As part of CraigAnslow's PhD we have built a multi-touch table to explore the possible techniques that could be used for software visualization and visual software analytics.

Demo Applications Running On My Table

MS Fluid by Memo Akten	Tuio Touch Drawing Demo

Film Demo of multi-touch table March 2010

Prototype 5 (November - December 2009)

Made orders to purchase the Sanyo PLC WXL46 short throw projector and a mounting bracket. This is the newer version of the Sanyo PLC WXE45 short throw projector. Put in an order for a sheet of Plexiglas acrylic RP 7D006, dimensions are 2200x1600x5mm. It will take a couple of months for the 7D006 to arrive. In the mean time I will be figuring out how to build a frame either out of steel or assembly kit aluminum.

Prototype 4 (September - October 2009)

Projector Frame

So I built a frame to help support a better image and so that I had a stable table when I moved it around, pictures to come.

Camera

My cameras came from PeauProductions. So I am now experimenting with different lenses.

Prototype 3 (July-August 2009)

Our third prototype we also built a Diffused Illumination (DI) multi-touch table and used Community Core Vision. In summary the IR lights work really well with the 99561 projection surface and clear acrylic on top. We will also try endlighten acrylic as well, but that would mean we will need to change the IR lights since they will need to be beemed in through the side of the acrylic. We are currently borrowing a PS3 camera and will get our own one which is equivalent to the one we are using. One issue is the projector since we are using a mirror to project up from. We endeavour to get a short throw projector for the next prototype.

Equipment

• Table: old trolley table dimension of surface 62cm x 54.5cm, bonus comes with wheels
• Camera: modified Sony Playstation 3 Camera from Peau Productions. Thanks to Jordan and Owen for lending it to me to get my prototype up and running. I will be purchasing my own for the next prototype.
• IR Lights: two spotlights from Jaycar plugged into 240 volts. Some wiring and cable connection was also required. See, 18 LED IR Spotlight for Cameras, had to tape the daylight sensor
• Projector: Sony XGA VPL PX35
• Surface Material: Acrylic Plexiglass 99561 Rear Projection
• Mirror: basic mirror from a hardware store or department warehouse
• Sides of table: plain cardboard that is white, can be picked up from most graphics shops
• Sticky Material: plain old duck tape

Community Core Vision

IR lights	Sony Playstation 3 Camera	Sony Projector

Trolley Multi-touch frame	Trolley Multi-touch table camera setup

Prototype 2 (May - July 2009)

Our second prototype we built a Diffused Illumination (DI) multi-touch table. We used the Community Core Vision blob detection software. In summary the main issue is that the lights are either too bright or not bright enough, we need something in between.

Table Surface

We used a computer desk table with a frosted glass table purchased from Dobbins Office Furniture. Approx 1200mm x 800mm. The frosting has proved to be too strong for our lights, but the main issue is the lights. We are likely to make a bigger table in the future.

We also tried using safety glass with drafting film and tracing paper. It seemed to work better than our table, probably more to do with our lights though.

Camera

We used a DSE camera (XH5223) with a band pass lense to only detect IR images.

Lights

We got the Electronics people to build two board with 8 IR LEDs and powered by a PCB. However, these weren't bright enough to go through our table. We also tried an infra-red heat lamp, but this was too bright.

Surface Materials

We experimented with a number of different materials on the safety glass since the frosted table had issues with the lights. We tried plain paper, OHP transparent paper, drafting film, tracing paper. Finally we tried some plastic persplex that had some paper like material attached to it.

Prototype 1 (May 2009)

I followed the instructions on the NUI group web site to create a track pad, How to Make a Cheap Multitouch Pad - Hardware Thread. I had a box some clear acrylic, drafting paper, and a modified web cam from Dick Smith. I got given the acrylic plexiglas and borrowed the web cam. The box was just lying around the department. I used CCV though.

Acknowledgements

• Thank to Jordan Hochenbaum and Owen Vallis from FlipMu who provided lots of advice since they have done this a few times before, plus letting me borrow their PS3 camera.
• Thanks to PippinBarr and RillaKhaled (Elvis Alumni) for spending time with the configuration and giving me lots of advice on what to do in terms of building this table and software requirements. While at Carleton University, Ottawaw, Canada they built a DI multi-touch table using a similar approach, see http://hotsoft.carleton.ca/hotsoft/pix/touch/
• Thanks to Roger for allowing us to use the OptiPortal room for building the table, spending a few hours to diagnose the tracking problems, and purchasing some surface materials from Gordon Harris.
• Thanks to Jason and Tim from the Electronics Group for helping with the LED lights, camera, and filter lenses.
• Thanks to Mel and Aaron from PSP for providing some samples of acrylic glass.
• Thanks to Laureen and Sue from VUW ITS teaching services for providing an old used trolley that I could experiment with.
• Thanks to Ian from Anderson Design for providing some acrylic glass and the magical 99561 rear projection acrylic glass.
• Thanks to Philippe Kruchten for creating a film of some of my work.