A method of determining electric pulses to provide to a plurality of unattended machines based on remotely-configured options for the plurality of unattended machines, the method comprising: at an application executing on a mobile device: detecting, based on respective broadcasts received from respective pulse-providing devices, each of which is coupled to a respective unattended machine, presence of the plurality of unattended machines in proximity to the mobile device; after detecting the presence of the plurality of the unattended machines, receiving, from a server: (i) information about a respective set of remotely-configured options for each unattended machine, and (ii) encrypted information that includes a respective authorization grant, for interacting with a respective unattended machine, wherein the encrypted information includes specifications regarding electric pulses to be provided to a respective unattended machine by a respective pulse-providing device in accordance with a respective option; in response to receiving the information about a first set of remotely-configured options and the encrypted information, displaying, in the application, first user interface objects that allow for selection of first respective options in a first set of remotely-configured options for a first unattended machine; detecting a selection of a first user interface object that corresponds to a first option in the first set of remotely-configured options; after detecting the selection of the first user interface object, in accordance with a determination that a trigger condition has been satisfied, sending the encrypted information that includes the authorization grant and the pulse specifications to the respective pulse-providing device coupled to the first unattended machine; and after sending the information that includes the authorization grant and the pulse specifications to the respective pulse-providing device, receiving a first indication, from the respective pulse-providing device, that the electric pulses were provided to the first unattended machine according to the pulse specifications. detecting, based on respective broadcasts received from respective pulse-providing devices, each of which is coupled to a respective unattended machine, presence of the plurality of unattended machines in proximity to the mobile device; after detecting the presence of the plurality of the unattended machines, receiving, from a server: (i) information about a respective set of remotely-configured options for each unattended machine, and (ii) encrypted information that includes a respective authorization grant, for interacting with a respective unattended machine, wherein the encrypted information includes specifications regarding electric pulses to be provided to a respective unattended machine by a respective pulse-providing device in accordance with a respective option; in response to receiving the information about a first set of remotely-configured options and the encrypted information, displaying, in the application, first user interface objects that allow for selection of first respective options in a first set of remotely-configured options for a first unattended machine; detecting a selection of a first user interface object that corresponds to a first option in the first set of remotely-configured options; after detecting the selection of the first user interface object, in accordance with a determination that a trigger condition has been satisfied, sending the encrypted information that includes the authorization grant and the pulse specifications to the respective pulse-providing device coupled to the first unattended machine; and after sending the information that includes the authorization grant and the pulse specifications to the respective pulse-providing device, receiving a first indication, from the respective pulse-providing device, that the electric pulses were provided to the first unattended machine according to the pulse specifications.