1. A system for communicating information relating to online games between user devices and physical objects, the system comprising: a user device comprising: one or more light sources; one or more sensors configured to capture modulated visible light emitted from a physical object that is separate from the user device; and one or more physical processors configured by machine-readable instructions to: analyze one or more parameters of the modulated visible light, and determine from the one or more parameters of the modulated visible light game-relevant information associated with the physical object; effectuate display of a game to a user, and to use the game-relevant information to effectuate presentation of a character or virtual object in the online game that corresponds to the physical object; and encode updated game-relevant information into a command signal, the command signal being configured to facilitate generation of encoded modulated visible light by the one or more light sources for reception by the physical object.