This inquiry is really about hardware. Apparently SGI machines and Vector
General mainframes have some type of additional input devices consisting of a
bank of programmable buttons and a row of knobs. These are used to control
some programs such as BRL-CAD which brought this matter to my attention.
I was wondering if anyone has seen any info on what devices like this can
work with Linux and how to set up such devices with XF86. Is xmodmap the
standard method? I saw some notes that "extra" devices could be added to the
XF86Config file, but I have been unable to find a list of what devices this
statement refers to. I am currently also looking through the Xext package for
My keyboard, for instance has a volume knob, and several extra buttons, but I
have no idea how to set them up with XF86. There is scant documentation on
such things. I suppose I'd need to write a kernel module to access the
> > I'm experimenting with BRL-CAD 5.0 Beta which has the capability to use
> > knobs, buttons, and joystick control. Currently none of these work with
> > the Linux version.
> > Is there a way to make a knob and button device and use it as an X input
> > extension?
> At first I thought you were talking about knobs and buttons as widgets
> on the screen, in which case it is up to the software to draw them.
Actually, this is not what I had in mind, but it proposes an interesting
idea... why not just program up some virtual dials and buttons that can be
adjusted with the mouse and interface in some standard way with X or xmodmap.
Who needs hardware?
> But since you mentioned joystick, I think you are talking about hardware.
> The answer is yes, of course you can make such a device.
> Take the bottom out of your mouse. A ball will fall out. You
> will see two rollers that rub against it. Make a knob and right
> angle gear to do the same.
This is a neat idea. Add a second mouse, and rip it apart and you get two
knobs and some buttons.
> Of course it is also possible to make a knob that doesn't act like
> a mouse, in which case you need some specs and a programmer with
> some time.
> Would you care to sharpen the question? Are you asking about
> BRL-CAD 5.0 Beta, or the X window system, device drivers,
> or hardware design?
I was just fishing around to see if anybody had something like this already
working actually. Hey, I'm into gizmos... the more knobs and buttons the
better : )