On Thu, May 29, 2008 at 7:11 PM, Joerg Reisenweber <[EMAIL PROTECTED]> wrote: > Am Do 29. Mai 2008 schrieb [EMAIL PROTECTED]: >> 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@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. _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
