This blog entry is a cross-posting of a DIY tool recently added to the Public Laboratory for Open Technology and Science (PLOTS) website. The website is a fabulous resource for activists, educators, technologists, and community organizers interested in new ways to promote action, intervention, and awareness through a participatory research model.
PlaceMatters has built and tested a variety of interactive touch screens and touchtables using Wii remotes and LCD projectors so participants can interact directly with maps, images, and brainstorming applications. Here is a video we have posted before showing how we integrated the use of the touchtables with GIS so that participants on Cape Cod could go through a scenario planning exercise looking at the linkages between land use, transportation, and climate change.
The use of Wii remotes to create DIY “smart boards” was pioneered by Johnny Chung Lee (who started at Carnegie Mellon’s Human-Computer Interaction Institute, moved to Microsoft to work on the Kinect, and now seems to work for Google). Teachers in particular have contributed to the development and refinement of these touch screens. We found the use of a reverse projection screen to work best for a vertical screen (see brief footage in our video).
Given our work with maps and our interest in developing low cost tools for stakeholders to be able to work with digital maps on a table, we started experimenting with ways to use the Wii remotes with projectors shining directly down onto tables. In total, we made 7 variations of the touch table experimenting with different stands for the projectors, different surfaces for the tables, and different projectors.
PlaceMatters built DIY touchtable with Plexiglas top and reverse projection
Two of the tables were made out of converted card tables with the middle replaced with Plexiglas and a mirror reflecting the image off the ground onto the underside of the table. We experimented with several white materials for reverse projection — our favorite ended up being a plastic shower curtain from Target. The advantage of this design was that the image was unaffected by hands and objects on top of the table (no shadows). The main disadvantages were 1) the table wiggled too easily and with the projector and Wii attached to the table we found we had to recalibrate often; and 2) the entire contraption weighed just under 50 lbs (minus the projector) which meant we could check it as baggage without paying for extra weight but too heavy and bulky to be able to travel with it easily.
A second generation of prototypes involved stands that either clamped to the table or stood directly on the table. The main disadvantage of this approach was that the clamps would easily get bumped causing the image to rock back and forth on the table. The advantage was that the whole contraction could be made to be quite portable.
Using the DIY touchtable in a GIS “where do we grow” exercise”
The third generation of tables (as shown in the image above and the SketchUp rendering at the top) uses converted tripods that are placed a few inches away from the table so that they are less prone to getting bumped. We finally have a version that is our favorite. On Cape Cod participants quickly learned how to use the pens and the set up worked well.
Key components of a touchtable include:
- Altered camera tripod/monopod or photography light stand for mounting the projector and Wii remote. This takes some tinkering to figure out how to mount the projector and Wii high enough. I will post my version soon.
- Lightweight portable LCD projector (the new LED and laser projectors emerging in the market are particularly good for this applications). We found LED projectors like the LG have a wide angle lens which means you can get a larger image with the projector closer to the table (better for a brighter image). The trade off, however, was that we found we needed to mount the Wii a good 18 inches above the projector for the Wii to cover the entire image.
- IR Light Pens: irpens.co.uk in the UK make our favorites with tips that light up when pressed (just like a pen) but not too expensive. irpens.com provides a higher end design.
- Wii Remotes: Because the latest generation of Wii remotes have motion technology you don’t need, best to buy used remotes from Amazon or eBay ($10 vs $30).
- Cloth or a cardboard trifold for a screen: Trifolds are available at most office supply stores and are nice and flat. The advantage of cloth is that the pens glide over the surface much more easily and the material is less reflective and therefore helps cut down on glare.
- Wii remote whiteboard software. Smoothboard is the best application we’ve tested on the PC. A dongle version means you can move the license from one computer to the next. For the Mac, we like WiimoteWhiteboard which has fewer features but is open source (free!).
- Computer: Finally, you’ll need a computer with bluetooth or buy a bluetooth dongle (main advice here, avoid Targus!).
I will add more links and pictures to this site over time. Will also post lessons learned and a progress report on efforts to create a USB version of the Wii.
One warning: test the room you’re going to use the table in ahead of time. Particularly if you are going to have a bunch of people to use the table in some sort of exercise. Natural daylight and halogen lights, for instance, can interfere with the infrared camera in the Wii and ruin your day.
Finally, we have put together a webpage for folks that are interest in renting or buying a DIY touchtable kit.
Send me your comments/suggestions. Ken