Abstract:
A light effect control method, computer program product and device are presented which allow an application to render a light effect by a networked lighting system based on the method, computer program product or device receiving an event being from the application. To provide a better user experience, light effects related to certain events need to be rendered even if a delay in rendering is expected whereas light effects related to other events need to be rendered without delay or else not rendered at all. As such, a decision is made to execute a first or a second scenario based on the event type of the event received and/or the capacity of the networked lighting system, wherein in the first scenario the lighting control command is always sent to the networked lighting system and in the second scenario the lighting control command is only sent to the networked lighting system if no unacceptable delay in rendering the light effect is expected.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to methods for light effect control and more in particular to a computer implemented method for allowing an application to render a light effect via a networked lighting system. The present invention further relates to control devices for light effect control and more in particular to a networked lighting system control device for controlling a lighting device in a networked lighting system. 
       BACKGROUND OF THE INVENTION 
       [0002]    Traditional lighting systems are typically stand-alone systems that offer on/off or dim-level control of a single color of light (e.g. white) via a physical switch. Recent developments have led to modern lighting systems that, for example, can emit various colors and can be controlled over a wireless network using a smart phone. Although such modern lighting systems offer advantages, they are far more complex than traditional lighting systems from a controls perspective. As an example, when in a traditional lighting system a physical switch is turned on, power to a lighting device is provided, and the lighting device turns on virtually instantly. In the modern lighting system of the example above, user input related to switching a lighting device on is captured via a user interface of a smart phone, a command is sent via the smart phone over one or more networks to the lighting system after which the lighting device responds to the received command by proceeding to emit light. In various implementations, additional steps, not mentioned above, need to be taken to effectuate control of the lighting device. Such complexity can introduce undesired effects, such as unpredictability related to the execution of lighting control commands and rendering of related light effects. There is a need for an improved lighting system that mitigates or avoids at least some of these undesired effects. 
       SUMMARY OF THE INVENTION 
       [0003]    Inventors have realized that in networked lighting systems, lighting control commands can, for example, get lost (e.g. dropped due to network load or buffer overflows in a network component) or be delayed (e.g. lag as a result of network load). It is an object of the present invention to provide a (computer implemented) method for allowing an application to render a light effect via a networked lighting system. It is a further object of the present invention to provide a computer program product and a networked lighting system control device for controlling a lighting device in a networked lighting system. 
         [0004]    In a first aspect of the invention, a (computer implemented) method according to the invention is provided for allowing an application to render a light effect via a networked lighting system. The method comprises: receiving an event from the application, the event related to a light effect for being rendered by the networked lighting system, determining an event type, from a set of event types, of the event received, wherein the set of event types comprises at least a first event type and a second event type, determining a capacity of the networked lighting system for executing a lighting control command, selecting for execution a scenario from a set of scenarios based on the determined capacity of the networked lighting system and the determined event type, the set of scenarios comprising at least a first and a second scenario, and executing the selected scenario, wherein the first scenario comprises sending one or more lighting control commands for rendering the light effect related to the event received to the networked lighting system and the second scenario comprises dismissing the event received by not sending a lighting control command to the networked lighting system. The method can be implemented, for example, as an Application Programming Interface (API) as part of a lighting engine or embedded in a hardware device, such as a bridge of a networked lighting system. The method allows to effectively dismiss certain events received, based on one or more of: the event type of the event received and the determined capacity of the networked lighting system. When used to prevent an overload situation of the networked lighting system, such as a situation where commands get lost in the networked lighting system (e.g. dropped due to network load or buffer overflows in a network component), the method can make the operation of the networked lighting system more predictable. For example, instead of an unpredictable or random pattern of lighting control commands being dropped by the networked lighting system, specific types of events are effectively dismissed and as such lighting control commands related to these events are not sent to the networked lighting system. To provide a better user experience, the events that are effectively dismissed, can be selected from a number of event types such that only event types that have limited impact on the user experience are not rendered by the networked lighting system in an overload situation. This can allow for a more optimal use of the capacity of the networked lighting system, for example, by increasing the likelihood of events of an event type that have a large impact on the user experience to be rendered successfully. 
         [0005]    In an embodiment of the computer implemented method according to the invention the set of scenarios further comprises a third scenario comprising: determining an approximate light effect based on the light effect related to the event received, and sending one or more lighting control commands, for rendering the approximate light effect, to the networked lighting system. This is beneficial as, for example, an approximate light effect can be determined that uses less capacity of the networked lighting system or a single approximate light effect can replace multiple light effects. In a further embodiment the number of lighting control commands required to render the light effect related to the event received is greater than the number of lighting control commands required to render the approximate light effect. This is beneficial as less capacity of the networked lighting system can then be used when rendering the approximate light effect than in a situation where the light effect related to the received event would be rendered by the networked lighting system. In yet a further embodiment, the number of lighting devices required to render the approximate light effect is smaller than the number of lighting devices required to render the light effect related to the event received. This is beneficial as a control command related to the approximate light effect would need to reach fewer lighting devices in the networked lighting system than in a situation where a control command would be sent to all lighting devices related to the light effect related to the received event. For example, when each lighting device that needs to be reached requires an individual control command (e.g. a unicast message) to be sent, then less control commands would need to be sent; and if multiple lighting devices are reached by a single control command (e.g. a multicast or broadcast message), then in a networked lighting system where messages are relayed by lighting devices to each other, the time needed to spread the message in the network could be less than in a situation where a control command would be sent to all devices related to the light effect related to the received event. 
         [0006]    In various embodiments of the method according to the invention: determining the capacity of the networked lighting system is based on a predetermined value indicative of an expected number of lighting control commands for which the networked lighting system has capacity; determining the capacity of the networked lighting system is based on a first predetermined value indicative of an expected number of lighting control commands of a first type for which the networked lighting system has capacity and a second predetermined value indicative of an expected number of lighting control commands of a second type for which the networked lighting system has capacity; determining the capacity of the networked lighting system is based on a number of lighting control commands stored in a buffer of a device in the networked lighting system; or determining the capacity of the networked lighting system is based on measuring the amount of network traffic present in the networked lighting system. Each of these embodiments provides benefits related to, for example, balancing the effort required to determine the capacity of the networked lighting system for executing a lighting control command and the quality of the determined capacity (e.g. the level of detail of the determination made or the likelihood of the determination made being correct). In an implementation of a networked lighting system, multiple applications and user actions can relate to control commands being sent to lighting devices. In determining the capacity of the networked lighting system these can be taken into account (e.g. by determining the number of applications requesting access to the networked lighting system or by negotiating between applications the number and/or type of control commands each application is allowed to send to the networked lighting system over a predetermined time period). 
         [0007]    In an embodiment of the method according to the invention, the first scenario is executed when the event received is of the first event type, wherein the first event type relates to a light effect for which successful rendering by the networked lighting system is of high importance. This is beneficial as an implementation of the method will, for an event of the first event type, send out a lighting control command to the networked lighting system to render the light effect related to the received event even when the capacity of the networked lighting system is determined to be insufficient (e.g. a delay for executing the lighting control command is expected or there is a certain likelihood that the control command will not reach the lighting device). This provides for a larger likelihood of the light effect being rendered by the networked lighting system than when no control command for rendering the light effect is sent to the networked lighting system. In a further embodiment of the method according to the invention, the second scenario is executed when the event received is of the second event type, and the determined capacity of the networked lighting system is indicative of an expected delay, above a predetermined threshold, in rendering the light effect related to the event received, wherein the second event type relates to a light effect for which timely rendering by the networked lighting system is of high importance. This is beneficial as an implementation of the method will, for an event related to the second event type, send out a lighting control command to the networked lighting system to render the light effect related to the received event when the capacity of the networked lighting system has been determined to be sufficient (e.g. no or an acceptable delay for executing the lighting control command is expected). This can prevent the light effect from being rendered too late when instead it is more beneficial, from a user experience for example, not to render the light effect rather than rendering it with a certain delay. 
         [0008]    In yet a further embodiment of the method according to the invention, the light effect for which successful rendering by the networked lighting system is of high importance relates to a lighting scene change based on a virtual character moving, in a virtual environment provided by the application, from a first location to a second location, wherein the first location is related to a first lighting scene and the second location is related to a second lighting scene different from the first lighting scene. The method according to the invention, can be used for rendering light effects by a networked lighting system (e.g. a general lighting system) based on a virtual environment provided by the application. In, for example, a computer game, a virtual character, such as a computer game character, can be controlled by a user. The computer game character can move around in a virtual environment, such as a level in a computer game. When the computer game character moves from a first location (e.g. indoors in the virtual environment) related to a first lighting scene (e.g. dimmed white light) to a second location (e.g. outdoors in the virtual environment) related to a second lighting scene (e.g. bright white light), then the lighting conditions in the room where the user is playing the computer game can be adapted to reflect the lighting scene change in order to provide a better (e.g. more encompassing) user experience. It is important that a scene change is effectuated, as it would seem strange to a user when sometimes the lighting conditions remain constant even though the scene changes and other times the lighting conditions reflect the scene change. The timing of executing the scene change in the networked lighting system however can be less important than the fact that the scene change is effectuated (e.g. it is better to render the light effect with a delay than not to render it at all). There can however also be light effects for which timely rendering is more important. In yet another embodiment of the method according to the invention, the light effect for which timely rendering by the networked lighting system is of high importance relates to a lighting feedback triggered by an event occurring in virtual environment provided by the application. Continuing the example of the computer game, the computer game character can interact with, for example, objects in the virtual environment. When the user controls the computer game character to jump onto a pedestal, for example, this can cause the user to collect points in the computer game. Lighting feedback can be provided related to this event and for such lighting feedback it can be important that the light effect is rendered with little delay, such that a video output rendered by the computer game and light effects rendered by the networked lighting system appear synchronized to the user. The timing of rendering the light effect in the networked lighting system can in this case be more important than the fact that the light effect is rendered (e.g. it is better to not render the light effect than to render the light effect with an unacceptable delay). 
         [0009]    In an embodiment of the computer implemented method according to the invention, the networked lighting system comprises one or more lighting devices arranged for receiving lighting control commands over a mesh network, such as ZigBee (Light Link), and wherein sending a lighting control command, for rendering the light effect related to the event received, comprises sending a message over the mesh network, such as ZigBee (Light Link). It is beneficial to apply this method when a ZigBee (Light Link) or other (mesh network type) wireless network is used by the networked lighting system, as in such networked lighting systems the capacity of the networked lighting system can be a more relevant factor in providing a satisfactory user experience when rendering light effects than in wired networks, due to, for example, capacity limitations of the networked lighting system. 
         [0010]    In a network, such as a mesh network, commands can be sent as, for example, unicast or broadcast messages. A unicast message is destined for a single node on a network, such as a single lighting device in the networked lighting system. A broadcast messages is sent to all nodes in a network. In a mesh network a broadcast message can be replicated to allow all nodes to receive it (e.g. the node that originates the broadcast messages can reach a first set of nodes in the network, yet not all nodes and therefore each node further propagates the message). Network capacity can be influenced by the type of message that is transmitted over the network. Typically a broadcast message takes up more capacity as more nodes are involved and the messages reaches some node more than once. 
         [0011]    In a second aspect of the invention, a computer program product is provided, the computer program product comprising program code for causing a computer to carry out the method of any of the preceding claims when the computer program product is carried out on the computer. The computer program product can be implemented, for example, as a lighting engine on a computer gaming system, a desktop or laptop personal computer, a tablet or smart phone or any other type of computing device. It can be provided as a piece of installed software, an optionally downloadable component, an application in an application store, etc. 
         [0012]    In a third aspect of the invention, a networked lighting system control device is provided, the networked lighting system control device arranged for controlling a networked lighting system. The networked lighting system control device comprises: an input arranged for receiving an event related to a light effect for being rendered by the lighting device, a network interface arranged for sending a lighting control command to the lighting device, and a processor operationally coupled to the input and the network interface. The processor is arranged for: determining an event type, from a set of event types, of the event received, wherein the set of event types comprises at least a first event type and a second event type, determining a capacity of the networked lighting system for executing a lighting control command, selecting for execution a scenario from a set of scenarios, based on the determined capacity of the network and the determined event type, wherein the set of scenarios comprises at least a first and a second scenario, and executing the selected scenario. The first scenario comprises sending one or more lighting control commands for rendering the light effect related to the event received to the networked lighting system, and the second scenario comprises dismissing the event received by not sending a lighting control command to the networked lighting system. Such a control device can be a bridge that can control lighting devices in a networked lighting system, a component (e.g. a general purpose processor) in a computer gaming system, etc. 
         [0013]    It shall be understood that the (computer implemented) method, the computer program product and networked lighting system control device, have similar and/or identical preferred embodiments, in particular, as defined in the dependent claims. 
         [0014]    It shall be understood that a preferred embodiment of the invention can also be any combination of the dependent claims with the respective independent claim. 
         [0015]    These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    To assist understanding of the present disclosure and to show how embodiments may be put into effect, reference is made by way of example to the accompanying drawings in which: 
           [0017]      FIG. 1  shows schematically and exemplarily an overview of an application interfacing a lighting system, 
           [0018]      FIG. 2  shows schematically and exemplarily a method for allowing an application to render a light effect via a networked lighting system according to the invention, 
           [0019]      FIG. 3A  and  FIG. 3B  show schematically and exemplarily screen shots of a computer game where a character is positioned in a first position related to a first light effect and a second position related to a second light effect, respectively, 
           [0020]      FIG. 4A  and  FIG. 4B  show schematically and exemplarily screen shots of a computer game where a character in a first scenario is not interacting with an object and in a second scenario is interacting with the object, respectively, the interaction with the object related to a light effect, 
           [0021]      FIG. 5A  and  FIG. 5B  show schematically and exemplarily a scene of a user playing a computer game where a lighting device renders a first light effect and a second light effect, respectively, 
           [0022]      FIG. 6  shows schematically and exemplarily a decision tree for determining what scenario to execute in relation to the determined capacity of the networked lighting system and the determined event type of the event received, and 
           [0023]      FIG. 7  shows schematically and exemplarily the routing of a lighting command in a lighting system. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]    In  FIG. 1  an overview  100  is provided showing a game engine  110  arranged for interfacing over a game engine to game code interface  120  with game code  130 , the game code  130  further interfaced over a game code to lighting engine interface  140  to a lighting engine  150 . The lighting engine  150  is further arranged for interfacing over a network interface  160  to a network  170  comprising a lighting system  180 . The lighting system, in this example, comprising various lighting system devices  182 ,  184 ,  186 . As an example, the game code  130  can initiate an action to be executed by the game engine  110  by calling a routine over the interface  120  that causes movement of a character in the video output of a computer game and initiate an action to be executed by the lighting engine  150  by using an API offered by the lighting engine  150  over the interface  140  that is intended to create a light effect rendered by at least one lighting system device  182 ,  184 ,  186  in the lighting system  180 . The game code  130  can comprise code that causes a character in the video output of the computer game to walk from a dark forest into a brightly lit building and related to this control a lamp, in the room where the user is playing the computer game, to increase its brightness. 
         [0025]    Although this example refers to a game engine  110  and game code  130 , the lighting engine  150  could interface other types of code, applications, etc. For example, light effects can be rendered by the lighting engine  150  based on triggers occurring in an light effects enriched video that a user is watching, light effects can be rendered by the lighting engine  150  based on actions taken by a user in a word processing application, light effects can be rendered in relation to events occurring in an application used by another user, or light effects can be rendered based on an event occurring on a network or in the cloud. 
         [0026]    In  FIG. 2  a graphical representation of a method  200  for allowing an application to render a light effect via a networked lighting system according to the invention is shown. The method  200  comprises receiving an event  210 , the event related to a light effect for being rendered by the networked lighting system. Such an event can for example be received from an application, such as game code executed on a computer, over an API. The method further comprises determining an event type  220  of the received event. Examples of event types are lighting scene changes, such as a scene change from a cool white to warm white ambience, and lighting feedback, such as an intense light flash. Such event types can relate to actions taken by a user which cause a character in a computer game to move from an outside environment covered in snow (related to cool white light) to an inside environment in a house with the fire place on (related to warm white light) or actions taken by the user that cause the computer game character to collect an extra life (related to an intense light flash). 
         [0027]    The method further comprises determining a capacity of the networked lighting system  230 . The capacity can be determined based on a predetermined threshold, for example: one lighting command per second, ten lighting commands per two seconds, three lighting commands of a first type (e.g. related to a unicast message) or one lighting command of a second type (e.g. related to a multicast message) per second. In various embodiments the capacity can be determined based on the number of lighting commands or messages sent in a predetermined time period, the queue of lighting commands or messages in a buffer (e.g. in a buffer of a gateway or a network device), a service offered by the networked lighting system that monitors capacity, etc. 
         [0028]    The method further comprises deciding based on the determined capacity of the networked lighting system and/or the determined event type, to execute a first or a second scenario  240 ; and executing the first scenario, comprising sending a lighting control command, for rendering the light effect related to the event received, to the networked lighting system or executing the second scenario, wherein the light effect related to the event received is not rendered by the networked lighting system  250 . As a first operational example, it can be determined that the network capacity is sufficient for the light effect to be rendered and the first scenario is executed, wherein a lighting control command is sent to the networked lighting system to render the light effect. As a second operational example, it can be determined that the network capacity is insufficient for the light effect to be rendered and the second scenario is executed by not sending a control command to the networked lighting system and effectively dismissing the event received. As a third operational example, it can be determined that the network capacity is low (e.g. beneath a predetermined value) and the second scenario is executed by determining an approximate light effect and sending a control command to the lighting system to render the approximate light effect. As a fourth operational example, it can be determined that the event type of the light effect that is to be rendered is of the first type and therefore the first scenario is executed, effectively always sending a lighting control command to the networked lighting system independent of the determined system capacity. As a fifth operational example, it can be determined that the event type of the light effect that is to be rendered is of the second type and therefore the second scenario is executed by effectively dismissing the event received. As a sixth operational example, it can be determined that the capacity of the networked lighting system is low (e.g. only one more command can be sent in the next second) and the first scenario is executed if the event is of the first event type whereas the second scenario will be executed if the event is of the second event type. There are numerous other variations related to making a scenario decision and executing the scenario. 
         [0029]    In  FIG. 3A ,  FIG. 3B ,  FIG. 4A ,  FIG. 4B ,  FIG. 5A  and  FIG. 5B  an example of an implementation of the method according to the invention is provided.  FIG. 3A  and  FIG. 3B  each show a position of a computer game character in order to illustrate an event related to a scene change.  FIG. 4A  and  FIG. 4B  each show a position of a computer game character in order to illustrate an event related to a lighting feedback.  FIG. 5A  and  FIG. 5B  each show a user of a computer game and a lighting device. More specifically, in  FIG. 3A  and  FIG. 3B , a first image  300  rendered by a computer gaming system is shown, the image comprising a computer game character  310  having a certain distance to a tree  320  and a house  330 . The computer gaming system can relate this to a light effect, such as a lighting scene appropriate for a sunny day. When the user moves the computer game character closer to the house  330  this can lead to the computer gaming system rendering a second image  350  wherein the computer game character  310  has moved closer to the house  330  and therefore stands underneath the tree  320 . The computer gaming system can relate this to a light effect, such as a lighting scene appropriate for receiving shade from a tree. In this example, both light effects relate to a lighting scene. The computer gaming system can render the appropriate light effect via the networked lighting system.  FIG. 4A  and  FIG. 4B  show an example wherein the light effect relates to lighting feedback. The computer game character  310  in the third image  400  rendered by the computer gaming system, is in the vicinity of a pedestal  410  which, as part of the game design, allows a user to collect points in the game. When the user controls the computer game character  310  to jump on the pedestal  410 , the user is given feedback that points have been collected through showing, in the fourth image  450 , an image of coins  460 . In this example, additional feedback can be given through the networked lighting system, such as by temporarily increasing the light output. The rendering of a light effect is shown in  FIG. 5A  and  FIG. 5B , where in a first representation  500  of a user playing a computer game, the user  510  is seen sitting on a chair  512  behind a desk  514 , the user operating a computer gaming system  516 , such as a laptop running a computer game. In the first representation  500  a lighting device  520  renders a first light effect  530  and in a second representation  550  the lighting device  520  renders a second light effect  532 . 
         [0030]    In a first example, the first light effect  530  is emitting bright white light and the second light effect  532  is emitting dimmed white light. The light effect  530 ,  532  being rendered by the networked lighting system is related to an event in a virtualized environment provided by the computer gaming system. The computer game character  310  positioned in sunlight, as in the first image  300 , can relate to the first light effect; and the computer game character  310  positioned in the shade of the tree  320 , as in the second image  350 , can relate to the second light effect. If the networked lighting system is rendering the first light effect, then when the user  510  moves the computer game character  310  closer to the house  330 , this can lead to the computer gaming system rendering the second image  350  as well as the generation of a first event related to the lighting scene change (i.e. the lighting scene changing from bright white light to dimmed white light). The lighting device  520  can transition from rendering the first light effect  530  to rendering the second light effect  532 . 
         [0031]    In a second example, the second light effect  532  is a short flash of red light and this effect is related to the computer game character  310  collecting points, such as by jumping on the pedestal  410 . When the user  510  controls the computer game character  310  to jump on the pedestal  410  the lighting device  520  should render the second light effect  532  and as such the computer gaming system will generate a second event related to this second light effect. 
         [0032]    A light effect can relate to an indefinite change in light output (e.g. a light effect is rendered until a subsequent light effect is rendered) or temporary changes in light output (e.g. a light effect is rendered for a period of time before the lighting device returns to its original state). A light effect can relate to color, color rendering index, saturation, brightness, beam angle, beam focus or any other light variable. 
         [0033]    The lighting engine  150  executing the method according to the invention and receiving the first and/or the second event referred to above, will determine the event type of the event received. In this example, the first event is related to the first event type and the second event is related to the second event type. The first event type relates to rendering a scene and the second event type relates to rendering lighting feedback. To provide a satisfactory user experience, it is critical that the scene change is executed, however this is less time critical than the execution of the lighting feedback. As an example, assume the user  510  controls the computer game character  310  to move underneath the tree  320 . The lighting device  520  should render the second light effect  532 , which in this case is dimming the white light. If this light effect is not rendered, this creates a bad user experience. Now assume the user  510  controls the computer game character  310  to jump on the pedestal  410 . The lighting device  520  should render the second light effect  532 , which in this case is emitting a flash of red light. If this light effect is rendered late (e.g. out of sync with the image rendered by the computer gaming system), this creates a bad user experience. As such, in this example, if the capacity of the networked lighting system is such that a light effect will (likely) be rendered with a delay, the lighting engine should send a control command to the networked lighting system to render the lighting scene change (in this example, dimming the light), yet should not send a control command to render the lighting feedback (in this example, the flash of red light). 
         [0034]    In  FIG. 6  a decision tree  600  is shown related to the example illustrated above. In a first step  610  in the decision tree, the question is “is the capacity of the networked lighting system greater than a (predetermined) value x”; if “yes” then follow path  612  and continue to the first outcome  620  of the decision tree of sending the control command; if “no” then follow path  614  and second step  630 . In the second step  630  the question is “is the event received of event type y”; if “yes” then follow path  632  and continue to the first outcome  620  of the decision tree of sending the control command; if “no” then follow path  634  and continue to the second outcome  622  of the decision tree of not sending the control command. The lighting engine  150  receiving the first event related to the first event type as per the example above (i.e. the event related to the lighting scene change, in this example the dimming of the white light) or the second event related to the second event type as per the example above (i.e. the event related to the lighting feedback, in this example the flash of red light), can execute the steps of this decision tree  600  as part of executing the method according to the invention. The lighting engine determines the capacity of the networked lighting system is above value x and as such the capacity is sufficient for a lighting control command to be rendered without a delay (e.g. within a predetermined time period, within a predetermined time period with a certain likelihood, or without any known or anticipated delays). If the capacity is sufficient, then a lighting control command will be sent to the networked lighting system irrelevant of whether the event received is of the first or the second event type. However if the capacity is insufficient, then the lighting engine  150  executing the steps of the decision tree  600  will consider the event type of the event received and, in this exemplary situation, send a control command if the event received is of the first event type (i.e. the lighting scene change), yet not if it is of the second event type (i.e. the lighting feedback). 
         [0035]    In  FIG. 7  some details are shown of where a delay can occur in a networked lighting system, by providing insight into the routing of a lighting control command in such a system. This exemplary networked lighting system  700  comprises a bridge  781  with a lighting control command buffer  782 , as well as a first lighting device  784  and a second lighting device  786 . The lighting engine  150  interfaces over the network interface  160  to the bridge  781 . In this example, the lighting engine  150  and the bridge  781  can be part of an Ethernet network and these devices interface over this Ethernet network. The bridge interfaces with a first lighting device  784  over a first lighting system interface  790  and the first lighting device interfaces with the second lighting device over a second lighting system interface  792 . In this example, the lighting devices can be part of a ZigBee network and the bridge  781  is able to reach the first lighting device  784  directly over the ZigBee network, yet reaches the second lighting device  786  indirectly over this network (e.g. because the second device  786  is out of reach of the radio link of the bridge  781 ). The capacity of the networked lighting system to process lighting control command depends on a multitude of factors, some of which are: the number (and/or type) of commands in the buffer  782  of the bridge  781 , the number (and/or type) of lighting control commands being dispersed over the radio channel(s) of the networked lighting system, the delay caused by the processing of the bridge  781 , the delay caused by the processing of the lighting device  784 ,  786  that has to execute the lighting control command, the delay caused by the first lighting device  784  relaying the lighting control command to the second lighting device  786 . 
         [0036]    Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. 
         [0037]    In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. 
         [0038]    A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. 
         [0039]    Any reference signs in the claims should not be construed as limiting the scope.