An access control system, comprising: a smart device comprising a touchscreen including a light-emitting diode, LED, for emitting a wireless optical signal in a visible light spectrum, the wireless optical signal including authentication information and a pattern of flashes comprising a predefined start sequence of flashes; and an electronic locking device responsive to the LED of the smart device so as to unlock an entry point in response to receiving the authentication information conveyed from the LED to the electronic locking device, the electronic locking device comprising: wireless communication circuitry to exchange access control information, the access control information including stored authentication and audit trail information for respectively, updating and reviewing user access of the electronic locking device; a memory for storing the access control information made available to the electronic locking device through the wireless communication circuitry; a photodetector configured to produce an electrical signal corresponding to a received optical signal comprising the pattern of flashes emitted by the touchscreen including the LED, the electrical signal representing the received authentication information; and electrical circuitry that, in response to detecting the predefined start sequence, is configured to change its operative state from a low power consumption state to an event initiation state, the low power consumption state characterized by the electrical circuitry forgoing an attempt to compare the received authentication information to the access control information stored in the memory, and the event initiation state characterized by the electrical circuitry making the attempt so as to unlock the entry point in response to the received authentication information corresponding to the stored authentication information thereby permitting access to the user holding the smart device. a smart device comprising a touchscreen including a light-emitting diode, LED, for emitting a wireless optical signal in a visible light spectrum, the wireless optical signal including authentication information and a pattern of flashes comprising a predefined start sequence of flashes; and an electronic locking device responsive to the LED of the smart device so as to unlock an entry point in response to receiving the authentication information conveyed from the LED to the electronic locking device, the electronic locking device comprising: wireless communication circuitry to exchange access control information, the access control information including stored authentication and audit trail information for respectively, updating and reviewing user access of the electronic locking device; a memory for storing the access control information made available to the electronic locking device through the wireless communication circuitry; a photodetector configured to produce an electrical signal corresponding to a received optical signal comprising the pattern of flashes emitted by the touchscreen including the LED, the electrical signal representing the received authentication information; and electrical circuitry that, in response to detecting the predefined start sequence, is configured to change its operative state from a low power consumption state to an event initiation state, the low power consumption state characterized by the electrical circuitry forgoing an attempt to compare the received authentication information to the access control information stored in the memory, and the event initiation state characterized by the electrical circuitry making the attempt so as to unlock the entry point in response to the received authentication information corresponding to the stored authentication information thereby permitting access to the user holding the smart device. <EOS>