On Fri, 17 Aug 2001
mate_stubb@... wrote:
> 2. The single most important useability feature would be to adopt the
> Yamaha convention of having the zero point be where you first put
> your finger down. That way you can touch down anywhere on the ribbon
> and do finger vibrato, or smooth sweeps away from the current control
> voltage. You could have another mode switch that allows it to operate
> the other way as well.
For those interested, here is how Yamaha did this:
http://www.cs80.com/csribbon.gif They just detect when the ribbon is touched and store the initial ribbon
contact voltage on an S/H cap. Part of this circuit shows the coarse/fine
tuning knobs used on a CS. The output drives the top end of the DAC
'octave' resistor ladder in the CS. Modular use would just need the
output scaled for +/-5V or whatever. I am unsure what the ribbon
resistance is, but that should not be too critical. I'll measure it the
next time I have the CS-80 open.
Oh, the 'down' and 'up' gates can be picked off those comparators and
buffered for gate/trig use.
Crow
/∗∗/