Ｚigbee Wｉreｌess Sensor Ｎetworｋin Eｎvironmｅntal Monｉｔoｒｉng ApplicaｔionsI.ﻩZIGBEＥTECHNOLＯGＹＺigbeｅis a wiｒeless stanｄarｄbasｅd oｎIEEE8０2.15．４ｔｈaｔw ａs deveｌopeｄto ａｄdｒeｓs the unique nｅeds of most wiｒeｌess seｎｓｉｎg ａｎｄcｏntrol aｐplｉcationｓ. Tｅｃｈｎoｌｏｇy iｓlow cost, ｌow power，a ｌｏｗdａtａｒatｅ，highly rｅliable，ｈighly secure ｗireleｓs net ｗoｒkiｎg protｏcol tａrgeｔed towａrｄsａｕｔomａｔiｏn ａnd ｒｅmote con ｔｒol apｐlicatiｏns.It’s ｄepictｓｔwo keｙpｅrｆormance chaｒａｃterisｔicｓ–wirelｅｓs radio rａnｇe and ｄata trａnｓmissiｏｎｒatｅｏｆthｅｗｉrelesｓspeｃtrum.Cｏmpaｒｉnｇto otheｒwｉｒeless neｔwｏrking prｏｔｏco ｌｓｓuch as Bluｅtoｏth, Wi-Fi, UWB andｓoｏｎ, shoｗｓｅｘcｅｌlent ｔranｓmissioｎabilityｉｎlｏweｒｔransmissｉoｎraｔe and higｈｌy capacity of nｅｔwork.A. ZｉgｂeｅFrameworkＦrameworｋis ｍade up of a set oｆbｌocｋs called ｌayeｒs.Ｅach layｅｒpｅrforｍｓa specifｉc set oｆservices for the layer abovｅ.Ａs shｏｗｎin Fｉg.1. Ｔｈe IEＥE 8０2.15.４ｓｔandarｄdefinｅs thｅtwo loｗｅr ｌayers: ｔｈｅｐhysiｃaｌ（PHY)ｌaｙer aｎd thｅmediumａｃｃeｓs ｃoｎtｒｏｌ(MAC)lａｙer. Ｔhe Alｌiａncｅbｕiｌds ｏn this foundation by pｒoviding the ｎｅtｗork ａnd seｃurity ｌaｙｅr and the framework for the ａpｐliｃａtion layeｒ.Fig.1 FraｍewｏrkThe IEＥE 802．1５.4ｈａs two PHY lａyerｓthat ｏperate ｉn tｗo separate ｆrequenｃy ranges: 8６８／９15ＭHz and ２.4ＧHz. Mｏreoveｒ，ＭAC suｂ－layｅr cｏntｒoｌs aｃcesｓto thｅrａdiｏchａnｎel usinｇａＣSMＡ-CＡｍecｈaｎism. Ｉtｓrespｏｎsｉbilities mａy also ｉncluｄｅｔransmｉｔtｉｎｇbeacon ｆrameｓ, syncｈrｏｎｉzation, aｎｄpｒoｖiding a ｒelｉable trａnｓmiｓsｉoｎmechanism.B. Ｚigbee’s TopoｌogyThe netｗork layer supports sｔａr, tｒｅe，and mesh toｐoｌogiｅｓ, as sh ｏwn in Fｉg.２. Iｎａstar tｏpology，the nｅｔwｏrk iｓcontrolled ｂyｏne ｓiｎgｌｅdｅｖｉce ｃａlled cooｒdｉnatoｒ. Thｅcoordinaｔor is ｒｅｓpons ｉbｌe for initiating ａnd ｍaintainｉng the ｄevicｅs ｏnｔhe netwoｒk．Ａll othe ｒdevicｅs，knowｎas ｅnｄdevｉｃes，dｉrectly comｍunicatｅｗith ｔhe coorｄinａtor. Ｉｎmesh aｎdｔrｅe tｏｐoｌｏgies，ｔhe coordinatｏr is ｒesponsible for ｓtａrtiｎｇｔhｅｎｅtwork ａnd foｒchoｏsing cｅrtain keｙｎe ｔｗorｋparａmｅteｒs, bｕt the nｅtwork may bｅｅｘｔendｅd throughｔhe use ofｒｏuｔers. Ｉｎtreeｎetworks, ｒｏuters ｍoｖe ｄatａａndｃｏnｔrol messageｓthrough the neｔwｏrk usｉｎg a ｈierarchicaｌrouｔingｓtraｔeｇy. Meｓh neｔｗｏrｋｓａｌlｏw fuｌl ｐeer-to-pｅeｒcoｍmunｉcation．Fｉg.2 ＭeｓｈtｏpologieｓＦig．３is ａｎｅtｗorｋmｏdeｌ，it ｓhｏwｓｔｈaｔsupports both ｓing ｌe-ｈoｐstａr ｔopologｙcoｎstrｕcteｄwith one coordinatｏr in thｅcenter anｄthe end dｅvices, and mesh toｐoｌogｙ. In ｔhe nｅtwoｒｋ，tｈe ｉntｅlligenｔｎodes aｒe comｐｏｓed ｂy Fuｌl Funｃtion Ｄｅviｃe (ＦFD）andＲeduced Funｃtｉon Devｉce （RFD)．Oｎly thｅFＦN defiｎｅs the fulｌfuｎctionality ａnｄcan bｅｃomeａｎetwｏｒｋｃoｏrdinａtｏr.Cｏorｄｉnatoｒmanages thｅnetwｏrk，ｉt is tｏsay that cｏｏrｄiｎator cａn starｔ a netwoｒkａnｄａllowother ｄｅvｉcｅsｔoｊoｉｎor leａvｅit. Mｏreｏver, it caｎpｒｏvidｅｂｉｎdｉng anｄaddreｓs-ｔaｂle sｅrvｉcｅs, aｎd ｓave mesｓages until tｈey can beｄelｉvｅreｄ.Fｉg.3 Zｉgｂeｅｎetwork modeｌII.THＥGREENHOＵSE ＥNVIＲＯＮＭENTAL MOＮITＯRIＮGSYSTEM DESIＧＮTraｄｉtionａl ａｇｒicuｌtｕre oｎly usｅmａchｉneｒy and equipment ｗｈｉch iｓolaｔｉng and nｏｃｏmｍｕｎiｃaｔing abｉｌity. Ａnd ｆａrmｅrs hａve to monｉｔｏr croｐs’ growth by tｈemselvｅs. Eｖｅn if some ｐeｏple uｓe elecｔrical deｖiｃｅｓ, ｂut mosｔｏｆtheｍwere reｓｔｒｉcteｄtｏsiｍple ｃｏmmｕnicatiｏn bｅｔｗeen ｃoｎtｒol comｐｕtｅr anｄｅnd dｅvicｅs lｉｋe senｓorｓinstｅad of wire conｎecｔｉon,wｈich couldｎ’t ｂe striｃtｌｙｄeｆineｄaｓｗｉｒeless sensｏr neｔwoｒk.Ｔherefore, by tｈrｏugh using seｎsｏｒｎetwｏrｋs and，agriculｔurｅcｏuld become mｏｒe automatiｏｎ，morｅnetworkｉng and ｓｍarｔer．In tｈis pｒojｅｃt, ｗe should dｅpｌoy fivｅkiｎｄs ｏｆsensors iｎｔｈｅgｒeeｎhｏｕse basement.Ｂy ｔｈｒoｕgh thesｅdｅpｌoyｅd senｓoｒs，the ｐarameters sucｈaｓtｅmperaｔure iｎthe ｇreenhoｕse，soil teｍperａｔurｅ，dew ｐoiｎt，hｕmidity ａnｄlight inｔｅｎsitｙcaｎbe ｄetecteｄrｅａl time. It is key to cｏlleｃt different pａrameters frｏm all kinds of sensors．And in the greenhouse, mｏnitoｒiｎg the ｖegetables groｗｉnｇcｏndｉtiｏns is tｈe ｔoｐissue.Therｅｆore，lonｇer bａｔｔｅｒy lｉfe and lｏweｒｄａta rate anｄless complｅxity arｅvｅryｉmporｔaｎt. From tｈe introductioｎaｂouｔabove,ｗeｋnｏw that ｍeet thｅreqｕireｍｅｎtsｆor reｌiａbilｉｔy, ｓecuriｔｙ, lｏｗcostsａｎｄｌow ｐoｗeｒ.A. ＳystemＯｖerviewThe oｖｅrvｉeｗof Ｇreenｈouｓｅenvironmental mｏnitoｒing sysｔem，ｗhicｈis ｍadｅｕp ｂyｏne siｎk node （ｃoordinator), many sｅnｓor nodes,wo ｒkstaｔion aｎd daｔabaｓe.Ｍote nｏｄｅａnd sensor ｎｏｄe tｏgethｅrｃｏmpｏｓed of ｅａｃh ｃｏｌlectｉng node. Ｗhｅn sｅｎsors colleｃt parａmeters rea ｌtime, sｕch as tempeｒature in the grｅenｈｏｕse, soil temperatuｒe,ｄew ｐoiｎt, huｍｉdity anｄlｉght intensiｔy，these ｄａｔa wｉll ｂeｏｆfereｄto A/D converter,thｅn bｙｔｈroｕｇｈｑuantizing ａnd encoding beｃoｍe tｈeｄigiｔａl signal that iｓaｂle tｏｔｒanｓmit by ｗireleｓs ｓensoｒcommunicatｉng nodｅ. Eaｃｈwireless seｎｓor coｍmuｎicaｔｉng node ｈａs ａbｉlity of tran ｓｍｉttｉｎg，ｒｅceiviｎg fｕｎcｔion.Iｎthis WSN,seｎsoｒｎodes dｅployｅd inｔｈｅgreeｎhouse, whiｃh can coｌleｃｔrｅal time ｄata andｔransmiｔdata to ｓink noｄe (Cooｒdiｎａtoｒ) by tｈｅwａy oｆmｕlti-ｈoｐ.Ｓink nｏde cｏmplete the task of datａaｎalysis aｎｄdata ｓtｏragｅ．Meanwhile，ｓink noｄｅｉs ｃonnecｔed ｗith ＧPRS/CDMＡcan prｏvｉde remotｅcoｎｔｒoｌaｎd data doｗnload serviｃe. Ｉn the mｏｎitorｉng aｎdｃoｎｔrolｌing rooｍ, ｂy running greeｎｈouse maｎａｇemｅnt softwarｅ，the sink noｄe caｎｐｅrioｄically ｒeceｉves tｈｅdata frｏm ｔｈｅｗiｒelｅsｓsensｏｒnodｅｓanｄdisplayｓthem on moｎitorｓ.ﻫB．Node Ｈａrdware ＤｅｓiｇnSｅnsoｒｎodeｓare ｔhe basiｃunits oｆＷSN. Ｔhe ｈａrdｗaｒｅｐlaｔforｍｉs ｍade ｕｐseｎsｏr nｏdｅs clｏsely relａｔed tｏthe ｓｐecｉfiｃappｌｉcaｔion requireｍｅntｓ．Thｅrefｏre, tｈe mosｔimportant work ｉs the nod ｅs dｅsign which cａn perfeｃt iｍpleｍｅnt tｈｅfuｎcｔion of dｅtectinｇand tr ａnsmissｉon as a ＷSN node, anｄｐerforｍits techｎｏlogy cｈaracteｒistics. Fig.４shｏws the universａｌstrucｔurｅoｆｔｈe WＳＮnodes. Powｅｒmｏｄu ｌｅprovｉdｅs the ｎｅｃｅssａrｙeｎerｇｙfor tｈe sｅｎｓor nｏdes.Ｄata collｅcｔｉｏnｍoｄuｌe ｉs ｕｓed ｔｏrecｅｉｖe and coｎverｔsｉgnals ｏfｓensｏｒs. Datａproceｓｓingａnd cｏntrol moduｌe’s fuｎcｔions are noｄｅdeviceｃontrol，tasｋsｃｈｅdｕling, aｎd ｅnergy compｕting aｎｄｓo o ｎ. Cｏmｍｕｎicatｉonｍｏdｕle ｉsｕｓed to send data bｅtwｅen nodes and ｆrequency chosen ａnd sｏon.Fig.4 Univeｒsal stｒucture of tｈe wsｎnodesIn the data ｔransfer unit，ｔｈe ｍodｕｌｅis embｅdｄｅd ｔo matｃｈｔｈe ＭＡC layer aｎｄｔheＮET layeｒｏf tｈe ｐrｏtocol.We ｃhooｓe ＣＣ243０asｔhe prｏtoｃｏl chips, ｗhｉch inｔeｇrａted thｅCPU, ＲF ｔｒansce ｉveｒ, nｅt proｔoｃol and thｅRAM together. ＣC2430 usｅｓan 8 bit MＣU （8051), ａnd hａｓ12８KＢproｇｒａmmａble ｆｌash memoｒyａnd 8ＫB ＲAM. Iｔalｓo ｉncｌudesＡ/D conｖeｒtｅr，soｍｅTimｅrｓ,AES1２８Ｃoproｃeｓｓor, Ｗatchdｏg Timｅr,32K ｃrｙsｔal Slｅep mｏdeＴimer, Ｐoｗer o ｎReset, Bｒoｗn out Deｔｅｃtｉｏn ａnd21 I/Ｏｓ.Based on ｔheｃhips, ｍaｎｙｍｏdulesｆｏr the pｒoｔocｏl aｒe provｉdeｄ.And tｈe traｎｓfeｒuｎｉｔcouｌd ｂe eａsiｌyｄesigneｄbased oｎthe moｄｕles.Ａs an ｅxａmpｌｅof a sensor eｎd dｅvicｅintegratｅdｔempｅratｕrｅ, hu ｍidity and lｉght，the deｓiｇn ｉs shown ｉn Fiｇ. 5.Fig.５Thｅhardware design ｏf a seｎsor node The SHT11 is a singｌe chip relative hｕｍiｄity ａnｄtempｅrature multｉsｅｎsor ｍoｄulｅcomprisiｎg ａcａlibratｅｄdigｉtal output. It can tesｔthe sｏｉl ｔｅｍperａtｕｒe aｎd humidｉｔy.ThｅＤS18B２0 iｓ a digitａl tempeｒatu ｒｅｓensor, which has３pins anｄｄatａｐin cａn ｌiｎk MＳP4３０diｒecｔly．Ｉt cａn deｔecｔｔｅmｐeraｔｕre ｉn greenhoｕse. TｈｅTCS320ｉs a digita ｌlight ｓeｎsｏｒ.ＳHT１1, DS18B20ａｎd TCS３２0ａｒｅbｏｔh digitａl ｓensoｒs with smaｌｌsｉｚe aｎｄlow pｏwｅｒconsumptioｎ．Othｅr seｎsｏｒｎoｄes ｃaｎbe ｏｂtaineｄby chanｇing tｈｅsensｏｒs.The sensor nｏdes aｒe powered fｒom onbｏard bａtteries and tｈe ｃｏoｒdinato ｒａlｓｏalｌoｗs ｔｏbe powｅreｄfrｏm aｎeｘtｅrnaｌpｏｗｅr sｕpｐly determined by a jｕmper．Ｃ.Nｏde Softwａre ＤesｉｇｎＴhｅａpplication ｓystｅｍconsistsｏf aｃｏｏrdinａtor ａｎd sｅｖeｒａl ｅnd deviｃeｓ．The gｅｎeｒal ｓｔrｕcture of ｔhe coｄe in eaｃh ｉs the ｓame，wｉth an initiａlization followed ｂｙa mａiｎloop.The software floｗoｆcoｏrdiｎaｔｏｒ, upｏn thｅcｏｏrdinatｏr bｅing ｓｔarted,thｅfirst acｔion of the apｐｌicatiｏn is ｔｈe iniｔｉａlization oｆtｈe hardware, liquidｃｒystal，stack aｎｄａpplｉcatioｎvａriablｅs and opｅning ｔhｅinterｒｕpt.Ｔhenａnetｗｏrk wｉll be formaｔted. Ｉf this neｔhas beｅn ｆormatｔed successfully,some networｋinformatiｏｎ, such ａｓphyｓical address, neｔID,chａｎnel nuｍber will be shown on ｔhｅＬCD. Thｅn ｐrogram wｉｌl stｅp ｉｎto apｐlication layer aｎd monｉtoｒsｉgnaｌ. If tｈeｒe ｉs ｅnd devicｅor rouｔer wanｔtoｊoiｎin tｈis net,LＣD wｉll sｈowｎthis infｏｒmaｔion，and sｈoｗtｈｅｐhysical adｄｒess ｏｆaｐplｙing node, an ｄthｅcooｒｄinatｏｒwilｌａlｌoｃaｔe ａnet adｄｒess to tｈｉsｎｏdｅ. Ｉｆthe node haｓbｅｅn joineｄin this network，ｔhe data tranｓmittedｂy this node will be receｉved by coｏrｄinａtoｒaｎd shown ｉｎthｅLＣＤ．The software flow ｏf a ｓensｏr nｏｄe, ａs eａch ｓeｎsor node is switchｅd on, ｉｔscans all channelｓaｎd, aｆter seｅing anｙbｅａcｏns, cheｃks thaｔthｅcoordinatoｒis the one ｔhat it is lookｉng for.Iｔthen pｅrforｍs a sｙnchroniｚaｔion aｎd ａssociａtioｎ．Oｎcｅaｓsoｃiａtion is completｅ, theｓensor ｎode enｔers aｒｅgular loop ofｒeaｄiｎｇiｔｓsenｓorｓand puttｉng out a f ｒame containing the sｅnsoｒdatａ．Ｉf senｄｉｎg successfｕlly，end deviｃe will ｓtep ｉnｔo idle ｓtate; ｂｙｃｏntrａsｔ,ｉt wｉll collecｔdata onｃe a ｇain anｄｓeｎd to coorｄinatｏr unｔil ｓｅnｄｉng sucｃｅｓｓfuｌly.D.Ｇｒeｅnhouse Mｏｎiｔoｒｉng Ｓoftwａre ＤｅsignWe uｓｅＶＢlanguaｇe to buｉｌd aｎｉnｔerface ｆoｒｔhe test ａｎd ｔｈｉs greenhouse senｓor networｋsoｆtware cａｎbｅｉnstaｌlｅd and launched on anｙWindows-based operating ｓyｓteｍ. Ｉt has ４ｄiaｌｏg box selｅctions: ｓeｔting coｎtrollｉngｃｏndiｔｉons, seｔting Timer，setting ｒelevant paraｍｅterｓａｎd sｈｏwing cｕrｒenｔstａtus. Ｂy sｅtｔｉng soｍｅｐaraｍe ｔers, it cａｎｐerfｏrm thｅｆuncｔioｎs oｆcommｕnｉcａting ｗith port, ｄａta collｅctｉoｎand daｔa viewiｎｇ.ﻬZigbｅe无线传感器网络在环境监测中的应用Ｉ.Zigｂｅｅ技术Ziｇbee是一种基于IEEＥ80２.15.４的无线标准上被开发用来满足大多数无线传感和控制应用的独特需求。