[sdiy] Keyboard Control

[Thomas Holley]

Thanks Harry,
 I have the keyboard controller arranged so that the current source is to
one end (HI) of a resistor ladder and the other end (LO) referenced to
ground. The keyboard is from an old broken ensonique with little spring
contacts on each key. I have it so when the key is pressed the contact
grounds that point in the resistor ladder. The reference voltage for the
controller is taken from the top of the resistor ladder where the current
source connects (copied from an old ARP patent). With this arrangement I
think the current source should then go on the low (left) key side to give
the highest voltage reference to the high (right) keys. Is this right or do
I have it turned around?

Thomas
----- Original Message ----- 
From: "harrybissell" <harrybissell at prodigy.net>
To: "Thomas Holley" <thomasholley at adelphia.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, October 18, 2003 1:57 PM
Subject: Re: [sdiy] Keyboard Control


> Hi Thomas
>
> Higher pitches (to the right side of the keyboard) get higher
> voltages...
> so the current source should go on the highest note side...
>
> H^) harry
>
> Thomas Holley wrote:
>
> >     I have a rather fundamental question. In a keyboard controller
> > resistor ladder, does the high voltage side go to high pitch key or
> > the low pitch key. I have been tinkering with an old keyboard and
> > soldered up a 100 ohm resistor between each key for a nice ladder when
> > it finally dawned on me that I had not a clue which side to put the
> > current source on and which one to ground. Thanks for your help Thomas
>
>