multi-tutch?

Bastian Muck bastian.muck at gmx.de
Fri May 30 15:30:48 CEST 2008


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No, the problem ist that the Freerunner does not have a multitouch 
display. Some developers just try to make one out of it :-)

Rahul Joshi schrieb:
| If I am to understand this thread discussion correctly, does it mean 
there is no public algo for multi-point touch sensing yet??
| With so much of work done on projects like MS Surface, iPhone, the 
Jeff Han stuff.. and recently HTC Diamond, I took it for granted that it 
must already be there among the large resource pool of opensource 
developers.
|
| Rahul J
|
|
| On Fri, May 30, 2008 at 2:46 PM, Ben Lau <benlau at embedded.hk 
<mailto:benlau at embedded.hk>> wrote:
|
|     On Thu, May 29, 2008 at 7:11 PM, Joerg Reisenweber 
<joerg at openmoko.org <mailto:joerg at openmoko.org>> wrote:
|     > Am Do  29. Mai 2008 schrieb boris.stender at gmx.de 
<mailto:boris.stender at gmx.de>:
|     >> Hi Joerg,
|     >> as it seems that my mail did not reach the community list (I am 
not a
|     > subscriber, just monitoring the archives) may I ask you directly 
the question
|     > regarding "multi tutch" :-) . See below:
|     >>
|     >>
|     >> Hi all,
|     >> if the geometric average point is returned if multiple points 
are touched
|     > wouldn't it be possible to have a fake multi touch, e.g., by 
doing the
|     > following:
|     >>
|     >> Press point A
|     >> -> Vector A is returned
|     >> Additionally press desired point B
|     >> -> X = (A+B)/2 is returned
|     >> -> calculate B = 2*X-A
|     >>
|     >> Questions:
|     >> Would this be managable?
|     >> What time difference would be required between first and second 
(and
|     > third ...) touch, to recognize such a multi-touch action and 
reliable
|     > distinguish it from a single touch at position X?
|     >>
|     >> And one more comment: If that would work you could also detect 
multi-touch
|     > gestures (even if limited), e.g., use the first point statically 
(maybe a
|     > focus centre) and handle the second point dynamically (maybe for 
zooming in
|     > and out).
|     >>
|     >>
|     >> Boris
|     >
|     >
|     > there are two resistors in the touchpad, one for X and one for 
Y. We only see
|     > them changing on a touch, thus giving us the coords. A 
concurrent second
|     > touch just changes the R values even more, but we get no info 
about whether
|     > we touched a second point or we moved the finger. So what you 
suggest is a
|     > gesture recognition. Things become nasty because even the 
"geometric middle"
|     > isn't true but depends on pressure of one to pressure of other 
touchpoint
|     > etc.
|     > You really get too few info out of the device to do anything 
reasonable with
|     > it beyond singletouch (at least that's the way it is now. I plan 
to see
|     > whether we can exploit dynamic pulse response of this design to 
get some
|     > additional info. Same way you're testing cat5-cable for breaks. 
Don't hold
|     > your breath though, chances are bad. And it's not on top of my 
todo-list)
|     >
|     > cheers
|     > jOERG
|     >
|     > _______________________________________________
|     > Openmoko community mailing list
|     > community at lists.openmoko.org <mailto:community at lists.openmoko.org>
|     > http://lists.openmoko.org/mailman/listinfo/community
|     >
|     >
|
|     Two-finger input with a standard touch screen
|     http://portal.acm.org/citation.cfm?id=1294239
|
|     This paper introduces a method to detect two fingers using a
|     "standard" touch screen. I haven't ready it deeply so I can not say is
|     it applicable on OpenMoko platform , but I think it is worth to study.
|
|     _______________________________________________
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|     community at lists.openmoko.org <mailto:community at lists.openmoko.org>
|     http://lists.openmoko.org/mailman/listinfo/community
|
|
|
| -------------------------
|
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