Now，Spray Paint Can Turns Any Surface into a Touchpad.

Scientists have developed a new technology that can turn any surface — including walls, furniture and steering wheels — into a touch screen using tools as simple as a can of spray paint.

The “trick” is to apply electrically conductive coatings or materials to objects or surfaces, or to craft objects using conductive materials, researchers said.

By attaching a series of electrodes to the conductive materials, researchers from Carnegie Mellon University in the U.S. showed they could use a well-known technique called electric field tomography to sense the position of a finger touch.

“For the first time, we have been able to take a can of spray paint and put a touchscreen on almost anything,” said Chris Harrison, Assistant Professor at Carnegie’s Human – Computer Interaction Institute.

With the new technology dubbed Electrick, conductive touch surfaces can be created by applying conductive paints, bulk plastics or carbon-loaded film.

Yang Zhang, a PhD student at the institute, said that Electrick is both accessible to hobbyists and compatible with common manufacturing methods, such as spray coating, vacuum forming and casting/molding, as well as 3D printing.

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, Mr. Zhang and his colleagues showed they could localise where and when such shunting occurs. Electrick can detect the location of a finger touch to an accuracy of one centimetre, which is sufficient for using the touch surface as a button or slider, Mr. Zhang said.