Sunday, September 13, 2009

proposed design for wiiCane modular walking surface

After this weekend's meetings, in which I met with Zach Eveland, Annette Gourgey, Raphael Baptista and Gene Bourquin to make plans leading up to our test version of the WiiCane apparatus to take place at four sites in November. We made significant progress in several directions, and I am hoping that Gene, Zach, Rafael, and Annette will also produce posts on this blog capturing their view of the work as it is right now.

I am going to discuss the design for a modular walking surface for the WiiCane system. We decided to go this way after considerable back and forth discussion. We decided in the end that the floor mounted lights will be easier to track along the entire distance of the walking course (compared to lights mounted 30' away at the goal end of the course. Also this approach gives us the ability to make any length track, and even to make courses with turns, etc. (although I can't think of a reason to have that yet). This approach will be more expensive, and much more difficult to transport and set up. But, there are also distinct advantages, and it will be much simpler to achieve reliable position awareness doing it this way. And there are additional complexities, for example because the IR LED's have some thickness and they are crushable, we have to cover them with a surface that will protect them and the associated wiring harness. We also have to camoflage them tactilely, so that cane will not discover them, thereby giving away the straight line travel path, which is what we are training our users to do.

I am proposing a series of folding lightweight panels. 5 of these would lie end-to-end, creating a surface that is 8' wide by 30' long. The panels will be extremely light, and when all folded up, they would fit in a box that is 6' by 4' x 6", which is very manageable. It would fit easily in a station wagon. I am thinking that the panels would be shipped in a wooden box that would then become a head unit at the goal end of the course. This would house a camera, flat panel display, speakers, computer and any other devices. Each of the five panels will consist of a 4' x 6' fixed section and two hinged side pieces that are 2' x 6'. The panels will be 3/8" thick masonite board. When the hinged panels are folded in (covering the treading surface), the whole thing is 3/4" thick. The treading surface will be a long permanent self-adhesive floor banner from the printer we use to make tactiles. that printer produces 30" wide prints of any length, so we will burnish the prints to the masonite and trim off the excess. I want to try to use the prints themselves as a continuous hinge for folding up the panels for shipping, but that will take some experimentation.

The printing on the treading surface can include a long ruler in metric and english units, a big wiiCane logo, and different color lines to indicate set ups for various courses (green course, red course, blue course, etc). I just remembered that I once designed a book cover with Elga Joffee that we nicknamed the Corridor of Pain. It was a rendering of a theoretical hallway with one of each of the hazards disallowed in the ADA regulations, things that you can smack your head on, etc. I was thinking that we could base the placement of obstacles in one of the training course on some of those things, as a way of preparing for those kinds of conditions. The obstacles that we actually use would be inflatable or Nerf material. I like the idea for a future line of nerf obstacles! In any case, we have to start thinking about the pedagogical objectives and capabilities of this way of training people. We should end up the project with a producct manual that explains our reasoning and sources. We should also all be starting to think about publishing this work soon, assuming that we get some good outcomes.

The lights will be in three strips that will run the entire length of the course, one right down the middle and one in either of the two wings. These will be marked on the printed floor surface, so we can just use that as a template when drilling holes. We would pop the little LED through a hole so that they are slightly recessed from the surface of the treading surface, then fill the holes with clear epoxy. This will level the surface and protect the LEDs while allowing IR light to pass through. A cable will connect the lights to a control device in the head unit/storage crate. I don't yet know how to join the units to one another mechanically or electrically yet, so any ideas about that would be appreciated. A big neoprene rubber starting block would be at the opposite end of the course. This would have little semicircular cutouts for their heels while squaring off.

So, please give me feedback. I am going to start building a sample on Wedenday, with the hope of bringing it up with me to Boston during the week of September 28.


1 comment:

GB said...


I was very pleased with the results of yesterday’s sessions. I am writing mostly for the mobility folks here, and I’ll summarized where Rafael and I went with the end user interface and the data we will collect to provide, the feedback we will use, and the schedule for the feedback.
• The system will estimate the location of the cane tip by triangulating the location of the waste and the length of the cane. We should know within an inch or two where the cane tip is falling
• We are collecting data on vision and hearing but both will be significantly occluded by the equipment during training. The artificial removal of vision and hearing is meant to exclude any use of echolocation or vision to influence the motor skills we are targeting. (The goggle models suggested by Dona are awesome!)
• We are doing basic skills and basic feedback. We do not want to introduce extraneous variables into the design and testing at this stage.
• Veering: we will introduce spoken messages (e.g., move right) when the subjects moves 14 inches from the intended straight line of travel. Immediate follow up feedback will continue to be issued by the system until the veering lessens.
• Arc coverage: we will introduce spoken feedback every three cane sweeps, base on the immediately previous cane behavior: “too wide” when the condition is on both left and right; “too narrow” when the condition is on both sides; “too [wide or narrow] on the [left or right]” dependent on which side has the greater deviation from proper cane tip placement
We expect to learn a lot from early trials and can make adjustments to the programming logic. Seems like the user interface design is well on its way. We continue to be indebted to David Guth and his research for this initial model.

I think this is a good time if folks have questions.