Apple patent application hints at iPhone that changes orientation mid-fall@ 2013/03/22
The sensors in question are pretty standard fare: accelerometers, gyroscopes, etc... but some of the countermeasures are quite unique. Shifting weights could be hidden under the hood, but other proposals include a locking headphone jack that would prevent the phone from hitting the ground, airfoils and even a reserve of gas for thrust. Many of the solutions are more than just a little impractical, especially when trying to design the sleekest smartphone possible. The concept could also be used in laptops and tablets, but it would certainly be most useful in shatter-prone mobile devices like the iPhone. If you really like digging through patent minutia check out the source link.