David Harris wrote...

>Hey this is great!  Can you push multiple keys?  That should be =
possible, but we
>would need a 16 bit A/D.

Multiple keys pressed simultaneously is a problem with this design. =20

=46or example, if you press the top left key in the diagram I posted then
the output of the voltage divider is Vcc no matter what other keys you
push.  Pushing other combinations of keys together will give you odd
voltage levels that could be misinterpreted, and I don't think any
amount of A/D resolution could fix that, especially since the resistors
themselves have tolerances and an allowance has to be made for that.

But hey, you can't get much simpler...

Dave

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