas, including robotics, MEMS, human-computer interfaces, and other areas that involve mechanical deformation."

Time will tell whether this tech will find its way into military uses; the work is funded by the Defense Advanced Research Projects Agency, the U.S. Air Force, the U.S. Department of Energy, the National Science Foundation, and the Knowledge Innovation Program of the Chinese Academy of Sciences.