Engadget appears to have been first with the story, but Motorola Mobility (which is now a Google company) has applied for a patent for an “electronic skin tattoo” that acts as a microphone and which connects to a cell phone. The technology of this is obviously not easy, but the idea of microphones that work either through bone conduction or by touching your cheek or neck body doesn’t seem to be new.
Another thing: the patent never actually addresses what an “electronic skin tattoo” is. Is it something like a Band-Aid, only thinner and with circuitry? Or are they talking about actually inking a microphone onto your body, in which case, ewww.