A bigger issue to me is what do you do with Lily after it has run out of battery. I don't think I want to carry it for the rest of the day on the ski fields, mountain biking, trail running or anything else, it is fairly cumbersome. And I wonder how tough it is when it is in a back pack and I fall and land on it.

Very cool device and it would have a lot of practical uses, but not sure it will ever be that useful for the masses.