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12-Key Keypad Reccomendation?

Discussion in 'Embedded' started by Al Cohen, Aug 9, 2004.

  1. Al Cohen

    Al Cohen Guest

    A project prototype that I'm working on calls for a small 12-key keypad
    as found in a cell phone (0-9, #, *), and fairly small (about the size
    of a cellphone keypad), that's easily mountable in a prototype box. It
    should be sealed (medical environment).

    I've been poking around, but have not found anything appropriate. Any
    suggestions would be greatly appreciated.

    The other alternative would be a small-run custom keypad. Any
    recommendations here would also be appreciated.


    Al Cohen
    Al Cohen, Aug 9, 2004
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  2. On Monday, in article <>
    The easiest solution for medical market I have found is use a plastic front
    panel that is clear, attache a marked out label behind the plastic, and
    use proximity detector ICs (see <http://www.qprox.com/> ). A lot easier and
    cheaper than mechanical switches. Perfectly sealed, if you need feedback add
    a keyclick speaker.

    These allow for n-key rollover and come in sizes from 1 to 64 key keyboard
    chips. They have a 16key chip (QT60161) that has serial/SPI/Parallel o/p as
    well as good eval boards with datasheets. Most parts and eval boards available
    from places like Farnell.

    The other advantage of a clear panel is you mount a pcb behind it with touch
    pads in the PCB, and can also mount LEDs or displays that show through a cut
    out in the label behind the plastic.

    The legends are still visible and not worn or scratched away. Just choose the
    right plastic that is inert to any cleaning methods likely to be used. I
    doubt even a mechinical switch assembly could withstand autoclaving !!!
    The above may help.
    Sounds like you would be looking at a membrane style keyboard or replacemnent
    for the whole front panel to reduce seals.
    Paul Carpenter, Aug 9, 2004
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  3. That's a cool sounding technique. Have you had any problems with false hits
    on adjacent keys?
    Michael R. Kesti, Aug 10, 2004
  4. Al Cohen

    Al Cohen Guest

    Thanks! That sounds like a really cool idea!

    Al Cohen, Aug 10, 2004
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