A mobile system (1,11) comprises a camera (3) and at least one processor (5). The at least one processor is configured to capture an image with the camera, e.g. of a light beacon (15), to determine whether a certain object is recognized in the captured image, e.g. by querying a database (19), and to start detecting and/or decoding data being communicated via visible light in dependence on the certain object being recognized.