After browsing/posting and annoying most people around here i thought i was time to post a little information on my current MultiTouch table..
Its still work in progress but its coming along nicely ..

Setup:
Windows Vista SP1
Intel Core 2 Dual E6750 2Gig of memory (and a Quad E6600 on standby ifneeded, lol)
Ati Raedon 2600 XT
Microsoft LifeCam VX-1000
Glass surface, 118x78x0,8cm (46"x31"x0.32"). Creating a 141cm screen (55,5") which i found close by all dirty in someone’s front yard in the bushes
Aluminum frame which is 1 meter in height (39").
Dual IR laser system using 2x 10mw IR laser’s bought from AlexP (thank man)
Panasonic PT-AX100E 1280x720 (HD )

Originally i started out building a DI table, which was setup with 56x 850nm IR leds.. but had a lot of problems getting the light spreading even, so with the money saved on the glass i bought 2 laser from Alex
Currently the MultiTouch part is working, however as you can see on the following images i do not have the beamer/screen setup correctly yet. I had to use 2 mirrors as it turned out the throw distance of my beamer was alot longer then expected and my mirror was too small :(

Pictures are taken with my mobile phone and a bit fussy at times :(

Pictures:

Aluminum frame setup, glass surface added:

Laser setup..

Beamer

The end result for now..

That looks really nice dude , great job.Really minimalistic and I like the orange juice box under the mirror :D

Vlado - 07 July 2008 04:45 PM

That looks really nice dude , great job.Really minimalistic and I like the orange juice box under the mirror :D

Thanks, that what i went for, open & simple. Thats also why DI wasn’t really the correct choice in the first place, you really need a close box then (which had then).
I still have to buy a good mirror, when i figured out the correct angle might use something nicer to hold the mirror

ps: the juicebox isn’t alone.. check out the pics and you might find a couple of other bottles

Hi nice work there!

Why did you place two mirrors instead of one? Are you using the smaller one to reflect the screen for the camera?

How the lasers are working? How wide the angle is? Have you tried to place the tracing papper under the glass?

Lot of cuestions, but… that’s why we are here =P

Cheers!

Very nice work Helza, I have a very similar setup in the works...will be making a thread soon.

How are the results on the blog tracking? Have you been able to calibrate the lasers and get some bloggage?

Very ingenius!

I love that set up Minimalism ftw. Everyone is curious about the blobs you are achieving, apparently, can’t wait to see myself.

If you’re getting good blobs, try removing one laser and see if you can still achieve good blobs. I want to do something similar, but since you’ve got it all set up already....

Probo - 07 July 2008 04:55 PM

Hi nice work there!
Why did you place two mirrors instead of one? Are you using the smaller one to reflect the screen for the camera?

I’m using 2 mirrors because the first one wasn’t high enough :( Still need to buy a bigger mirror for it.
I’m using the second one to add a couple extra cm it it

Probo - 07 July 2008 04:55 PM

How the lasers are working? How wide the angle is?

Lasers are working very well, not very strong blobs with only 1 laser, but with 2 its very good. I aligned the laser’s pretty quickly so i expect the mo be aimed a little too high, causing the laser to hit too high on the fingers and not causing very strong blobs, the 2nd laser might be aligned a little lower

The lasers have an angle of 120%, way more then i need

Probo - 07 July 2008 04:55 PM

Have you tried to place the tracing papper under the glass?

That is the idea, i was just testing it out with this small piece too see if it works on top (not all that great).. 
I’m going to use chalk paper instead of tracing paper which is very “even”. That will give an more even picture then the tracing paper, however i would have to use 2 pieces to get it to fit nicely..

As soon as the mirrors are aligned correctly and the paper is attached i’ll try and post a video with the blobs

Small update:

I just bought a new mirror, so now i got the image to project almost fullscreen at 118x64cm, there is a black bar at the top and bottom in height of about 5cm (10cm total) as its a 16:9 beamer, and not a 4:3, and getting the full height would require me to put the beamer even further way than it already is....

I still have to apply the chalk paper. I have to attach 2 pieces as 1 isn’t big enough but i just destroyed the first one while getting a bit too frustrated try to get it to stick :(
I’ll have to wait until friday to get some help, as i can’t turn over the glass by myself and working up-side-down isn’t working well with the whole gravity thing.. (unless someone knows how to disable it?)

If i find some window frosting plastic (or whatever its called) that is high enough i might even try that instead of the chalk paper, that way i don’t get a line in the middle

Unable to show any picture/video of any blobs as the projecting surface isn’t up yet..

Just stick a little piece of glue on a corner of the chalk paper and stick it to an edge , then another corner , then the entire surface and stick it to the glass , repeat and presto shazam.
Just be pacient , it gets iritating at times , I know the feeling.

Helza1 - 08 July 2008 03:09 PM

If i find some window frosting plastic (or whatever its called) that is high enough i might even try that instead of the chalk paper, that way i don’t get a line in the middle

Yes! You can use frosted glass window film. There are many different textures, but I got one very even and soft. I test using only one layer but is not enough light diffused, so I plan to stick two layers for an improved projected image

Cheers!

So i’ve finally been able to setup the table with the projection surface.
As i only had 1 piece of chalk paper left and the store was closed i choose to use the window foil. It applied easily and it works as a projection surface, but its not diffusing enough of the beamer light.
If you stand exact inline with the beamer you got some very bright spots at times but it works

I re-calibrated the lasers one by one. Setting up the a white plank in in 90% angle to the laser exact in the middle of the screen.
It turned out the lasers were way out of focus, so i had to turn the lens a couple of times.
After that i checked alignment of the laser pane, so see if it would just glow when i put my finger down. I did this in 3 places, right in front of the laser, middle of the screen and then at the end of the screen. As a couple of time the angle of the laser was pointing down. Causing the laser pane to look perfect at the start, but then move away from the glass hitting my finger at the furthers point too high.

I strongly suggest using clay to align your lasers. This makes it so easier to align

After doing this for both i started playing around with the blob recognition. The recognition dropped like 30-40% using the foil over no foil :(
The blobs were pretty faint and I had to using some DI filters for the blobs to be recognized correctly.

However did put the webcam a little back, so its getting pretty far away from the screen (also 1,5m). This way the projection area takes up only 75% of the webcam range, which makes the blobs alot smaller. So i might have to figure out a way to put the webcam closer by without getting in the projection path.

But for now its enough to work with it .. Smoke looked pretty awesome but also showed the weakest point from my system.. the MS VX-1000 webcam :( using AlexP fixed binaries i saw that i only got 24fps.. which is just lagging behind too much :(
I should be able to get 30fps out of this webcam, but no such luck today. I tried every setting, but was only able to get less fps :(
20fps vs 24fps makes a huge difference in lag. I’m wondering what 30fps would look like

I also checked out the different projection surfaces i had.

Normal printing paper:
Blocks too much light (what a shocker)

Tracing paper (2 different types):
It works well. Although the tracing paper it does have a bit of ‘ragged’ look. It doesn’t diffuse exact even everywhere, it looks a bit spotty.
Hides imperfections very well..

Window plastic foil
It gives a bit of fuzzy display and doesn’t diffuse the projection enough, causing the light to be a bit blinding at times. Also the foil shows some imperfections of the glass/glue/plastic.
Using 3 or 4 lasers of the plastic foil did help, but didn’t even come close to use some of the others. Although i wonder if this would block too much IR..
It is however extremely easy too apply..

Chalk paper:
This was the clear winner. It was very even unlike the tracing paper. Diffused the very well. It really captured the projection good, while still letting enough light pass.
It did make a bit blurry picture when tested on the underside because it diffused so well. I’m using 8mm glass, if it would be less thick it would be less blurry.
Compared to the tracing paper it was pretty even in blurrynes. but contract is 2x as good on the Chalk..

So i guess i’ll have to figure out how to apply chalk paper upside-down to the glass without it handing loose. I’m also will have to ask/look around for any chalk paper that comes in bigger sheets.
The current store had sheets of 100x50cm or something. Not enough to cover the complete screen. So i would have to use 2 sheets making a line in the middle of the screen.

Helza , here’s a few tips , don’t use the same mirror for the projection and camera , it gives awfull blobs , we are not shure why yet , but by using a mirror in from of the camera IR light intensity fades , find a way to place the camera under your table directly viewing the screen.And go out and buy some roscoe gray as a projection screen , it makes a huge difference.

I have also gotten very weak blobs with my first test, not strong enough to even be picked up.

Although i’ll have to fully try many configs before making my official cry for help!

Let me know how it works out, seems as if your setup if pretty identical to mine (also in size).

I agree with vlado, you have to have the camera pointing straight at the surface. I think unless you buy special mirrors (I think they are called hot mirrors?), then they don’t bounce infra red as well as visible light so that might explain why your blobs are dim.

Also, I tried frosting but found the same problem with the projector glare. But then I tried purlfrost white from this website http://www.purlfrost.com/purlfrost.php
It’s a much more frosty frosted effect if you know what I mean?! It worked much better, but I’m still hoping that when I get my lasers I can use Rosco because the image is so mch better.

It looks like you’ll have a real nice set up when you’re done, congrats dude!