[sdiy] Minimoog clone

[David Griffith]

On Sun, 11 Jul 2010, Paul Perry wrote:

> If you want a CV from a matrixed  keyboard, isn't this a matter of a D to A 
> converter?
>
> paul perry (hasn't been inside a keyboard, could be very wrong)

A keyboard is called "matrixed" because it electrically appears to be a 
grid of switches.  You know when a particular key is pressed when a 
circuit is completed when a circuit goes from the column to row wire.  If 
too many keys are down at once, false keypresses or "ghosting" can be 
created.  People using gutted computer keyboards to create arcade 
controller interfaces had lots of problems with this and that's why 
special non-matrix gizmos exist for that application.  Careful design of 
the matrix can lessen, but not prevent the occurence of ghosting.  From 
some mental doodling, a matrix can be made into a non-matrix with an AND 
gate for each key, but it's still prone to ghosting.

I'm still waiting for a response from Mark (who runs 
http://www.arpeggi8.com/synth/minimoog/mini.html) on which Casio keyboard 
he used and how he got it to work with whatever it's connected to.

-- 
David Griffith
dgriffi at cs.csubak.edu