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
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 ). 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.
That's a cool sounding technique. Have you had any problems with false hits on adjacent keys?
Thanks! That sounds like a really cool idea!
Paul Carpenter wrote:
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