some very cool features for a capacitive touchscreen

Gonzalo Odiard gonzalo at
Fri Oct 25 09:24:58 EDT 2013

The last time I checked, the width was as pressure in evdev,
but was not available in the gtk event.
Another option is prepare circles of may be 5 mm and paste them behind the
in different positions. A program can detect that circles as touches,
and recognize the figure using the relative postions. Our touch screen
can detect 4 touches, but can be confused if are aligned in horizontal or


On Fri, Oct 25, 2013 at 8:50 AM, Jon Nettleton <jon.nettleton at>wrote:

> On Fri, Oct 25, 2013 at 1:40 PM, Manuel QuiƱones <manuq at> wrote:
>> 2013/10/24 Sameer Verma <sverma at>
>> >
>> > I saw some very cool features in a presentation today at the Internet
>> > Archive. The presentation was by Eitenne Mineur, as part o the "Books
>> > in Browsers 13" event.
>> >
>> > They are using paper and other simple objects that have kind of
>> > conductive patterns to create story platforms, but with interactivity.
>> > Start with a story screen, place a paper cutout of one of the
>> > characters, and the story comes to life. Place a second character, and
>> > the scene changes.
>> >
>> > All very interesting ideas for us to use on the XO-4 Touch, although
>> > the XO4 does not use capacitance, but the idea is very cool.
>> >
>> >
>> Wow, this is very inspiring.  Somebody should try this technique on an
>> XO-4.
> Unfortunately because of the way our touch technology works, this exact
> implementation won't work.  However our touch technology is actually nicer
> because you don't need special material to activate the touches.  I think
> what would work well for us would be an activity that allowed you to
> program what shape/character was attached to different size touch points.
>  Then use small wooden/plastic disks of different sizes glued or clipped to
> the back of the cutouts to trigger the touch events and let the program
> know what story to tell.
> smallest disk = dog
> medium disk = frog
> large disk = frisbee
> I would have to double check but I think we pass along the touch width as
> the pressure value for evdev.  Should be easy to parse the event and figure
> out what is on the screen, and should work with 2-4 touches/items.
> -Jon
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