BlaXwan: October 2007 Archives

I know that my Multitouch Display page has been left alone since I wrote it, with no updates even while I was anyway going on with my multitouch work and tests. In addition, when I write something on the multitouch matter, I'm assuming that everybody knows a lot of things, quite all I've learnt on it until now and I know that is not so useful. On the other side some of you rightly wrote me saying "why you don't give further and detailed informations on the construction, the components used etc.?".

I know that there are already tons of informations on the internet on this subject and there are some very good information depots as well. One of the best is the NUI Group wiki and, of course, the blogs of his users (thanks to DzHiBaS that aggregated them). But, in my opinion, there is still the need for something that may be a more or less complete walkthrough in the theory and the construction of those displays, like it is the how-to guide by Gravano that, unfortunately, was not updated lately with all the great improvements he made.

For all those reasons early this week I started to update the Multitouch Display page...and not only! While writing I reealized  all those reasond and I decided to try to explain more clearly and starting from the beginning the whole story, aiming to reach the goal to put up together a quite comprehensive homemade multitouch guide.

Obviously this is not aiming to be "the ultimate guide" because I played just with FTIR setup and, in addition, my experience is limited just to my project and to the solutions and materials I used. But, anyway, I tried to put together all I know, I experienced and I read on this subject so I can surely say that, hopefully, this will be the best I can do.

Of course this is still a work in progress: there are already three pages to look at but there are some sections that  still need to be written. Anyway, I really hope that at least anybody who is approaching for the first time this fabulous world may enjoy it and find it useful for its multitouch work.

I'll really appreciate any comments and suggestions you would post to enrich this guide and, why not, to correct any mistake in it. It could be a good tools for everybody or at least a good starting point.

Some days ago I was finally able to make a complete test of my new compliant surface made of the silicone rubber layer and the sketch paper. As usual, I can say that this was also a partial success.

The layers of silicone and paper gave great sensibility to my FTIR multitouch setup. Actually a very light touch is enough to trigger the blob recogniction, even the passage of a paper tape roll is detected!

As I was saying, there are anyway something to work on. The silicone rubber is still a little bit sticky and this cause the sketch paper to adhere to it for a little time after the finger touch passage. The result is a visible tray left after the finger movement. The software I used until now, Touchlib from NUI Group, is recognizing those trays as finger touches as well so that moving a finger result to several touches moving in a tray.

This bad effect is not impacting on simple application like Smoke but, unfortunately, it hardly impact on applications like the one used to play with photos. With this app, moving a photo result in enlarging it because of the multiple touches detected in the tray of the real finger touch. Anyway, you'll have a better idea looking at the video I shooted during the last test:



Actually, to be honest, I don't have big ideas on how to overcome this issue. I'm quite convinced that all those problems are coming from the type of silicone rubber I used, the Prochima Crystal Rubber, that is a good silicone rubber but probably not for this kind of (strange) applications. The other guys from NUI Group had infact better results with the silicone rubber layer without this kind of issues. My only workaround, for now, will be to buy and try other kind of papers and, probably later on, to try a different kind of silicone rubber itself.

But, anyway, actually I'm moving my interests also on software for multitouch. What I saw until now is that there's a lot of pieces around, most of them built using libraries or scriptable frameworks, few of them are compiled, mostly commercial and closed source. Unfortunately it seems to me that it is a lot of work done but in a fragmented way: there is no coordination and every app is a monolithic, separate app so that you cannot have a "multitouch system" but rather some multitouch-capable applications launched on a computer.

Actually I'm thinking about how to approach this matter, also because hopefully sometime in the near future I'll have a good multitouch screen and I will like to use it without the need for a mouse, keyboard or other "old" computer equipment.

In this brainstorming phase, every comment and suggestion is really welcome, feel free to contact me also privately.