Hi Gary, This is an interesting idea, although I don't much believe in an internalized biological sense of direction. some people are good at it and many aren't
I've been working with a "tactile" compass at work using a servo motor driving a pointer on a "braille" dial. Problem is the motor in the servo messes with the magnetic compass sensor. So you need two boxes and I consider that unacceptably clunky. Also I've found that when continuously following a compass in a tipical urban environment, there is a heck of a lot of iron about which causes the compasses heading to be effected a lot. I plan to add a "solid state gyro" module and try to average out the two headings in software, thus hopefully the short term instabilities in the magnetic compass will be evened out by the gyro, and the long term drift expected from the gyro can be corrected by the compass. The idea of using pager vibrators is interesting, but I'd still worry about proximity effects on the compass. I've looked in to non-magnetic motors and so far they all seem way to weak to do the job. Still an idea in the research phase. My possible uses included crossing large open areas with no sound or tactile cues The compass in the referenced article would give only 30 degrees of resolution, maybe not bad over the long haul, but not good enough to get you to that entrance across the big parking lot. All very interesting thanks tom Fowle Smith-Kettlewell RERC San Francisco.