Compass Vibro Anklet
Eric and Skory are currently working on a vibro-tactile compass in anklet form.
Like everyone, we are inspired by that German dude's belt, but think the big, clunky belt is too impractical. Skory thought of pairing an accelerometer with a compass to build a bracelet that responds to the relative difference in motion of the arm vs. direction to north. Eric suggested doing that instead in an anklet. Running into difficulties with the whole accelerometer business, we're starting simple just building a vibrating anklet, and teaching an Arduino to talk to it and some 2-axis compass chips (we are actively pursuing economical ways of upgrading to a 3-axis chip).
Other people have also been inspired by the wired article, see for instance the other Eric: On the Haptic Compass - I've worn this belt and it's actually very intuitive. Note that he used 12 motors. There are many helpful links to parts (sensors, cables, vibrators, Arduinos, etc) in both the article and the comments. I am especially intrigued by Todd's idea of a "“foveated” motor distribution, where you have, say, three motors spaced narrowly across the forehead/belly, and the rest spread out around the less crucial sides and back. This might give you high accuracy where it counts (at the leading edge of most movement) without sacrificing too much function along the rest of the arc."
Ted talked with Skory about the steps to do this and made a document of Compass Vibro Anklet Directions with steps how to do this. So far it's an untested document but Ted intends to use these steps to try to make one himself.