Edson Brusque wrote:
> Hello,
>
>      I've been thinking about using the PIC A/D to scan a 16 keys
> keyboard. The example bellow have only 4 keys for simplicity:
>
>              ,----K1----VDD
>              |
>              1k
>              |
>              +----K2----VDD
>              |
>              1k
>              |
>              +----K3----VDD
>              |
>              1k
>              |
>       ADC----+----K4----VDD
>              |
>              1k
>              |
>             GND
>
>      Without any key pressed, the ADC would read 0V, with K1 pressed
> it would be 1.25V, with K2=1.66V, K3=2.5V, K4=5V.
>
>      I think this would be very interesting for projects using a PIC
> with ADC and short of I/O.
>
>      Best regards,
>
>      Brusque


Other than that, look this design we made and used 11 years ago;

http://www.ustr.net/electronics/akeys.shtml

Wagner.

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