Multitouch Wall

After creating multitouch table i was thinking about extending the technique and usability. Horizontal displays good for smaller displays between 19′ to 40′ but when the display size gets bigger system height increases. if you want to show something with multitouch table only the people around the table can see it. So i put the things in another perspective and redesigned the multitouch system vertically. This way display size can be much bigger. By combining multitouch devices together, bigger systems are possible. Another advantage is the space needed for vertical setup is less then space needed for the horizontal table. Projection distance can be decreased by using mirrors. In addition Multitouch wall system can be used as advertisement displays and become interactive when user touches it.

I started by calculating the display size and found that 80×60 cm display size is best for me. Then i calculated the width, height, projection distance, projector and mirror orientation. After that i designed the structure of the multitouch wall by using these inputs. The main problem of this setup is stability. It must be solid when user interacts with it but also it must be light weight to be able to carry to another place. So i used aluminium bars for main structure and plexiglass for the display. All system is modular and combined using screws. Another problem is the projection surface. It must be thin, soft for touch, and tense for displaying projection. I found the projection material from a small shop Hong Kong. And luckily they ship to Istanbul. Camera, lasers, laser lenses and infrared camera lenses were from my previous setup.

Hardware setup worked as expected. Then i started to work on software. I used tbeta software for image processing and blob detection. The communication between tbeta and main application done over TUIO 2.0 Protocol. Flash AS3 language is widely used in internet applications from games to interactive webpages. Video, sound, dynamic drawing capabilities helps users to develop applications fast and easily. Navigation and usability is very important in multitouch applications. Flash provides a good environment to develop such applications. So i started to write a library to make developing multitouch applications easy called TUIOLite. Touch points and their orientation can be accessable through this framework.

My report can be found here

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