Multigesture.net

If you take a look at multitouch videos on Youtube, most of them are related to photo manipulation.These demo movies show the possibility of scaling, rotating and translating multiple photos at the same time.

A few days ago I created a small demo application called tDesk. tDesk is an experimental tool running on Windows XP which enables users with an FTIR multitouch screen to move and resize (multiple) applications with their bare hands.

(1) This movie shows how to move and scale dialogs in windows:

(2) This movie shows how to move multiple dialogs in windows:

Hmm you probably noticed it already in the movie, I kinda screwed up at the end of the movie.
Since my panel is not mounted on a frame it can move if you press with too much pressure… and that’s happened at the end.

* About the video clip played in movie 2, it’s Jamiroquai with Virtual Insanity. You might notice his whole environment is moving as well …

Last week I managed to get touchlib compiled under Ubuntu Linux (thanks Xvarg). While bug fixing and updating my touch tracer source code, I also tried to compile it in Ubuntu. Since I am not a linux guru, getting the code compiled took quite some time (linking libs, changing cflags). After fixing a few compiler warnings and errors (g++ seems to be more strict) I managed to get touch tracer compiled.

It is nice to see that touch tracer is actually running smoother/faster in linux than in windows. Obviously my Intel Extreme Graphics 2 (aka Intel Extreme Crap) is not a high end videocard, but where Windows does 40-50 fps on average, Linux is able to boost it up with 10 fps extra.

In the video below you will notice a few glitches. These are not caused by touch tracer (really )!. My FTIR panel seems to ‘leak’ light on the edges. After creating some demo movies I noticed that not only my finger tips where reflecting the light. Also other parts seems to reflect (just enough) IR light to fool touchlib. It’s even possible to create blobs when you hover your hand near the edges. A possible solution is to extend the baffles just a bit.

Touch Tracer v0.2 example video

Changelist:
- Added tracelines
- Added funky blob colours
- Made the source linux compatible
- General code cleanup

Download:
I’ve included a windows binary and the source code of touch tracer for linux users.
By using the included Makefile you should be able to get it up running in notime.

Touch Tracer v0.2 Binary
Touch Tracer v0.2 Source code

Optional downloads
msvcr80.dll and msvcp80
- Required if no vs2k5 runtime dlls are installed
Visual Studio 2005 SP1 Redist. Package
- Entire package if the one above fails

It works!

After the last blog not much had to be done about the FTIR screen. Actually I only used some tape to hide the wires on the sides.
With all LED’s in place and the frame being placed on two chairs it was time to finally test the FTIR screen.

All LED’s are fully functioning !

Testing with 5 and 2 fingers…

10 finger test:

Video containing a summary of the project and some demo applications

To get the Touch Tracer tool (from the demo video) please click on read more.
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In this final step of building the FTIR prototype I will cover the soldering of LEDs.
In my previous blog post I already calculated that 30 LED’s would be enough to cover the entire plate.

As power source for my LED’s I will be using a 12V DC Adapter (1000 mA).
To calculate the LED array and the amount of needed resistors I used an internet tool the LED Wizard.

According to the wizard I should create 5 array’s of LED’s. Each array should contain 6 LED’s and one resistor of 68 ohms.

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Inspired by other FTIR prototypes I decided to use an aluminum frame. The main reasons for are because its cheap and strong.

Before actually working on the frame, I made a drawing in AutoCAD. Within this drawing I could easily calculate the amount of IR LED’s I would need and at the same time see how the IR light beams would spread.

FTIR Prototype Drawing

The local tool shop was friendly enough to cut the aluminum frame (H shaped) into the sizes of my drawing.
So at home I just needed to remove the edges in 45 degrees.

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