Saturday, June 27, 2009

Designing the WiiCane

In response to general agreement among team members that I have spoken to, I am going forward with some preliminary sketches for the fitting that we will use to mount the WiiMote device to the cane. My operating assumptions are as follows:

1. The fixture needs to be able to hold the wii so that it can point in any direction along a vertical plane that passes through the idealized travel path. There may be different ways to use the device that call for positioning lights in ways that are hard to predict now. This fixture will let us experiment with various configurations and courses. For example, with this design, we could place lights on the floor, at the goal, on the user's body or shoes, or on the ceiling. This appears to give us enough flexibiliy so that we will be able to determine the best way forward experimentally.

2. The fixture needs to distribute the weight of the device evenly and symetrically regardless of which way the device is pointing. In the current design, as long as the cane is held so that the flat portion of the grip is sideways, the cane will remain balanced. Since the direction that the flat of the grip points is determined by the hand it is held in, it may be necessary to remove the wii from the fixture and reverse it depending on whether the user is a rightly or a lefty.

3. The fixture needs to be lightweight, so that the experience of using WiiCane is not very different from using a regular cane.

4. The fixture has to be strong enough to withstand reasonable abuse. Since we are replacing an 8" section of the cane with the plastic fixture, significant forces may be imposed on this part. While the design will take into account this requirement, we may not be able to acheive the same strength from the 3D print as we would expect from a metal casting or mass produced plastic part.

5. In this approach, where we modify a standard cane with our plastic fixture, it will probably be most practical to use an adjustable length cane like the one we borrowed from Rob in K-z00, rather than multiple fixed-length canes as in our prior approach.

6. there needs to be a very simple way to insert and remove the device in the fixture. I am thinking about a thumb screw or hand-tightened knob on the side that will permit us to loosen the knob or screw, then swivel the unit to the desired angle and then tighten it.

7. There should be some form or pointer or indicator to register the angle of the unit's tilt (in some suitable units), so that teachers can set the angle with precision.

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