MTmini

Hello all!

Recently, I decided to begin working on a multi touch project, inspired by many, particulary Jeff Han, Bridger Maxwell, and other NUIGroup members. Essentially, there are two approaches to multi touch: FTIR (frustrated total internal reflection), and DI (diffused illumination). These techniques are explained well in the NUIGroup Wiki, here. Before embarking on a rather large scale, expensive project, I wanted a smaller scale, basic, proof-of-concept type example to create. I found this in Seth Sandler‘s MTmini. The MTmini is essentially a very basic form of front DI, composed of no more than a webcam, cardboard box, glass/acrylic, and a few sheets of paper.

How it works: the webcam goes in the cardboard box, the glass on top. The webcam is plugged into your computer, and when you press down on the glass, your fingers create shadows. The webcam picks these up, relays it to software that can comprehend these blobs on the glass (for example, TouchLib), and then TouchLib sends the data to an application which uses the touch event.

It seemed simple enough, and after a quick trip to Home Depot, I had everything I needed, and literally, in 5 minutes, I was done with the hardware. Now, for the software-TouchLib. From the NUIGroup website, I downloaded the latest version of TouchLib (2.0). From this point on, I had a bit of trouble with various components. I ran config.bat, as the instructions said to, which was fine, but with the MTmini, with no display, it was rather difficult to calibrate. Anyways, I was ready to try to run some applications, but I found that it wasn’t all that simple. Running TouchLib successfully requires among other things, .Net 2.0 framework (which in turn requires Windows XP SP2, which requires Windows Update 3.0, which requires Windows Genuine Advantage Tool….). After I was done with these downloads, I ran into some more trouble as I found that in order to run Flash-based apps, which the demos are, I needed FLOSC, and JRE 1.6. Several other multi touch users helped me out at nuigroup’s irc channel (irc.freenode.net #nuigroup) to help me get to a working MTmini setup, so much thanks to them. Nuiman explains the need for FLOSC/OSC very well:

1) The TUIO (OSC) data is SENT from Touchlib’s “osc.exe”.

2) The FLOSC gateway CONVERTS the OSC (UDP) data into XML (TCP)

3) The Flash client uses an XMLSocket to RECEIVE and parse the XML data then renders the cursors within your application.”

This is necessary because Flash cannot understand UDP data.

Anyways, I downloaded a whole bunch of things (more details later), and I was able to run Flash apps-basically, I should’ve downloaded this package, and I wouldn’t have had the problems I was having, because cerupcat, the user who designed MTmini, had a special package for those using it, as it needed certain filters. Two .bat files downloaded with that package (similar to the TouchLib files I downloaded earlier), took the place of the FLOSC and OSC applications that I previously needed to run to have Flash apps recognize touch events.

So….now, my MTmini is in pretty good shape, and I am trying to fine tune the calibration of it, as the touches are not very accurate right now, and I am also trying to find ways to improve the hardware-better lighting, better webcam, etc. Software, of course, is a big part of it, and I am starting to learn to program in C++ in order to program applications for my multi touch device. Eventually, I plan to move past MTmini, and design and build a larger-scale, more stable, preferably FTIR multi touch table. But for now, I plan to work more with the software, and do what I can with MTmini.

Pictures of my MTmini setup coming soon!

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8 Responses to “MTmini”

  1. carlos andres Says:

    hola, pues necesito ayuda, tengo el sftware pero no veo mi camara

  2. carlos andres Says:

    please help me can not get to see the webcam

  3. rbedi100 Says:

    Hi Carlos,
    I’m not sure what you mean – is it plugged in correctly, and is TouchLib looking for the correct webcam? Does the webcam work with other applications?
    rbedi100

  4. carlos andres Says:

    hello, I solved the problem with my camera, but I can not activate any flash demo. I can please reply to this email: decimapuerta2000@yahoo.es
    thank you very much

  5. carlos andres Says:

    I have Windows Vista, ¿do I need Windows XP, and windows, SP2, Windows Update 3.0,Windows Genuine Advantage ?

  6. rbedi100 Says:

    Carlos,
    Yes, you need all of the above that you mentioned.
    To run flash demos, follow these instructions exactly: http://nuigroup.com/forums/viewthread/1577/

    good luck
    rbedi100

  7. carlos andres Says:

    hi
    ok I have Windows Vista, I need to uninstall it? Why?
    my windows is original, please help me¡, I can not find in the forum response…and my touch is not working

  8. rbedi100 Says:

    hey carlos
    no, u don’t need to – vista works fine.
    it should work, fine, provided you followed the instructions. try posting in the forums – create an account.

    rbedi100

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