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OK, so maybe it won't fit your particular application, but I have in the past built my own multitouch table using an old LCD monitor, a couple of USB webcams, some clear acrylic, and a bit of hacker ingenuity.

If you are tempted to go the DIY route, Community Core Vision a good place to start.

Happeh hacking!

Hmmm. I don't think the sensor described here would work for you, because it doesn't detect where the touches happen.

I've been building an FTIR based tabletop for my D&D games....

I think that a portable projector with a cam facing the same way could be exploited to make one of these multitouch units made at http://www.nuigroup.com/ that rock. Mount it on a tripod and all you would need would be a touch surface. Very portable multitouch interface you could use with or without your desktop to power it.

My understanding is that the capacitive and resistive tech gets a bit hard to implement for larger screens, so they all use infrared in one way or another (a camera with a filter is pointed at the screen (the back or the front) and then various techniques are used to get brighter illumination at points where something is touching the screen).

There is brief discussion of it here:

http://wiki.nuigroup.com/Multitouch_Technologies

Does this help at all ?

http://nuigroup.com/forums/viewthread/1731/

Steve

I expect the growth of forums like http://www.nuigroup.com/forums/ and wide use of http://nuigroup.com/touchlib/ which is part of Google's Summer of Code 2008 projects might have something to do with it. Now that it's accessible to DIY'ers there is a lot more community support for home-lab research into materials and methods like http://easterisland-llc.com/ or http://www.multitouch.nl/ as examples.

I expect the growth of forums like http://www.nuigroup.com/forums/ and wide use of http://nuigroup.com/touchlib/ which is part of Google's Summer of Code 2008 projects might have something to do with it. Now that it's accessible to DIY'ers there is a lot more community support for home-lab research into materials and methods like http://easterisland-llc.com/ or http://www.multitouch.nl/ as examples.

NUI Group has been doing this for a while. They have an active community of amateurs as well for anyone interested.

http://www.nuigroup.com/

There are lots of research labs working with low-cost multi-touch-sensitive tables. At this point, one can practically build such a table for a few hundred dollars (plus a computer).

I literally spent today demonstrating my lab's table. An early prototype is shown at http://www.youtube.com/watch?v=doK66IYG0Ug, and instructions for building one are at http://open-ftir.sourceforge.net/. Unfortunately the pictures and video from today's open house are not up yet, but they should be shortly (search for "Equis lab").

There are also lots of free libraries for handling the input. Mine (EquisFTIR) happens to be Windows-only and aimed at Microsoft XNA developers. There are lots of portable ones, often built on Intel's OpenCV library: check out http://nuigroup.com/ for more information.

Couple the table with some object-recognition libraries, and you could probably build yourself a Surface-equivalent with a few hundred dollars and nothing but FOSS.

Can't have a topic touch screens without mentioning Jeff Hans work on cheap multi touch tech.
http://cs.nyu.edu/~jhan/ftirtouch/

Then there's the homebrew crew at nui group.
http://www.nuigroup.com/

I know someone who is building one of these and the overall cost to date is under £100.

My colleague and co-founder of NUI Group, Pawel Solyga, developed Opentouch (c++), for Google Summer of Code. This multitouch solution library is partly open source and partly NUI inhouse software. touchEarth is solely NUI inhouse software. Touchlib (c++) was originally started by NUI Group co-founder David Wallin and further developed by the NUI Group community. Whereas TouchAPI (Flash) was mostly put together by colleague Christian Moore, also co-founder of NUI Group. More info at http://www.multitouch.nl/ and http://www.nuigroup.com/

You can even do it with a regular webcam and some IR lights - check out the forums at http://nuigroup.com/ I recently built my own touch table from scratch - some IR lights point at a perspex surface, and an old projector back projects onto the perspex to provide a picture to interact with. The webcam has a small IR filter attached to the front, and this cuts out the regular lights. When my fingers touch the surface, they create hotspots that are tracked (known as Diffuse Illumination). You can also put the lights along the side of the perspex, and create a surface that uses FTIR (frustrated total internal reflection). So there are two ways of achieving similar results to Surface. If you are interested, check out nuigroup - everyone is very helpful if you run into any problems

Plan 9: Plan 9 was not always open source. It was originally a research project at bell labs, and released to the public sometime around 1995. The first open source release was ~2000ish, iirc. It was not developed as an open source project, anyway.

Portal: Portal was not in any sense of the word a Mod. The authors of an independant (closed-source) game called Narbicular Drop were hired by Valve, and wrote Portal while employed. Aside from the gameplay development, it was written and voice acted by professionals[1], and was sold at retail.

Multitouch: While Multitouch hardware is obviously not free, the software to intepret and build interfaces for them is Open Source.

[1] It's not often you get to refer to OMM staff as professional.

It would be great if you could post your source code somewhere along with some description (and maybe even pics) of your setup.

I'm currently (and very slowly) working on an FTIR multitouch interface, similar to the stuff at NUI Group but haven't gotten to the software part yet. They have libs there, but I'd be very interested in seeing your python stuff, as I'd much rather work in Python :).

Also, the IR pen setup should be quicker to build than the FTIR setup. I was especially impressed when I first saw it being used w/ a regular lcd, as the projector is usually the most prohibitively expensive part of building an interactive display.

I ran across this open source group via the fancy Jeff Han stuff. www.nuigroup.com. They're taking images from a webcam, and doing fancy blob detection for a multi-input touch interface kind of thing. They work in windows mostly, with a c++ lib, porting into other windows-y programming environments. Open sound control (a lightweight protocol) VVVV (I'm still not sure what this is), DirectX layers, and more.

It would work great to try and integrate as a lower level windows driver. Right now only applications work with a library. But perhaps a driver, working with a webcam driver, presenting itself as an input device? Eh? Well its certainly got potential to consider.

Ironically I got interested in the project from the perspective as a linux project. It would work very well on an embedded linux system, passing information on the pci or usb bus to any which os. But embedded programming is a whole different ballpark from the rest of the programming world.

It's a nice product and all, but it's not really that innovative or new that other people within the community haven't thought about or developed. you can easily build a multitouch display yourself. i got some guidelines on my blog on how to build a multitouch display @ www.multitouch.nl. There's also an open source multitouch community called NUIgroup with alot of information about hardware and software related to multitouch @ www.nuigroup.com

Also see nuigroup.com for multiple projects and open source software. I'm working on a 70" multitouchscreen myself, for less than 1/10th of Microsoft's price.. Very easy and fun to build.

Ordinary webcams can easily be converted to IR camera's btw.