Abstract:
In one aspect of an embodiment for controlling operation of a light source, a method of associating a light source with an area for which the light source is positioned to provide lighting comprises: identifying, based on a determined physical position of a light source, one of a plurality of areas as the area for which the light source is positioned to provide lighting; identifying at least one desired lighting condition for the identified area; and controlling, using a processor, operation of the light source based on the identified at least one desired lighting condition for the identified area.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority benefit to U.S. Provisional Patent Application No. 61/669,319 filed Jul. 9, 2012, the contents of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The embodiments disclosed herein relate in general to a light emitting diode (LED)-based light for replacing a conventional light in a standard light fixture, and in particular to a lighting control system for controlling the operation of an LED-based light. 
     BACKGROUND 
     Fluorescent lights are widely used in a variety of locations, such as schools and office buildings. Although conventional fluorescent lights have certain advantages over, for example, incandescent lights, they also pose certain disadvantages including, inter alia, disposal problems due to the presence of toxic materials within the light. 
     LED-based lights designed as one-for-one replacements for fluorescent lights have appeared in recent years. LED-based lights can be used in a building with a control system capable of managing various aspects of the building, including its lighting conditions. A lighting control system can be designed to regulate the lighting conditions in a building through selective control of the operation of LED-based lights, in order to, for example, improve usability of the building or to optimize its energy use. Some of these lighting control systems can remotely regulate individual lighting conditions of multiple different areas within the building. Such individualized regulation requires some form of association between each LED-based light and the particular area in which the LED-based light is positioned to illuminate. Association can entail, for example, manually assigning an LED-based light positioned to illuminate a particular area with a logical address designated within the lighting control system to correspond to that area. Once associated, the lighting control system can correctly control operation of an LED-based light based upon the desired lighting conditions for its respective area. 
     SUMMARY 
     Disclosed herein are embodiments of methods and systems for controlling operation of a light source. In one aspect, a method of associating a light source with an area for which the light source is positioned to provide lighting comprises: identifying, based on a determined physical position of a light source, one of a plurality of areas as the area for which the light source is positioned to provide lighting; identifying at least one desired lighting condition for the identified area; and controlling, using a processor, operation of the light source based on the identified at least one desired lighting condition for the identified area. 
     In another aspect, alighting control system comprises: a light source positioned to provide lighting for an area; and a control unit configured to: identify, based on a determined physical position of the light source, one of a plurality of areas as the area for which the light source is positioned to provide lighting, identify at least one desired lighting condition for the identified area, and control operation of the light source based on the identified at least one desired lighting condition for the identified area. 
     In yet another aspect, a method of selecting a lighting condition for controlling operation of a light source comprises: storing, in memory, a plurality of position-dependent lighting conditions; and selecting, using a processor in communication with the memory, one of the position-dependent lighting conditions for controlling operation of the light source based on a determined physical position of the light source, such that the operation of the light source is controlled based on the selected position-dependent lighting condition. 
     These and other aspects will be described in additional detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various features, advantages and other uses of the present system and methods will become more apparent by referring to the following detailed description and drawings in which: 
         FIG. 1  is a system view of a lighting control system configured to control operation of an LED-based light; 
         FIG. 2  is a flow chart illustrating a process including operations for installing and associating the LED-based light of  FIG. 1  within the lighting control system; 
         FIG. 3  is an exploded perspective view of an example of an LED-based light for use in the lighting control system of  FIG. 1 ; and 
         FIG. 4  is an exploded perspective view of an alternative example of an LED-based light for use in the lighting control system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Manual association between an LED-based light and the particular area in which the LED-based light is positioned to illuminate can be time consuming and error-prone. Further, associations can be broken if a logically addressable LED-based light is moved and/or replaced during service, which can cause incorrect control over the operation of the LED-based light. 
     Disclosed herein are example configurations of a lighting control system for a building that can use information relating to the position of an LED-based light to associate the LED-based light with a particular area for purposes of regulating the lighting conditions for that area. Further disclosed herein are exemplary configurations of a control system that can reduce the amount of user input required to determine the information relating to the position of the LED-based light. 
     A building can include systems for managing various aspects of the building. These aspects can generally include the environmental conditions of the building, such as heating, ventilation and air conditioning (HVAC) conditions, security conditions and/or lighting conditions, for example. A “smart” building can include a control system, such as a building automation system, that can automatically manage the environmental conditions of the building in accordance with desired environmental conditions. Such buildings can include one or more areas located throughout the building, with each area lending itself to individualized regulation of one or more of its environmental conditions. 
     A representative building  10  including a building automation system implementing a lighting control system  12  for regulating the lighting conditions of multiple areas  14  throughout the building  10  is shown in  FIG. 1 . The terms “building” and “building automation system” are used herein to describe the lighting control system  12  with reference to a representative setting in which the lighting control system  12  can be implemented. However, the lighting control system  12  could be implemented in other settings, such as outdoors, for example, or in other settings in which a number of different areas  14  lending themselves to individualized regulation with respect to their lighting conditions can be defined. 
     Regulation of the environmental conditions of the multiple areas  14  located throughout the building  10  can include a process of defining the areas  14  to be controlled. Each area  14 , as it relates to individualized regulation of its environmental conditions, can correspond to some characteristic of the building  10  or its contents, or can correspond to some characteristic of the defined area  14 . With respect to regulation of lighting conditions with the lighting control system  12 , for example, the area  14  could be defined as an individual room or group of rooms located within the building  10 . The area  14  could additionally or alternatively be defined in terms of its physical surroundings, such as an area adjacent to source of light extrinsic to the lighting control system  12 , for instance a window supplying natural light. The area  14  could also be defined in relation to its particular functional considerations and/or constraints with respect to lighting conditions. For example, the area  14  could be defined above a workstation, or the area  14  could correspond to a particular type of room within the building  10 , such as an office, a conference room, a hallway or a bathroom, for example. Similarly, the area  14  could be defined in relation to its particular requirements with respect to lighting conditions, which could involve requirements of performance lighting, efficient lighting, safety lighting, comfort lighting and/or alarm lighting, for example. As a non-limiting example, an area  14 A could be an individual room located within the building  10 , an area  14 B could be located adjacent an east facing window receiving natural light and thereby requiring less artificial light from the lighting control system  12 , and an area  14 C could be located adjacent a desk or other workstation. 
     An area  14  could be one discrete individual location within the building  10 , or could comprise some grouping of locations lending themselves to similar regulation of their environmental conditions. A building  10  could include a single area  14  or multiple areas  14 , and each area  14  of a building  10  need not be defined according to an approach used to define another area  14  of the building  10 . The building  10  can include more or less than the illustrated areas  14 A,  14 B and  14 C, and the building  10  can include alternative and/or additional areas  14  depending upon which of a variety of environmental conditions is regulated. That is, with respect to regulation of environmental conditions other than lighting conditions, areas  14  could be defined within the building  10  other than as the areas  14 A,  14 B and  14 C described above, and alternative and/or additional areas  14  could be defined for purposes of individualized regulation of the various other environmental conditions. 
     A building automation system for the building  10  can implement the lighting control system  12  to individually regulate the lighting conditions for each of the areas  14  located throughout the building  10 . The illustrated lighting control system  12  may include one or more LED-based lights  16  positioned to illuminate each of the areas. The lighting conditions for the area  14  in which an LED-based light  16  is positioned can be regulated through selective control of the operation the LED-based light  16 . For ease of understanding, the lighting control system  12  is generally described below with reference to a single LED-based light  16  positioned to illuminate a singular area  14 . However, it should be understood that the lighting control system  12  can include a plurality of areas  14 A,  14 B and  14 C, each of which can include one or more respective LED-based lights  16  positioned to illuminate the areas  14 A,  14 B and  14 C. 
     The lighting control system  12  includes one or more devices for controlling the operation of the LED-based light  16 . In a basic lighting system, operation of an LED-based light  16  could be controlled by electrically connecting a device such as a light switch, dimmer or other similar operator actuated device between the LED-based light  16  and a power supply. These devices control operation of the LED-based light  16  by regulating a supply of AC or DC electrical power to the LED-based light  16 . For example, a supply of electrical power to the LED-based light  16  can be selectively switched to control an on/off function of the LED-based light  16 , and a supply of electrical power to the LED-based light  16  can be selectively modulated to control a dimming function of the LED-based light  16 . 
     The illustrated implementation of the lighting control system  12  includes a control unit  20  configured to control the operation of the LED-based light  16  by selectively controlling a supply of electrical power to the LED-based light  16 . The control unit  20  can be or include one or more controllers configured for controlling the operation of multiple LED-based lights  16  positioned in different areas  14  located throughout the building  10 . A controller could be a programmable controller, such as a microcomputer including a random access memory (RAM), a read-only memory (ROM) and a central processing unit (CPU) in addition to various input and output connections. Generally, the control functions described herein can be implemented by one or more software programs stored in internal or external memory and are performed by execution by the CPU. However, some or all of the functions could also be implemented by hardware components. Although the control unit  20  is shown and described as a single central controller for performing multiple functions related to multiple areas  14 , the functions described herein could be implemented by separate controllers which collectively comprise the illustrated control unit  20 . 
     The control unit  20  can be electrically connected between the LED-based light  16  and a power supply and configured to control operation of the LED-based light  16  by directly switching and/or modulating a supply of electrical power to LED-based light  16 . Alternatively, the control unit  20  can be configured to control operation of the LED-based light  16  by indirectly controlling a supply of electrical power to the LED-based light  16 , for example by communicating a control signal α to a switching device. For example, as shown in  FIG. 1 , lighting control system  12  may include a switching unit  22  communicatively coupled to the control unit  20 . 
     The switching unit  22  is electrically connected between the LED-based light  16  and a power supply and is configured to receive the control signal α and, in response to the control signal α, selectively regulate a supply of electrical power to the LED-based light  16 . The switching unit  22  can control an on/off function of the LED-based light  16  by including a relay or other mechanical, electrical or electromechanical switch configured to selectively switch a supply of electrical power to the LED-based light  16 . The switching unit  22  can alternatively or additionally be or include components configured to selectively modulate a supply of electrical power to the LED-based light  16  to control a dimming function of the LED-based light  16 . The switching unit  22  can selectively regulate a supply of electrical power to the LED-based light  16  to control operation of the LED-based light  16  in a variety of other manners. For example, in addition to controlling on/off and dimming functions of the LED-based light  16 , the switching unit  22  can also be configured to regulate a supply of electrical power to the LED-based light  16  to achieve continuous, intermittent or other non-continuous operation of the LED-based light  16 . For example, the LED-based light  16  could be operated steadily, variably, or could be blinked, flashed or amplified according to some timed pattern by the switching unit  22 , depending upon the desired lighting conditions for the area  14  in which the LED-based light  16  is positioned to illuminate. 
     Each area  14  located throughout the building  10  can lend itself to individualized regulation of its lighting conditions in accordance with respective desired lighting conditions. The lighting control system  12  includes the control unit  20  for controlling the lighting conditions of the area  14  through selective control of the operation of the LED-based light  16  positioned to illuminate the area  14 . As described above, the control unit  20  controls the operation of the LED-based light  16  by communicating a control signal α to the switching unit  22  configured to selectively regulate a supply of electrical power to the LED-based light  16 . The control signal α generally corresponds to the desired lighting conditions for the area  14  in which the LED-based light  16  is positioned to illuminate. The control signal α can be representative of a setpoint illumination level for the area  14 , or could be representative of some other particular requirement or characteristic with respect to the desired lighting conditions for the area  14  in which the LED-based light  16  is positioned to illuminate. For example, the control signal α could be representative of a requirement for performance lighting, efficient lighting, safety lighting, comfort lighting and/or alarm lighting in the area  14 . 
     The control unit  20  is configured to determine the desired lighting conditions for the area  14  in which the LED-based light  16  is positioned to illuminate, and to generate the control signal α corresponding to the desired lighting conditions. The control unit  20  can generate the control signal α with logic implementing various algorithmic or heuristics techniques. As non-limiting examples, the control unit  20  can include logic implementing timers, alarms, and/or rules relating to occupancy sensing, daylight harvesting or manual override control. 
     The lighting control system  12  can further include one or more input devices  24  corresponding to each of the areas  14 . The input devices  24  are configured to relay information relating to the actual or desired lighting conditions and/or other environmental conditions of the area  14  to the control unit  20 . The lighting control system  12  can utilize the information from an input device  24  for purposes of individualized regulation of the lighting conditions for its area  14 . The input devices  24  are configured to generate one or more input signals β. The input devices  24  are communicatively coupled to the control unit  20 , and the logic of the control unit  20  can be responsive to the input signals β to generate the control signal α for communication to the switching unit  22 . 
     The illustrated input devices  24  can include a user interface  26  and various sensors  28 . The user interface  26  is configured to receive information from a user of the building  10  relating to requested lighting conditions for the area  14  to which the user interface  26  corresponds, and to generate corresponding input signals β for communication to the control unit  20 . The user interface  26  can be or include a switch, dimmer or other user actuated device. The user interface  26  could also include a web-based or similar computer-based component for receiving information relating to requested lighting conditions for an area  14 . 
     The lighting control system  12  can incorporate the input signals β communicated from the user interface  26  to varying degrees as compared to input signals β communicated from other input devices  24 . For example, the lighting control system  12  could give priority to the user interface  26  by providing for manual override control of the operation of the LED-based light  16  on the basis of a user&#39;s actuation of the user interface  26 . In this example, the control unit  20  could include logic for generating a control signal α directing the switching unit  22  to regulate a supply of electrical power to the LED-based light  16  in direct accordance with an operator&#39;s requested lighting conditions. Alternatively, the lighting control system  12  could be arranged such that a supply of electrical power to LED-based light  16  is regulated directly by the user interface  26  in accordance with an operator&#39;s requested lighting conditions without regard to a control signal α generated by the control unit  20 . 
     The sensors  28  may be configured for measuring, monitoring and/or estimating various environmental conditions within a corresponding area  14  and for generating corresponding input signals β for communication to the control unit  20 . Sensors  28  can include, for example, a sensor for measuring the actual lighting conditions of the area  14 , or sensors  28  could include a sensor for monitoring or estimating occupancy of the area  14 . The sensors  28  could include a motion sensor, a voice-activated sensor or a clock or calendar, for example. Similar to the input signals β from the user interface  26 , the input signals β from the sensors  28  can be incorporated into the logic of the control unit  20  for generation of the control signal α. 
     An exemplary communications link  40  is included in the lighting control system  12  for communicatively coupling the components of the lighting control system  12 . The communications link  40  may generally be configured to support digital and/or analog communication between the components included in the lighting control system  12 . For example, the communications link  40  may be configured to communicatively couple the control unit  20 , the switching unit  22  and the input devices  24 . The communications link  40  can include wired and/or wireless communications channels using any industry standard or proprietary protocols. As a non-limiting example, a wired communications link  40  could be implemented with 0-10V signals, DALI or Ethernet. As a further non-limiting example, a wireless communications link  40  could be implemented, for example, with wireless DALI, IEEE 802.11, Wi-Fi, Bluetooth or RF channels, or through infrared, ultrasonic or modulated visible light, such as light emitted from the LED-based lights  16 . Further, the communications link  40  could be implemented with multiple communications channels, each using differing protocols. 
     The illustrated lighting control system  12  can provide localized regulation of the lighting conditions for multiple different areas  14  with the control unit  20  by selectively controlling the operation of the respective LED-based lights  16  positioned to illuminate the respective areas  14 . The control unit  20  can determine differing desired lighting conditions for each of the areas  14 . For example, the desired lighting conditions for area  14 A could necessitate that the LED-based light  16  positioned to illuminate area  14 A be controlled to an on state, the desired lighting conditions for area  14 B could necessitate that the LED-based light  16  positioned to illuminate area  14 B be controlled to an off state, and the desired lighting conditions for area  14 C could necessitate that the LED-based light  16  positioned to illuminate area  14 C be controlled to a modulated state. 
     In order for the lighting control system  12  to efficiently regulate the lighting conditions in multiple areas  14 , the lighting control system  12  may be configured to control the LED-based light  16  positioned to illuminate a particular area  14  without affecting the operation of LED-based lights  16  positioned to illuminate other areas  14 . Proper functioning of the lighting control system  12  generally requires some association between each LED-based light  16  and the area  14  in which the LED-based light  16  is positioned to illuminate. Association can entail, for example, manually landing wires between terminals of the control unit  20  and switching units  22  and/or corresponding LED-based lights  16 . Alternatively, association could entail manually assigning a switching unit  22  and/or corresponding LED-based light  16  with a logical address designated within the lighting control system  12 , for example within the logic of the control unit  20 , to correspond to a particular area  14 . Once associated, the lighting control system  12  can control operation of an LED-based light  16  to regulate the lighting conditions for its respective area  14  according to its desired lighting conditions. 
     The illustrated lighting control system  12  may include a plurality of communications units  42  configured to receive information relating to the position of an LED-based light  16  within the building  10 . The lighting control system  12  is configured to use the information relating to the position of the LED-based light  16  within the building  10  to associate the LED-based light  16  with the area  14  in which the LED-based light  16  is positioned to illuminate. For example, the lighting control system  12  can be configured to compare the position of an LED-based light  16  with known or determined positions of the areas  14  located throughout the building  10 . The lighting control system  12  can then correlate the position of the LED-based light  16  with a particular area  14  in which the LED-based light  16  is positioned to illuminate. Once a correlation is drawn between a particular LED-based light  16  and the area  14  in which the LED-based light  16  is positioned to illuminate, the lighting control system  12  can associate the LED-based light  16  to the area  14  for purposes of future regulation of the lighting conditions for that area  14 . 
     The communications units  42  may be communicatively coupled to the lighting control system  12  through one or more communications channels that can be included in the communications link  40 . As shown in  FIG. 1 , the communications units  42  may be communicatively coupled to the switching units  22 . Each of the communications units  42  may include a communications device  44  configured to receive a location signal γ from a communications device  46  included in the switching units  22 . The communications devices  44  and  46  can be configured for communication through a communications channel implemented to communicatively couple the communications units  42  and the switching units  22 , and the communications channel need not be the same as used elsewhere in the communication link  40 . For example, an existing building automation system for the building  10  may already include wired communications channels for communicatively coupling the control unit  20 , the switching unit  22  and the input devices  24 . The building automation system for the building  10  could be retrofitted to implement the lighting control system  12  by including a wireless communications channel configured to communicatively couple the communications units  42  to the switching units  22 . In this non-limiting example, the communications devices  44  and  46  can be the illustrated transceivers  44  and  46 . However, the communications devices  44  and  46  could be other devices known to those skilled in the art configured to send and/or receive the location signal γ over a chosen communications channel included in the communications link  40 . 
     As shown in  FIG. 1 , the communications units  42  may be communicatively coupled to switching units  22  to receive the location signal γ from the communications devices  46 . The switching units  22  including the communications devices  46  can be located adjacent to or included in corresponding LED-based lights  16 , such that the location signal γ conveys information generally relating to the position of the LED-based light  16 . Although the communications devices  46  are described with reference to the switching units  22 , the communications devices  46  could alternatively be included in the LED-based lights  16 , or could be otherwise included in the lighting control system  12  according to some known or determinable spatial relationship with the LED-based light  16 . 
     The lighting control system  12  is configured to determine, or estimate, the physical position of each of the LED-based lights  16  based at least partially upon the location signal γ. The position of an LED-based light  16  could be determined absolutely, for example, or could be determined relative to some aspect relating to the building  10  or lighting control system  12 . In the exemplary implementation of the lighting control system  12 , multiple communications units  42  form a spatially distributed network of communications units  42 . The communications units  42  can be distributed within and/or without the building  10  to form the spatially distributed network of communications units  42 . The location signal γ can be received by one or more of the communications units  42 , which can be configured to determine the position of the LED-based lights  16 , either individually, in some combination with each other, and/or in combination with the control unit  20  or other components of the lighting control system  12 . 
     The lighting control system  12  can be configured to determine the position of the LED-based light  16  using various techniques, either individually or in some combination. As non-limiting examples, the position of an LED-based light  16  can be determined based upon time of arrival (TOA) of RF, infrared or ultrasonic signals, or based upon TOA of light signals, such as visible light signals emitted from the LED-based lights  16 ; the position of an LED-based light  16  can be determined based upon direction finding (DF) of RF, infrared or ultrasonic signals, or based upon DF of light signals, such as visible light signals emitted from the LED-based lights  16 ; the position of an LED-based light  16  could be determined by superimposing currents on power lines forming a power grid, or though other branch circuit monitoring methods; or the position of an LED-based light  16  could be determined by monitoring the strength of the location signal γ throughout the spatially distributed network of communications units  42 . The position of an LED-based light  16  could also be determined through communication with components external from the lighting control system  12 , for example by using 3g or 4g signals to communicate with global positioning systems (GPSs) or other external location systems. The position of the LED-based light  16  could also be determined more accurately through some combination of the above techniques. 
     A process of installing an LED-based light  16  into the lighting control system  12  of a building  10  is illustrated in  FIG. 2 . In step S 10 , information relating to the positions of each of the areas  14  located throughout the building  10  is stored in the lighting control system  12 . The lighting control system  12  can be configured to know or determine the positions of each of the areas  14 . Similar to the positions of the LED-based lights  16 , the positions of the areas  14  could be known or determined absolutely, for example, or relative to some aspect relating to the building  10  or the lighting control system  12 . For example, the physical aspects of the building  10 , such as floor plans or power supply structures, could be stored in memory on the control unit  20 , along with information relating to the relative positions of the areas  14  within the building  10 . 
     In step S 12 , an LED-based light  16  is installed into the lighting control system  12 . In step S 14 , the LED-based light  16  joins the lighting control system  12  by communicating with the control unit  20  through the communications link  40 , and in step S 16 , the control unit  20  recognizes the LED-based light  16  as newly installed into (or newly positioned within) the lighting control system  12 . The LED-based light  16  can have a logical address readable by the control unit  20 , for example, or can be otherwise recognizable by the control unit  20  as a distinct lighting element. 
     In step S 18 , the location signal γ is communicated to the spatially distributed network of communications units  42 . The location signal γ can be communicated autonomously, for example, or at the direction of the installer or at the direction of the lighting control system  12  or control unit  20 . In step S 20 , the position of the LED-based light  16  is determined using one or more of the above described location techniques, as well as others. The logic for determining the position of the LED-based light  16  can be implemented by one or more of the communications units  42 , or can be distributed between one or more of the communications units  42  and the other components of the lighting control system  12 . The position of an LED-based light  16  could also be determined physically externally from the lighting control system  12 , for example through communication with a GPS or other location system. The position of the newly installed LED-based  16  could also be determined and/or verified with reference to one or more LED-based lights  16  whose positions are manually determined. 
     In step S 22 , the lighting control system  12  can use the determined position of the LED-based light  16  to associate the LED-based light  16  with the area  14  in which the LED-based light  16  is positioned to illuminate. For example, the lighting control system  12  can implement logic using the control unit  20  to compare the determined position of the LED-based light  16  with the known or determined positions of the areas  14  located throughout the building  10 . By correlating the determined position of the LED-based light  16  with a position of a particular area  14 , the control unit  20  can determine that the LED-based light  16  is positioned to illuminate that particular area  14 . Finally, in step S 24 , the lighting control system  12  can associate the LED-based light  16  to the area  14  within the control unit  20  for purposes of future regulation of the lighting conditions for that area  14 . 
       FIG. 3  illustrates an example of an LED-based light  116  for use in the lighting control system  12 . The LED-based light  116  is configured to replace a conventional light in a standard light fixture  110 . The light fixture  110  can be designed to accept conventional fluorescent lights, such as T5, T8 or T12 fluorescent tube lights, or can be designed to accept other standard lights, such as incandescent bulbs. The light fixture  110  could alternatively be designed to accept non-standard lights, such as lights installed by an electrician. The light fixture  110  can connect to a power supply, and can optionally include a ballast connected between the power supply and the LED-based light  116 . The switching unit  22  could be compatible with the fixture  110  to electrically connect between the power supply and the LED-based light  116 , or the switching unit  22  could be included in the fixture  110 , for example. 
     In some implementations, the LED-based light  116  includes a housing  112  at least partially defined by a high dielectric light transmitting lens  114 . The lens  114  can be made from polycarbonate, acrylic, glass or other light transmitting material (i.e., the lens  114  can be transparent or translucent). The term “lens” as used herein means a light transmitting structure, and not necessarily a structure for concentrating or diverging light. The LED-based light  116  can include features for uniformly distributing light to an environment to be illuminated in order to replicate the uniform light distribution of a conventional fluorescent light. For example, the lens  114  can be manufactured to include light diffracting structures, such as ridges, dots, bumps, dimples or other uneven surfaces formed on an interior or exterior of the lens  114 . The light diffracting structures can be formed integrally with the lens  114 , for example, by molding or extruding, or the structures can be formed in a separate manufacturing step such as surface roughening. In addition to or as an alternative to light diffracting structures, a light diffracting film can be applied to the exterior of the lens  114  or placed in the housing  112 , or, the material from which the lens  114  is formed can include light refracting particles. For example, the lens  114  can be made from a composite, such as polycarbonate, with particles of a light refracting material interspersed in the polycarbonate. In other embodiments, the LED-based light  116  may not include any light diffracting structures or film. 
     The housing  112  can include a light transmitting tube at least partially defined by the lens  114 . Alternatively, the housing  112  can be formed by attaching multiple individual parts, not all of which need be light transmitting. For example, the housing  112  can be formed in part by attaching the lens  114  to an opaque lower portion. The housing  112  can additionally include other components, such as one or more highly thermally conductive structures for enhancing heat dissipation. While the illustrated housing  112  is cylindrical, a housing having a square, triangular, polygonal, or other cross sectional shape can alternatively be used. Similarly, while the illustrated housing  112  is linear, housings having an alternative shape, e.g., a U-shape or a circular shape can alternatively be used. The LED-based light  116  can have any suitable length. For example, the LED-based light  116  may be approximately 48″ long, and the housing  112  can have a 0.625″, 1.0″ or 1.5″ diameter for engagement with a common standard fluorescent light fixture. 
     The LED-based light  116  can include an electrical connector  118  positioned at each end of the housing  112 . In the illustrated example, the electrical connector  118  is a bi-pin connector carried by an end cap  120 . A pair of end caps  120  can be attached at opposing longitudinal ends of the housing  112  for physically connecting the LED-based light  116  to a standard fluorescent light fixture  110 . The end caps  120  can be the sole physical connection between the LED-based light  116  and the fixture  110 . At least one of the end caps  120  can additionally electrically connect the LED-based light  116  to the fixture  110  to provide power to the LED-based light  116 . Each end cap  120  can include two pins  122 , although two of the total four pins can be “dummy pins” that provide physical but not electrical connection to the fixture  110 . Bi-pin electrical connector  118  is compatible with many standard fluorescent fixtures, although other types of electrical connectors can be used, such as single pin connector or screw type connector. 
     The LED-based light  116  can include a circuit board  124  supported within the housing  112 . The circuit board  124  can include at least one LED  126 , a plurality of series-connected or parallel-connected LEDs  126 , an array of LEDs  126  or any other arrangement of LEDs  126 . Each of the illustrated LEDs  126  can include a single diode or multiple diodes, such as a package of diodes producing light that appears to an ordinary observer as coming from a single source. The LEDs  126  can be surface-mount devices of a type available from Nichia, although other types of LEDs can alternatively be used. For example, the LED-based light  116  can include high-brightness semiconductor LEDs, organic light emitting diodes (OLEDs), semiconductor dies that produce light in response to current, light emitting polymers, electro-luminescent strips (EL) or the like. 
     The circuit board  124  can include power supply circuitry configured to condition an input power received from, for example, the fixture  110  through the electrical connector  118  to a power usable by and suitable for the LEDs  126 . In some implementations, the power supply circuitry can include one or more of an inrush protection circuit, a surge suppressor circuit, a noise filter circuit, a rectifier circuit, a main filter circuit, a current regulator circuit and a shunt voltage regulator circuit. The power supply circuitry can be suitably designed to receive a wide range of currents and/or voltages from a power source and convert them to a power usable by the LEDs  126 . 
     The circuit board  124  is illustrated as an elongate printed circuit board. The circuit board  124  can extend a length or a partial length of the housing  112 . Multiple circuit board sections can be joined by bridge connectors to create the circuit board  124 . The circuit board  124  can be supported within the housing  112  through slidable engagement with a part of the housing  112 , though the circuit board  124  can alternatively be clipped, adhered, snap- or friction-fit, screwed or otherwise connected to the housing  112 . Also, other types of circuit boards may be used, such as a metal core circuit board. Or, instead of the circuit board  124 , other types of electrical connections (e.g., wires) can be used to electrically connect the LEDs  126  to a power source. 
     The LEDs  126  can emit white light or light within a range of wavelengths. However, LEDs that emit blue light, ultra-violet light or other wavelengths of light can be used in place of or in combination with white light emitting LEDs  126 . The number, spacing and orientation of the LEDs  126  can be a function of a length of the LED-based light  116 , a desired lumen output of the LED-based light  116 , the wattage of the LEDs  126  and/or the viewing angle of the LEDs  126 . For a 48″ LED-based light  116 , the number of LEDs  126  may vary from about thirty to sixty such that the LED-based light  116  outputs approximately 3,000 lumens. However, a different number of LEDs  126  can alternatively be used, and the LED-based light  116  can output any other amount of lumens. The LEDs  126  can be evenly spaced along the circuit board  124  and arranged on the circuit board  124  to substantially fill a space along a length of the lens  114  between end caps  120  positioned at opposing longitudinal ends of the housing  112 . Alternatively, single or multiple LEDs  126  can be located at one or both ends of the LED-based light  116 . The LEDs  126  can be arranged in a single longitudinally extending row along a central portion of the LED circuit board  124 , as shown, or can be arranged in a plurality of rows or arranged in groups. The spacing of the LEDs  126  can be determined based on, for example, the light distribution of each LED  126  and the number of LEDs  126 . 
     An alternative example of and LED-based light  216  is shown in  FIG. 4 . The construction of the LED-based light  216  can be similar to the construction of the LED-based light  116  of  FIG. 3 , and the LED-based light  216  can include the housing  112 , the lens  114 , the bi-pin  122  electrical connectors  118  carried by a pair of end caps  120 , the circuit board  124  and the LEDs  126 . 
     In addition, the LED-based light  216  can incorporate one or more of the above described components of the lighting control system  12 . For example, the switching unit  22  can be included the LED-based light  216 . The switching unit  22  can be included in the circuit board  124  and can be electrically connected between the fixture  110  conveying electrical power from a power supply and the LEDs  126  of the LED-based light  216 . The switching unit  22  of the LED-based light  216  can be configured to receive the control signal α and, in response to the control signal α, selectively regulate a supply of electrical power to the LEDs  126  to control operation of the LED-based light  216 . 
     The LED-based light  216  can also incorporate one or more of the sensors  28 , for example, and can incorporate a communications unit  42  for determining the location of other LED-based lights  216 . For example, multiple LED-based lights  216  including a communications unit  42  can together form the spatially distributed network of communications units  42 . The positions of one or more LED-based lights  216  including a communications unit  42  can be determined manually, with the positions of the remainder of the LED-based lights  16 ,  116  or  216  installed into the lighting control system  12  being determined according to the process and techniques described above. In this example, the LED-based light  216  also includes communications devices  44  and/or  46  for sending and receiving location signals γ, although the LED-based light  216  could also communicate with the lighting control system  12  through the communications channels of the communications link  40 . 
     The LED-based lights described herein are presented as examples and are not meant to be limiting. The embodiments can be used with any lighting components known to those skilled in the art and compatible with the scope of the disclosure. In addition, the disclosed processes and techniques can be applied in a variety of building automation system implemented control systems to regulate environmental conditions other than lighting conditions. For example, the disclosed processes and techniques can be applied to determine the position of printers, alarm system components and/or HVAC components, and various controllers can be control operation of these components for purpose of regulating related environmental conditions of the building  10 . 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.