When I saw the 'northskirt' the first time I had an idea similar to this one. Vibrate the little buzzer in your phone more aggressively when you're going the wr

When I saw the 'northskirt' the first time I had an idea similar to this one. Vibrate the little buzzer in your phone more aggressively when you're going the wrong way, slowing it down as you are going the right way. Simple, only one 'bit' output needed (you could even tape a slave buzzer to your ankle or so). Instant pigeon sense of direction where-ever you go. No peeking at the screen required. Special signal: three rapid buzzes when you've reached your destination.