This technique uses the energy in radio waves, broadcast from a transmitter and harnessed by an antenna, to generate electricity.

ECONOMIST: Wireless charging

Once the device syncs with a navigation unit, the audio is then piped to the Mainnav via a 3.5-millimeter audio cable, and if you're actually in one of those remote areas where an FM transmitter can broadcast something other than fuzz, you're good to go.

ENGADGET: Mainnav MG-920 Bluetooth GPS receiver touts FM transmitter