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Cheap, Small LED or LCD Touch Sensitive Screens?

Posted by ryuzaki0 on from the off-the-shelf-or-DIY-project dept.

emf2268 asks: "I'm looking to either purchase or build (I'll do the circuitry myself if I have to) several dozen, small screens for an arcade game that uses a touch interface. Each screen, which should be around 6-10 inches, needn't be extremely advanced in the display department, since 16 colors will do just fine. An LED or LCD would do the job. But each screen also needs to be touch sensitive...it only needs to know if it's been touched, not where it was touched. How, can I build this as cheaply as possible?"

3 of 39 comments (clear)

  1. Real cheap by Peter+Simpson · · Score: 3, Interesting

    If I were trying to do this on the real cheap, I'd use conductive bags. Cut a square of the material, place it backwards (inside out) over a plexi backer, with the LEDs behind it. A non-conductive) bezel over the front to keep all in place. Connect the conductive inner layer of the bag material to a high impedance circuit with a spring contact and sense the "body antenna effect" (as on the old microwave ovens),

    It's much cheaper than metallized glass. But maybe you want to go that way.

  2. Old fashioned way by cyber_spaz · · Score: 2, Interesting

    Back in the day, we used to see articles for homebrew touch screens that were basically picture frames with a few infrared LEDs on one side, and some phototransistors on the other with a bit of circuitry. Your finger would break a beam and get detected.

    For a tiny production run, this might be an acceptable method. (For a *real* product, you'll want something better.)

    Another thought: If you can get a conductive transparent plastic sheet, then you could make a sandwich where one sheet is against the screen, and the other is floating a small distance away. Then you can just detect the conductivity change when someone pokes the top sheet enough to make it touch the bottom sheet.

    --
    "Time flies like an arrow, fruit flies like a banana" --Karl or Groucho, I forget...
  3. You can use an LED matrix as both display & se by saccade.com · · Score: 5, Interesting

    It turns out you can use LED arrays as both displays and sensors. People have successfully used them for touch sensor controllers. See this blog for some experiments. The original concept came out of the NYU media lab.