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Subject: DIY keyboard

From: "J. Larry Hendry" <jlarryh@...>
Date: 2000-08-13

Despite the fact that I have more MIDI keyboards than I need and a perfectly
good Kenton pro-2000, I decided to take the DIY plunge and construct a CV
keyboard for contolling my modular. As luck would have it, I found a very
nice 5 octave keyboard mechanism built into a very nice walnut case that has
3 contacts per key. In addition, the precision resistors for the CV are
already installed. And, in the appropriate place is a great spot for a
joystick or whatever.

Now, I have the easy part of this down pat. The pitch CV with the resistors.
I will probably stick in a nice DC op amp with a little summing network so I
have pitch bend with the joystick, and maybe put in an aux CV input for
other toys. Now, the rest is wide open and I am in the learning mode. The
arrangement of the contacts is such that they do not all have to close at
the same time. So, looks like a velocity CV is possible too.

Under the generally accepted principal that "many heads are better than one"
I ask, "what would you include in such a controller?" I am thinking pitch
CV out, joystick X and Y CV out with the ability to couple one axis of the
joystick to pitch CV internally, gate AND trigger out, velocity CV, and
maybe the ability to split the keyboard. And, when using gate only, it
would be nice to be able to retrigger for the next keystroke (selectable).
I am planning to avoid DACs, PICs, matrix and all that stuff. I have the
DAC accuracy in the Kenton. What I want here is monophonic analog.

So, I would appreciate anyone's opinion of what they would choose to include
in the functionality. And, any pointers toward additional reading material
or schematics that would help me become more familiar with the typical type
of circuity used in CV keyboards would be appreciated too.

Larry Hendry