[sdiy] Matrix keyboard idea

[Byron G. Jacquot]

>My take (I'm hardware..) would be to co Midi to CV convert, then build a
special
>
>quantizer, with an extra "bit" that would be a controllable GATE output.  So
>lets
>say 64 notes come in (thats 6 bits)...  You convert the same 6 bit number that
>corresponds to note, into a 1 of 64 output decoder, and 64 switches. You enable
>the
>gate to the synth via switches that are closed.  You could control two synths
>this way with a second bank of switches...
>
>I'd have to give lots of thought to the matrix deal, I don't think it would
help
>much.
>The hardware would get very complex to control all the switches. Maybe no
>benefit.

Things might get interesting if you put a ROM in there.  Address it with
those 6 bits, and use the data outputs to the 1 of 64 decoder.  With an
N-address by 8-bit ROM, you could have 2 bits left over after the 6 to use
for gates & stuff too.  You could build all sorts of crazy sets of
translations into an EEPROM, and use the higher address lines to select
between them.  A 32 K EEPROM would give you 512 possible 64 byte tables.

Things could get even crazier if you cascaded several EEPROMs this way,
daisychaining the data outs of one to the address ins of the next!

Of course it might not be too easy to do real-time changes to the data in
the ROM, but with that many tables, you could surely work around it.

It's also worth mentioning that the old MUSE hardware sequencer is somewhat
related to these ideas, where the "next state" logic was controllable and
tweakable on the fly.  Hal Chamberlin's Musical Applications Of
Microprocessors goes into details.

Byron Jacquot