Friday, September 18, 2009
new concept: putting the IR lights on a cable overhead
After thinking through the problems associated with constructing a floor mat system for tracking position of a student during cane travel training with a wii remote, I want to consider a new idea that may resolve many problems. This approach calls for creating an overhead string of LED lights on a three or four wire cable stretched tightly between two poles. The poles would be floor-to-ceiling aluminum rods of the type I have here in the office to hold up the desks. These are telescoping poles from IKEA that extend up to 12'. I believe this could be easily installed in a wide variety of places. Even if they didn't have a full 30', they could use set up and use a shorter course.
Here are the pluses and minuses of the proposed system:
1. We can control the distance between the camera and the lights this way. In the floor mat arrangement, the shortest cane held the Wii device only about 18" or so above the floor, so the portion of the floor that the camera could see at once was very small. If we point the wii device straight up instead of straight down, and if we string the lights on a single cable directly above the course, I believe that we should be able to be far enough from the lights that we would mostly always able to see one light, and usually more than that. In the floor scenario, we were talking about making multiple rows of lights so that the cane would be seen even when the subject was not standing in the middle of the course. If we are far enough from the lights, we may only need one row. This has to be demonstrated experimentally.
2. The poles will be rigidly held in place, so, as long as they are padded, it won't pose too much of a hazard in the case of inevitable collisions. Because the poles are rigidly supported, we can draw the cables very tight, reducing the amount of sag. We will probably need some kind of mechanical tensioner in the cable for setting up the apparatus. While a little sag might not matter, a large amount of sagging could lead to measurement inaccuracies. I think this set up is a fairly low hazard level.
3. This apparatus will be much easier to package and ship, much, much cheaper to produce and less prone to damage and wear, because no one will be walking on it.
4. The system will be very scalable. It will be relatively easy to extend or reduce the length of a course. It would also be possible to include additional legs, as long as the subject is prepared to negotiate a free-standing pole along the route.
5. There may be other applications for the set up that I am envisioning, such as Wii Fencing. I just googled it, and it does not appear that wiiFencing has been done. Here's a link to a thread on that subject. A cheap set up for tracking linear motion along a virtual course may have a range of uses in both therapeutic and gaming domains.
So...I am going to go shopping tomorrow and buy stuff to set this up. I will be ready to start testing next week, and if it looks promising, the next thing we have to do is to go to all of the sites and make sure that they have a location where the poles could be set up.