Networked device with power usage estimation

Description of equivalent WO 2011050013 A2

NETWORKED DEVICE WITH POWER USAGE

ESTIMATION

0003Background

0004Technical Field The present subject matter relates to home automation networking. It further relates to the monitoring and reporting by networked devices of their power or energy usage.

0005Description of Related Art

0006Providing home automation functionality using networking means is well known in the art. Control of lighting and appliances can be accomplished using systems from many different companies such as X10, Insteon® and Echelon. Some home automation systems utilize sensors to measure the electricity that has been consumed, but adding sensors for that purpose adds cost to products. Measuring the energy consumed and reporting it to the user or home owner is becoming more important over time as more and more people want to make their lifestyle more "green" and carefully monitor and control their energy usage. At the same time, home automation is becoming more prevalent and easier to use. Devices enabled for home automation include control and communication means allowing the devices to include more functionality. Summary

0007Some embodiments use a method of reporting energy usage status by a networked device that includes receiving an energy usage status request from a network and retrieving a set of power usage data from a non-volatile memory located within the networked device. The method continues by calculating a best estimate of the energy usage status based on the set of power usage data retrieved from the non-volatile memory and sending the best estimate of the energy usage status over the network as a reply to the energy usage status request. Another embodiment is a networked device including a controller, a nonvolatile memory containing a set of power usage data communicatively coupled to the controller, and a network adapter communicatively coupled to the controller. In that embodiment the network adapter receives an energy usage status request from the network and communicates it to the controller. The controller retrieves the set of power usage data from the non-volatile memory and calculates a best estimate of the energy usage status based on the set of power usage data. It then

0008communicates the best estimate of the energy usage status to the network adapter, and the network adapter sends a message over the network containing the best estimate of the energy usage status. In some embodiments, the networked device is a networked light bulb.

0009Brief Description of the Drawings

0010The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate various embodiments of the invention. Together with the general description, the drawings serve to explain the principles of the invention. In the drawings:

0011FIG. 1 A & 1 B show two views of a networked light bulb;

0012FIG. 2 shows a block diagram of the electronics utilized in one embodiment of the networked light bulb;

0013FIG. 3A & 3B show flowcharts of two alternative ways to maintain a log of device operating conditions;

0014FIG. 4 shows a flowchart of how a networked device may estimate energy usage status; and

0015FIG. 5 shows a block diagram view of a network of home automation devices that can report and display their energy usage.

0016Detailed Description

0017In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures and components have been described at a relatively high- level, without detail, in order to avoid unnecessarily obscuring aspects of the present concepts. A number of descriptive terms and phrases are used in describing the various embodiments of this disclosure. These descriptive terms and phrases are used to convey a generally agreed upon meaning to those skilled in the art unless a different definition is given in this specification. Some descriptive terms and phrases are presented in the following paragraphs for clarity.

0018The term "LED" refers to a diode that emits light, whether visible, ultraviolet, or infrared, and whether coherent or incoherent. The term as used herein includes incoherent polymer-encased semiconductor devices marketed as "LEDs", whether of the conventional or super-radiant variety. The term as used herein also includes semiconductor laser diodes and diodes that are not polymer-encased. It also includes LEDs that include a phosphor or nanocrystals to change their spectral output.

0019The term "energy usage status" refers to any parameter that could be useful in determining the energy used by a networked device. Specifically included in the definition are the instantaneous power used by the networked device at the current or any previous point of time, and the energy used by the networked device over an explicit or implicit period of time, but other parameters could also be used so the definition should not be limited to the specific parameters defined.

0020The term "network" refers to a bidirectional communication medium and protocol to allow a plurality of devices to communicate with each other.

0021The term "networked device" refers to any device that can communicate over a network.

0022The terms "networked light fixture", "networked lighting apparatus" and

0023"networked light bulb" all refer to a networked device capable of emitting light. While there are subtle differences in the generally agreed upon embodiments for these terms, they may be used interchangeably in this disclosure unless additional detail is provided to indicate that a specific embodiment is being discussed.

0024Reference now is made in detail to the examples illustrated in the

0025accompanying drawings and discussed below.

0026FIG. 1 A shows a front view (with inner structure not shown) and FIG. 1 B shows a side view (with selected inner structure shown in broken lines) of a networked light bulb 300. In this embodiment a networked light bulb 300 is shown but other embodiments of the present subject matter could be a permanently installed light fixture with a socket for a standard light bulb, or a light fixture with embedded LEDs or any other sort of light emitting apparatus. It is also representative of any other type of networked device such as a networked coffee maker, a networked refrigerator, a networked clock radio, a networked television or any other type of device that may participate in a home automation network. The light bulb 300 is AC powered but other embodiments could be battery powered or solar powered. The networked light bulb 300 of this embodiment has a base with a power contact 301 and a neutral contact 302, a middle housing 303 and an outer bulb 304. Each section 301 , 302, 303, 304 can be made of a single piece of material or be assembled from multiple component pieces. The outer bulb 304 is at least partially transparent and may have ventilation openings in some embodiments, but the other sections 301 , 302, 303 can be any color or transparency and be made from any suitable material. The middle housing 303 has an indentation 305 with a slot 306 and an aperture 307. A color wheel 221 is attached to the shaft of rotary switch 206 which is mounted on a printed circuit board 207. The printed circuit board 207 with the color wheel 221 is mounted horizontally so that the edge 202 of the color wheel protrudes through the slot 306 of the middle housing 303. This allows the user to apply a rotational force to the color wheel 221 . As the color wheel 221 rotates, different sections of the colored area of the color wheel 221 are visible through an aperture 307. In FIG. 1 A, the current position of the color wheel 221 is such the color section with color 4 is visible through the aperture 307, indicating that the user has selected color 4 at this time. The color selection mechanism 428 may be designed to provide a detent at each section of the colored area to make it clear what color is currently selected.

0027In this embodiment, a second printed circuit board 310 is mounted vertically in the base of the networked light bulb 300. A board-to-board connection 31 1 is provided to connect selected electrical signals between the two printed circuit boards 207, 310. A third printed circuit board 314 has a plurality of LEDs 31 3 mounted on it and is backed by a heat sink 315 to cool the plurality of LEDs 313. In some embodiments the third printed circuit board 314 with a plurality of LEDs 313 may be replaced by a single multi-die LED package or a single high output LED. In some embodiments the heat sink 315 may not be needed or could be a completely different configuration than what is shown. A cable 31 2 connects the printed circuit board 207 with the third printed circuit board 314. The cable 312 carries the power for the plurality of LEDs 313. In some embodiments it may be connect the second printed circuit board 31 0 directly to the third printed circuit board 314 instead of passing the signals through the printed circuit board 207.

0028FIG. 2 shows a block diagram of the control electronics 400 used in the networked light bulb 300. While the following discussion directed primarily at the embodiment of a networked light bulb 300 the same principles and concepts can be applied by one skilled in the art to any other networked device. The block diagram is divided into three sections 410, 420, 430 corresponding to the three printed circuit boards of FIG. 1 . Other embodiments may partition the system differently and have more or fewer printed circuit boards or circuit elements. The three sections are the LED Driver section 410, corresponding to the second printed circuit board 310, the networked controller section 420, corresponding to the printed circuit board 207, and the LED section 430, corresponding to the third printed circuit board 314, The base with contacts 301 , 302 provides AC power to the AC to DC rectifier 41 1 to power the LED driver 412. The LED driver may be an integrated circuit such as the NXP SSL21 01 or similar parts from Texas Instruments or others. Several signals are shared in common between the LED driver section 410 and the networked controller section 420 through a board-to-board connection 31 1 . The board-to-board

0029connection 31 1 may be a pin and socket connector system, an edge finger connector system, soldered right angle pins, a cable, or any other method of connecting two boards. The shared signals comprise a ground connection, the LED power signal 441 , a regulated power voltage 442, a control signal 443 and a serial communication signal 444. In some embodiments, the regulated power voltage 442 may be sufficient to power all the electronics in the networked controller section 420. In other embodiments, where more power is needed, a DC to DC converter may be included in the networked controller section 420 running off the LED power signal 441 . The ground signal and the LED power signal 441 are then sent from the networked controller section 420 to the LED section 430 over cable 31 2. The LED section 430 may have a plurality of LEDs 313 powered by the LED power signal 441 . The LED driver section 410 and LED section 430 could correspond to other sections that transform and consume electrical power or perform operations of a different embodiment of a networked device 300, such as the heating element of a networked coffee maker, under the control of the networked controller section 420.

0030The networked controller section 420 would be very similar in any

0031embodiment of a networked device. It has a wireless network adapter 422 that receives radio frequency signals through antenna 425 and is connected to controller 421 by a digital bus 423. In some embodiments, the wireless network adapter 422 may connect to a Z-wave, Zigbee (IEEE 802.15.4) or Wi-Fi (IEEE 802.1 1 ) wireless network. Other embodiments may use a wired or power line network adapter instead of a wireless network adapter. In some embodiments, the controller 421 is implemented as a microcontroller and in some embodiments, the controller 421 , wireless network adapter 422, and digital bus 423 may be integrated onto a single chip 424 such as the Zensys ZM3102. In some embodiments a timer or clock function is included in the networked controller 420. The timer or clock function could be implemented as a separate chip, a hardware block within the controller 421 , a firmware function within the controller 421 , or any other way of implementing a timer or clock function. A user interface such as a color selection mechanism 428 may also be connected to the controller 421 providing rotational position information through an electrical connection 426. In other embodiments a user interface may be provided using other means such as a graphical user interface on a display or a keypad or buttons or any other device or combination of devices that allows the user to make a selection and provide information on the selection to the controller 421 . A non-volatile memory 426 also may be included in the networked controller section 420. The non-volatile memory 426 can be a flash memory, an EPROM, a battery- backed up RAM, a hard drive, or any other sort of memory device that retains its contents through a power cycle. The non-volatile memory 426 can be implemented as a single integrated circuit, a set of integrated circuits, a block of memory cells integrated with another function such as the controller 421 or the wireless network adapter 422 or any other implementation. The non-volatile memory 426 is connected to the controller through a digital connection 427. The digital connection could be an I2C bus, an SPI bus, a parallel connection, an internal bus within an integrated circuit, or any other electrical connections means, using a standard or proprietary protocol. The non-volatile memory 426 can contain any number of different data depending on the embodiment including program instructions for the controller 421 , configuration information for the networked device, temporary data for the program running on the controller 421 , a log of different operating conditions of the networked device over time, networking settings or any other digital information useful in a specific embodiment. Some embodiments have a set of power usage data 450 stored in the non-volatile memory 426. The set of power usage data 450 has at least one data point indicating the amount of power used by the networked device such as the networked light bulb 300. In some embodiments, the set of power usage data 450 has multiple data points of the power used corresponding to different operating conditions of the networked device. In some embodiments, the operating condition parameters are explicitly stored with the power data points. In other embodiments, the operating condition associated with each data point is implicitly understood by the controller 421 so only a set of power data points is stored. In one embodiment, the different operating conditions of the networked light bulb 300 are different brightness levels of the LEDs 31 3. In one embodiment, the brightness levels are explicitly stored with the power level as paired data points such as (25, 1 .3), (50, 2.0), (75, 2.5), (100, 2.8) indicating that the networked light bulb 300 uses 1 .3W of power when the LEDs 31 3 are set to a 25% brightness level, 2.0W of power when the LEDs 313 are set to a 50% brightness level, 2.5W when the LEDs 31 3 are set to a 75% brightness level and 2.8W when the LEDs are set to a 100% brightness level. In another embodiment, the set of power usage data 450 for the networked light bulb 300 is simply a set of 1 1 data points such as (0.02, 0.7, 1 .0, 1 .4, 1 .8, 2.0, 2.2, 2.4, 2.6, 2.7, 2.8) corresponding to the power used by the networked light bulb 300 at "Standby" (Dark), 10%, 20%, 30%, 40%, 50%, 60%, 70% 80%, 90% and 1 00% brightness, the brightness levels understood implicitly by the controller. In other embodiments, the set of power usage data 450 has two data points such as (0.02, 2.8) corresponding to a standby power usage and a full power usage. And in at least one other embodiment, only a single power usage data point is stored to represent the best overall estimate of power used whenever the device is in use.

0032In some embodiments, the set of power usage data 450 is determined based on design data, qualification test data where similar devices are measured, data from the LED supplier, life testing where similar devices are measured, best guess by an engineer or some other method that does not involve measuring the power used by the particular networked device in question. In some embodiments, the data is calculated and then used for each and every instantiation of that particular design built. In other embodiments, each individual networked device is tested and power usage data 450 collected for one or more operating conditions at the time of manufacturing, final product test, final packaging or sometime before it is sold to the end customer, and that measured data from that individual device is used to create the set of power usage data 450 that is stored in the non-volatile memory 426 of the individual networked device.

0033In some embodiments, the controller 421 controls the brightness of the plurality of LEDs 313 by driving the control signal 443 back to the LED driver 412. In one embodiment the controller 421 may simply drive the control signal 443 low to turn the plurality of LEDs 31 3 on and drive the control signal 443 high to turn the plurality of LEDs 313 off. In other embodiments, the controller 421 may drive the control signal 443 with a pulse-width modulated signal to control the brightness of the plurality of LEDS 313. In some embodiments, the LED driver section 410 is designed to accept power that has been controlled by a standard thyristor-based light dimmer which varies the phase where the AC power is active. This can interact with the dimming control taking place over the network. To determine the current dimming level of the LEDs 313, the networked controller section 420 may, in some embodiments, include circuitry to monitor the LED power signal 441 to determine the amount of dimming taking place. In other embodiments, the controller 421 may communicate with the LED driver 41 2 over the serial communications signal 444 to query and perhaps override the current dimming level. The serial communication signal 444 may also be used to communicate the current operating condition of the networked device, actual measured power used if the additional circuitry to measure power is included in the networked device, color temperature control, device temperature information or any other status or control information that might need to be communicated between the controller 421 and the LED driver 412 in a particular embodiment. The serial communication signal 444 may be implemented with a unidirectional or a bidirectional communication protocol such as RS-232, I2C, USB, SPI or any other standard or proprietary protocol. FIG. 3A and 3B show flow charts 500, 510 for different embodiments of creating and/or maintaining a log of operating conditions in the networked device. Other methods may also be used in other embodiments. In one embodiment 500 the controller 421 detects if the networked device undergoes a change 501 of current operating condition. A change of operating condition could be turning on, turning off (standby), changing volume, changing a fan speed, changing the heating level of a heating element, changing the brightness level, or any other change in the condition of the networking device that could impact the amount of power it uses. If a change of state is detected, the controller 421 gets 502 the current time from the timer operating as a function in the controller or in another device. The time does not need to be highly accurate or even set to a real world clock time; it just needs to allow relative values of the time to be compared to get an elapsed time convertible to hours. The controller 421 must then ascertain 503 the current operating condition of the networked device. In some embodiments, the controller 421 always knows the operating condition because it is controlling the operating condition. In other embodiment, the controller 421 must query other devices in the networked device, such as the LED driver 41 2, to ascertain the current operating condition. Once the current operating condition and time have been collected, a data point identifying the current operating condition and the time are stored 504 in a data structure in memory. The controller 421 then waits 505 for the next change of operating condition.

0034The flow chart 510 of FIG. 3B shows an alternative embodiment of creating a log of operating conditions. In the flow chart 510, a clock tick is generated at regular intervals and detected 51 1 by the controller 421 . The clock tick can be generated using the same sort of means as the timer of the first embodiment discussed. For each clock tick, the current operating condition is ascertained 513 as described above and a data point describing the current operating condition is stored 514 into a data structure. With this method, the time is implicitly known based on the clock tick. The time between clock ticks may vary depending on the type of device, the accuracy required of the power estimation, how often the power usage will be queried, and the embodiment, but one clock tick every 10 minutes might be used in one embodiment. The controller 421 then waits 515 for the next clock tick. The memory used for the data structure of the log of operating conditions may be a separate location in the same non-volatile memory 426 that holds the set of power usage data or in some embodiments, it may be a different memory device, volatile of non-volatile. The data structure may be a circular queue of fixed size determined at the time the instructions for the controller are created. In some embodiments, the data structure may be dynamic in size depending on the way the networking device is used. In some embodiments, the data structure may be a linked list or a table. It is clear to one skilled in the art that a log of operating conditions cannot be of infinite size due to storage limitations, so tradeoffs must be made in the design of a particular embodiment. In the case where a data point is created every 10 minutes as in the embodiment described above and where an 8 bit byte can sufficiently describe the operating condition, such as a brightness level at 0.5% granularity or less, a data structure of 256 bytes can hold a log containing over 42 hours of data before some data is lost. That would be adequate for an embodiment where it is expected that all devices will be queried by a centralized power management console at least once each day. Other embodiments may use different sized, static or dynamic data structures.

0035FIG. 4 shows a flow chart 600 for calculating a best estimate of the energy usage status based on the set of power usage data 450 stored in non-volatile memory 426. The network adapter 422 receives 601 a message from the network and relays it to the controller 421 which checks 602 to see if it is a request for energy usage status. If it is not, the controller 421 processes 603, whatever the message is, and then waits 604 for the next message. If it is a request for energy usage status, the controller 421 examines 606 the request to see if it is a request for the current power being used by the networked device or if it is a request for the amount of energy used over a given period of time. If it is a request for the current power used, several different techniques can be used, depending on the set of power usage data 450 stored in non-volatile memory 426 and the accuracy required by a particular embodiment. The flow chart 600 shows a method where the controller 421 ascertains 607 the current operating condition of the networked device and then searches the set of power usage data 450 to find 608 the two data points closest to the current operating condition. If one of the data points exactly matches a stored data point, the power given for that data point can directly become the estimate of current power used. If the current operating condition does not exactly match a data point from the set of power usage data, the controller 421 may interpolate 609 between the two closest data points in the power usage data 450 set. As an example for the networked light bulb 300, if the current operating condition is 60% brightness and the two closest data points are (50, 2.0) and (75, 2.5) the controller would determine that 60% brightness is 40% of the way between 50% brightness and 75% brightness and would then calculate the estimate of the current power by adding the power level at 50% to 40% of the difference between the power levels at 50% and 75% as shown in the following equation: 2.0+0.4^*(2.5-2.0 ) = 2.0+0.4^*0.5 = 2.0+0.2 = 2.2W. In other embodiments, the data point from the power usage data 450 nearest to the current operating condition may be used instead of interpolating values, in this example, the 50% brightness operating condition leading to a power estimate of 2.0W. In other embodiments where only a single point is included in the set of power usage data 450, that data point may be used as the estimated power for all cases where the networked device is considered "On" and zero (or some other low value determined by a constant when the instructions for the controller where created) used as the power estimation for cases where the networked device in "Off" or in standby mode. Once the estimation of the current power has been completed, the estimate is sent 610 over the network to the device that made the original request and the networked device then waits 604 for the next network message.

0036If the request is for the energy used over a period of time, the controller 421 retrieves 61 1 the log of operating conditions from memory. It must then determine the amount of time to use for the energy calculation. In some embodiments, the amount of time will be explicitly included with the request. In other embodiments the amount of time may be implicit, and the controller 421 then makes a calculation based on the instructions created at the time the networked device was designed. For this example, the request explicitly requests the power usage from the last hour. The controller starts with the most recent entry of the log of operating conditions and determines 612 the power used by the networked device at that operating condition using the methods described above for estimated the current power used. The power determined is then multiplied 613 by the amount of time (converted to hours) represented by that entry in the operating condition data structure. If the method of FIG. 3A was used, the time between the current time and the time stored in the data structure must be used for the first entry and the difference in the time entries between adjacent entries used for other entries. If the method of FIG 5B was used, each entry constitutes an equal amount of time. If that method was used, an additional energy factor for the energy used between the last entry of the log and the current time may be added using the current operating condition for more accuracy in some embodiments. A running sum of the energy used for each entry in the log is kept. The time of the next entry in the log is examined 614 to see if enough data from the log has been analyzed to cover the period requested. If another entry is required, the power level for that entry is determined 612 and multiplied 613 by the time and summed. In some embodiments the amount of time for the operating condition entry will be determined by the length of time requested for the energy calculation. For example, if the first entry in the log of current operating conditions is from 4 hours ago because the networked device has not been used since then, the power estimation will multiply the power level for the operating condition stored in the first entry of the log multiplied 61 3 by 1 hour in the current example because that is the period requested, even though the first entry in the log is 4 hours earlier. In some embodiments, the networked device may not maintain a log of operating conditions. In those embodiments, the networked device may simply use the current operating condition as the operating condition for the entire period requested or may simply use a fixed average power usage value multiplied times the period to come up with an estimate. Once the estimation of the energy used has been completed, the estimate is sent 610 over the network to the device that made the original request and the networked device then waits 604 for the next network message.

0037FIG. 5 shows a set of networked devices in a networked home that is used for an example of how the energy usage status estimation methods described above may be used. A computer 140 running a power management console application with display 700 may be connected to a gateway device 124. The gateway device 124 has a computer interface 124a that allows communication with a standard personal computer. The interface 1 24a can support any method of communication including but not limited to USB, Ethernet, IEEE-1394, Wi-Fi, Power line networking or any standard or proprietary communication means. The gateway device 1 24 has its own controller 124c and a network adapter 124n to allow it to connect to the network 130 and communicate with other networked devices 1 15, 1 17, 120, 123, 125. The power management console 700 may query the network controller 120, communicating with its controller 120c through its network adapter 120n, to determine what networked devices 1 15, 1 17, 123, 1 25 are currently available on the network 130. For this example, the network controller 120 provides information to the power management console 700 that the light bulb 1 15, the floodlight 1 17, the refrigerator 123 and the television 125 are available and support energy usage status requests.

0038The power management console than sends a request for the energy used over the last 24 hours to the floodlight 1 17 because it has not been available for requests for some time and the power management console 700 does not have any recent information. The power usage request then goes through the network from the gateway's network adapter 124n to the floodlight's network adapter 1 17n. In this embodiment, the network is a mesh network so the message may be routed through other networked devices to be properly delivered to the floodlight 1 17. Once the floodlight's controller 1 17c gets the request, it estimates the power used over the last 24 hours. In this example, the floodlight is not dimmable and it only has two entries in its set of power usage (0.05 & 15). Its first operating condition log entry was turning on 20 minutes ago and the next entry was turning off 36 hours earlier. So the controller uses that data to estimate an energy usage of 23.67^*0.05+0.33^*15 = 6.18Wh and returns that information to the power management console 700 which may store the estimate in a database.

0039The power management console 700 then determines that it only needs the last 2 hours of energy usage from the networked light bulb 1 15, so it sends a request over the network 130 to the light bulb's network adapter 1 15n, the light bulb's controller 1 15c retrieves the log of operating conditions which has an entry every 15 minutes and shows that over the last 8 entries covering the two hour time period of interest, the light bulb has been at full brightness for 6 of those entries and at 30% brightness for the other two entries. The controller 1 15c then gets the set of power usage data and finds a single entry of 20W so it estimates the energy used over the last two hours by interpolating the power used when the brightness was 30%. It interpolates between 0 and 20W to get 6W for a brightness level of 30% and multiplies it by the 0.5 hour time for two periods to come up with an estimate of 3Wh used for that 0.5 hour time period. It then adds that to the energy used during the 1 .5 hours that the light bulb was at full brightness, 20^*1 .5 = 30Wh to get an estimate of 33 Wh used for the 2 hour time period and returns the estimate to the power management console 700.

0040The power management console 700 has been pre-programmed in this example to query the refrigerator 1 23 with network adapter 123n and controller 123c, and the television 125 with network adapter 125n and controller 1 25c only once every 24 hours and since the television 125 was queried 4 hours ago in this example, the power management console 700 does not query the television 1 25 at this point in time. It is due to query the refrigerator 123, so it sends a request for the energy used by the refrigerator over the last 24 hours over the network 130. The refrigerator's controller 123c receives the request from the network adapter 123n. The refrigerator's set of power usage data has a single data point giving the power used with the compressor is running (600W). The log of operating conditions stores one entry each hour showing how many minutes the compressor has run. So the controller 123c goes through the last 24 entries of the log and multiplies the number of minutes of each entry by 600/60, accumulating the total, estimating that the refrigerator has used 800Wh over the last 24 hours, and send the estimate to the power management console.

0041The power management console 700 may display the information it has received and stored in a database in many different ways to help the homeowner determine how to utilize her home in a way to be more "green". One display is a simple bar chart showing the energy used in the last month by each device. Other displays may show the highest peak users or the amount used by each networked device when electrical rates are at their highest. In some embodiments, the power management console 700 may be able to communicate with the networked electric meter 126 to get the total electrical usage of the home as well as possibly receive messages from the electrical utility. Different embodiments of the power

0042management console 700 may provide a wealth of other information.

0043Unless otherwise indicated, all numbers expressing quantities of elements, optical characteristic properties, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the preceding specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviations found in their respective testing measurements.

0044The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1 , 1 .5, 2, 2.75, 3, 3.80, 4, and 5).

0045As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to an element described as "an LED" may refer to a single LED, two LEDs or any other number of LEDs. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

0046As used herein, the term "coupled" includes direct and indirect connections. Moreover, where first and second devices are coupled, intervening devices including active devices may be located there between.

0047The description of the various embodiments provided above is illustrative in nature and is not intended to limit the invention, its application, or uses. Thus, variations that do not depart from the gist of the invention are intended to be within the scope of the embodiments of the present invention. Such variations are not to be regarded as a departure from the intended scope of the present invention.