Sensor devices (1) are provided with trigger signal generators (2) for repeatedly generating trigger signals and light detectors (12) for detecting light parameters such as intensities and colors and color temperatures and patterns and fluctuations of light (43) at a location and transmitters (9) for, in response to trigger signals, transmitting control signals based on detections to control devices (20) for controlling light sources (40) to influence the light (43) at the location. The sensor devices (1) may further comprise theme code generators (3), location code generators (4), processors (5), scanners (10), and position detectors (6). The control devices (20) comprise receivers (27) for receiving the control signals from the sensor devices (1) and controllers (26) for, in response to the control signals, controlling the light sources (40) and may further comprise theme code detectors (21) and/or processors (22) and/or location code detectors (23) and/or setting detectors (24) and/or communicators (28) for communication with scanners (10) and/or transmitters (29) and/or arbiters (25).