On popular demand, here are some details on what I used to build our table, and pointers that can help you to build your own :
First of all, it is important to choose which technology you want to use to detect the multi touch input. Here is a book available with a nice survey of the existing technologies : Multi-Touch_Technologies_v1.01 .
I chose to use Laser Light Panel (LLP), as it doesn’t require a lot of hardware, it is relatively easy to set up and it does not require any pressure on the fingers to detect the input.
Some pointers :
- http://peauproductions.com/store/ : The store where we bought most of the specialized hardware.
- http://nuigroup.com/forums/ : The biggest community on DIY multi touch.
- http://wiki.nuigroup.com/Main_Page : A Wiki with tons of information from the same community.
- http://ccv.nuigroup.com/ : The open source tracking library to capture the input.
- http://nuigroup.com/forums/viewthread/9500/P0/ : A very nice semi-professional example set-up.
- http://arbi.trario.us/2008/11/02/diy-laser-multi-touch-table/ : A very useful blog entry which helped me to get started with the laser set up.
- TUIO.org The most used open protocol for multi touch input.
- MT4J : A nice multi touch framework in Java.
The build details :
The parts I used :
- 1x Projector : I used an HD projector, the Epson EH-TW5000. For ease of installation and calibration, features such as lens shift and key stone correction might prove useful.
- 4x 25mW 780nm infrared lasers with line generator (120 degrees), can be bought here : http://peauproductions.com/store/index.php?main_page=product_info&products_id=37, This page even has a very nice explanation on how to install and adjust the lasers.
- 2x sheets of glass
- 1x big sheet of chalk paper
- 1x webcam with infrared filter removed (Playstation eye’s work well), I bought a special 780nm filter here : http://peauproductions.com/cams.html
- 1x Mirror : it works with a cheap of the shelf mirror, but for crisp non-double reflecting you need a front surface mirror.
- something to power the lasers. I used an old PSU.
- Self hardening clay for positioning the lasers. Later on I made a small adjustable laser-holder for more accurate calibration.
- Some wood or metal to build a table 😉 For the first version, I just used two tables, and put some wooden beams in between to hold the glass.
If you have some more specific questions, don’t hesitate to contact me. And if you are building a multi touch application or a table, let me know ! I’m always interested in new ideas/projects 🙂