Controlling the Glide/Pressure sensor

[Patrick Dubroy]

Never mind -- it turns out I wasn't pressing hard enough on the tablet
area. I can now see the tablet events in both the firmware tests, and
using evtest.

Pat

On 1/22/08, Patrick Dubroy <pdubroy at gmail.com> wrote:
> I've got my hands on a B2 machine, and finally got around to giving this a go.
>
> When I boot into the firmware tests and get to the tablet test, it
> doesn't seem to detect anything at all except in the center third (the
> capactive area). Does this mean that the firmware in this machine
> doesn't support the pressure tablet at all?
>
> On 1/14/08, Wade Brainerd <wadetb at gmail.com> wrote:
> > You can watch the output of the PT by downloading and compiling evtest:
> >
> > wget http://david.woodhou.se/evtest.c
> > gcc -o evtest evtest.c
> > ./evtest /dev/input/event5 0
> >
> > It's event5 on my XO, you might have to use a different number.
> >
> > Anyway, then drag something around on the PT and watch the output.  This is
> > the output from the olpc.c driver in the kernel.  So the driver appears to
> > be working, but there is something preventing X (possibly the HAL?) from
> > recognizing the events as mouse movement.
> >
> > I'm not sure whether the driver correctly reports the GS's (quite limited)
> > pressure sensitivity though.
> >
> > If you want to see the raw data, just boot the XO with the left gamepad key
> > held down and run through the firmware tests to the one which tests the
> > tablet, it lets you see both GS and PT input as well as pressure.
> >
> > Best,
> >
> > Wade
> >
> > On Jan 14, 2008 11:29 AM, Patrick Dubroy <pdubroy at gmail.com> wrote:
> > > I'm the student Mike mentioned who will be working on this project.
> > >
> > > Does anyone have any more details on how much low level work needs to
> > > be done? I know there will need to be work done to map the input from
> > > the tablet to X events. Is the device driver fully functional?
> > >
> > > I'd appreciate any more details that people could give me.
> > >
> > > Thanks,
> > >
> > > Pat
> > > --
> > > Patrick Dubroy
> > > http://dubroy.com/blog - on programming, usability, and hci
> > >
> > >
> > >
> > >
> > > On 1/10/08, Mike C. Fletcher <mcfletch at vrplumber.com> wrote:
> > >
> > > > I have a student who's interested in doing a term project on the UI for
> > > > the track sensor.  I've put together this quick summary.  Deadline looms
> > > > for starting the project, so if people have "don't do that" or "we've
> > > > already done that" feedback, please speak up ASAP.
> > > >
> > > > Background:
> > > >
> > > >     * XO has two different devices, resistive glide-sensor and
> > > >       pressure-sensitive tablet
> > > >           o Both of these are currently showing up as "core pointer"
> > > >             events in X AFAIK
> > > >           o Changes between pressure and glide-sensor activity have the
> > > >             potential to cause "jumps" of the cursor (absolute versus
> > > >             relative mode)
> > > >     * There is currently no UI to map the pressure-sensitive tablet's
> > > >       area into a particular area on the screen (nor, AFAIK an API to
> > > >       accomplish the mapping)
> > > >           o Use case: use the entire drawing area to draw into a small
> > > >             area of a drawing in Paint
> > > >     * Activities currently do not have control over the mapping of the
> > area
> > > >           o Use case: in a penmanship course, collect samples of the
> > > >             child's letters in special widget areas within a "test",
> > > >             focusing a new area should remap the pen to that area
> > > >
> > > > Trackpad UI Design Requirements:
> > > >
> > > >     * API for configuring the resistive/pressure sensor allowing control
> > > >       of all the major features
> > > >           o Note that there will likely be some X11 hacking here, to get
> > > >             the pointer mapping working
> > > >     * Standard UI controls for redirecting input areas
> > > >           o Standard GTK UI for positioning, and scaling
> > > >           o Standard GTK widget for e.g. handwritten text entry, provide
> > > >             access as a bitmap (or a series of strokes optional)
> > > >                 + Allow for capturing all data (full resolution) or just
> > > >                   scaled data as configuration option
> > > >           o Intuitive (HIG-compliant) standard mechanisms for
> > > >             controlling the various configuration parameters
> > > >           o A 6 year old should be able to figure out how to direct
> > > >             their drawings, written text and the like into the desired
> > areas
> > > >           o Standard feedback on where the tablet area is bounded on
> > > >             screen when drawing with the tablet
> > > >     * System level (possibly on Sugar's Frame) trigger to bring up the
> > > >       control mechanisms (optional)
> > > >           o Most pen-aware applications will likely use internal logic
> > > >             and the API to determine position and the like, but a
> > > >             general trigger to the functionality should be useful for
> > > >             non-pen-aware activities
> > > >     * Paint Controls
> > > >           o Work with Paint's authors to provide intuitive controls to
> > > >             make using the pen/tablet intuitive within the context of
> > paint
> > > >
> > > > Obviously we would need to find a machine to work on to make the project
> > > > feasible.  I'll see if we can repurpose one that's local to the task.
> > > >
> > > > Discussions welcome,
> > > > Mike
> > > >
> > > > --
> > > > ________________________________________________
> > > >   Mike C. Fletcher
> > > >   Designer, VR Plumber, Coder
> > > >   http://www.vrplumber.com
> > > >   http://blog.vrplumber.com
> > > >
> > > >
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> > >
> >
> >
>