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Subject: Re: Joystick stuff - circuits

From: "J. Larry Hendry" <jlarryh@...>
Date: 2000-02-24

> From: jwbarlow@...
> Wow! Normal and Bradley together! Who'd a thunk it!

I think normal and Barlow together would be more amazing <grin>

> In a message dated 2/21/2000 11:22:33 PM, jlarryh@... writes:
> >More joystick ramblings.
>
> >And, while I was working on my schematic, I finally decided what I am
going
> >to do with that dang button on top. It will have two functions.
>
> >mode 1: When the button is pressed. Voltage on all 4 outputs goes to
> >zero. I think I have this figured out. To me this would make it very
> >easy
> >to adjust the "trim" or "offset" to the exact zero point by ear quickly.
>
> >mode 2: Button generates a gate.
>
> I like mode 1 (it didn't occur to me until I gave it some thought how
useful
> this might be -- though I thought about having a three position switch to

> select CALIBRATE X OFF CALIBRATE Y -- Larry, don't you mean two outputs,
or
> am I missing something?), but it might make things a bit difficult to
figure
> out how to do it.

John, my joystick will have 4 voltages out at the same time. Instead of X
and Y out using a polarity switch, I will put in unity gain inverters and
have X+, X-, Y+, and Y- outs all at the same time.

I have it drawn up. I don't think it will be hard. However, it isn't
built yet. So, we will see.

> So here's what I thought about today:
> 2U panel
> Four pots -- X OFFSET, Y OFFSET, X SCALE, Y SCALE
> (scale pots are reversing attenuators, naturally).

The 4 outs eliminates the need for reversing attenuators.

> I've been thinking of having separate inputs to allow crossfading from
two
> sources (CV or audio). I finally realized this was possible with some
> slightly more sophisticated switching jacks than Paul typically uses.
Very
> difficult to describe, but with nothing plugged in each joystick pot
would
> have +V on one side, -V on the other. Plugging in a jack to the right (or

> top) input both disconnects the +V (while connecting the input) and
> disconnects the -V (while connecting ground, or the left (or bottom)
input if
> something is plugged in to that input).
>
> Any thoughts?
>
> Larry, I didn't follow the PAiA CV input you mentioned.
>
> John B.

John, This would be similar to what you are describing. However, it would
be just a X IN and Y IN. Plugging in the external CVs or audio would
disconnect the joystick and give you two reversing attenuators with
controls for gain and offset.

Larry