AU2012244109A1 - An energy saving electrical outlet device - Google Patents

Abstract

An Energy Saving Electrical Outlet Device Abstract An energy saving electrical outlet device comprises: at least two groups of 5 outlets, at least two load sensing circuitries, at least two switching circuitries, at least one external control signal input and at least one micro processor. The device is able to disconnect mains power from one group of outlets when the appliances connected to them are not being used; the device is also able to disconnect mains power from all controlled outlets when the appliances of one 10 specific group of outlets are not being used; the device is even able to disconnect mains power from the specific group of outlets but maintain mains power to the other groups of outlets. so /I f /2 3 /4 1 Fu 'C2' 15 Figurel

Description

-1 An Energy Saving Electrical Outlet Device Description 5 FIELD OF THE INVENTION The present invention relates to an energy saving electrical outlet device, particularly to an energy saving electrical outlet device for intercepting standby power consumption and active power waste, wherein comprising load 10 sensing circuitries, switching circuitries, at least one external control input unit and at least one micro processor. BACKGROUND OF THE INVENTION 15 Human activity generates greenhouse gas continuously, which is increasing the global warming and causing the climate to change. Governments and social organizations all over the world encourage people to save energy and reduce carbon emission. Standby power consumption and active power waste of electrical appliances, especially AV and IT appliances, is 20 mostly concerned. Standby power consumption is the power consumed by the appliance which does not perform its primary function, like TV still consumes power to sense IR control signal when it is turned off by its remote. According to the 25 Australia government, in 2000, standby power accounted up to 11.6% of Australia's household energy consumption. In 2002, a typical home pays AU$95 and emits 734 kilograms greenhouse gas for the standby power consumption. 30 Patent PCT/GBo2/05093 disclosed a power distribution apparatus which comprises a master electrical outlet coupling to a master appliance, like TV or PC, and at least a slave electrical outlet coupling to at least a slave appliance, like DVD player or speakers. In this invention, the load of master appliance is sensed, when the master appliance is ON, the mains power is -2 connected to slaves outlets; when the master appliance in NOT ON, the mains power is disconnected from slaves outlets, the standby power consumption of slave appliances is saved. This ties the power supply status of slave outlets to the working status of the master appliance, and results in two negative effects. 5 Firstly, when the master appliance is ON, the power supply to the slave outlets is always connected, even though no slave appliance is needed, the standby power consumption of slave appliances still occurs. Secondly, when the master appliance is NOT ON, the power supply to slave outlets is always disconnected, and thus the slave appliances cannot be used separately. For 10 example, you cannot listen to stereo without turning TV (the master appliance) ON. Or, you cannot use the copier without turning PC (the master appliance) ON. You need to turn on the master appliance even though you just need to use one of the slave appliances. This causes change in user behavior and active power waste as well, both of which may reduce the benefit of this 15 energy saving device. Patent PCT/AU2007/oo1824 disclosed a power supply control device which distinguishes the state of electrical appliances by detecting the power fluctuation and generating dynamic baseline. This enables the system to be 20 dynamic and self-learning. The tie of power supply status of slave outlets to the working status of the master appliance is removed. The user can use one appliance regardless of the working status of the other appliances. For example, he can listen to the stereo without turning TV on, or he can use the copier without turning PC on. But the term "master appliance" in this 25 invention is intended to cover a combination of appliances, especially in AV application. The power use signal produced by the power sensor is the combination of power contribution of all controlled appliances, not solely of one specific appliance. TV, the well recognised "master appliance" for many years, loses its control function over the peripherals. When TV is turned off, if 30 power fluctuation is still detected, the power supply to all controlled devices will be maintained, the peripheral appliances which are in use cannot be switched off automatically, and then active power waste may occur. Also, if power fluctuation is detected, the power supply to all controlled appliances is -3 maintained, even though some appliances are not in use; they still consume the standby power. SUMMARY OF THE INVENTION 5 The present invention is directed to an energy saving electrical outlet device that provides better energy saving, no change in user behavior and better control reliability. Accordingly there is proposed in one form of the invention, an energy 10 saving electrical outlet device comprises: A main body with a plug or a power cord adapted to connect to mains power supply; At least two groups of outlets, each group of outlets consists of one or more electrical outlets; 15 At least two load sensing circuitries adapted to sense the load of each group of outlets individually; At least two switching circuitries adapted to switch the mains power supply to each group of outlets individually; At least one external control input unit; 20 At least one micro processor adapted to analyze the load sensing signals and external control signals and then generate control signals for switching circuitries. The first advantage of an energy saving electrical outlet device of the 25 invention is that, it is able to disconnect mains power from one group of outlets automatically of which the appliances are not in use, regardless of the working status of appliances of other group of outlets. For example, when TV is in use, if the peripherals are not in use, the mains power supply to the peripherals will be disconnected automatically; or when the peripherals are in 30 use, if TV is not in use, the mains power supply to TV will be disconnected automatically. This results in reducing more standby power consumption. The second advantage of an energy saving electrical outlet device of the invention is that, it is able to maintain the power supply to one group of -4 outlets when the mains power supply to the other groups of outlets is disconnected. For example, the device is capable to maintain the power supply to the outlet for stereo when the power supply to the outlet for TV is disconnected; or maintain the power supply to the outlet for copier when the 5 power supply to the outlet for PC is disconnected. This allows the user to use peripheral appliances without turning main appliance on, requires no change in user behavior. The third advantage of an energy saving electrical outlet device of the 10 invention is that, it is able to disconnect mains power from all controlled outlets when the appliances of one group of outlets are not in use, regardless of the appliances of other groups of outlets. For example, when the appliance of one group of outlet is TV, since one load sensing circuitry senses the TV separately, so when TV is turned from ON mode into standby or off mode, the 15 device is capable to disconnect power supply from all controlled groups of outlets precisely, regardless of the appliances of other groups of outlets. This results in better control reliability. After mains power supply to all controlled groups of outlets is 20 disconnected, an interruption of mains power supply or an external control signal input will make the device to connect mains power to all controlled groups of outlets again, and then the automatic control cycles. These and other features, aspects, and advantages of the present 25 invention will become better understood with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the present invention will now be described 30 in detail by way of example and with reference to the accompanying drawings wherein: Figure 1 shows an perspective view of a preferred embodiment, PEa, which comprises one always-on outlet, four groups of outlets in which there is -5 one outlet in each group, a button on the main body and an infra-red sensing unit linked to the main body by a wire. Figure 2 is a schematic of a power PCB for the preferred embodiment 5 PEa, including mains power protection, low voltage power supply, one button control input, one conjunction port linking to a control PCB for PEa and one conjunction port linking to a infra-red sensing PCB for PEa. Figure 3 is a schematic of the control PCB for the preferred 10 embodiment PEa, including four load sensing circuitries, four switching circuitries, one micro processor and one conjunction port linking to the power PCB for PEa. Figure 4 is a schematic of the infra-red sensing PCB for the preferred 15 embodiment PEa, including one infra-red signal sensor, one micro processor and one conjunction port linking to the power PCB for PEa. Figure 5 shows a control flow chart of the preferred embodiments of the present invention. 20 Figure 6 shows an perspective view of another preferred embodiment, PEb, including an always-on outlet, two groups of outlets in which there is one outlet in one group and four outlets in another group, an external control unit which includes a button, an infra-red signal sensor and an energy display 25 LCD, linked to the main body by a wire. Figure 7 is a schematic of a power PCB for the preferred embodiment PEb, including mains power protection, low voltage power supply, one conjunction port linking to a control PCB for PEb and one conjunction port 30 linking to a external control unit for PEb. Figure 8 is a schematic of the control PCB for the preferred embodiment PEb, including one load sensing circuitry for all outlets, two load -6 sensing circuitries for two groups of outlets, two switching circuitries, one micro processor and one conjunction port linking to the power PCB for PEb. Figure 9 is a schematic of the external control PCB for the preferred 5 embodiment PEb, including one button, an infra-red signal sensor, a micro processor, an LCD display and one conjunction port linking to the power PCB for PEb. Figure 10 shows an perspective view of another preferred embodiment, 10 PEc, including two groups of outlets in which there is one outlet in each group, an external control unit which includes a button, an infra-red signal sensor and an energy display LCD, linked to the main body by a wire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 15 Hereunder, with reference to the attached drawings, three preferred embodiments are illustrated for the present invention. Like parts shown on multiple drawings are referenced by the same number. Elements in drawings are reasonably simplified for better demonstration. 20 A preferred embodiment of the invention, which is called as PEa, is illustrated by Figure 1, Figure 2, Figure 3, figure 4 and figure 5. Figure 1 shows a perspective view of PEa which comprises a main body 25 10, a plug 20 to connecting to mains power supply, a power cord 21, one always-on outlet 30, four groups of outlets in which there is one outlet in each group 31, 32, 33 and 34, a button 40 on the main body, an infra-red sensor 41 on the external body 50 and a wire 51 linking the external body 50 to main body 10. On the main body, there are power indicators 60, 61, 62, 63 and 64 30 for each outlet respectively and there is an overload circuit breaker 70 and a surge protection indicator 72. The always-on outlet 30 is for appliances demanding continuous power supply, like wireless phone, fax machine, or VCR.

-7 Controllable appliances, like TV, stereo, satellite box, game console, can be connected to outlet 31, 32, 33 or 34. For easy description below, outlet 31 is defined as main outlet, outlet 32, 33 and 34 are defined as peripheral outlets. 5 When a power indicator above an outlet lights up, it means the mains power supply to the respective outlet is connected; when a power indicator above an outlet is off, it means the mains power supply to the respective outlet is disconnected. 10 Figure 2 shows a schematic of a power PCB for PEa, including mains power protection 130, low voltage power supply 131, external button control input 111, conjunction port 121 linking to the control PCB for PEa and conjunction port 122 linking to the external infra-red sensing unit 50. 15 The mains power protection 130 consists of an overload circuit breaker 1301 which will break the mains power when overload occurs for safety; three surge protectors 1302 are connected between any two wires of live, neutral and earth, to protect the appliances connected from surge; when the surge 20 protection indicator 1303 lights up, it means the surge protectors are working properly. The low voltage power supply 131 adopts an PWM power switcher IC 1311, a high frequency electronic transformer 1312 and peripheral components 25 to supply isolated DC power supply 1313 for the external infra-red sensing PCB for PEa and non-isolated DC power supply 1314 for the control PCB for PEa. The signals 1002 and 1003 on the control PCB for PEa are converted into 1012 and 1013 by isolation provided by photo coupler 1315 and 1316 on the power PCB for PEa. Signals 1315 and 1316 then connect to the external infra 30 red sensing PCB for PEa. Figure 3 shows a schematic of a control PCB for PEa, including four individual load sensing circuitry 81, 82, 83 and 84, four individual switching -8 circuitry 91, 92, 93 and 94, a micro processor 100, and one conjunction port 121 linking to the power PCB for PEa. Take the first load sensing circuitry 81 as example to explain in detail, 5 the load sensing circuitry 82, 83 and 84 are same as 81 in components and function, they only differ in load of different outlet they sense. Load sensing circuitry 81 consists of a single phase energy metering IC 81o, a voltage sensor by resistors 811 and 812, a current sensor by shunt 813, 10 and other peripheral components. The load sensing circuitry 81 keeps sensing the load of outlet 31, and keeps outputting a number of pulses 814 proportional to the load. This load sensing signal 814 is connected to an input of the micro processor 100. 15 Take the first switching circuitry 91 as example to explain in detail, the switching circuitry 92, 93 and 94 are same as 91 in components and function, they only differ in different control signal from the micro processor and different outlet they control. 20 Switching circuitry 91 consists of a transistor 911, a relay 912 and a freewheeling diode 913. A control signal 1004 from the micro processor 100 controls the switching status of 911, the relay 912 then pulls up or breaks accordingly. When the relay 912 pulls up, the mains power supply to outlet 31 is connected, when the relay 912 breaks, the mains power supply is 25 disconnected from outlet 31. The micro processor 100 analyzes four load sensing input 814, 824, 834 and 844, external button control signal 1001 and external infra-red sensor input 1002, follows the control flow chart illustrated in Figure 5, and then 30 outputs control signal 1004, 1005, 1006 and 1007 to control the four switching circuitries 91, 92, 93 and 94, and the power indicator of each outlet respectively. Based on the working status of switching circuitries 91, 92, 93 and 94, the micro processor also output a power status symbol for all controlled outlets. When the mains power supply to all controlled outlets are -9 disconnected, the symbol 1003 will be in low level; when the mains power supply to at least one controlled outlet is connected, the symbol 1003 will be in high level. The symbol 1003 is isolated by photo coupler 1316 on the power PCB for PEa and then is converted into signal 1013 as an input of micro 5 processor 101 which is on the infra-red sensing PCB for PEa. The control PCB for PEa shows in Figure 3 links with the power PCB for PEa through the conjunction port 121 to get DC power supply and communicate with the infra-red sensing PCB for PEa. 10 Figure 4 shows a schematic of an infra-red sensing PCB for PEa, including a micro processor 101, an infra-red signal sensor 112 and a conjunction port 122 linking to the power PCB for PEa. The infra-red sensor 112 converts an infra-red signal into a series of pulses. The micro processor 15 101 analyzes the width pulses and interval between each pulse to determine the validity of the infra-red signal. When one valid infra-red signal is determined, the micro processor controls the LED 1014 to flash a couple of times, for example one time, and sends a signal 1012 to the power PCB for PEa indicating one valid infra-red signal sensed. The approach by which the micro 20 processor 101 determines the validity of an infra-red signal is unrelated to the coding protocol of infra-red signals, so the user does not need to pair their infra-red remote controllers to the infra-red sensing unit. The micro processor also controls the LED 1014 according to signal 1013, the power status symbol of all controlled outlets . When the signal 1013 is in high level, it means the 25 mains power supply is connected to at least one controlled outlet, the micro processor 101 turns on the LED 1014; when the signal 1013 is in low level, it means the mains power supply is disconnected from all controlled outlets, the micro processor 101 turns off the LED 1014. When there is no valid infra-red signal sensed in a preset period of time Tdlyo, the micro processor 101 30 controls the LED 1014 to flash for a period of time Tdly3. The infra-red sensing PCB for PEa shows in Figure 4 links with the power PCB for PEa through the conjunction port 122 to get isolated DC power supply and communicate with the control PCB for PEa.

-10 Figure 5 shows a control flow chart of the present invention, it is applicable to PEa. After an interruption of mains power supply or a valid input of external control signal, the micro processor 100 sends controls signals to 5 switching circuitries to connect mains power supply to main outlet 31, peripheral outlets 32, 33 and 34. Meanwhile, the micro processor 100 starts counting a preset period of time Tdlyo (for example 1 hour) and a preset period of time Tdlyi (for example 1 minute). If the load of main outlet 31 is turned on in T-dly1, when it is turned off afterward, the micro processor 100 10 will control the switching circuitries to disconnect mains power from the main outlet 31 and peripheral outlets 32, 33 and 34 with a delay time Tdly2 (for example 5 seconds). If the load of main outlet 31 is not turned on in Tdly1, the micro processor 100 maintains the mains power to peripheral outlet 32, 33 and 34 afterward, and controls the switching circuitry 91 to disconnect mains 15 power from the main outlet 31 with a delay time T_dly2. After T dly1, the micro processor 100 will control switching circuitries to disconnect mains power from the peripheral outlet of which its load is turned off or not in use with a delay time Tdly2. If there is not valid input of external control signal 1001 or 1002 in Tdlyo, the LED 1014 on infra-red sensing unit will flash for a 20 period of time T_dly3, for example 2 minutes. If there is no valid input 1001 or 1002 in Tdly3, the micro processor 100 will control the switching circuitries to disconnect mains power from main outlet 31 and peripheral outlets 32, 33 and 34. An interruption of mains power supply or a valid input of external control signal, 1001 or 1002, will make the micro processor to 25 control the switching circuitries to connect mains power to the main outlet 31 and peripheral outlets 32, 33 and 34 again, and then the automatic control cycles. Another preferred embodiment of the invention, which is called as PEb, 30 is illustrated by Figure 6, Figure 7, Figure 8, figure 9 and figure 5. Figure 6 shows an perspective view of PEb which comprises a main body 10, a plug 20 to connecting to mains power supply, a power cord 21, one always-on outlet 30, one group of outlets which consists only one outlet 31, -11 another group of outlets 32 which consists of four outlets, one external control unit further comprising an external unit body 50, a button 40, an infra-red sensor 41 and an LCD display 52, a wire 51 linking the external body 50 to main body 10. On the main body, there are power indicators 60, 61 and 62 for 5 each group of outlets respectively and there is an overload circuit breaker 70. The always-on outlet 30 is for appliances demanding continuous power supply, like wireless phone, fax machine, or VCR. 10 Controllable appliances, like TV, stereo, satellite box, game console, can be connected to outlet groups 31 or 32. For easy description below, the outlet 31 is defined as main outlet; the outlet group 32 is defined as peripheral outlets. 15 When a power indicator above one group of outlets lights up, it means mains power supply to the respective group of outlet is connected; when a power indicator above one group of outlets is off, it means the mains power supply to the respective group of outlets is disconnected. 20 Figure 7 shows a schematic of a power PCB for PEb, including mains power protection 130, low voltage power supply 131, a conjunction port 121 linking to the control PCB for PEb and a conjunction port 122 linking to the external control PCB for PEb. 25 The mains power protection 130 consists of an overload circuit breaker 1301 which breaks mains power when overload occurs for safety; three surge protectors 1302 are connected between any two wires of live, neutral and earth, to protect the appliances connected from surge. 30 The low voltage power supply 131 adopts a PWM power switcher IC 1311, a high frequency electronic transformer 1312 and peripheral components to supply isolated DC power supply 1313 for the external control PCB for PEb and non-isolated DC power supply 1314 for the control PCB for PEb. The signal 1002 and 804 on the control PCB for PEb are converted into 1012 and -12 1013 by isolation provided by photo coupler 1315 and 1316 on the power PCB for PEb, and then are connected to the external control PCB for PEb. Figure 8 shows a schematic of a control PCB for PEb, including one 5 load sensing circuitry 80 for loads of all outlets, two load sensing circuitries 81 and 82, two switching circuitries 91 and92, a micro processor 100, and one conjunction port 121 linking to the power PCB for PEb. Take the load sensing circuitry 81 as example to explain in detail, the 10 load sensing circuitry 8o and 82 are same as 81 in components and function, they only differ in load of different outlets they sense, circuitry 8o senses the load of all outlets, circuitry 81 senses the load of main outlet 31, and circuitry 82 senses the load of peripheral outlets 32. 15 Load sensing circuitry 81 consists of a single phase energy metering IC 81o, a voltage sensor by resistors 811 and 812, a current sensor by shunt 813, and other peripheral components. The load sensing circuitry 81 keeps sensing the load of outlet 31, and keeps outputting a number of pulses 814 proportional to the load. This load sensing signal 814 is connected to an input 20 of the micro processor 100. Take the switching circuitry 91 as example to explain in detail, the switching circuitry 92 is same as 91 in components and function; they only differ in different control signal from the micro processor and different outlet 25 they control. Switching circuitry 91 consists of a transistor 911, a relay 912 and a freewheeling diode 913. The control signal 1004 from the micro processor 100 controls the switching status of 911, the relay 912 then pulls up or breaks 30 accordingly. When the relay 912 pulls up, the mains power supply to outlet 31 is connected, when the relay 912 breaks, the mains power supply is disconnected from outlet 31.

-13 The micro processor 100 analyzes two load sensing input 814 and 824, external control signal input 1002 (consolidating the control signal of from the button and the infra-red sensor), follows the control flow chart illustrated in Figure 5, and then outputs control signal 1004 andioo5 to control the two 5 switching circuitries 91 and 92, and the power indicator of each group of outlets respectively. The control PCB for PEb shows in Figure 8 links with the power PCB for PEb through the conjunction port 121 to get DC power supply and 10 communicate with the external control PCB for PEb. Figure 9 shows a schematic of the external control PCB for PEb, including a micro processor 101, a button input circuitry il, an infra-red signal sensor circuitry 112, a display circuitry 102 , and a conjunction port 122 15 linking to the power PCB for PEb. The button input circuitry in will generate control signal 1016 which is connected to an input of the micro processor 101. The micro processor 101 sends a signal 1012 to the main PCB for PEb for every valid button control input indicating one valid external control signal sensed. The infra-red signal sensor circuitry 112 converts a infra-red signal into a 20 series of pulses 1o1. The micro processor 101 analyzes the width of pulses and interval between pulses to determine the validity of an infra-red signal. When one valid infra-red signal is determined, the micro processor controls the LED 1014 to flash a couple of times, for example one time, and sends a signal 1012 to the main PCB for PEb indicating one valid external control signal sensed. 25 The approach by which the micro processor 101 determines the validity of infra-red signal is unrelated to the coding protocol of infra-red signals, so the user does not need to pair their infra-red remote controllers to the external control unit. When there is no valid external control signal (including button input and infra-red signal) sensed in a preset period of time Tdlyo, the micro 30 processor 101 controls the LED 1014 to flash for a period of time T dly3, and the buzzer 1013 to beep for a period of time Tdly4.

-14 The external control PCB for PEb showed in Figure 9 links with the power PCB for PEb through the conjunction port 122 to get isolated DC power supply and communicate with the control PCB for PEb. 5 Figure 5 shows a control flow chart of the present invention, it is also applicable to PEb. After an interruption of mains power supply or a valid input of external control signal, the micro processor 100 sends controls signals to switching circuitries to connect mains power supply to main outlet 31, and peripheral outlets 32. Meanwhile, the micro processor 100 starts counting a 10 preset period of time T dlyo (for example 1 hour) and a preset period of time Tdlyi (for example 1 minute). If the load of main outlet 31 is turned on in Tdlyi, when it is turned off afterward, the micro processor 100 will control the switching circuitries to disconnect mains power from the main outlet 31 and peripheral outlets 32 with a delay time T-dly2 (for example 5 seconds). If 15 the load of main outlet 31 is not turned on in T dlyi, the micro processor 100 maintains the mains power to peripheral outlets 32 afterward, and controls the switching circuitry 91 to disconnect mains power from the main outlet 31 with a delay time T-dly2. After Tdlyi, the micro processor 100 will control switching circuitries to disconnect mains power from the peripheral outlets if 20 their loads are turned off or not in use with a delay time T-dly2. If there is not valid input of external control signal 1002 in Tdlyo, the LED 1014 on external control unit will flash for a period of time T dly3, for example 2 minutes, and the buzzer on the external control unit will beep for a period of time Tdly4, for example 1 minute. If there is no valid input 1002 in Tdly3, 25 the micro processor 100 will control the switching circuitries to disconnect mains power from main outlet 31 and peripheral outlets 32. An interruption of mains power supply or a valid input of external control signal 1002 will make the micro processor 100 to control the switching circuitries to connect mains power to the main outlet 31 and peripheral outlets 32 again, and then the 30 automatic control cycles. Another preferred embodiment of the invention, which is called as PEc, is illustrated by Figure 10.

-15 Figure 10 shows a perspective view of PEc which comprises a main body 10, a plug 20 to connecting to mains power supply, one group of outlets 31 which consists only one outlet, another group of outlets 32 which only consists of one outlet, an external control unit further comprising an external 5 body 50, a button 40, an infra-red sensor 41 and an LCD display 52, a wire 51 linking the external body 50 to the main body 10. On the main body, there are power indicators 61 and 62 for each group of outlets respectively and there is an overload circuit breaker 70. 10 The preferred embodiment PEc is same as PEb on the power PCB, the control PCB, the external control unit, and the control flow chart. They only differ from each other in: there is no always-on outlet 30 on PEc; the group of outlets 32 on PEc only consists of one outlet; and PEc connects to mains power supply by a plug directly. The preferred embodiment PEc is featured 15 with compact in size and portable mobility. The detailed description set forth above is provided to aid those skilled in the art in practicing the present invention. The invention described and claimed herein, however, is not to be limited in scope by the specific 20 embodiments disclosed because these embodiments are intended to be illustrative of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of the present invention. Various modifications of the invention that do not depart from the spirit or scope of the present invention, in addition to those shown and described herein will 25 become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.

Claims (15)

1. An energy saving electrical outlet device comprising: A main body with a plug or a power cord adapted to connect to mains 5 power supply; At least two groups of outlets, each group of outlets consists of one or more electrical outlets; At least two load sensing circuitries adapted to sense the load of each group of outlets individually; 10 At least two switching circuitries adapted to switch mains power supply to each group of outlets individually; At least one external control input unit; At least one micro processor adapted to analyze the load sensing signals and external control signals and then generate control signals for switching 15 circuitries.

2. An energy saving electrical outlet device as claimed in claim 1, further comprising at least one always-on outlet which is always on after an interruption of mains power supply, for the appliances demanding continuous power supply, like codeless phone, or fax machine. 20

3. An energy saving electrical outlet device as claimed in claim 1, further comprising an LCD display. The LCD displays the instant wattage of the appliances connected to the device, or cumulative energy, or cumulative energy cost, or cumulative C02 emission, or their combinations.

4. An energy saving electrical outlet device as claimed in claim 3, wherein the 25 LCD display is on the main body or on the external control unit which links to the main body by a wire or by a wireless means.

5. An energy saving electrical outlet device as claimed in claim 1, wherein the load sensing circuitries either adopting a current transformer to output an analogue signal proportional to the load, or adopting an energy metering IC to 30 output a number of pulses proportional to the load, or a combination of them.

6. An energy saving electrical outlet device as claimed in claim 1, wherein the micro processor determines the in-use status of appliances connected to each group of outlets by comparing the sensed load to a preset threshold or by analyzing the fluctuation of sensed load, or a combination of them. -2

7. An energy saving electrical outlet device as claimed in claim 1, wherein after the appliances of a group of outlets are determined not in-use, the micro processor delays a period of time T_dly2 and then generates a control signal to disconnect mains power from the group of outlets. 5

8. An energy saving electrical outlet device as claimed in claim 1, wherein the external control input unit is a button, an infra-red signal sensor, and PIR sensor, a radio frequency signal receiving module, an optical signal sensor, an audible signal sensor, a pressure sensor, a temperature sensor, a humidity sensor, or a combination of them. 10

9. An energy saving electrical outlet device as claimed in claim 1 or claim 8, wherein the external control input unit is on the main body or has an external body which links to the main body by a wire by or a wireless means.

10. An energy saving electrical outlet device as claimed in claim 9, wherein the external control input unit comprises an infra-red signal sensor, when a valid 15 infra-red signal is sensed, the micro processor generates control signals to connect mains power to all controlled outlets; if there is no valid infra red signal sensed in a preset period of time T-dlyo, the micro processor generates control signals to disconnect mains power from all controlled outlets.

11. An energy saving electrical outlet device as claimed in claim 9, wherein the 20 external control unit has an auxiliary LED light, the LED light flashes a couple of times to indicate a valid control signal sensed.

12. An energy saving electrical outlet device as claimed in claim 9, wherein the external control unit includes an auxiliary LED light, the LED light flashes for a period of time T_dly3 when there is no valid control signal sensed in a preset 25 period of time Tdlyo.

13. An energy saving electrical outlet device as claimed in claim 9, wherein the external control unit has an auxiliary buzzer, the buzzer beeps for a period of time T_dly4 when there is no valid control signal sensed in a preset period of time Tdlyo. 30

14. An energy saving electrical outlet device as claimed in claim 10, wherein the infra-red signal sensor converts a infra-red signal into a series of pulses, the micro processor determines the validity by analyzing the width of pulses and intervals between pulses. -3

15. An energy saving electrical outlet device as claimed in claim 8, wherein the external control input unit comprises a button, on each button control signal input, the micro processor generates control signals to change the power supply status of all controlled outlets once.