[sdiy] Diode Matrix Keyboard Circuits?

[Gene Stopp]

I've done this - I modded the digital scanner interface from Electronotes (#68 I think). That circuit uses a bunch of multiplexors to scan all of the keys, with a 64-to-1 mux selected by the 6-bit scan counter. I just used the 3 high bits to drive a 1-to-8 demux as a group select, and the 3 low bits to drive am 8-to-1 mux from the key groups. This make an 8 by 8 diode matrix scanner. No schematics, sorry...

- Gene

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of DSL FODA01
Sent: Thursday, December 07, 2006 12:06 PM
To: klosmon
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Diode Matrix Keyboard Circuits?


Hi G,

Thanks for the reference.  I couldn't find anything on that source, but I
did find this:
http://neolase.lasers.org/PAiA/8782/schematic.htm
Is this something similar?  It looks like it's part of a larger system - I'm
not sure if it could be operated as a stand-alone.  Hmmm....

Dave


----- Original Message ----- 
From: "klosmon" <klosmon at sbcglobal.net>
To: "DSL FODA01" <foda01 at epix.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, December 07, 2006 1:38 PM
Subject: Re: [sdiy] Diode Matrix Keyboard Circuits?


> One of the simplest I've seen is the old Paia diode encoded keyboard -- 
> details were in "Friendly Stories about Computers & Synthesizers" by John
> Simonton.
>
> ~G
> At 09:51 AM 12/7/2006, you wrote:
> >Hello Harald,
> >
> >Thank you for the reference.  I took a look at that web page, but I had a
> >hard time understanding it, even using an online translation program
> >(Babelfish).  From what I could understand, it seems to me as though they
> >are working with MIDI.  I am looking for a way to bypass MIDI altogether
and
> >go right from a matrix-keyboard to CV/Gate/Trigger output.  If I am
> >mistaken, please let me know.  I have a 16F877A which could give analog
> >outputs via PWM but I have yet to learn how to program it ;-)
> >
> >thanks sincerely,
> >
> >Dave
> >
> >
> >----- Original Message -----
> >From: <HA.Synth at t-online.de>
> >To: "DSL FODA01" <foda01 at epix.net>; "Synth DIY"
> ><synth-diy at dropmix.xs4all.nl>
> >Sent: Thursday, December 07, 2006 10:44 AM
> >Subject: Re: [sdiy] Diode Matrix Keyboard Circuits?
> >
> >
> > > Hi Dave,
> > >
> > > look at this: http://www.heise.de/ct/Redaktion/cm/klangcomputer/
> > > Sorry its German, but they sell the PCBs you need and you can download
the
> > > firmware there.
> > >
> > > Harald
> > >
> > >
> > > Am Donnerstag, 7. Dezember 2006 04:56 schrieb DSL FODA01:
> > > > Hi all,
> > > >
> > > > Does anyone here know of a good way to create a scanner circuit for
a
> >diode
> > > > matrix keyboard?  I have a 49 key Yamaha keyboard here that already
has
> >a
> > > > diode matrix type of board on it and I would like to use it to
generate
> > > > CV/Trig/Gate outputs.  I think a PIC or something like that would be
> >best
> > > > but unfortunately I don't yet have a high enough skill at low-level
> > > > programming.  I have seen some designs in hardware, but the only
board I
> > > > saw (Ray Wilson's) is discontinued.  Any other suggestions?
> > > >
> > > > Dave
> > >
>
>
>