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Researchers Create Touchpads With a Can of Spray Paint (phys.org)

Posted by BeauHD on from the can't-touch-this dept.

Researchers at Carnegie Mellon University have figured out a way to turn any surface into a touchpad using none other than spray paint. "Walls, furniture, steering wheels, toys and even Jell-O can be turned into touch sensors with the technology, dubbed Electrick," reports Phys.Org. From the report: The "trick" is to apply electrically conductive coatings or materials to objects or surfaces, or to craft objects using conductive materials. By attaching a series of electrodes to the conductive materials, researchers showed they could use a well-known technique called electric field tomography to sense the position of a finger touch. With Electrick, conductive touch surfaces can be created by applying conductive paints, bulk plastics or carbon-loaded films, such as Desco's Velostat, among other materials. 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 tradeoff, in comparison to other touch input devices, is accuracy. Even so, Electrick can detect the location of a finger touch to an accuracy of one centimeter, which is sufficient for using the touch surface as a button, slider or other control, Zhang said. You can watch a video about how it works here.

9 of 31 comments (clear)

  1. Pencil "lead" trick by xxxJonBoyxxx · · Score: 2

    I remember there were a few electronics kits you could buy in the 1980's that did the same trick with pencil "lead". First, you scribbled onto some paper, then you attached a lead and pressed onto the graphite square you drew to make different sounds, etc.

    1. Re:Pencil "lead" trick by PolygamousRanchKid+ · · Score: 4, Funny

      I remember there were a few electronics kits you could buy in the 1980's that did the same trick with pencil "lead". First, you scribbled onto some paper, then you attached a lead and pressed onto the graphite square you drew to make different sounds, etc.

      When I was a lad, we couldn't afford pencils or paper.

      However, we were quite adept at making different sounds, with our armpits and hands.

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    2. Re:Pencil "lead" trick by sootman · · Score: 1

      Like this: https://www.youtube.com/watch?...

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    3. Re:Pencil "lead" trick by OhSoLaMeow · · Score: 1

      Oh, I'll do you one better!

      Pull my finger?

      --
      They can take my LifeAlert pendant when they pry it from my cold dead fingers.
  2. Re:That's cool... by chuckugly · · Score: 1

    Maybe you can just paint your favorite keyboard.

  3. Your UI sucks by bursch-X · · Score: 1

    Accuracy of +/â" 1cm is good enough for buttons? Maybe if your test users have a green complexion and talk in two-word sentences...

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    1. Re:Your UI sucks by willoughby · · Score: 2

      I read an article long ago about how you can't truly understand an engineering design unless you understand the context. One example they used was the dashboard of the Saab automobile. Saab, in those days, had a very clunky looking dashboard with large controls spaced far apart. To Americans it looked ugly. What they pointed out in the article was that the Saab was designed in Sweden, by Swedish engineers. The engineers assumed the driver would be wearing winter gloves most of the year and so designed the controls to accommodate.

      Anyway; sometimes a big, fat button makes sense.

  4. just spray paint? by shadowrat · · Score: 1

    It's not like you just grab some rattle cans and go to town. It sounds more like they put in an array of sensors, connect that to special software, and apply a coating of special conductive paint. I guess we can just say that researchers have learned how to create microprocessors out of rocks as well.

  5. Comment by WallyL · · Score: 1

    http://web.stanford.edu/class/sts175/NewFiles/Negroponte.%20Being%20Digital.pdf

    That's only a few pages, but it gives you an idea. I had to read Negroponte's book as assigned reading, and I remember he predicted painted-on computer displays. This spray-on touchpad sounds like we're one step closer!