New technique turns anything into a touch sensor

Researchers at Carnegie Mellon University have created a new way to turn almost any surface into a touchpad with just a little conductive spray paint. The system, called Electrick, uses a technique called “electric field tomography.”
 
Created by CMU Ph.D. student Yang Zhang, Electrick uses small electrodes attached to the edges of a painted surface and it can turn wood, plastic, drywall, and even Jell-O and Play-Doh into a touch sensitive surface. They’ve successfully added touch sensitivity with positional control to toys, guitars, and walls.
 
“For the first time, we’ve been able to take a can of spray paint and put a touch screen on almost anything,” said assistant professor in the Human-Computer Interaction Institute, Chris Harrison.
 
From the report:  “Like many touchscreens, Electrick relies on the shunting effect — when a finger touches the touchpad, it shunts a bit of electric current to ground. By attaching multiple electrodes to the periphery of an object or conductive coating, Zhang and his colleagues showed they could localize where and when such shunting occurs. They did this by using electric field tomography — sequentially running small amounts of current through the electrodes in pairs and noting any voltage differences.”
 
The creators envision tools like interactive walls and even an interactive smartphone case that can sense the position of a finger on the back surface and interact with apps on the phone. You can also add a protective coating to the paint to keep it from chipping off.
 
Zhang will show off the technology at the Conference on Human Factors in Computing Systems in Denver.

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