You could probably build a rotating magnet array off the end of a hub to generate the EM field, you then just need an ' electronic stuff' pocket near the magnet array to put the stuff in to be charged.
EDIT: magnet arrag pay collect passing ferrous crap so don;t be surprised to find half a dozen rusty nails and bits of car stuck to it at the end of your commute.
You could probably build a rotating magnet array off the end of a hub to generate the EM field, you then just need an ' electronic stuff' pocket near the magnet array to put the stuff in to be charged.
EDIT: magnet arrag pay collect passing ferrous crap so don;t be surprised to find half a dozen rusty nails and bits of car stuck to it at the end of your commute.