12-Key Keypad Reccomendation?

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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.

Thanks,


Al Cohen

Re: 12-Key Keypad Reccomendation?
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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 !!!

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The above may help.

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Sounds like you would be looking at a membrane style keyboard or replacemnent
for the whole front panel to reduce seals.

--
Paul Carpenter        | snipped-for-privacy@pcserv.demon.co.uk
<http://www.pcserv.demon.co.uk/ Main Site
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Re: 12-Key Keypad Reccomendation?
 
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That's a cool sounding technique.  Have you had any problems with false hits
on adjacent keys?

--
========================================================================
          Michael Kesti            |  "And like, one and one don't make
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Re: 12-Key Keypad Reccomendation?
Thanks!  That sounds like a really cool idea!


Paul Carpenter wrote:
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