Re: multitouch + audio feedback linux dev - XO-2?

2009-01-27 Thread Wade Brainerd
On Mon, Jan 26, 2009 at 11:57 PM, da...@lang.hm wrote:

 On Mon, 26 Jan 2009, Wade Brainerd wrote:

 Here's to staying focused,


 agreed, but I don't see how you can do a keyboard and not have some
 multi-touch stuff (shift keys to start with)

 I am in the group that has serious doubts about the current XO-2 design. I
 suspect that when push comes to shove the idea of the second screen being
 the keyboard will go the way of the crank in the XO-1


You've got a point about the keyboard, in my haste to rant I totally
sidestepped that :)  A piano keyboard would be pretty lame if it didn't
support chords.  That said, I was reacting to the idea that Multi-Pointer X
was the way to handle the screen from a software standpoint.  Instead, if
the hardware supports multitouch, a custom API should be developed just for
the keyboard based on instantaneous pressure.  Multi-pointer would be
overkill to a simple solution.

-Wade
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Re: multitouch + audio feedback linux dev - XO-2?

2009-01-26 Thread Nirav Patel
 1) Are there any existing hooks/systems for Linux for multi-touch?
 That's the only proper way you can get a virtual keyboard to work for
 a double-touchscreen clamshell device (the feasibility of which is not
 sold to me because of the power consumption of running a 2nd screen vs
 a keyboard, and mostly mostly mostly the lack of haptic feedback from
 a virtual keyboard).

Peter Hutterer has been working on Multi-Pointer X for several years.
It is getting pretty usable, judging by the Youtube videos.
http://wearables.unisa.edu.au/mpx/
http://www.youtube.com/watch?v=olWjnfBoY8E

 In fact, you could pretty much do multitouch systems with just a
 camera (the XO's would be good enough, the machine would just need a
 CPU with stronger horsepower to do the image processing :P) and any
 surface where discrete image sections can be formed for img recog aid,
 like using shadows from hands or maybe a color-reactive transparent
 surface where if pressure or contact is applied, a particular color
 shade (like a chroma key) will appear to aid img rec.

You can use the pygame camera module to do multitouch on an XO,
though it is far from usable for anything but drawing.
http://www.youtube.com/watch?v=HIDdxY3L5V8

Nirav
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Re: multitouch + audio feedback linux dev - XO-2?

2009-01-26 Thread Nate Ridderman
On Mon, Jan 26, 2009 at 7:22 PM, Nirav Patel o...@spongezone.net wrote:

 1) Are there any existing hooks/systems for Linux for multi-touch?
 That's the only proper way you can get a virtual keyboard to work for
 a double-touchscreen clamshell device (the feasibility of which is not
 sold to me because of the power consumption of running a 2nd screen vs
 a keyboard, and mostly mostly mostly the lack of haptic feedback from
 a virtual keyboard).


 Peter Hutterer has been working on Multi-Pointer X for several years.
 It is getting pretty usable, judging by the Youtube videos.
 http://wearables.unisa.edu.au/mpx/
 http://www.youtube.com/watch?v=olWjnfBoY8E


Jim Gettys put together a synopsis of multi-touch input for XO-2 in
September - http://wiki.laptop.org/images/9/99/Gen-2_touch.pdf

2) Audio feedback
 A big problem with touch-screen/virtual keyboards is lack of haptic
 feedback (and haptic feedback would probably eat batteries a lot). A
 standardized/universal audio mapping to keyboard keys similar to
 QWERTY, Dvorak or Braille would help solve this.


I have some insight into this topic from experience in the cell phone
industry. There are several ways to do haptic responses: linear vibrators,
piezo-electric elements, speakers. Localized haptics are best (the vibration
comes from the area on the screen that has been touched), but that's still
an emerging technology. The challenge with your idea is latency. For
applications like typing, the haptic response must happen very quickly to
trick the brain into thinking it is related to the press. I think I've heard
the number 25 ms before, but don't quote me on that. A quick google search
couldn't confirm or deny this. I did find an interesting paper (
http://aig.cs.man.ac.uk/people/jayc/jay_quantifying_latency.pdf) that stated
100-200 ms was the limit, but I don't think the results apply to typing. The
game in their experiment took a second to complete, which is way longer than
a keystroke takes. If you don't care about typing repeatedly, the latency is
less important. But for typing quickly with a  limit of 25 ms, it will be
hard to interrupt the processor, load a sound file, and play it in time. A
dedicated microprocessor might be up to the task though.

Also, I'm not sure if a speaker would draw significantly less power than a
piezo or linear vibrator. I don't remember hard numbers for either use case.

Thanks,
Nate
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Re: multitouch + audio feedback linux dev - XO-2?

2009-01-26 Thread david
On Tue, 27 Jan 2009, Carlos Nazareno wrote:

 1) Are there any existing hooks/systems for Linux for multi-touch?
 That's the only proper way you can get a virtual keyboard to work for
 a double-touchscreen clamshell device (the feasibility of which is not
 sold to me because of the power consumption of running a 2nd screen vs
 a keyboard, and mostly mostly mostly the lack of haptic feedback from
 a virtual keyboard).
SNIP
 So back to the question: any existing Linux multi-touch hooks/drivers/APIs?

there has been some discussion on the kernel mailing list recently. they 
are still hammering out what reasonable APIs will be (different 
multi-touch systems provide different capabilities)

David Lang
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Re: multitouch + audio feedback linux dev - XO-2?

2009-01-26 Thread Wade Brainerd
My (unasked for) opinion is that multitouch should not be a focus of OLPC's
development efforts.  The real benefit will just come from being able to
touch the screen in the first place.

Writing a decent multitouch interface requires massive UI design and coding
efforts that we frankly cannot muster right now, and the concept is so
immature in the Linux world that we cannot rely on someone else to do it for
us.  A real multitouch device would require a development effort similar to
what Apple put into the iPhone, that is hundreds of engineers over several
years with absolute control over the software stack.  Given financial
realities that's just not going to happen with XO-2.

That said, here's hoping the final solution is pressure sensitive!  The
Nintendo DS gets all kinds of wonderful features out of that, and it's
already part of XInput.

Imagine the possibilities of a screen that can become any kind of keyboard
you can imagine (computer, piano, drum, painting canvas, etc).

Here's to staying focused,

-Wade

On Mon, Jan 26, 2009 at 11:25 PM, da...@lang.hm wrote:

 On Tue, 27 Jan 2009, Carlos Nazareno wrote:

  1) Are there any existing hooks/systems for Linux for multi-touch?
  That's the only proper way you can get a virtual keyboard to work for
  a double-touchscreen clamshell device (the feasibility of which is not
  sold to me because of the power consumption of running a 2nd screen vs
  a keyboard, and mostly mostly mostly the lack of haptic feedback from
  a virtual keyboard).
 SNIP
  So back to the question: any existing Linux multi-touch
 hooks/drivers/APIs?

 there has been some discussion on the kernel mailing list recently. they
 are still hammering out what reasonable APIs will be (different
 multi-touch systems provide different capabilities)

 David Lang
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Re: multitouch + audio feedback linux dev - XO-2?

2009-01-26 Thread david
On Mon, 26 Jan 2009, Wade Brainerd wrote:

 My (unasked for) opinion is that multitouch should not be a focus of OLPC's
 development efforts.  The real benefit will just come from being able to
 touch the screen in the first place.

 Writing a decent multitouch interface requires massive UI design and coding
 efforts that we frankly cannot muster right now, and the concept is so
 immature in the Linux world that we cannot rely on someone else to do it for
 us.  A real multitouch device would require a development effort similar to
 what Apple put into the iPhone, that is hundreds of engineers over several
 years with absolute control over the software stack.  Given financial
 realities that's just not going to happen with XO-2.

 That said, here's hoping the final solution is pressure sensitive!  The
 Nintendo DS gets all kinds of wonderful features out of that, and it's
 already part of XInput.

 Imagine the possibilities of a screen that can become any kind of keyboard
 you can imagine (computer, piano, drum, painting canvas, etc).

 Here's to staying focused,

agreed, but I don't see how you can do a keyboard and not have some 
multi-touch stuff (shift keys to start with)

I am in the group that has serious doubts about the current XO-2 design. I 
suspect that when push comes to shove the idea of the second screen being 
the keyboard will go the way of the crank in the XO-1
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