Smart phones batteries often run off. Under that circumstance, one must still be able to unlock-lock a bike lock that would otherwise be controlled through a smart phone. One way would be to enable using...
Technologies such as Bluetooth 4 or Bluetooth Low Energy, which are supported across many iOS and Android mobile devices, can be used to communicate a lock/unlock key to a bike lock.
Bike locks that connect to a system that enables unlocking/locking of bikes for authorized users only, would enable bicycle sharing systems without expensive docking stations (eliminating the need for...