Patent Publication Number: US-2013241420-A1

Title: Dynamic lighting control

Description:
BACKGROUND OF THE INVENTION 
     A. Field of the Invention 
     The present subject matter relates to lighting. More particularly, the present subject matter relates to a lighting control system and method. 
     B. Description of Related Art 
     In large buildings or outdoor spaces, it is often desirable to provide a control system for the lighting in the building or outdoor space in order to reduce energy costs. Currently, lighting in an area such as a corridor or room, can be controlled by various means such as from a central location, by remote control, or by motion detection. Centrally located lighting control systems can require the integration of sensors and lighting drivers into a dedicated analogue/digital/communications system such as can be implemented by the digital addressable lighting interface (DALI) protocol. This often requires rewiring of a facility, which can be time-consuming, disruptive to operations, and expensive. Additionally, once the lighting control system is installed, commissioning and maintenance are required, and this can be expensive and involves special expertise. Moreover, the lighting control may not be automatic and requires input in order to control the luminosity in a room. Further, although wireless communication systems can be installed, the lighting control is still not automatic. 
     Additionally, lighting in an area can be controlled by a remote control, but this requires user input as well, and is also not automatic. Thus, energy savings are not likely to be great. Motion sensors can also be used to control lighting in an area to save energy, but such a system can be characterized by abrupt on and off cycles that do not provide continuous light to an area where a user is present, such as when the user is at the border of the detection area of one of the motion sensors. Therefore, while the use of a centrally located lighting control system, a remote lighting control system, or motion detector system can provide for some energy savings, a lighting control system that is more energy efficient, that does not require total rewiring of an area, that does not require expensive maintenance, and that does not have abrupt on and off cycles would be beneficial. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
     One exemplary aspect of the present disclosure is directed to a lighting system for controlling illumination of a first area and a second area. The lighting system can include a first lighting fixture located at (or in) the first area. The first lighting fixture can include a first sensor and a controller. The first sensor can be configured to detect the presence of a user in the first area. The lighting system can also comprise a second lighting fixture located at (or in) the second area and a communication circuit configured to provide for communication between the first lighting fixture and the second lighting fixture. Upon detection of the presence of a user in the first area the controller can be configured to illuminate the first lighting fixture and send a signal to trigger illumination of the second lighting fixture. 
     Another exemplary aspect of the present disclosure is directed to a method for controlling illumination of a first lighting fixture and a second lighting fixture. The method includes monitoring for the presence of a user in a first detection area with a first sensor. Upon detection of the presence of a user in the first detection area by the first sensor, the method includes illuminating the first lighting fixture, and sending a signal from the first lighting fixture to the second lighting fixture to trigger the illumination of the second lighting fixture. 
     A further exemplary aspect of the present disclosure is directed to a lighting fixture. The lighting fixture can include a lighting source, a sensor configured to detect the presence of a user in a detection area, and a controller. Upon detection of a user in the detection area, the controller can be configured to illuminate the lighting source and generate a signal to trigger the illumination of a second lighting fixture. 
     Variations and modifications can be made to these exemplary embodiments of the present disclosure. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  is a block diagram of a lighting fixture of a lighting control system according to an exemplary embodiment of the present disclosure; 
         FIG. 2  is a block diagram of a lighting fixture of a lighting control system according to an exemplary embodiment of the present disclosure; 
         FIG. 3  is a flow chart of a method for controlling illumination of a plurality of lighting fixtures according to an exemplary embodiment of the present disclosure; 
         FIG. 4  is a side view of a lighting system based on a first occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 5  is a side view of a lighting system based on a second occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 6  is a side view of a lighting system based on a third occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 7  is a top view of a lighting system based on a first occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 8  is a top view of a lighting system based on a second occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 9  is a top view of a lighting system based on a third occupancy scenario according to an exemplary embodiment of the present disclosure; 
         FIG. 10  is a top view of a lighting system based on a fourth occupancy scenario according to an exemplary embodiment of the present disclosure; and 
         FIG. 11  is a top view of a lighting system based on a fifth occupancy scenario according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     Generally, the present disclosure relates to an occupancy or motion-based dynamic lighting control system and method. The system can include at least two lighting fixtures that can communicate with each other over a wireless communication channel and/or network using infrared, BLUETOOTH®, or similar forms of wireless transmission and reception. Such an integrated design can be simple and low cost without the need for a central control system. The design can also be expandable without limit, does not require new wiring or device commissioning, allows for automatic power saving in large rooms or outdoors, and provides for maximum user comfort, without rapid switch on and off cycles that can be disturbing to a user. 
       FIG. 1  depicts a lighting fixture  100  that can be used as part of a lighting system for dynamic lighting control according to an exemplary embodiment of the present disclosure. The lighting fixture  100  has a lighting source  150 , a sensor  200 , a ballast  250 , a controller  255 , a signal generator  300 , and a signal receiver  350 . The signal generator  300  and signal receiver  350  can each be a part of a communication circuit with nearby lighting fixtures (not shown). The lighting source  150 , for example, can be instant on and can be a fluorescent tube, a white light emitting diode (LED), an LED array that combines white and red LEDs, a combination of fluorescent tubes and LEDs. The lighting fixture could also include other suitable lighting sources, such as high intensity discharge lamps, including ceramic metal halide lamps, or any other suitable lighting source. 
     The sensor  200  is used to determine if a user is located in a detection area corresponding to the sensor so that the illumination of the lighting source can be triggered or initiated. The sensor  200  can be a motion sensor or an occupancy sensor. Motion sensors respond to walking or other movements. Motion sensors can perceive movements in the selected detection zone and respond to them. A lighting source  150  can be controlled to turn on upon detection of movement by the motion sensor. The lighting source  150  can be controlled switches that turn off after no movement is detected for a period of time. The use of motion detectors or sensors can be preferable for detecting moving objects outdoors or in corridors indoors, where there is more likely to be constant movement that is detected. 
     The sensor  200  can also be an occupancy sensor. Occupancy sensors detect the presence of a user in an area instead of detecting movements. Thus, occupancy sensors can be more effective in areas such as offices where the user is more sedentary, as opposed to areas such as corridors where more movement is occurring. Numerous types of occupancy sensors exist, including passive infrared (PIR) occupancy sensors, active ultrasonic occupancy sensors, dual-technology passive infrared and active ultrasonic occupancy sensors, dual-technology passive infrared and microphonic occupancy sensors, and other suitable sensors. A technical effects associated with embodiments of the invention is that such an arrangement provides sufficient illumination but can save significant energy because remote areas are not lit. Another technical effect is that when the user moves through a space having multiple lighting fixtures that detect the user&#39;s presence and/or movement and communicate with each other, the lit area can follow the user. 
     The lighting fixture  100  can also include a ballast  250  to regulate the power provided to the lighting source  150 . In general, ballasts stabilize the current through an electrical load to provide the proper power to the lighting source. The ballast  250  can be used to ensure the proper current is provided to power fluorescent lamps, high-intensity discharge lamps, or other lamps used as lighting source  150 . 
     Controller  255  control illumination of the lighting fixture through control of the ballast. Upon receipt of a signal from the sensor  200  indicating the presence of a user in a detection area, the controller  255  can send a signal to the ballast  250  and/or lighting source  150  to trigger illumination of the lighting source  150 . The controller  255  can be any suitable control device, such as a microcontroller, processor, control circuit, or other suitable control device. 
     As shown in  FIG. 1 , the lighting fixture  100  can also include a communication circuit  375 . The communication circuit  375  can include a signal generator  300  and a signal receiver  350 . The signal generator  300  can be its own, dedicated component and can be used to send a signal to a second lighting fixture to trigger the illumination of the second lighting fixture. In particular, the controller  255 , which illuminates the lighting fixture  100  upon the detection of the presence of a user by the sensor  100 , can also control the signal generator to send a signal to a nearby second lighting fixture to trigger its illumination. The signal generator  300  can send an optical, infrared, ultrasonic, radio frequency, or hard-wired signal to the second lighting fixture. The signal receiver  350  of  FIG. 1  is used to receive signals generated from signal generators associated with other lighting fixtures in the area. Upon receipt of a signal from another lighting fixture, the controller  255  can illuminate the lighting source  150 . 
       FIG. 2  depicts a lighting fixture according to another embodiment of the present disclosure. The lighting fixture depicted in  FIG. 2  is similar to the lighting fixture of  FIG. 1 . In the embodiment of  FIG. 2 , however, the signal generator that is part of communication circuit  375  is not a dedicated device as described in  FIG. 1 . Rather, the signal generator includes modulated lighting source signal generator  400 . The modulated lighting source signal generator  400  is configured to modulate the light emitted from the lighting source  150  at a specified frequency. Preferably, the specified frequency is beyond a frequency modulation detectable by a human eye, such as greater than about 50 Hz. A second lighting fixture is configured to detect the modulated light from the first lighting fixture and trigger the illumination of a second lighting fixture based on the modulated light. In this manner, the lighting control system does not required dedicated communication devices for sending signals between fixtures. 
       FIG. 3  depicts a flow chart of an exemplary method  300  for dynamically controlling lighting in an indoor or outdoor space through use of a lighting system that covers at least two areas and has at least two lighting fixtures. The method involves controlling the lighting by monitoring for the presence of a user in a first area ( 302 ) using a sensor. If a user is not detected as present in the first area ( 304 ), the system continues monitoring for the presence of a user in the first area ( 302 ) until a user is detected. If a user is detected as present in the first area ( 304 ), the first lighting fixture is illuminated ( 306 ) via a controller associated with the first lighting fixture. Next, a signal is generated to illuminate the second lighting fixture ( 308 ), and this signal is then transmitted to the second lighting fixture ( 310 ) via a communication circuit. The signal can then be received by the second lighting fixture ( 312 ), and then the second lighting fixture is illuminated ( 314 ) via its controller. The method can also include monitoring for the presence of a user in a second area with a second sensor in the same manner as described above for monitoring the first area. 
     An exemplary illustration of the operation of a lighting system will now be discussed with reference to  FIGS. 4-11 .  FIGS. 4-6  represent side views of a lighting system that includes three lighting fixtures  101 ,  102 , and  103  based on three different occupancy scenarios as a user progresses through a space, which could be a hallway, office or outdoor space, for example. Based on the logic shown below in Table 1, a lighting fixture can be illuminated based on the detection of a user in various areas: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Control Logic 
               
            
           
           
               
               
               
            
               
                   
                 Input 
                 Output 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Neighbor 
                 Signal to 
                 Lighting Fixture 
               
               
                 Scenario 
                 Sensor 
                 Detection 
                 Neighbor 
                 Status 
               
               
                   
               
               
                 1 
                 ON 
                 OFF 
                 ON 
                 ON 
               
               
                 2 
                 OFF 
                 ON 
                 OFF 
                 ON 
               
               
                 3 
                 OFF 
                 OFF 
                 OFF 
                 OFF 
               
               
                 4 
                 ON 
                 ON 
                 ON 
                 ON 
               
               
                   
               
            
           
         
       
     
     For example, in scenario 1, if a lighting fixture&#39;s sensor detects a user in the view angle of the sensor, the sensor is “on.” Because the sensor is “on,” the lighting fixture status output is “on,” indicating the lighting fixture is illuminated. Because the sensor is on, a signal is also sent to a neighboring or nearby lighting fixture, as shown by the signal to neighbor output being “on.” The signal is sent to the neighboring area&#39;s lighting fixture via a communication circuit so that the lighting fixture in the nearby area can then be illuminated by its controller. Additionally, as shown by the neighbor detection input being “off,” a user is not present in a nearby or neighboring area. 
     In scenario 2, if a sensor does not detect a user in the detection area or view angle area below its lighting fixture, the sensor input will be “off” and it will not send a signal to a neighboring lighting fixture. Thus, the signal to neighbor input is also “off”. However, if the neighboring lighting fixture&#39;s sensor detects a user in the neighboring area, the lighting fixture is still illuminated or turned on, as shown by the neighbor detection input being “on” and the lighting fixture status being “on.” Thus, as shown in scenarios  1  and  2  above, there are at least two ways in which a single lighting fixture can be illuminated: (1) by a neighboring lighting fixture detecting a user in its area and sending a signal to the lighting fixture and (2) the lighting fixture detecting a user in its own area, triggering illumination. 
     Meanwhile, scenario 3 shows that if a sensor does not detect a user in the lighting fixture&#39;s detection area, as shown by the sensor being “off,” the lighting fixture will not be illuminated and no signal will be sent to a neighboring lighting fixture, as shown by the neighbor detection input being “off”. Additionally, if there is no neighboring lighting fixture that detects a user in its area, as shown by the neighbor detection input being “off,” then the lighting fixture will remain “off.” 
     Lastly, scenario 4 shows the situation where a lighting fixture&#39;s sensor detects a user in its area, as shown by the sensor being “on,” so that the lighting fixture is sending a signal to a neighboring or nearby lighting fixture, as shown by the signal to neighbor output being “on.” Additionally, the lighting fixture is receiving a signal from a nearby lighting fixture that a user is present in the neighboring lighting fixture&#39;s detection area, as shown by the neighbor detection input being “on.” In this scenario where a user is detected in the detection area of the lighting fixture and a user is detected in a neighboring area, the lighting fixture is illuminated, as shown by the lighting fixture status output being “on.” 
     In one embodiment, the logic in Table 1, and/or modifications and/or equivalents thereof, may be stored in a computer-readable medium in the form of computer-readable instructions that when executed by a processor cause one or more of the steps  302 ,  304 ,  306 ,  308 ,  310 ,  312  and  314  ( FIG. 3 ) to be performed by one or more lighting fixtures  100  ( FIG. 1 ). 
     Turning to  FIG. 4 , the logic of Table 1 above can be applied to an everyday situation of walking in a room or outdoor space. In  FIG. 4 , three lighting fixtures are shown,  101 - 103 . Although it appears in  FIG. 4  that the lighting fixtures are adjacent to each other, they can be spaced apart or across the room from each other so long as the signals generated from each lighting fixture can be received by the other lighting fixtures via a communication circuit. As shown in  FIG. 4 , a user  900  is present within the view angle (or detection area)  1001  of the sensor associated with lighting fixture  101 . Thus, the sensor associated with lighting fixture  101  detects a user and is “on,” meaning the controller associated with lighting fixture  101  triggers the illumination of its lighting source. Because no user  900  is present within the view angle (or detection area)  1002  of the sensor associated with lighting fixture  102  or the view angle (or detection area) of  1003  of the sensor associated with lighting fixture  103 , the sensors that would be used detect the presence of a user to illuminate lighting fixture  102  and lighting fixture  103  are “off.” Thus, only lighting fixture  101  is illuminated or “on” due to the presence of a user in the area associated with the lighting fixture. However, lighting fixture  102  is illuminated as well, due to the presence of user  900  in its neighbor&#39;s area, namely the area associated with lighting fixture  101 , as shown in  FIG. 4  where lighting fixture  102  neighbor detection is “on.” 
     Although it is possible to have communication with more than one lighting fixture, as will be shown in subsequent figures, lighting fixture  101  is only configured to communicate with lighting fixture  102 , not lighting fixture  103 . Because a user  900  is present in the area associated with lighting fixture  101 , the signal generator (not shown) associated with lighting fixture  101  is activated by its controller so that it generates a signal  950 . This signal  950  triggers the illumination of its neighboring lighting fixture  102 , which receives the signal  950  sent by lighting fixture  101 . The controller associated with neighboring lighting fixture  102  then turns on or activates its lighting source. Because a lighting fixture configured to communicate with lighting fixture  103  has not detected a user in order to trigger the generation and sending of a signal to lighting fixture  103 , nor has lighting fixture  103  detected a user in its detection area lighting fixture  103  remains switched off. Note that although the term “switched off” can mean that the lighting fixture is turned off or unlit, it can also mean that the lighting fixture is on, but in a dimmed lighting state. 
       FIG. 5  shows a side view of a lighting system based on a second occupancy scenario. Now, the user  900  is standing under lighting fixture  102 , which corresponds to sensor detection area or view angle  1002 . Because the sensor associated with lighting fixture  102  has detected a user in its detection area, the controller associated with lighting fixture  102  triggers the illumination of its lighting source. Note that a user  900  is not present in view angle/detection area  1001  or view angle/detection area  1003 , so lighting fixtures  101  and  103  are not illuminated based on the presence of a user  900  in their respective detection areas. The sensor associated with lighting fixture  102  is on, however, due to the presence of user  900  in detection area or view angle  1002 . Thus, the controller associated with lighting fixture  102  initiates the generation of a signal  950  that is sent to lighting fixture  101 , while signal  952  is generated and sent to lighting fixture  103 , as both lighting fixtures  101  and  103  are configured to communicate with lighting fixture  102  via a communication circuit. Although neither sensor associated with lighting fixture  101  or  103  is on because no user is present in their view angles of  1001  and  1003 , respectively, the signals  950  and  952  sent from lighting fixture  102  trigger the illumination of both lighting fixtures  101  and  103 . Thus, the user  900  is surrounded by light on each side of the lighting fixture  102  under which the user stands, which provides for a comfortable environment, while also saving energy, as nearby lighting fixtures not configured to communicate with lighting fixture  102  remain off or unlit. 
     Next,  FIG. 6  shows a side view of a lighting system as the user  900  has progressed farther to the right in the space. Now, user  900  is standing under lighting fixture  103 , within view angle/detection area  1003 , so that the sensor associated with lighting fixture  103  detects the user  900 &#39;s presence, thus illuminating lighting fixture  103  via its controller. Additionally, lighting fixture  103  is configured to communicate via a communication circuit with lighting fixture  102 . Thus, the controller associated with lighting fixture  103  triggers the generation and sending of a signal  950  via the communication circuit to trigger the illumination of lighting fixture  102  by its controller. Note that lighting fixture  101  is not illuminated because it has not received a signal from lighting fixture  103  as they are not configured to communicate with each other via a communication circuit. It could be possible, however, to transmit a signal from lighting fixture  103  to lighting fixture  101  if desired. 
       FIGS. 7 ,  8 ,  9 ,  10  and  11  show a progression of illuminated lighting fixtures as a user  900  moves from left to right across a room, corridor, or outdoor space.  FIG. 7  is a top view of a lighting system based on a first occupancy scenario where the user  900  is farthest to the left of the space. The user  900  is standing under lighting fixture  102 , which is configured to communicate via a communication circuit that can generate and send signals to lighting fixture  101  above, lighting fixture  105  to the right, and lighting fixture  103  below. Once the user  900  is detected by the sensor (not shown) associated with lighting fixture  102 , lighting fixture  102  is illuminated via its controller. The controller then triggers the communication circuit to generate a signal to nearby or neighboring lighting fixtures that are configured to communicate with lighting fixture  102  via the circuit. Thus, signal  950  is sent to lighting fixture  101 , signal  951  is sent to lighting fixture  105 , and signal  952  is sent to lighting fixture  103 . Once these signals  950 ,  951 , and  952  are received, the lighting fixtures associated with them are illuminated via their respective controllers. This provides for a well-lit space around user  900  as he travels across the space, while at the same time saving energy, as lighting fixtures  104  and  106 - 115  in the room remain off or dimmed. 
     Next,  FIG. 8  is a top view of a lighting system based on a second occupancy scenario. Now, the user has traveled further into the space (to the viewer&#39;s right in  FIG. 8 ), and the lighting fixture  105  under which the user stands is configured to communicate with neighboring lighting fixture  102  to its left, neighboring lighting fixture  104  above, neighboring lighting fixture  108  to its right, and neighboring lighting fixture  106  below. Once the sensor associated with lighting fixture  105  detects the user  900 , lighting fixture  105  is illuminated via its controller. The controllerthen triggers the communication circuit to generate and send signals to the nearby or neighboring lighting fixtures that have been configured to communicate with lighting fixture  105 . Thus, signal  953  is sent to lighting fixture  102 , signal  954  is sent to lighting fixture  104 , signal  955  is sent to lighting fixture  108 , and signal  956  is sent to lighting fixture  106 . Once signals  953 ,  954 ,  955 , and  956  are received, the lighting fixtures associated with them are illuminated via their respective controllers, although no user  900  is detected in their sensors&#39; view angles/detection areas. Again, this provides for a well-lit space around user  900  as he/she travels across the space, while at the same time saving energy, as lighting fixtures  101 ,  103 ,  107 , and  109 ,  110 ,  111 ,  112 ,  113 ,  114  and  115  in the room remain unlit, switched off, or dimmed. 
       FIG. 9  is similar to  FIGS. 7-8  described above, although the user  900  has moved to the right and down one area in the space. The lighting fixture  109  under which he stands is configured to communicate with lighting fixture  106  to the left, lighting fixture  108  above, and lighting fixture  112  to the right. Once the user  900  is detected by the sensor associated with lighting fixture  109 , lighting fixture  109  is illuminated via its controller. The controller then triggers lighting fixture  109 &#39;s communication circuit to generate and send signals to the nearby or neighboring lighting fixtures that have been configured to communicate with lighting fixture  109 . Thus, signal  957  is sent to lighting fixture  108 , signal  958  is sent to lighting fixture  112 , and signal  959  is sent to lighting fixture  106 . Once signals  957 ,  958 , and  959  are received, the lighting fixtures associated with them are illuminated via their respective controllers, although no user  900  is detected in their sensors&#39; view angles/detection areas. Again, this provides for a well-lit space around user  900  as he travels across the space, while at the same time saving energy, as lighting fixtures  101 - 105 ,  107 ,  110 - 111 , and  113 - 115  in the room remain unlit, switched off, or dimmed. 
       FIG. 10  represents a top view of a lighting system based on a fourth occupancy scenario. The user  900  has now moved to the right and up once space compared to  FIG. 9 . The lighting fixture  111  under which the user stands is configured to communicate with neighboring lighting fixture  108  to the left, neighboring lighting fixture  110  above, neighboring lighting fixture  114  to the right, and neighboring lighting fixture  112  below. Once the user  900  is detected by the sensor associated with lighting fixture  111 , lighting fixture  111  is illuminated via its controller. The controller then triggers lighting fixture  111 &#39;s communication circuit to generate and send signals to the nearby or neighboring lighting fixtures that have been configured to communicate with lighting fixture  111 . Thus, signal  960  is sent to lighting fixture  110 , signal  961  is sent to lighting fixture  114 , signal  962  is sent to lighting fixture  112 , and signal  963  is sent to lighting fixture  108 . Once signals  960 ,  961 ,  962 , and  963  are received, the lighting fixtures associated with them are illuminated via their respective controllers, although no user  900  is detected in their sensors&#39; view angles/detection areas. Again, this provides for a well-lit space around user  900  as he/she travels across the space, while at the same time saving energy, as lighting fixtures  101 - 107 ,  109 ,  113 , and  115  in the room remain unlit, switched off, or dimmed. 
       FIG. 11  is a top view of a lighting system based on a fifth occupancy scenario where user  900  has moved to the right one space. The lighting fixture  114  under which he stands is configured to communicate with lighting fixture  111  to the left, lighting fixture  113  above, and lighting fixture  115  below. Once the user  900  is detected by the sensor associated with lighting fixture  114 , lighting fixture  114  is illuminated via its controller. The controller then triggers the communication circuit associated with lighting fixture  114  to generate and send signals to the nearby or neighboring lighting fixtures that have been configured to communicate with lighting fixture  114  via the circuit. Thus, signal  964  is sent to lighting fixture  113 , signal  965  is sent to lighting fixture  115 , and signal  966  is sent to lighting fixture  111 . Once signals  964 ,  965 , and  966  are received, the lighting fixtures associated with them are illuminated via their respective controllers, although no user  900  is detected in their sensors&#39; view angles/detection areas. Again, this provides for a well-lit space around user  900  as he travels across the space, while at the same time saving energy, as lighting fixtures  101 - 110  and  112  in the room remain unlit, switched off, or dimmed. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.