Keyboard Mechanical Design

[Gene & Debby Stopp]

> From: Ken Stone <sasami at blaze.net.au>
> Subject: Re: Keyboard Mechanical Design
> Date: Wednesday, August 27, 1997 11:14 PM
> 
> Would you care to elaborate on your digital scanner? It sounds
interesting.
> I assume it remains a mono proposition, as you are wiring them into mono
synths.
> 
> Ken.

There is a circuit in Electronotes which works well - counter, 64-to-1 mux,
latch, DAC, with latching logic that latches either the lowest note or the
highest note, depending on which direction the counter is counting. The
lowest note case for example gives identical behavior to a resistor string
design such as a minimoog. I usually make it up as I build it, so they're
all a little different. The EN design was based around 1975-era TTL, and
has some timing problems if built with ACT/FCT parts or burned into an
Altera EPLD (for example), but some fiddling with the logic can fix it up.

- Gene