Abstract:
A lighting system includes a light emitting element operable to emit light at a level between zero and 100 percent, a light level sensor positioned to detect a total level of light, and a motion detector positioned to detect a motion in a predefined space. A controller is coupled to the light emitting element, the light level sensor, and the motion detector and is operable to compare a measured total level of light to a set point and to activate the light emitting element in response to the measured total light level being below the setpoint. The controller is further operable to activate the light emitting element in response to the detection of motion within the space.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/619,226, filed on Apr. 2, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a control system for a lighting assembly, and more particularly to an infrared (IR) remote control system for a lighting assembly. 
         [0003]    Lighting systems for lighting large facilities, such as warehouses and factories, typically utilize fluorescent or light-emitting diode (LED) lights to illuminate certain portions of space under certain conditions. Control of these lighting systems is important not only tier proper illumination but to minimize energy usage. To that end, environmental sensors, such as motion sensors, are often used to activate lights in only those areas specifically occupied, serving both purposes. 
         [0004]    Electronic switches, for example DIP switches, incorporated on a circuit board of a. lighting controller are often used to set lighting function parameters such as the threshold level of motion at which the lights will activate and/or the duration the lights will remain on in the absence of motion. Due to the physical location of the lights and the controller(s) within such facilities, i.e., at or near the ceiling, adjusting the sensors and other lighting parameters is often difficult, time consuming, and carries a degree of safety risk. 
         [0005]    The present invention provides a method of controlling lighting parameters, to include various sensor thresholds for light activation and timing intervals for light deactivation, from a position distant from the lighting controller. A remote control device using infrared (IR) signaling permits a user to quickly and safely communicate with the lighting controller to adjust such parameters. Moreover, the lighting controller also includes an ambient light sensor and a dimmer that work in conjunction to maintain the light intensity of an activated light at a predetermined level. 
         [0006]    In one construction, the invention provides a. lighting system that includes a light emitting element operable to emit light at a level between zero and  100  percent, a light level sensor positioned to detect a total level of light, and a motion detector positioned to detect a motion in a predefined space. A controller is coupled to the light emitting element, the light level sensor, and the motion detector and is operable to compare a measured total level of light to a set point and to activate the light emitting element in response to the measured total light level being below the setpoint. The controller is further operable to activate the light emitting element in response to the detection of motion within the space. 
         [0007]    In another construction, the invention provides a lighting system that includes a plurality of fluorescent light emitting units arranged to emit light in an area between a level of zero and 100 percent. A light level sensor is positioned to detect a total level of light and transmit a signal indicative of a measured light level and a controller is operable to receive the measured light level and compare the measured light level to a preset desired light level and to adjust the plurality of fluorescent light emitting units in response to that comparison to emit a level of light between zero and  100  percent in order to change the measured light level to substantially match the preset desired light level. A remote control device is operable from a position apart from the controller to change the preset desired light level. 
         [0008]    In another construction, the invention provides a method of controlling a light level within a space. The method includes sensing a current light level at a predetermined location, storing a first desired light level in a controller, comparing the sensed light level with the first desired light level, and adjusting the light output of a plurality of fluorescent lights in response to the comparison of the sensed light level to the first desired light level until the sensed light level is about equal to the first desired light level. The method also includes remotely adjusting the desired light level to a second desired light level and adjusting the light output of the plurality of fluorescent lights in response to a comparison of the sensed light level to the second desired light level until the sensed light level is about equal to the second desired light level. 
         [0009]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic illustration of a room including the lighting assembly. 
           [0011]      FIG. 2  is a schematic diagram of the layout of the lighting assembly of  FIG. 1 . 
           [0012]      FIG. 3  is a flow chart of a control algorithm for the lighting assembly of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. And as used herein and in the appended claims, the terms “upper”, “lower”, “top”, “bottom”, “front”, “back”, and other directional terms are not intended to require any particular orientation, but are instead used for purposes of description only. 
         [0014]      FIG. 1  schematically shows a portion  10  of a large building and a lighting assembly  100  for that portion  10  The lighting assembly  100  includes one or more groups of lights  110  positioned at or near the ceiling  112  to maximize the illumination of objects in an area  40  below. The lights  110  can be of any known type, for example, fluorescent lights or LED lights. 
         [0015]    Referring also to  FIG. 2 , the lights  110  are controlled by a controller  120 . As illustrated, the lights  110  are integrated with the controller  120 , but in other constructions the controller  120  is spaced apart from the lights  110 . The controller  120  includes electrical and electronic components to power and control the lights  110  which, if of the fluorescent type, will include a ballast  130  to regulate the voltage and current supplied to the lights  110 . One or more groups of lights  110  for lighting the area  40  can be controlled by the same controller  120 . 
         [0016]    The controller  120  includes a power supply  140  that receives alternating current (AC) power and transforms the power to direct current (DC) for use within the controller  120 . Such power supplies are known to those of skill in the art and need not be further detailed. A microprocessor  150  controls all functions within the controller  120  hereinafter described. 
         [0017]    Referring also to  FIG. 1 , the building portion  10  utilizes motion control to control the activation and duration of the lights  110 . A motion detector or sensor  160  is positioned and oriented to detect motion in the area  40 . Motion sensors suitable for use with the lighting assembly  100  include those that utilize IR, ultrasonic, electric eye, visual systems (cameras) or a combination thereof to detect motion. One of ordinary skill in the art will recognize that the suitability of any motion detector is dependent on the circumstances of use and, for example, a sensor that uses infrared technology to detect the heat signature of a person entering a space, or that uses a camera to detect motion through frame comparison, may be more suitable for daytime use. As illustrated, the motion sensor is incorporated into the controller  120  but in some constructions, the motion sensor  160  is positioned at another point in the building a distance from the lighting assembly  100  and provides remote signaling back to the controller  120 . The controller  120  activates one or more of the groups of lights  110  in response to motion detected in the area  40  by sending a discrete signal to the ballast  130  through a relay output  170 . 
         [0018]    The controller  120  stores a threshold level of motion that, if not detected by the motion detector  160 , will initiate deactivation of the lights  110 . To reduce nuisance deactivation, the controller  120  includes an internal timer or other device that measures or calculates the passage of time. If the timer commences due to sub-threshold motion, the lights  110  will remain on for a pre-selected time duration, or interval. As an example, in one construction the lights  110  may stay on for one minute after the motion sensor  160  has stopped detecting the threshold level motion. If within that minute the motion detector  160  detects motion in the area  40 , the tinier will reset or, alternatively, could incrementally increase by one minute or any other period of time determined by the user. If the timer times out, the relay output  170  will cease sending a signal to the ballast  130 . 
         [0019]    An ambient light sensor  180  is positioned to detect ambient light in the area  40 . The ambient light includes light entering area  40  from all sources, natural and artificial, and is used to adjust the light emitted from the lights  110 . In some constructions, the ambient light sensor  180  is positioned at another point in the building a distance from the lighting assembly  100  and provides remote signaling back to the controller  120 . 
         [0020]    At least two modes of light control are contemplated with the ambient light sensor  180 . If the groups of lights  110  to be controlled are stoppable light sources, i.e., the ballast  130  permits either “on” or “off” states of the lights  110 , the controller  120  will operate in a first mode. In this mode, if an ambient light level threshold stored in the controller  120  is not net by the detected light level, the controller  120  will output a discrete signal through the relay output  170  to the ballast  130 . in one construction, a single signal is sent by the relay output  170  to the ballast  130 . For example, if the threshold setpoint for turning on the lights  110  is 100 lux, lighting levels detected by the sensor  180  at or below 100 lux will trigger a signal from the relay output  170 . In another construction, the lights  110  can be configured such that one group of lights  110  is powered with a first signal from the relay output  170  and, if the resultant lighting does not meet a second threshold value stored in the controller  120  (as determined by the ambient light sensor  180 ), an additional group of lights  110  of the assembly  100  is powered with a second discrete signal from the relay output  170 . For example, if the ambient light sensor  180  does not detect adequate light levels after the first relay is energized, the controller  120  will output a second discrete signal to the ballast  130  to control the activation of a second group of lights  110 . In yet another construction, the first discrete signal from the relay output  170  only partially powers a group of lights  110  (e.g., 50%), and a second discrete signal sent from the relay output  170  in response to insufficient lighting levels fully powers that group of lights  110 . 
         [0021]    If the group of lights  110  to be controlled are dimmable light sources, i.e., if the ballast  130  is a dimmable ballast or includes dimming functionality for receiving an analog input control signal, the controller  120  will operate in a second mode. In the second mode, if the ambient light level threshold is not met, the controller  120  will generate an analog signal from an analog output  190  to the dimmable ballast  130 . The analog signal can be, for example, a 0-20 mA, 4-20 mA, or 0-10 VDC signal. Upon receiving an analog signal, the dimmable ballast  130  adjusts the voltage and current supplied to the lights  110  accordingly. Specifically, if the ambient light sensor  180  detects a level of light below the threshold level set in the controller  120 , the analog output  190  provides a signal within the analog range, e.g., 0-10 VDC, to the ballast  130 . In this mode of operation, a separate predetermined light intensity level can be set within the controller  120  and the ambient light sensor  180  operated to continually monitor the light level within the area  40 . The controller  120  will adjust the analog output signal to maintain a level of light in the area  40  commensurate with the predetermined light intensity level setpoint. A control algorithm, such as PI or PID control, is used for this purpose to reach and maintain the light illumination at or near the light intensity level setpoint. The controller  120  can also measure the ambient light levels received from the sensor  180  during periods when no lights  110  from any groups are activated in order to determine the amount of natural light available in the area  40 . For example, where pulse width modulation control is utilized, the sensor  180  can measure the varying light levels between pulses, i.e., the high/low pulses of the ballast  130 , to differentiate brightness due to the lights  110  versus brightness from other sources. In some instances, a second sensor  180  is used for this differential detection and positioned such that one sensor  180  is above the assembly  100  and one below the assembly  100 . 
         [0022]    Motion control and ambient light level control can be implemented separately or together. In some constructions, the controller  120  can control both steppable lights and dimmable lights and is therefore configured to generate both relay and analog outputs. For example, motion control can be used to initially turn on groups of lights  110  that are then controlled with the ambient light sensor  160  while motive activity is ongoing within the area  40 . 
         [0023]    Referring to  FIG. 3 , in one embodiment of a control algorithm using both motion control and ambient light level control for dimmable lights, the routine begins at step  300 , in which the area  40  is monitored by the motion sensor  160 . During this monitoring, the values received from the motion sensor  160  are evaluated within the controller  120 . If motion is detected above the threshold level stored in the controller  120  (step  304 ), then the controller generates a signal from the analog output  190  to the ballast  130  (step  308 ). In most applications, the analog signal generated will initially be nearer to the low output value, e.g., nearer 0 volts in a 0-10 VDC output range, in order to slowly ramp up the illumination level after the lights  110  have been off. As the light levels in the area  40  are now also monitored by the ambient light sensor  180  (step  312 ), if the light intensity has not reached the predetermined light intensity level the analog output signal is adjusted until the setpoint is reached. 
         [0024]    If motion within the area  40  ceases to be above the threshold level (step  316 ), the timer within the controller  120  will reset and commence counting time (step  320 ) for the predetermined time duration, or interval, throughout which the lights  110  will remain on and controlled. If no motion above the threshold level is detected by the sensor  160  during the timing period (step  324 ) and the timer times out (step  328 ), the lights  110  will be deactivated (step  332 ). If motion is detected above the threshold level during the timer interval, however, the controller  120  stops the timer (step  336 ) and continues with analog output signal control. 
         [0025]    The controller  120  stores multiple setpoints to control different lighting parameters, including any and all of the setpoints previously identified, e.g., the threshold level of motion, the time duration or interval for light activation after cessation of motion, the ambient light level threshold, and the light intensity level. 
         [0026]    In order to efficiently adjust these setpoints, the controller  120  is responsive to an IR remote control  200  ( FIG. 2 ). The remote control  200  can be activated from a position distant from, but within the line of sight of, the controller  120 . When activated by a user, the remote control  200  sends out a signal consisting of a series of infrared pulses. An IR receiver  210  in the controller  120  receives these pulses and accordingly adjusts the appropriate setpoints. For example, a user may decide to increase the sensitivity of the light assembly  100  to motion within the area  40 . By depressing the correct series or sequence of buttons on the remote control  200 , the user can adjust the motion setpoint within the controller  120  down, i.e., to require less motion to activate the lights  110 . The user can similarly adjust the light intensity level setpoint from the remote control  200  to increase or decrease the amount of illumination maintained by the controller  120 . The user can also adjust the duration, or time interval, after which the controller  120  will turn off the lights  110  if no motion in the area  40  is detected by the motion sensor  160  and in turn, can adjust the function of the tinier to reset or instead increase the time duration by a fixed amount if motion is detected in the area  40  within the interval. The user can additionally adjust the mode of light control from the remote control  200  to change between the first mode of control and the second mode of control previously identified. Though described using infrared technology, other wireless control systems are possible for the remote control  200 . 
         [0027]    In some applications, a separate IR transmitter or beacon can be coupled directly to either a person or to material handling equipment, such as a forklift, or be incorporated within the remote control  200 . The IR beacon signals the controller  120 , through the IR receiver  210 , of the presence of the person or equipment. For example, if the IR beacon is located on a forklift that enters the area  40  or is within the line of sight of the controller  120 , the controller  120  will automatically activate the lights  110  and commence lighting control as previously described. When the forklift exits the area  40 , the controller  120  initiates deactivation of the lights. As the forklift enters and exits additional areas, lights will be activated and deactivated in turn. 
         [0028]    The controller  120  also includes an LED display  230  consisting of a plurality of LEDs that provide a visual cue of the current status of the controller  120 . Besides confirming the operational condition of the controller  120 , to include the various modes of operation, the LED display  230  can show concurrent responsiveness to signals from the remote control  200 . 
         [0029]    The controller  120  can further include a radio frequency (RE) transceiver  240 . The transceiver  240 , which has both a transmitter portion and a receiver portion, is able to transmit and receive radio signals and permits communication between similarly configured controllers  120  within other lighting areas of the building. When the motion detector  160  detects motion at the threshold level, the controller  120  activates its associated lights  110  and further signals the transceiver  240  to generate a radio signal at a pre-selected power level. A corresponding RF transceiver  240  at a second controller  120  within the broadcast range of the generated signal receives the transmitted signal and activates additional lights  110  in communication with additional lighting assemblies  100 . As a result, motion within the area  40  activates not only the lights  110  for the area  40 , but additional lights in surrounding areas. Pre-selection of the surrounding areas is accomplished by changing the power level transmitted by the transceiver  240 , which can be adjusted through the remote control  200 . 
         [0030]    In addition, the transceiver  240  permits communication of operational data of the controller  120  for logging purposes. For example, current setpoints stored within the controller  120  and historical power usage of the lights  110  are transmittable through the transceiver  240  to a receiver incorporated with a computer, where such data can be logged and analyzed. In such a manner, safe, efficient, and economical operation and adjustment of the lighting assembly  100  is achieved. 
         [0031]    Thus, the invention provides, among other things, a lighting system. Although the invention has been described in detail with reference to certain preferred constructions, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.