Intelligent Lighting System Using Wireless Sensor Networks

International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 DOI : 10 .5121/ijasuc.20 10.1402 17 Intelligent Lighting System Using Wireless Sensor Networks A.A.Nippun Kumaar 1 , Kiran.G 2 , Sudarshan TSB 3 Department of Computer Science & Engineering, Amrita Vishwa Vid ya peetham, S chool Of Engineering, Bangalore Campus, India. 1 nippun05 @gmail.co m 2 kiran.pe r.sempre@ gmail. com 3 sudarsha n.tsb @gmail.com A BSTRACT This paper exa mines the use of Wireless Sen sor Networks interfaced with lig ht fittings to allow for da ylight substitution techniq ues to redu ce energy usage in existing buildin gs. This create s a wire free system for existing b uildings with minimal disrup tion and cost. K EYWORDS Wireless sensor n etworks, d aylight sub stitution. 1. Introduction Power conservation is no longer j ust a fashionable expression. It has now becom e a necessity. Static method of conservation like usage of electrical devices with lower power consumption or scheduled power cuts are not v ery efficient. This paper pr oposes a d ynamic automated power conservation system which u ses wireless s ensor networks(WSN). The advantage of using WSN i s that this system can be easily installed in already ex isting buildings where as a wired system will be expensive and difficult to install in the sam e scenario. The use of wireless sensor network greatly r educes the size and cost of the system and is suit able for a lighting system. In t he proposed system , ther e is an array of light sensor no des which can communicate with a master nod e(MN), providing information a bout the light conditions at each sensor nod e. Based on the feedback information the M N decides which all light sources to control. Once this is decided the MN transmits the data fram e to a particular light control node to control the light, which is electrically connected to it. 2. Literature Survey Examined the use of Wireless Sensor Networks interfaced with Di mm able Fluorescent light fittings[1]. Dimmable fluorescent fittings, using modern electronic ballast dimmers are widely f itted to new buildings, t o allow for the accurate di mm ing and control of building lighting[2] F.O’Reilly & J.Buckley. Factoring in natu ral incident daylight, allows a red uction i n the a rtificial light (daylight substitution), which amounts to savings between 10% and 40%.The DALI l ight control International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 18 interface prov ides a two wire low v oltage control bus to al low the a ddressing and control of individual light fittings[3]. Figure1 shows a Wireless Sensor Network sy stem which can provide work plane light measurements, and is i ntegrated with a standard building monitoring s ystem, the wireless network controls the dimmable ballast elements, allowing t he retrofitting of existing installations without the need to re-cable and with minimal d isruption. The specifications and variations required for work plane lig hting, for some sample areas are shown in Table 1, full specifications are av ailable in the CI BSE Lighting Guides[4]. Individual work plane light levels are typically read and forwa rded to a facilities m anagement system which can issue control signals to the lighting elements. Even though in some s ystem s human behavior has been considered as a factor and system behavior is based on predictions based on these factors[6][7]. But this paper is directed t owards the efficient algorithm design for intellig ent lightening system using wireless sensor networks with day light as a important factor. 3. Proposed Implementation In the pr oposed s ystem, t here is no separate base station. One of t he nodes will act as t he base station. Base station’s po wer is replenishable. Dynam ic topol ogy control is d one by base station, by periodically ensuring the presenc e of all nodes and accepting new nodes on the run. Figure 1: Wireless Daylight Substitut ion Table 1: Light intensity v alue for various environment International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 19 As shown in Fi gure2 there are three kinds of nodes in the network, master node (MN), sensor n ode (SN), and light control node (LCN). Master node is the one acts as a ba se station as well as sensor node. Sensor no de senses the en vironment and instructs the li ght level to the master node. Light control node will respond to t he master node by dimm ing or bri ghtening t he l ight according to the data received. The sensor node s ar e placed such that each sensor node ranges to two light ballast. This arrangement will m ake the light control precise. 4. Hardware Basically the hardware level of this system is classified in two forms, one is in sensor n odes another is i n light control node. One of t he SN is chosen to be a MN which is loaded with ad ditional control software. Both SN and LCN is controlled by PIC 1 6F877A controller as shown in Fi gure4 and Figure5 [5]. 4.1. Sensor Node Main task of sensor node is t o sense the surrounding l ight level and report to master node. For sensing t he light level l ight dependent resistor (LDR) is i nterfaced to t he controller. As the name suggest resistance of LDR changes when light falls on it. When light increases resistance decreases and vice versa. Figure 2: Infrastructure Under Test Figure 3: Block Diagram - Sensor Node International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 20 The resistance of the Light Dependent Resistor (LDR) varies according to the amount of light t hat falls on it. The relationship between the resistance RL and light intensity Lux for a typical LDR is With the LDR connected to 5V through a R1 K resistor, the outpu t voltage of the LDR is Reworking the equation, we obtain the light intensity LUX -Intensity of light. Vo -Output voltage from LDR. R1 -Series resistance connected to LDR System has a RF transmitter (FS 1000A) a nd receiv er (PCR 2) for wireless transm ission and reception. Each node has a pair of Tx and Rx, through this arrangement point to point and broadcast arrangement is possible. Som e features of Tx anr Rx is listed below:  Operating frequency - 315/433 MHz  Range - 80m  Data rate - 4KB/s  Working mode - AM  Power - 10mW Transmitter consists of encoder HT 640L. This helps in addressing individual nodes in p oint to point c omm unication. T his allows a maximum of 8bit address and 8 bit data f ram es. This converts parallel transmission of dat a into serial transmission 4.2. Light Control Nod e LCN is used to control light intensity according to the received signal. Light contr oller is nothing but a D/A convertor which will give analog v oltage with respect to digital signal. RF Tx and Rx are same as that used in SN. PIC is used as a controller in both the nodes and plays different role in all the nodes. In sensor nodes A/D convertor of PIC is used to convert LDR voltage into di gital voltage, and according to voltage level t hat has been sense d a data frame is formed and t ransmitted to MN. In MN t he received data is analyzed and data signal is sent t o corresponding LCN to control light. MN also maintains three tables MN, LCN and SN ta ble, LCN address table and SN table. In LCN the received signal is analyz ed and action is taken according ly, through light controller. International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 21 In al l the three nodes receiver stack is maintained with received data fr ames. To pology control process is carried out in all the nodes p eriodically at fixed inte rval of time. 5. Software The s oftware level of t he network is i n three for ms each in MN, SN and LCN. Th ere is specially designed frame format for control a nd data frame transm ission. 5.1. Frame Format The frame is designed to be 8bi t. Addressing of nodes is carried out both i n hardware and software. An addr ess of t he node is assigned by the hardware and ID to each node is assigned by software running on MN. Th e frame is a s shown in Figure5, which consists of 2 control bits C1,C2, a topology control bit, a data and acknowledgem ent bit and 4-bits for assigning address and I D. Figure 4: Block Diagram- Light Control Node Figure 5: Frame Format International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 22 5.2. Algorithm To e nable communication between SN and LCN there a re three algorithm s in the system runni ng in parallel: • MN Algorithm. • SN Algorithm. • LCN Algorithm. 5.2.1. MN Algorithm LISTEN any data from LCN VERIFY IF the data is Invalid f ram e or Addr ess present in LCN ta ble END goto LISTEN RECEIVE the data Sen d acknowledg ement to LCN Ass ign address to LCN Updat e LCN table Sen d LCN address END CHECK IF LCN table Is full or Ti mer expires END goto PHASE2 ELSE goto LISTEN PHASE2 : BROADCAST MN address to all SN LISTEN2 : any acknowledgement from SN VERIFY IF the data is Invalid frame or Address present in LCN table END goto LISTEN2 International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 23 RECEIVE the data Update SN table END CHECK IF SN table Is full Or Timer expires END goto PHASE3 ELSE goto LISTEN2 END PHASE3 : SEND increment da ta to LCN LISTEN request For decrease light from SN Check for five request from sam e SN END UPDATE SN table with LCN address CH ANGE LC N address GOTO SEND END repeat for all LCN CHECK IF for For all LCN m apped Or Ti mer expires END goto NORMAL ELSE goto PHASE3 NORMAL : LISTEN any data fr om SN VERIFY the data for Invalid f ram e END goto LISTEN READ data For SN I D Chec k ti IN C or DEC light International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 24 Get the LCN address f rom SN table END SEND the control signal to that LCN END goto NORMAL This h as 4 phases. In the first phase address are assig ned f or LCN’s. Whenever a fr ame from LCN is released it is updated in the LCN table. In the second phase MN broadcasts its own address and wait for the SN to reply. Replies from SN are used to update the SN table. In the third phase a mapping is done be tween LCN and SN i.e. a table is updated that maps the SN, controlled by a particular LCN. This is don e by selectively brightening the lighting source controlled by a SN to t he maximum value of the LCN. In the fourth phase, which signifies a normal operation SN frames are received by MN and “inc rease or decrease light” frames are sent to the LCN for finer control of luminance. 5.2.2. SN Algorithm LISTEN any broadcast data is received VERIFY IF the data Is invalid END goto LISTEN READ the frame T ake the MN address Set it as its TX address Sen d ACK as its ID END LDR SENSE : check the lig ht intensity level VERIFY IF the value Is higher or l esser than threshold Sen d the data to MN accor dingly END goto LDR SENSE END goto LDR SENS E Here, SN waits for the MN broadcast. Once it rec eives the address, it configures its transmitter to a permanent address. As acknowledgement it sends its own ID. During normal operation it co nstantly senses the l ight and whenever the light goes below or above the threshold, it will send “increase os decrease light” frame. International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 25 5.2.3 LCN Algorithm SEND its ID to MN LISTEN to any data from MN VERIFY IF the data Is invalid END goto LISTEN READ the frame Ext ract ID Chec k with its ID Got o LI STEN2 if ID is same Or d iscard data END END LISTEN2 to any data from MN VERIFY IF the data Is invalid END goto LISTEN2 READ the frame Ext ract the address Set the address as its R X address END END NORMAL : any data from MN VERIFY IF the data Is invalid END goto NORMAL READ the received data Chec k for IN R or DCR light Cont rol the light acco rdingly END goto NORMAL END International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 26 Initially LCN will send its own ID t o MN. M N will reply receiver’s address allotted to it through three way handshaking. LCN will configure its receiver with t his address. During normal op eration, it listens for MN frame. W hen it receives “increase or decrease light” M N frames, it controls the luminance accordingly. 6. Results Experimental Setup: 1. A room with five lights, four at corne rs and one at the m iddle. 2. Consider the intensity required in the room should be 400Lux and the light should be lit up for 12 Hrs/day (6Hrs day & 6Hrs nig ht). 3. The tube light used will consum e 40W of power. 4. In normal system all light should glow in full intensity therefore consum es 40W each. 5. In the proposed system all lights in co rner needs only 50% of the power in day time. Table 2 shows the comparison for the given setup between normal s ystem and the proposed system. The savings in energy consumed for the given setup is observed to be 14400 Wh/Month. 7. FUTURE IMPLEMENTATION So by ad ding PIR sensor which will detect human presence alone will ad d more intelligence to the system and further helps in reduction of power by selectively dimming or switching off some light sources and thus keeping av erage power consumption constant. 8. CONCLUSION Through this sy stem we introduce one m ore w ay of “G oing Green”. I nstalling wired devices for t he same purpos e may not be cos t efficient a nd can even be counter productive. Our device is easy to install and m anage and thus more appealing. Normal Power Hrs Used No. Of. Light Energy Consumed Per d ay Tota l Energy Consumptio n System Day 40W 6 5 1200W h 2400 Wh/ Day 72000 Wh/ Month Night 40W 6 5 1200W h Propo sed system Day 20W 6 4 480W h 1920 Wh/ Day 57600 Wh/ Month 40W 6 1 240W h Night 40W 6 5 1200W h Table 2: Result ana lysis International J ournal of Ad ho c, Sensor & Ub iquitous Computing (IJ ASUC) Vol.1, No.4, Dece mber 2010 27 Compared to the original paper our system is more s calable and flexible. Runtime additi on of nodes is possible an d better power e fficiency can be obtained. Usage of custom contr ol equipment reduces the cost as well. Thus addin g to the appeal. 9. REFERENCE [1] F.O’Reilly & J.Buckley, “Wireless Se nsor Network Control o f Fluorescent Lighting usin g Dimmable Ballasts a nd Da ylight S ubstitution”, 40 th In ternational Universitie s Po wer En gineering Conference, Cork, Irela nd, 7-9 Septe mber 2005 . [2] T. Ribbarich, J. Ribarich, “A Ne w Co ntrol Method for Dimmable High Freq uency Electr onic Ballast,”IE EEIAS Con. Rec 1 998 . [3] Digital Addre ssable Lightin g Interface, http://www.dali -ag.org. [4] 2004 Buildings Energy Data b ook, http ://buildingsdatab ook.eren.do e.gov/ [5] Microchip Technolog y Inc. PIC16F87 7A Datasheet,Re visionC,2000 . [6] Vipul Singhvi, Andre as Krause, Carlos Guestrin, J ames H. Garrett, Jr., H. Scott Matthews “Intelligent light co ntrol using sensor net works”, Con ference On E mbedd ed Net w orked Sensor Systems, P roceed ings o f the 3rd international co nference on Embedde d networked sensor systems, San Diego, California, US A. [7] Antimo Ba rbato, Luca B orsani, Antonio Capo ne: "A W ireless Sensor Ne twork based System for Reducing Ho me Energy Co nsumption" (IEEE SECON 2010 Boston, USA, June 2 1-25, 20 10). Authors A.A. Nippun Ku m aar is currentl y a grad uate st udent p ursuing Masters in E mbedded Systems fro m Amrita Vishwa Vidyapeet ham, Schoo l Of Engineering, Bangalore Campus. He co mpleted his Dip loma in Electr onics and Co mmunicatio n En gineering with First C lass Hono rs in T hiyagarajar P olytechnic College, Salem, T amilnadu, India in 2003 . He com plete d his Bac helors de gree, B.E. in E lectronics and Communicatio n E ngineering with First C lass Honors in Sona College of Te chnology, Salem, T amilnadu, India in 2 006. His areas o f interest are Wirele ss Sensor Net w orks and Robo tics. Kiran. G is curre ntly a gra duate st udent purs uing M asters in E m bedd ed S ystems from Amrita Vishwa Vid yapeetham, School O f Engi neering, Ba ngalore Ca mpus. He completed his graduation in Electr onics a nd c ommunicatio n fro m I nstitute o f science and T echnology, E rnaKulam, Kerala, India in 2007, followed b y a PG Diplo ma in Embedde d Syste m De sign. He started de veloping interest in e mbedded systems during his grad uation and his other areas of interest are unix syste m p rogrammin g, digital signal p rocessing. Dr. Sudarsha n T SB is a Professor, Amrita Viwa V idyapeetham, Sc hool of Engineering, Ba ngalore Campus., I ndia. Earlier he served a s Assistant P rofessor and then Head of the depart ment of Co mputer Science & Engine ering, BIT S, Pilani for 1 3 years. He co mpleted his Doctr ate from BIT S, Pilani, India in the are a of compute r networks. His research I nterests are M ulticore Computi ng and W ireless Networ ks.