A wireless networked lighting system that comprises: - lamps; - a controller for controlling the lamps; - a device comprising: - a target detector configured to detect a presence of a target in a first area and - a transmitter, the transmitter configured to transmit to the controller; and - a light detector for detecting light in a second area; the wireless networked lighting system characterized in that: the transmitter is configured to: - transmit a multicast message to switch on lamps to the controller and to one or more of the lamps in response to a detection of the presence of the target in the first area when the device establishes a need for a first response speed, and - transmit a unicast message to the controller to cause the controller to send a message to switch on one or more of the lamps when the device establishes that the first response speed is not needed; and wherein the device is configured to establish, in response to the detection of the presence of the target in the first area that: - the first response speed is needed when a first amount of light is detected by the light detector, the first amount of light being smaller than a threshold value and - the first response speed is not needed when a second amount of light is detected by the light detector, the second amount of light being larger than the threshold value and wherein the first and second areas (1, 2) are at least partly overlapping areas. - lamps; - a controller for controlling the lamps; - a device comprising: - a target detector configured to detect a presence of a target in a first area and - a transmitter, the transmitter configured to transmit to the controller; and - a target detector configured to detect a presence of a target in a first area and - a transmitter, the transmitter configured to transmit to the controller; and - a light detector for detecting light in a second area; the transmitter is configured to: - transmit a multicast message to switch on lamps to the controller and to one or more of the lamps in response to a detection of the presence of the target in the first area when the device establishes a need for a first response speed, and - transmit a unicast message to the controller to cause the controller to send a message to switch on one or more of the lamps when the device establishes that the first response speed is not needed; and - transmit a multicast message to switch on lamps to the controller and to one or more of the lamps in response to a detection of the presence of the target in the first area when the device establishes a need for a first response speed, and - transmit a unicast message to the controller to cause the controller to send a message to switch on one or more of the lamps when the device establishes that the first response speed is not needed; and wherein the device is configured to establish, in response to the detection of the presence of the target in the first area that: - the first response speed is needed when a first amount of light is detected by the light detector, the first amount of light being smaller than a threshold value and - the first response speed is not needed when a second amount of light is detected by the light detector, the second amount of light being larger than the threshold value - the first response speed is needed when a first amount of light is detected by the light detector, the first amount of light being smaller than a threshold value and - the first response speed is not needed when a second amount of light is detected by the light detector, the second amount of light being larger than the threshold value and wherein the first and second areas (1, 2) are at least partly overlapping areas.