Ford has recently received US patent number 9,842,444 for a smartphone case that would function as a key fob, which seems to be both clever and several years out of date, thanks to the advent of dedicated mobile apps from manufacturers like Tesla.
The patent, filed on 12/12/2017, shows a reasonably typical smartphone case design with the added benefit of NFC communication features as well as UHF transmitters and receivers that would, in theory, make this device backward compatible with older vehicles that make use of proximity key technology.
While this would have limited interest in brand new vehicles, thanks to the advent of "key on the phone" apps, as someone who until recently owned a 2014 Fiesta ST, the idea of replacing the somewhat awkwardly shaped key fob with a slim case on my smartphone would be incredibly appealing.
It's unclear whether this will be produced, and if built, what Ford's intended use for the designs would be as patents like this are more often about excluding other manufacturers from doing something. If Ford does go through with it though, we're interested in any way for people to cut down on the number of things they have to carry every day, and this seems like a reasonable way to retrofit modern functionality to less than cutting-edge vehicles for minimal expense.