Is Detcting object on multitouch capacitive lcd screen possible ? 
Posted: 15 November 2014 07:42 AM   [ Ignore ]
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Dear all,

I was working for a long time with object recognition with the First version of microosft surface and latetly with the Samsung Sur40 and build great app with object interaction.
Today I am looking how to bring that object interaction on standard multitouch lcd display.

I have seen some using some silicon pad under objects, but I am wondering if it is only the trick or the hardware need to have something more

Any idea to light me up on this ?
If those silicon pads are really working as it is on capacitive displays, how to make difference between object and fingers, I thing you need to position those silicon pad in a certain way to make object difference ?

thanks for all

regards

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Posted: 01 December 2014 05:57 AM   [ Ignore ]   [ # 1 ]
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Hello,
I’m not familiar with capacitive/resistive layers for multitouch systems, but it seems to me that the problems can be:
- the reliability of the silicon pads (don’t know how effective they are)
- the resolution of you capacitive screen: you should have pads large enough so that they can be detected without merging with others, but not too large to improve density
- and what seems to me the critical point: the number of “touch” that your touchscreen allows. Most commercial stuff allows 10 or 20 distinct points. If your silicon pads are large (or compouned by several small ones) you will “consume” many points.

Hope it can help you.

Regards,
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H.

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Posted: 01 December 2014 06:18 AM   [ Ignore ]   [ # 2 ]
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Thanks for your reply.

The touch screen I am using is supporting up to 60 touch point so this is not an issue from that side.
If I referrer to tablet pen that we use sometimes, the end of the pen is like a rubber and you can touch with it.

So I was thining to place this kind of silicon below an object

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Posted: 01 December 2014 06:32 AM   [ Ignore ]   [ # 3 ]
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So if you can make “points” (no reason it wouldn’t, for sure) you should test for the minimal distance between 2 “points” to be clearly seen as distinct by you touch surface. It will show you the max density of coding you could create.

But even with 60 points it can be a little limited. You have to create a “structure” of points to identify each object. This structure should be dense enough in order to 1. recognize it is an object (and not few fingers) 2. be able to “code” enough information 3. to stay reliable (may also depend on effective resolution)

5 points seems to be the minimum set for an object (i.e. 1 per corner + 1 inside for the information), which may whatever difficult to distinguish from a 4-fingers contact. It would allow you ~10 objects (probably a less if you switch to 6 ou 7 points per object for reliability), in particular if you still want to be able to interact with fingers.

After that as I said I never played with that technology so I can’t give you more on this subject.

Regards,
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H.

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Posted: 03 December 2014 04:48 PM   [ Ignore ]   [ # 4 ]
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i have been working on this for quite a while. Check our solution http://www.tangibledisplay.com/gallery/objectviz
Let me know if you need more infos

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