electric aluminum blinds - WSEAS · blinds would waste much time and people. (b) Hidden danger: The...

To Develop a New Electric Aluminium Blinds Based on InfraredRemote Control Technology

CHIH-YU, HUNG *1 CHIEH-TSUNG, CHI *2

Department of Electrical EngineeringChienkuo Technology University

No. 1, Chieh Shou N. Rd., Changhua City 500, Taiwan, R.O.C*1 [email protected] *[email protected]

Abstract: - The conventional aluminium blinds have many outstanding functions, for example, closed off overdaylight, sun shading, environment decorating, less dissipated energy consumption in air-conditioner andlighting system. However some critical problems have not solved yet. First, the inclined angle of blinds is overrelied upon user. The operation efficiency is too low to use. Second, some media reported that the operationrope of aluminium blinds used for adjusting the inclining angle of blinds wind around child and even lose theirlive finally. Third, the total indoor room decoration would be destroyed in order to install aluminium blindsbody. Fourth, the operation of traditional aluminium blinds can only be controlled by people directly by usingtheir hands. Because of designed unfriendly, it is inconvenient and not comfortable. Therefore, this paperpresents a new compound electric aluminium blind which is composed of most mechanical mechanism of thetraditional aluminium and limited manufacturing cost. Alternating current (AC) power line, battery or adapter(DC), or even solar cell can be selected as the power source of the proposed electric aluminium blinds. Nooperation rope is needed again. The amount of wind around events for home children should then be decreasedor disappeared completely. Since the infrared remote controlling equipment is introduced in new aluminiumblinds system, users need not operate and touch the compound electric aluminium blinds directly and theoperating range of equipment is also increased too. Especially, the total indoor room decoration will not beaffected or destructed due to the affiliation of aluminium blinds. When the intensity of outdoor daylight isstrong enough, the PV is naturally chosen as the power of compound electric aluminium blinds. This is apractical step to pursue the object of green buildings. The economic value of these compound electricaluminium blinds would be as well as promoted.

Key-Words: - Conventional aluminum blinds, Compound electric aluminum blinds, DC motor, Solar cell,Alternating current, Battery.

1 IntroductionIn the past, the increasing buildings and houserooms are widely built in the whole world.Moreover, there is more and more electrical energyis dissipated in lighting purposes. If the powersaving purpose only depends on the building ownersor lighting users, this purpose must not be easilycome true. In order to improve the lightingefficiency, more and more technicians use moderntechnology and sensors in the lighting area. Ifsomeone enters the monitored lighting area, a signalwill be sensed by a suitable sensor and immediatelytransmitted this signal to the system controller. Thesystem controller will command the lightingequipment is illuminated. In case of the peopleleaves the monitored area; the lightings will bedistinguished right now. The disadvantages of thislighting control method is that the lighting intensityof monitored area which maybe come from other

lighting. At the same time, a movable sensor forsensing the lighting intensity is required. A lot ofmovable lighting sensors are necessary; therefore,the installation cost would be increased too.

The other power-saving method in the generalbuildings is to change or modify that the lightingintensity by fine tuning strategy. By means of theoperation of user or owner, the lighting intensity ofinside building is suitably controlled. Although thelighting intensity is adjusted by people, much moreelectrical power energy is then saved. If indoorspace should have a constant lighting intensity, it isdifficult and impossible for people to control thelighting intensity at any time. In the recent decades,there are some experts paid more their attention onthe control method research related to the lightingintensity. By using the sun shine to provide part ofthe lighting intensity inside building, a fewresearchers have successfully achieved the electrical

WSEAS TRANSACTIONS on INFORMATION SCIENCE and APPLICATIONS Chih-Yu Hung, Chieh-Tsung Chi

E-ISSN: 2224-3402 103 Issue 4, Volume 9, April 2012

energy-saving result which original dissipation inindoor illumination. For example, the energycommittee of California state government wasaimed at researching the method how to save theelectrical energy dissipated in public illumination.This project was only to consider the lighting turnon/off control of indoor illumination. The effect ofthe outside lighting intensity on the indoor lightingintensity was never considered [1,5].

For achieving the power efficiency of indoorillumination, it is very inexpensive for the user tocontrol the indoor light intensity by turning on/offmethod. The other one may also be more effectiveand reasonable a bit by using fine tuning method.According to many experimental results, if part ofthe indoor light intensity is supplied with outdoorsunshine, generally about 20~60 percentage of thetotal electrical power dissipated in indoor lightillumination may be reduced. The actual electricalenergy-saving percentage is entirely decided to thecontrolled area neighbouring environmental sunintensity [2-4,6]. If the outdoor sunshine intensity issufficient, it should be rewarded for the buildingowner to adopt outdoor sunshine intensity tosupplying with the indoor illumination. If a buildingreserves a lot of skylights or windows, there is a lotof chances to save more electrical energy dissipatedin indoor light illumination. Many indoor spaceslike offices, public buildings and schools, maybemore outdoor sunshine can be used and projectedinto indoor space and served as indoor illumination.It is a reasonable result for the more windowinstalled, the more electrical energy saved. Someequipment such as the aluminium blinds have to beprepared for blocking the excessive sunshineintensity some time. To achieve higher electricalpower energy-saving purpose from indoorillumination, the illumination designer should firstrealize that different lamps often have differentcharacteristics as well. In general, a natural lightsuch as sunshine can be obtained from outdoor, it ischeap. On the contrarily, an artificial light is oftengenerated by a light bulb and it should be suppliedwith electrical power. The other important factorsconcerning to the indoor illumination, such as theinstallation position and inclination angle of light,the installation position of light sensor and so on.Furthermore, the colour of indoor illumination isalso affects the read value [7].

Up to now, a lot of different control methodswere proposed to control the angle of inclination ofaluminium blinds. Chen et al. [4] designed a controlmethod which included a fuzzy controller and twofeedback loops for controlling the inclination angleof aluminium blinds. In most applications, the

critical and concerned things by users almost is theamount of sunshine thrown into inside building,therefore, it is not a important problem whether theinclination angle of natural light can be preciselycontrolled by the controller or not. The proposedcontrol method by Chen’s therefore can be furthersimplified to a control structure only with afeedback loop. In reference [5], Viereck has evermade use of some MEMS devices to complete theinclination angle control of light. In another controlmethod, the wireless communication approach wasalso used to transmit the sensed environmental lightdata between all the installed light sensors. Thecontrol structure of this method basically has twoadvantages such as easy installation and free of anyconnection cable. But the manufacturing cost isexpensive and it is easily interfered by otherenvironmental noise sources. According to the basicconfiguration and using experiences over past years,some disadvantages related to the traditionalaluminium blinds can be concluded and given asfollowings [8]:

(a) Larger size: To obtain more natural sunshinethrown into inside building, lots of buildings has acommon feature is that installed number of windowgenerally as many as possible. As the season change,the inclination angle of sun is different as well.Sometimes, more sunshine is thrown into insidebuilding through window and made peopleuncomfortable. The people works or lives inbuilding. Sometimes, he or she needs a personalspace for special purpose. The aluminium blindsmay be the best choice product. In case of the sizeof aluminium blind is too large to easily control, it isinconvenient. The operation of traditionalaluminium blinds is controlled by people is noteconomic too. As the number of window isincreasing, the control of traditional aluminiumblinds would waste much time and people.

(b) Hidden danger: The traditional aluminiumblinds are controlled by people directly. Forexample, the adjustment like scroll up or scrolldown and the inclination angle of the Aluminiumblinds. All the adjusting operations of thealuminium blinds are completed through a rope withpebble material. To take the manufacturing cost intoconsideration, the operating mechanism of thistraditional aluminium blind is designed as simple aspossible. In recent years, some accidental eventsoccurred and even people died due to theconventional aluminium blinds. Most of accidentalcases were made by babies. However, the using orbuying willing of the traditional aluminium blindshas greatly decreased in recent year.



(c) Insufficient appearance: In general, the valueof the building is not only affected by theenvironmental living functions, but also does theindoor building whether is decorated well or not. Inorder to promote the value of building, extradecorations will be added into the indoor building.The type and material of curtain plays an importantrole under the building decoration process. Inaddition, the installation of the window curtainshould not require destroying original buildingframe.

(d) Inconvenient operation: The choice of thewindow curtain should first consider whether it issuitable for the basic necessities of building owners.Furthermore, the operation convenience is anothercritical consideration as well. In modern society,time is money, the operation of curtain dependsupon people should be kept off now.

(e) Insufficient robustness: For some specialpurposes, the room arrangement is generallyallowed to be adjusted at any time. This event oftenhappens indoor of building. A movable windowcurtain is a better choice. Therefore, the flexibilityof curtain design is important. Curtains only havefix appearance and frame becomes a worse design.

(f) Automatic temperature adjustment: One ofimportant curtain functions is used to blocksunshine directly projected into indoor building. Ifthe projecting time is too long and the sunshine isstrong, the temperature inside building would beincreased very soon. For decreasing the temperatureas soon as possible, much more electrical powerwould be then dissipated in the air conditioner ofindoor building.

For the sake of using the outside naturesunshine, this paper presents an electronic controllerwhich uses a low-cost hardware circuit and softwareto control the actions of window curtain. Due to partof the indoor illumination is partly provided byusing outdoor sunshine. However the scroll-up,scroll-down and the inclination angle of curtain isdriven by a DC brush motor with reduced gear box.The system is controlled by an electronic controlunit (ECU). The control command is transmitted bymeans of a remote wireless communication throughinfrared medium. The amount of projected outdoorsunshine is controlled by using electronic controlunit. In addition, the required electrical energy ofthe controller circuit can be selectively applied bydc adaptor or battery or solar-cell group. Theproposed electronic controlled window curtain isthen also called as compound electronic drivenaluminium blinds.

2 The Structure of Electric AluminumBlinds

In order to achieve the operation of the electricvenetian blinds through wireless remote control, thesystem controller commands is transmitted from aremote terminal via wireless infrared medium toreceiver terminal. Since the manufacturing cost ofinfrared wireless remote control structure isinexpensive and reliable when it is used in indoorbuilding application [11,12]. Consequently, manyconsumer electronic equipments have beencontrolled by employing this control method. Inmany applications, the manufacturing cost andremote control distance are two importantconsidered control factors. From past many usedexperiences in practical applications, the electricaluminium blinds is being remote wirelesscontrolled method by means of infrared medium.Fig. 1 shows a typical functional block structure of apopular infrared practical application. Fig. 1(a) isthe functional block in transmission terminal. Whenthe operator hope to control equipment throughpressing an operating key, this control commandsignal will be first occurred and combined withaddress data of receiver terminal together and thenencoded into a series of data. This action can onlybe completed by using an encode IC. By usinginfrared served as a transmitting medium,transmitted command is transferred from localterminal to the remote receiver terminal accordingto the address data. It should be worthy of noticethat the infrared light is invisible and easy interferedby other signals, especially the outdoor sunshine.

In order to improve the transmitting yieldpercentage of wireless communication, there is acircuit is added to the latter circuit of decoder IC forstrengthening the output signal. Fig. 1(b) diagramsthe functional block related to the receiving circuitof infrared signal based on an infrared receivingmodule. When a signal is received by infraredreceiving module, it will be decoded two parts, suchas command and address data. In case of the addressdata of received data is identical to the remoteaddress setting data of decoder IC, the received datawill be output from the output pins of decoder IC.Certainly, the output data of decoder IC is the sameas the transmitted command (or key data) in theory.Otherwise, transmission failure occurs and nosignals or commands output from decoder IC pins.

(a)



(b)Fig. 1 Basic functional configuration in (a)transmitter terminal (b) receiver terminal.The mechanism of the proposed new type

electronic aluminium blinds in this paper is alsotraditional aluminium blinds. In fact, only thenecessary driven force for operating the aluminiumblinds is changed from by people to by a DC motor.In the following, we will introduce the designingideas and the working principle of detailed interfacecircuits in the transmitter and receiver terminals,respectively.

2.1 Remote Control TerminalBased on infrared transmitting medium, the controlcommand of electronic aluminium blinds will begenerated from the transmit terminal. When thiscommand is transmitted by infrared medium andreceived by infrared receiver module finally, thereceived data or command is decoded and outputtedrelative control command. The decoder IC willimmediately inform the single chip to read the dataappeared on the output pins of decoder IC [7]. Byusing suitable calculation and identification process,the real control actions will be carried out by therelated mechanical and electrical mechanism in thereceiver terminal.

The remote control of proposed new type ofaluminium blind is generated by the operator. Thecommands are transferred from the transmitterterminal to the receiver terminal by means ofwireless communication [10-15]. When a controlcommand is received and decoded by the systemcontroller in receiver terminal, a responding actionwill be switched on by the system controller. Asshown in Fig. 2, the default number of commands inthe transmitter terminal is four keys. That is scrollup, scroll down, auto light tracking, and stop. Whenone of four keys is pressed, the decoder IC includedin Fig. 2 will decode the pressed key command intoa series of binary data. This binary data consists ofaddress, and meaning. To reduce the interference oftransmitted infrared signal in the transferred processas possible as, the transmitted data will be firstamplified and then transmitted by employing aninfrared emitting diode with high frequency on/offsquare wave.

Encoder

UP

DOWN

AUTO

STOP

Modulation ICHT-12E

D0

D1

D2

/TE

Carrierfrequency

Photodiode

Fig. 2 Implementation idea related to the transmittercircuit through infrared media.

2.2 Receiver and Interface CircuitsFig. 3 is the functional block diagram of the receiverterminal of the proposed infrared remote controller.As shown in Fig. 3, the designing ideas and theoperating principles of the sub-system or interfacecircuits will be introduced in the following:

Fig. 3 Functional blocks of infrared receiverterminal and interface circuit .

2.1.1 Single chipThe infrared receiver of the system controller isdeveloped based upon a single chip, which isproduced by Microchip Company and serial numberis PIC16F84A. The important electrical parametersare listed below [11]:

(1) 1K bytes EEPROM;(2) 36 bytes SRAM and 15 special function

registers;(3) 64 bytes EEPROM，4 interrupt sources;(4) 35 instructions, max. working frequency is 10

MHz。(5) 13 I/O pins, includes input and output function,

and they can be individually programmed;(6) Every I/O pin has high driving capacity. It can

drive LED directly. The maximum value of outputcurrent for each I/O pin is 20 mA and the maximumsink current is 25 mA .



(7) Includes an 8 bits timer or counter, there is apre-scalar installed before the signal input of timeror counter and its counting range is 8 bits.

(8) There is a sleeping mode function. When thereceiver terminal is needed to be situated in standbystate, the single chip can enter into the sleepingmode for energy-saving purpose. If the powersource is supplied with battery, the using time canthen be prolonged since a little electrical energy isrequired by the electric circuits.

2.1.2 Circuits for sensing motor current andtracking the intensity of sunshineIn order to sense the dynamical moving position ofaluminium blinds, there are two limit switches willbe installed at top and bottom positions of thealuminium blinds. The proposed new electrical typeof aluminium blinds is required to have a betterappearance. Any of the mechanical switch like limitswitch is not allowed to installed outside of themechanism of the electric aluminium blinds. Thedynamic moving position will be known bycounting series of pulses generated from the outputof an encoder-like mechanism. The encoder-likemechanism is composed of a reflected type of lightinterrupter. When the driven motor of electricaluminium blinds starts working, the lightinterrupter is rotated at the same time and a series ofsquare pulses are outputted. These pulses aredynamically received and then counted by the singlechip. The dynamical moving position of thealuminium blinds is then being updated immediately.In addition, a resistor with very low resistance isused as a current sensor and connected with thedriven dc motor in series [8]. The dynamical currentvalue of the dc motor will be first amplified andtransmitted to the system controller. When thealuminium blinds has touched the top terminal ofthe mechanism, an abnormal larger current of the dcmotor is generated and transmitted to the systemcontroller. For the sake of safety, the dc motor willbe commanded to stop running immediately.

The stable rated current value of DC motor isabout 0.3 A, but the current value may suddenly beincreased over 0.7 A when the electric aluminiumblinds touches the top mechanical terminal. In orderto test the happening time for this heavy load, acurrent comparator is designed and embedded in thesystem controller. If there is a signal is generated inthe output of the current comparator, this representsthat the mechanism of electric aluminium blinds hastouched the top mechanical terminal. This signal isoften used to turn the power source of DC motor offimmediately in order to protect the mechanism and

electric circuit devices from being destroyed. Inaddition, this signal is also employed to reset theposition counter which is implemented by thesoftware of the single chip to an initial value.

On the contrarily, when the mechanism of theelectric aluminium blinds is controlled scroll down,a little current value generated because the loadeffect of DC motor is very light. The measuredcurrent value is about 0.15 A in this situation. If theoverflow status occurred to the position counter, thisrepresents the mechanism of electric aluminiumblinds has touched its bottom end terminal. Themechanism will become scroll up if no stop signal isproduced to turn the power of DC motor off. Ofcourse, the motor current is increased right now.

Fig. 5 shows that the normal stable currentvalues of DC motor during different workingprocesses.

(1) Scroll down: there is a minimum loadoccurred to the DC motor, the stable current of DCmotor is normally lower than 0.3 A ;

(2) Scroll up: the required current of DC motoris increased from 0.3 A to 0.7 A ;

(3) Upper limit: the mechanism of electricaluminium blinds has touched the top end terminaland even no movement again. Normally, the currentvalue in this stage is larger than the other two stagesand over 0.7 A .

Fig. 5 It is shown that the required current ofDC motor when it is run in different working

processes.

Fig. 6 The circuit for controlling rotating directionof DC motor.



The DC motor is reversible. In other words, itcan be rotation in clockwise or counter-clockwisedirection. Fig. 6 shows that the circuit forcontrolling the rotation direction of DC motor. Thecurrent sensor which is really a resistor associatedwith a very low fix resistance, 20 m , is connectedwith the DC motor in series. The benefits of thecurrent measuring method are cheap, small, andreliable. The physical current value of DC motor issensed by reading the amplified voltage drop acrosscurrent sensor resistor.

2.1.3 Dynamic position sensory circuit:As mentioned above, in order to measure thedynamic position of electric aluminium blinds, thereis encoder-like sensor is equipped with the rotor axisof the DC motor. There are eight small circlesdistribution on its edge for measuring the rotationangle of DC motor. Therefore, the measuringresolution is 45 degrees. Fig. 7 indicates that theinstalled position of encoder-like sensory device.

Fig. 7 Demonstrates that the equipped position ofencoder-like device.

2.1.4 The speed control circuitIn order to control the inclined angle of aluminiumblinds by using fine adjusting function, two voltagevalues are set for supplying with DC motoralternately. At the beginning stage, the DC motor issupplied with a typical voltage source, +5 V. After 5seconds, a +12 V voltage source is in turn applied tothe DC motor. The running speed of latter case ismore than that in +5 V. The voltage supplyingcircuit is shown in Fig. 8.

Fig. 8 The speed control circuit of electricaluminium blinds.

2.1.5 Light tracking circuitBecause the material of electric aluminium blindspossesses more or little expanded characteristic, therequired small inclined angle of the electricaluminium blinds is always a very difficult work formost people. In this paper, two light intensity sensor,Cds, are installed indoor and outdoor building,respectively. These two light sensors are combinedwith the other two resistors with fix resistance toconstruct a typical full bridge circuit. The lightintensity in indoor is able to be set as you wish witha wide adjustable range from 0~100% in theory. Thelight tracking circuit always works if the outputvoltages across these two sensors are different. Thefinal implemented control circuit is demonstrated inFig. 9.

Fig. 9 Diagrams the light tracking circuit.

2.1.6 Power module

Fig. 10 Shows that solar-cell power module.

The implemented electric aluminium blindscan be supplied with three types of power sourcesuch as AC adaptor, battery, and solar cell. Thegenerated voltage value, Vpv, of the solar cell isproportional to the light intensity of sunshine. Thismeans the voltage value Vpv of solar cell is variable.Therefore, the power source of solar cell can not bedirectly applied to the later electric circuit. For thesake of reducing the size of the used solar cell, avoltage boost converter is often used to increase thesupplying voltage of the solar cell. Two specialpurposes are anticipated to be achieved here. Thefirst purpose is able to increase the supplying



voltage value of the solar cell. The required timewhen a rechargeable battery is charged with solarcell is as soon as possible. The second purpose ishoped to overcome a problem that the outputvoltage of solar cell is variable and it is affected bythe environmental light intensity. The latter problemwill be solved by adding an energy-saving device totemporarily save the generated power source of thesolar cell. For example, a super-capacitor orrechargeable battery is a very suitable device forachieving this purpose. Moreover, the worse loadregulation often occurred in most of solar-cellsupplying circuits would also be improved as well.

In order to reduce the designed andimplemented complication of system controller, theelectric aluminium blinds is able to be powered by agroup of solar cell which is composed of four piecesof single solar cell and connected in series. The totalrated open voltage across output terminals of solarcell, ocV , is about 10 V and the rated short current is150 mA . A diode D is arranged between the solarcell and super-capacitor to avoid discharging whenthe output voltage value of solar cell is lower thanthat of super-capacitor. According to the theoreticalformulas, tIVCQ , which is reserved in thesuper-capacitor, the capacitance and reservedelectrical quantity of super-capacitor can beobtained under the required power energy ofelectrical circuit. (where C is the capacitance ofsuper-capacitor, V is the voltage across the super-capacitor, I is rated current, and t is the workingtime)

However, most of heavy load like inductive orcapacitive load, the stating current is always largerthan that of normal rated current. In order tostabilize the output voltage of power source, anenergy buffer such as rechargeable battery like Ni-Hbattery or Li-ion battery is required. Since theserechargeable batteries have higher energy density,although their power energy may be is low. Theother type of electric energy reserved device is thesuper-capacitor. The power density of the super-capacitor is very outstanding. The number ofrecharging times of the super-capacitor is very short.These devices are allowed to discharge and chargeunder a very short required time interval. Theallowed charging and discharging current is abouthundred times that of each type of rechargeablebatteries. Especially, some important features suchas high charging rate, compact, and intolerance tocold are very remarkable too. The required biggestpower energy of the electric circuit is dissipated byDC motor. Fortunately, the total spent time for theDC motor moving from the bottom to top is not

more than one minute. Therefore, the dynamicallygenerated electric power of solar cell has beensufficient to supply with the required electric energyof all electric circuit. In recent year, lots of domesticmanufacturers are able to design and produce mnaytypes of super-capacitor. Of course, the cost ofsuper-capacitor would be decreased year by year.

3 Designing Procedures of Solar CellModule

As mentioned earlier, the required power of theelectric circuit can be supplied with an AC powerline through an adaptor or a rechargeable battery ora group of solar cells. In case of the power ofelectric circuit is supplied with a group of solar cell,the supplying voltage of solar cell is decided to theoutdoor light intensity. As we known, the lightintensity of outdoor sunshine is changeable;therefore, the output voltage value is naturallyvariable too. In order to overcome this problem, thegenerated electric energy should be stored in anelectric energy reserved device in advance. Whenthe system control of electric aluminium blinds isturned on, the stored electric energy in device willbe used to supply with the electric circuit. Thedesigning procedures regarding to the detailedcircuits for storing the generated electric energy ofsolar cell will be described as follows:Step1: Decides the total dissipated electric energyfor one operating cycle: According the measuredresults from the prototype of electric aluminiumblinds, a current value 60 mA will flows through theDC motor when it executed scroll-up action. Oneoperation cycle is composed of one scroll-up andone scroll-down action. The amount of requiredelectrical quantity of the circuit is given as follows:

Coulum33 1036003010602 (1)

Step 2: Assumes that one day works two cycles: Inorder to increase the reliability of the system powersupply, it is assumed to that the aluminium blindshave to be operated two cycles within one day. Next,the required electrical quantity is stored in reserveddevice is:

Coulum33 1072001036002 (2)

Step 3: Selects a suitable device to reserve electricalenergy: Basically, the total electric quantity which itis required by all control circuits and DC motor asshown in (2). The rated working voltage of the



circuit is assumed as 5.4 V, the capacitance ofsuper-capacitor can be calculated as follows:

FCC

333.14.5107200 3

(3)

Here, we want to further improve the reliability ofthe system power supply. A super-capacitor with 5F is used as the electric energy storing device here.Step 4: Selects a solar cell with suitablespecifications: The required solar cell is that shouldsupply with sufficient electrical energy to all electriccircuit designed in electric venetian blind. The ratedopen voltage is ( OCV ) 4 V and the short-circuitcurrent is (Isc) 75 mA, respectively. If the totalworking time for one day is five hours and thegenerating efficiency must be over 60 percentages.By using these electrical specifications, thegenerated electric power energy of solar cell forevery day can be calculated in the following:

Joul3240606056.010754 3 (4)

If the capacitance value of the super-capacitoris F5 , the rated working voltage is assumed as

V4.5 . The allowable charged electrical energy mustbe sufficient to supply with all circuits requiredelectric energy for two operation cycles, then

Joul

VCWC

9.72

4.552121

2

2

(5)

Apparently, the stored energy shown in (4) is muchbigger than that shown in (5), it represents that theamount of generated electric energy of solar cell issufficient.Step 5: Independent power supply: Most ofelectrical energy will be dissipated in the receivercircuits due to the action of DC motor. The amountof generated electrical energy of solar cell will bealways enough if and only if a super-capacitor withlarge capacitance and power density enough. Inmost application cases, an AC power source throughan adaptor are used to supply with the requiredelectrical circuit is not necessary at any time.Step 6: Indirect operation: the new developedelectric aluminium blinds is operated by remotecontrol method. The control command is transferredfrom the transmitter terminal to the receiverterminal by means of wireless infrared medium. Theoperator is really not required to control the

aluminium blinds by their hand. It is veryconvenient and suit for the future developing trendin most consumer electronics.

4. ControllerAccording the functional block of system controllerbased on wireless infrared medium, the detailedtransmitter and receiver circuits designed forcontrolling the proposed electric aluminium blindswill be gradually examined in the following:

4.1 Transmitter CircuitFig. 11 shows that an IC 74HC148 is used to decodea key code into a four-bit data. A communicationpair of ICs, HT-12E and HT-12D which areproduced by domestic manufacturer, Holtek, isresponsible for encoding and decoding data andaddress. The HT-12E is an encoder IC and arrangedin transmitter circuit, it has following importantfeatures:

(1) A0~A7: Input pins for address A0~A7 setting;(2)AD8~AD11: Input pins for address/data

AD8~AD11 setting;(3) OSC1: Oscillator input pin;(4) OSC2: Oscillator output pin;(5) /TE: Transmission enable, active low;(6) Dout: Encoder data serial transmission output;(7) Vss: Negative power supply, grounds;(8) Vdd: Positive power supply.A transmission action is enabled by applying a

low signal to the TE pin. The designed purpose ofintegrated circuit, UN2003A , wants to promote thedriving capability of the transmitted signal.

Fig. 11 Detailed transmitter circuit.

When the transmitter circuit is triggered tobegin transmitting data, that is /TE pin become lowvoltage level, the data D0~D3 are being transmittedfrom Dout pin by serial form. The resting timeinterval between each transmission is also 12 bitstransmitting time. Assuming that the oscillatorfrequency is 3 KHz , that is the period for



transmitting one bit is 3 msec, the total spent timefor transmitting 12 bits is about 36 msec. Atransmitted data will be repeated four times and thenwaiting for the same time. Therefore, the total spenttime for transmitting 12 bits is 2(4 x 36)=288 msec.As shown in Fig. 12, it is the working flowchart ofHT-12E.

Fig. 12 Working flowchart of integrated circuit HT-12E.

4.2 Receiver CircuitThe HT-12D is a decoder IC and arranged inreceiver circuit. The receiver circuit is composed ofa decoder IC, a single chip, and a few passivedevices. The operation principle of receiver circuitis described in the following.

The receiver circuit of electric venetian blind isshown in Fig. 13. It consists of a group of solar cell,infrared receiver module, decoder IC, single chipand status display, current sensory circuit, light-intensity tracking circuit, and a counter formeasuring the moving length of electric venetianblind. As can be seen in Fig. 13, the main part of thereceiver circuit includes an infrared receivingmodule, decoder IC, and an 8-bits single chip. Theoutput signal of infrared receiving module is reversefirst for coming back the data like in transmitterterminal and then transmitted to the input pin ofdecoder IC. On the one hand, the decoder IC willcompare the received address to the default address;on the other hand, it will output data from thereceived data if and only if four times of addresscomparison is equivalent.

As mentioned above, HT-12D is acommunication pair of integrated circuit, HT-12E. Itis used as for decoding the received data andaddress which transferred from remote controlterminal. The main features of this integratedcircuit are introduces as follows:

(1) A0~A7: Input pins for address A0~A11setting;

(2)D0~D3: Output data pins;(3)OSC1: Oscillator input pin;(4)OSC2: Oscillator output pin;(5)VT: Valid transmission, active high;(6)Din: Serial data input pin;(7)Vss: Negative power supply (GND);(8)Vdd: Positive power supply.

Fig. 13 The detailed receiver circuit.



Fig. 14 Working flowchart of the decoder IC inreceiver terminal.

5. Experiments and DiscussionsAccording to the required functions in the respectivetransmitter and receiver terminal circuits, Fig. 15shows the completed prototype of electricaluminium blinds. Fig. 15(a) is the prototype ofremote control circuit or transmitter. Fig. 15(b) isthe prototype of receiver circuit or receiver. Fig. 16demonstrates the experimental process that theelectric aluminium blinds is powered by a solar cell.The generated electrical energy of the solar cell onthe one hand charges the super-capacitor, on theother hand supplies with the required electricalpower of all the circuits in receiver terminal. Asshown in Fig. 17, after the electric aluminium blindshas been completed, the circuit in remote controlterminal or transmitter is powered by a group ofbattery when the circuit in receiver terminal is

supplied with an AC adaptor. The electricaluminium blinds is operated by an indirect or non-touch method through an infrared wirelesscommunication. Especially, the maximumcommunication distance is over ten meters. Thistransmission distance is sufficient to the remotecontrol requirement for the electric aluminiumblinds or the other remote control applications ofpopular electronic appliances. The NEC Infraredremote transmission format is used as command ordata transmission standard of the proposed electricaluminum blinds.

(a)

(b)Fig. 15 The photographs of completed prototype (a)

transmitter circuit (b) receiver circuit.

Fig. 16 The photograph of a completed receivercircuit which includes solar cell, super-capacitor,

and related control circuits.



Fig. 17 The photograph demonstrates theexperimental process during testing the completed

prototype.Fig. 18(a) demonstrates the action of electric

aluminium blinds when a scroll-up command is setand transferred from the transmitter terminal. Thekey data is first compliance with the address dataand then formed as a series of pulses. In order toincrease the communication distance of infraredtransmitter, the output pulses of encoder IC ismodulated by an oscillator with high workingfrequency again, as shown in Figs. 18(b)~18(d). Thepin Dout of encoder IC is an output and connectedto a modulation circuit which is composed ofinverse NAND gates, resistor, and capacitor. Duringthe high voltage level, the CH2 and CH3 waveformsshown in Fig. 18(c) show that the modulated signalis generated by modulation circuit.

(a)

(b)

(c)Fig. 18 Shows some important measured

parameters’waveform in transmitter (CH1 and CH2)and receiver terminals (CH3 and CH4), respectively.

From the shown waveforms in Fig. 18, thedemonstrated the functions or results related to theimplemented prototype control circuits are agreewith the anticipated designing goal well.

6 ConclusionOne compound power source supplying structure isdesigned and implemented in this paper. All therequired electrical energy of the proposed controlmethod of electric aluminium blinds can be suppliedwith one of the power supplies at the same time.The final choice of the power source is decided tothe personal custom of owner and the providedenvironmental power supply. When the user wantsto operate the electric aluminium blinds, he or sheneed not touch the electric aluminium blindsdirectly and just control it by remote method. This isa convenient and save-time operating method.Many consumers who are always pursue high livingquality must be satisfied with this control method.Take the manufacturing cost into consideration; theinfrared wireless control method is selected as theremote control method. All the commands aretransferred from transmitter terminal to receiverterminal. Under the allowable communicationdistance, any type of electric aluminium blinds isable to be controlled by using the same infraredtransmitter and receiver circuits. Regardless of thecontrolled weight and volume of the load, therobustness of proposed control method here is veryoutstanding. Moreover, the electric aluminiumblinds is often installed without destroying anybuilding structure. The user can almost be controlledthe default actions of the electric aluminium blindsat any place of indoor building. Besides the point-to-point control, many electric aluminium blinds canalso be controlled by means of broadcast method at



the same time. Much more time will be saved bypeople. In other words, the operating efficiencywould be improved or increased.

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[3] IEEE Recommended Practice for EnergyConservation and Cost-Effective Planning inIndustrial Facilities, IEEE Std 739-1984, 1984,p. 0_2.

[4] Y. Chen, et al.,“Venetian Blind Control SystemBased on Fuzzy Neural Network for IndoorDaylighting," Proc. of the 2nd Int. Conf. onComputer and Electrical Engineering, 2009, pp.269-273.

[5] V. Viereck, et al., “Sun Glasses for BuildingsBased on Micro Mirror Arrays: Technology,Control by Networked Sensors and ScalingPotential," Proc. of the 5th Int. Conf. onNetworked Sensing Systems, 2008, pp. 135-139

[6] M. S. Peng, et al., “Design and Implementationof a WSN-Based Intelligent Light ControlSystem," Proc. of the 28th Int. Conf. onDistributed Computing Systems Workshops,2008, pp. 321-326.

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of Communication Protocol in the InfraredControl System of Intelligent Home," Controland Automation, Vol. 23, No.1.1, 2007, pp. 28-30.

[10] K. Mandai, K. Miyauchi,and M. Sugimoto, etal., “An Advanced Infrared Remote ControlSensor," IEEE Tran. on Consumer Electronics,Vol. 36, No. 3, Aug, 1990, pp. 669-677.

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2008, pp. 36-37.[14] Z. C. Xue and S. X. Wu, “The Design of

Electronic Locks Based on Infrared Remote-Control with MCU,” Proc. of 2009 4th Int. Conf.on Computer Science & Education, 2009, pp.592-594.

[15] G. F. Li, Microcontroller C ProgrammingExamples Guide, Beijing: Beijing University ofAeronautics and Astronautics Press.



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