pouët.net

http://www.multitouch.fi/ - really cool modular multitouch screens. Seeing as they are finnish, use physics with particles as demos and everyone in their demo videos seems to have long hair - any sceners there? :)

The demos are a bit dumb :( But the thing itself seems interesting.

I am looking at all kinds of multitouch solutions for an upcoming museum gig, and it would be nifty if the guys from Finland were actually sceners (or ex-sceners), because most multitouch sellers (and resellers) out there appear to be very uncooperative with regards to SDKs, specs etc.

Also, they are twice as expensive.

nice ones! They mention that you can make not only walls, but ceilings and floors with those things: walls + ceiling + floor = CUBE!

I didn't find the price of that multitouch thing. :\

indeed (I'm a bit tired of the "pan and rotate the photos, just cause MS did it" demo btw).

As all the touchscreens I have tested/seen, the delay seems to be quite of a problem to me.... Or is it acceptable for you guys?

they mentioned "60 frames per second" at least 4 or 5 times, so they must be from the demoscene :)

p01: The 32" is roughly 5000€ without computer, shipping or tax. Then there is an additional 2000€ for the SDK.

IQ: The lag on these units are among the lowest I have seen (in the "affordable" price-range) but yes, mildly annoying yet acceptable.

bartman: ..which is funny, seeing as they only display very simple things.

how very undemoscene'ish. btw, cubes, anyone? :)

For that price it's almost better to buy some 100s iphones and stack them.

reminds me, I have a multitouch project coming up soon and a tough problem to solve for it. Maybe somebody here can help.

The plan is to project the screen onto a big wall, and use IR cams & pens (a pen with an IR LED at the end) to track input. Pretty standard...

Now, the catch: we want several people to use the screen at the same time, and we need to identify each pen. Any suggestions? Ideas so far are using several LEDs on each pen in a shape (triangle, square etc) and combining IR and colour LEDs to identify by colour. Colour seems more workable to me.

What other options are there? It has to be cheap, and making it ourselves isn't a problem.

psonice: how about different wavelengths for IR? it might be an idea.

hmm... How would it work? Would different wavelength LEDs show as different colours in the camera image? That could work nicely if so.

I'll pick up a ps3 camera at some point and do some testing.

I think so, infrared is just a longer-than-visible-light wavelength, so variations between infrared and terahertz would give at least different intensities / colors if I am not mistaken. I think it is worth trying :). I actually have a board with a bunch of infrared LEDs and a crappy phone camera that can see them, but I think an infrared-sensitive camera would perform better with very tiny alterations in the wavelength.

holy crap those are great

One chip color cameras use a filter pattern on the image sensor to distinguish the different wavelenghts, the most common pattern is called bayer pattern. For infrared "colors" you would need another kind of filter, I doubt you will find a cheap camera with it.

The usual approach is using different arrangement of LEDs as psonice suggested. For best results you should use monochrome camera with low-pass filter glass for visible light (aka black glass ;-).

Is it sad if I recognized the video they were scaling as "Elephant's Dream" from the Orange Open Movie Project? :)

As in: in order to brag about things going in 60 FPS, they'd better show something that was more graphical og interface heavy. What they have now is equivalent to showing a static frame on an Amiga and shouting "OMG! Look everyone! One-frame C2P!!!!1!", which is rather pointless.

What's with the lag?

Today a pair of these arrived here. Let's see when they get setup.

gloom: in norway these are licensed by onecom, which means heavy pricing. These boxes are quite easy to build, especially if you go for diffused illumination and http://ccv.nuigroup.com/. I recommend using tbeta/touchlib by nuigroup and buy projector, acryl, and ir camera yourself.

I forgot to mention
http://reactivision.sourceforge.net which also is a great place to start with multitouch.

psonice:

What about intensity? Maybe 2 or 3 different intensities can be differenced easily - and this looks easier to achieve than wavelenghts.

Also, blinking.

One cool thing of the shaped thing is that, if you do asimetrical shapes, you could rotate the pencil by its axis and the rotation recognized.

My last idea: maybe you can get an aproximation of the position of the pencil by the shape of spot in the wall it is proyected. Frontal it should generate a circle, but lateral should generate an oval. By its size you might get an aprox. of the distance from the wall and that... I'm not sure if that would be enough info or not but... maybe it is a thing to try

psonice: You could use multiple webcams with different IR bandpass filters matched to the unique wavelength of each IR Led.
You could also use specialized IR camera's but they are rather expensive.

I think it would be much easyer to track different colours of visible light though, as long as the light is bright enough, it should be doable using cheap-ish hardware. Maybe if you replace the leds with different colour laser pointers?