MONITORING ENVIRONMENTAL VARIABLES USING SENSORTAG · Picture 1. Concept of a monitoring system. 6...

transcript

Bachelor’s thesis

Degree Programme in Information Technology

Internet Technology

Tam Nguyen Truong Thanh

MONITORING ENVIRONMENTAL VARIABLES USING SENSORTAG

BACHELOR’S THESIS | ABSTRACT

TURKU UNIVERSITY OF APPLIED SCIENCES

Information Technology

2017 | 42

Tero Virtanen

Tam Nguyen Truong Thanh

MONITORING ENVIRONMENTAL VARIABLES USING SENSORTAG Thepurposeofthisthesiswastocreateasystemconsistingofamulti-functionalsensorandaweb-basedapplicationinordertomonitorenvironmentalvariables,suchastemperature,humidity,light,densityandsoon.Withanintentionofusingthesensortotrackobjectmovements,agyroscopesensorwasadditionallycreated.Theapplication,calledsensorApp,canbeseenasafull-stackwebdevelopingexamplewhichtakesadvantageofsuchtechnologiesasNodeJS,MongoDB,jQueryandSocket.io.

Theback-endpartofthisprojectisaNodeJSwebservercommunicatingwiththesensordeviceinordertoretrieveinformationthenforwardtotoaMongoDBdatabaseserverforstoring.Ontheotherhand,forthefront-endpart,thedatareceivedfromthesensorisalsotransferredtoaweb-interfacetopresentandmonitorinreal-timewiththehelpofWebSocket’slibrarynamedSocket.io.Inaddition,theHighChartslibraryisusedtocreategraphstovisualizeallthedatafromthesensororfromthedatabaseserver.

Theresultofthethesiswasthe”sensorApp”app.Theappiscapableofpresentingdatafromthesensorsand,especially,ispackedwithdatabaseextractionfeaturewhichisnotsupportedbyotherservices.Therewerefewobstaclesinthisproject,suchashardwarefaulty,overloadeddatatransmissionandsecuritymethods.Inaddition,limitationsintechnologywerealsoaddressed,forinstancepowerconsumptionandgyroscopeaccuracy.

KEYWORDS:

Node.js,MongoDB,JavaScript,jQuery,Sensor,Web,Server.

CONTENTS

LIST OF ABBREVIATIONS (OR) SYMBOLS 6

1 INTRODUCTION 6

2 TECHNOLOGIES 82.1 SensorTag 8

2.2 Bluetooth Low Energy 8

2.3 NodeJS 92.4 NodeJS Modules 9

3 PROCESS 12

4 IMPLEMENTATION 144.1 NodeJS and modules 144.2 JavaScript Libraries 154.3 Wire up 16

4.4 Setting up connection 174.5 Data Flow 204.6 User interface 234.7 Database 25

5 PERFORMANCE 27

6 ASSESSMENT 296.1 Obstacles 29

6.2 Potential Future Improvement 29

6.3 Limitations 30

7 CONCLUSION 34

REFERENCES 35

APPENDICES

Appendix 1. Application Tree Appendix 2. Sensortag module code

EQUATIONS

Equation 1. Differences when sensor changing position. 32

FIGURES

Figure 1. Data transfer from UI to server via “custom” socket. 21Figure 2. Socket “valuesOut” structure. 21Figure 3. Socket “signal”. 22Figure 4. Records are sent to database. 22

PICTURES

Picture 1. Concept of a monitoring system. 6Picture 2. SensorTag CC2650. 8Picture 3. The implementation structure. 12Picture 4. Discovery mode. 17Picture 5. Broadcasting connectivity signal. 18Picture 6. Sensor information recognized by node server. 18Picture 7. Sensor panel in dashboard. 19Picture 8. Responses from server when connected to SensorTag. 20Picture 9. Dashboard interface. 23Picture 10. Show records panel. 24Picture 11. Visualized graph of data. 24Picture 12. Exporting feature of HighCharts. 25Picture 13. Structure of a key in MongoDB database. 26Picture 14. A point transferred from server to graphs. 27Picture 15. How data is handled upon requests. 28Picture 16. Light density presentation. 30Picture 17. Gyroscope presentation. 32

TABLES

Table 1. JSON format. 11Table 2. NPM installing syntax. 14Table 3. Create project with Express Generator. 14Table 4. Sensortag module install command. 15Table 5. Link to “socket.io” library in HTML. 15Table 6. Get “socket.io” functions in JavaScript. 15Table 7. Link to your mLab database. 16Table 8. Link to HighCharts Library in HTML. 16Table 9. Start NodeJS server command. 17Table 10. Power consumption. 31

Table 11. Sensor states decided by Delta. 33

LISTOFABBREVIATIONS(OR)SYMBOLS

API Application Program Interface

BLE Bluetooth Low Energy

DOM Document Object Model

HTML Hyper Text Markup Language

IoT Internet of Things

JSON JavaScript Object Notation

MVC Model View Controller

RDBMS Relational Database Management System

UI User Interface

XML Extensible Markup Language

TURKUUNIVERSITYOFAPPLIEDSCIENCESTHESIS|TamNguyenTruongThanh

1 INTRODUCTION

Monitoringaserverplaysanessentialroleinanadministrator’sroutine.Asthenetworkgrows,keepingtrackofalltheactivitiesisbecomingmoreandmorecomplicated.Moreover,theperformanceofserversdoesnotonlydependonthehardwareorsoftwarealonebutalsoonotherfactorssuchastemperatureorhumidityofsurroundingenvironment.Especially,overheatingisoneofthemainreasonstocauseincreasinglatencyinnetworks.Therefore,theneedofasurroundingmonitorsystemwhichcanbesupervisedremotelyseemstobenecessary.

Picture1.Conceptofamonitoringsystem.

AspresentedinPicture1above,thecentralizedsystemisinchargeofretrievingdatafromanysensorbuilt-indevices.Sensordataconsistsoftemperature,humidity,lightdensity,magneticlevel,etc.Therawdataistransferredtothesystemwhereitwillbeconvertedintohumanreadablevalues.Whilebeingprocessed,thedataisalsocapturedbythedatabaseserverthensavedinformofrecords.Theadvantageofthedatabaseserverhereistokeeptrackofallmeasurementsduringthewholeoperation.Thedatabaserecordsarealsousedasafuturereferenceortoanalyzetrendingofsensorvalues.Therearemanyformsofpresentingdataforadministrator.Sincetherequirementistomonitorremotelywithanydevicesavailable,awebsiteisconsideredasthebestchoice.

Thisthesisdemonstratestheprocessofestablishingthemonitoringsystem.Withtheweb-basedapplicationbeingacoreofthesystem,theapplicationdoesnotprovideonlyagraphicalinterfacethatsuitseverydevicefromcomputertomobilephonebutalsoareal-timereportingfunctionality.Thethesisstartswithintroducingallthetechnologiesusedintheproject.ChapterProcessexplainswhytheselectedtechnologiesaresuitablefortheproject.ChapterImplementationdescribeshowtheprojectwasimplemented.ChapterPerformancereportsonhowtheperformancewasvalidated.Thefinalchapterdiscussesobstaclesandlimitationsinthisproject.

2 TECHNOLOGIES

2.1 SensorTag

SimpleLink™BluetoothSmart®/Multi-StandardSensorTagfromTexasInstrumentisanexpandablesensor-basedBluetoothdevice.TherearemanyversionsbuttheoneweuseinthisprojectparticularlyisCC2650SensorTag.Basically,thisversionhas10sensorsbuilt-insuchassupportforlight,digitalmicrophone,magneticsensor,humidity,pressure,accelerometer,gyroscope,magnetometer,objecttemperature,andambienttemperature[1]onthesamecircuitandoperatesatalowenergylevel.Intermsofexpandability,moresensorscouldbeaddedwithDevPackinordertofiteveryneed.Regardingpowerconsumption,accordingtoTexasInstrument,withanintervalof1second,itcanrunsforatleast1yearstraight.Moreover,italsoprovidesanoptiontotransfermeasurementstotheCloudviaanappforbothiOSandAndroidplatforms.Inaddition,iBeacon,ZigBee®/6LoWPANtechnologyarealsosupportedbythesensor.

Picture2.SensorTagCC2650.

Developmentkit(DevPack)[2]isanoptionalcircuitwhichprovidesUSBinterfaceforSensorTagtoenablethephysicalconnectiontocomputer.Updatingfirmwareandmakingmodificationtothesensorarethemainrolesofthekit.Ontheotherhand,italsohelpsthesensortouseexternalpowersupplywhenrunningoutofbattery.

2.2 BluetoothLowEnergy

BluetoothLowEnergy(BLE)orBluetoothSmartisalatestversionofBluetoothTechnology[3].InordertoaccommodateInternetofThings(IoT)trend,BLEnowconsumeslesspowerthanpreviousversionssoitcankeepoperatingforlongtimewithonlyacoin-cellbattery.Regardingsecurity,BLEcanenhancesecurityabilitysuchasfullycompatiblewith128-bitAESencryption.Moreover,withawideavailabilityalongwithmentionedfeaturesabove,BLEisgraduallymakingitswaytomoreandmoreIoTprojects.

2.3 NodeJS

Toaccomplishahugestreamofdataconstantlytransferringtotheserver,oneofthebestimplementationinthemarketatthemomentisNodeJSserver. Node.js/NodeJSisanevent-drivenenvironment.ItisalibrarywasinventedbyRyanDahlin2009.After45-minutetalkatJSConf,RyanintroducedNodeJSwhichchangedJavaScriptforever[4].WithanintentionofexpandingJavaScriptbeyondjustawebbrowserlanguage,NodeJSnowbecomesoneofthemostpowerfulserversinthemarket.ANodeJSserveriscapableofhandlingavastamountofconnectionsatonce.Despitethefactthatitisasingle-threadserver,itprovidesadecentperformanceasopposedtoothermulti-threadservers.ConcurrentoperationsissmoothlyexecutedwiththehelpofV8enginewhichisanenginefromGooglebuilttoimprovetheperformanceofJavaScript.ThereareaexcessivenumberofAPIsandmodulesavailableforNodeJSoutofthebox.ThousandsandthousandsofmodulesaredevelopedandcontributedbycommunityuptonowmakesNodeJSadaptitselftomanyprojectsoriswidelyusedbylargecompanies.

2.4 NodeJSModules

NodeJShasamodular-orientedstructure.Modulesareblocksofcodeincertainlanguagewhicharebuilttoaccomplishcertaintasks.Theirfunctionalitiescouldbestandaloneorcombinedwitheachotherinordertoachievemuchsophisticatedoperations.

Sensortag

SensortagmoduleforNodeJSwascreatedbySandeepMistryin2013[5].ItisanAPImadespecificallyforTexasInstrumentsSensorTags,namelyTICC26xxseries.Thismoduleisoneofthemostimportantpiecesofthisapp.Itprovidesfunctionstoestablishaconnectionbetweenthesensorandtheserveraswellasallowsdevelopersdisplayextracteddetailinformationofthedeviceforexampleserialnumbers,type,nameorevenfirmwarerevisions.Apartfromconnectivity,theAPIalsoenablesustotakecontroloverbuilt-insensorsinjustafewlinesofcode.Inotherwords,fromenablingacustomizedsensortoexportingdatainordertoprocessinfurtherstages,allofthosetaskscanbedoneeasilywithoutanyknowledgeoflowlevelprograminglanguage.Thecomprehensivelistofprovidedcategorizedfunctionsasfollows:

• Discovery• Connect/Disconnectdevice• DeviceInformation• Sensors

o Accelerometero IRTemperatureo Humidityo Magnetometero BarometricPressureo Gyroscopeo Luxometer(CC2650only)o IO

• SimpleKey

Socket.io

Sincewebapplicationisessentiallymainstream,datawhichtraversesacrossnetworksdemandsahighresponserateinordertomaintainuserexperience.Inmodernwebapplications,userinputsarefrequentlyprocessedinreal-time,thenexchangedbackandforthbetweenback-endandfront-endsections.ThatiswhenadefinitionofWebSocketcomesalong.Basically,WebSocket[6]isintentionallyaprotocolwhichenablesustosetupacommunicationchannelformessageexchangingfromaservertoclientsorviceversa.Regardingcompatibilityissuesbetweenmodernbrowsersandolderones,socket.iowasinventedtomaintainaconsistencyforusingWebSocketonanybrowserswithoutadjustments.Asamatteroffact,socket.iogrowsincrediblyfastandisimplementedinthemajorityofwebapplicationsalongsidewithNodeJS.

jQuery

jQuerywascreatedasaJavaScriptlibrary.Technically,everythingcanbedonewithJavaScript,whichnowisevenfasterandsimplerwithjQuery.Moreover,userinteractionisnowhandledinamorestraight-forwardway.Therearevarioustypesofactivityhappeningon-site,forexample,DOMmanipulation,eventschedulewhichnowcanaccomplishevenmorerapidlywithjQuery[7].Inaddition,pre-createdsnippetsforanimationsareavailablerightoutoftheboxfordevelopersaswell.Allinall,jQueryiswidelyusedinvastnumbersofprojectsinanyscaleandbecomeoneofthemostpopularJavaScriptlibrarieswithoutadoubt.

MongoDB

Adatabaseessentiallyisamust-haveinawebapplication.Sincethebeginning,RDMShastakenaleadinthewebdevelopmentindustry.Asaresultofthedominanceoflarge-scalewebapplications,theNoSQLdatabasehasbecomingstrong.Becauseofitnumerousfeaturessuchasscalable,adaptivetochanges,supportingJSON-likeformat,NoSQLhasreceivedsignificantattentionfromstart-upstolargescaleenterprises.OneofthemostpopulardatabasesinthiscategoryisMongoDB[8].Apartfromcharacteristicinheritanceofnon-relationaldatabases,MongoDB’smosthighlightingfeatureisaJSON-likedatabase.JSONformathasbeenwidelyusedtotransferdatabetweenclientsandservers.Table1.JSONformat.

{ 'key':value, 'Name':"John", 'ID':1}TheexampleaboveisasimpledeclarationofaJSON-formatvariable.Aspresentedinapairofkeyandvalue,JSONhasamoreflexiblestructurethanitsformer,XML.Inaddition,avaluecanbestoredinformofaJSONaswell.WiththeuseofJSONscheme,datafromservernowcanbedirectlystoredinMongoDBwithoutmakinganyconversions.Inaddition,complicatedtableconstraintsoftraditionaldatabasearecompletelyeliminated.Intermsofapplicationscaling,itisextremelyunsophisticatedtoappendmorerecordsorattributesastheappgrows.ThementionedfactorsmakeMongoDBsuitableforanycriteriaofthisprojectespeciallyinmobilegenerationwhereJSONcanbeseenasanewstandardfordatatype.

3 PROCESS

Aftercarryingoutsomeresearchtodecidewhichtechnologyissuitableforthisproject,alistofrecentoneswereselectedasfollows:NodeJS,MongoDB,jQuery,HighCharts,Socket.io.ThemainreasonforchoosingNodeJSinthefirstplaceisitshighperformancewhichisidealforreal-timewebapplications.Apartfromthat,thousandsofpluginsaredevelopedandavailabletoaccommodateanyrequirements.Especially,sensortagistheonelibrarythatcanenabledeveloperstoopenupthepotentialofTexasInstrumentsensors.Withthatfoundation,thesystemalreadyhasawebserverwithbuilt-infunctionalitytoconnectandcommunicatewiththesensordevice.Intermsofdatabases,MongoDBwaschosensinceitiseasytocorporatewithNodeJSandrecommendedthemostinwebdevelopmentcommunity.MeasurementsfromthesensorarestoredinMongoDBwhiletheyarepresentedonthewebsitesimultaneously.Thedatabasecomesinhandywhenitcomestoreviewthetrendinganalysisofvaluesfromthesensorinthefuture.Moreover,theabilitytointeractwithJSONformatalsoistakenintoaccount.

Picture3.Theimplementationstructure.

WiththeconvenienceofJSONstructure,HighCharts[9],ajQuerylibrarycanprocessdatafromdatabasetransparentlythendisplayitinanappealingway.TheadvantageofHighChartsliesinbuildingchartsorgraphswithsimplisticvisualregardlessofdeviceresolutionaswellasinprovidingafallbackcompatibilityforallcurrentweb-browsers.

Lastbutnotleast,socket.io,ontheotherhandisanupgradedversionofWebSocketwhichprovidescompatibilityacrossdevices.Withhighperformanceandstability,itisobviouslyaflawlesschoiceforreal-timewebapplication.Otherthanthat,socket.iowasalsobuiltonJavaScriptfoundationwhichmakesaseamlesscombinationwiththeothertechnologiesusedforthisconcept.

4 IMPLEMENTATION

Inordertogetthesystemoperated,allthepuzzlepieceshavetobeputtogetherinalogicalway,startingwithinstallationsoftheinfrastructurecore.Thefollowingsectionwillcovertheinitialstepstosetupabasicskeletonfortheapp.

4.1 NodeJSandmodules

NodeJSisavailabletoalmosteveryplatformavailableincludingWindows,MacOS,Linux.Thewalk-throughinstructionisclearlyavailableonNodeJS.org.However,fordemonstrationpurposes,allthestepsbelowthispointwillbetakenpartonMacOS.Thevisualinstructionfromthe‘.pkg’filedownloadedtoinstallNodeJSframeworkandNodepackagemanager(NPM)altogether.NPMisanessentialpartyetpowerfulofNodeJSenvironment.Itallowsustocustomizetheservertosuiteveryneedsfromprojecttoproject.ThemainfunctionofnpmistoaddorremovepackageswhichareexclusivelydevelopedforNodeJS.Table2.NPMinstallingsyntax.$ npm install <PACKAGE_NAME>

Express.jsframework

Express.js,whichintroducedafterRubyprojectSinatra,isanessentialframeworkforeveryonetobecomefamiliarwithNodeJS.AccordingtoJimR.Wilson,Expressprovidesmosttheplumbingcodethatcoderswillotherwiseendupwritingthemselves[10].Withonlyfewlinesofcode,afullyfunctionalbackbonewassetupandreadytogo.TheconceptbehindExpressisthatitispredefinedfollowingMVC(ModelViewController)architecturewiththesupporttemplateengines.ExpressGeneratorwascreatedforbeginnerstojumpintothedevelopingphasewithoutgoingthroughdeeplyconfigurationstepswithExpressbydefault.Abasicwebserverwillbedeployedrightoutoftheboxafterwithjustonelineofcode.Table3.CreateprojectwithExpressGenerator.

$ express sensorApp WejustcreatedasensorAppinthecurrentdirectorywithasimplewebserverwithanindexpage.

Sensortagmodule

SensortagmoduleisprovidedthroughNPMandisinstalledbythecommandbelow:

Table4.Sensortagmoduleinstallcommand.

$ npm install sensortag Anexamplecodecomesinthepackageenabletheserverreceivestemperatureandhumidityfromthesensorrightoutofthebox.Bymakingmodificationsinordertoadapttothisproject,specificfunctionsregardinglightsensorandgyroscopearealsoadded.Therearenotonlyvaluereceivingfunctionsareimplementedbutanumberofcalculationsarealsoplacedinthecodetocalculatetheoutputontheflybeforeitleavesforpresenting.

Socket.io

Themechanismofsocket.ioconsistsoftwoparts:theserverandclientside.TheserversideisdistributedfromNPM.Ontheotherside,theclientoneisslightlydifferent.First,thelibraryhastobeembeddedintothewebpage.Table5.Linkto“socket.io”libraryinHTML.

var socket= io.connect('http://yourdomain.address');

Additionalmodules

Inadditiontothementionedpackagesabove,therearesomeotherdependenciesneededtohelptheapplicationoperatingsuchas:serve-icon,morgan,body-parser,cookies-MongoDB,assert.

4.2 JavaScriptLibraries

mLabwasrenamedfromMongoLabinFebruary2016[11].mLabisanonlinedatabaseserviceusingMongoDB.ItprovidesanconvenientwaytointeractwithMongoDBwhichisalsocompatiblewithmanyexistingtechnologies.EasytosetupandreliableareadvantageswhenusingmLab.AregisteredaccountisneededtostartusingmLab.

Cloud-baseddatabasesareverypopularrightnowduetotheirportabilityandconvenience.mLabisagreatexample.Foreducationortestingpurposes,settingastandalonedatabase-servercouldbetime-consuming.mLabisconsideredasabetterchoicebecauseofitssimplicityininstallationandreliability.Tosetup,mLabcreatedanURLtoallowdeveloperstoaccessthedatabaseremotely.MongoclientisanobjectprovidingconnectingfunctionstoMongoDBdatabase.Byusingit,manipulatingthedatabasescanbedonewithonlyfewsteps.Table7.LinktoyourmLabdatabase.

url = ”MongoDB://<adminuser>:<password>@<link to your database:<port>/<database name>”; var MongoClient = require('mongodb').MongoClient; MongoClient.connect(url,function(err,database) {...};

HighCharts/HighStocks

ThereareplentyofJavaScriptlibrariesfordesigningchartsfromourdatabase.HighChartsisoneamongthebestsofarwhenitcomestoreliabilityandcompatibility.Table8.LinktoHighChartsLibraryinHTML.

4.3 Wireup

WithafoundationoftheExpresspredefinedserver,thenextstageisconnectingallthecomponentstogether.Bydefault,Expresshasitsstartingpointsetto‘www’file.Anyactivityfollowedbywillderivefromthere.‘www’file’sjobistoconfigureaportfortheserverandhandlerelatederrorsorexception.App.jswillactasastationwheredataflowwillbeprocessedandtransferredtoeverypartofthesystem.Thepurposeofapp.jsisto:

• Createandconfigurewebserver.• Importlibraries/plugins.• Handleviews.• Connectwithdatabase.• Processandmanipulatedata.

4.4 Settingupconnection

Inordertostarttheapp,weissuethiscommandintheappdirectory:Table9.StartNodeJSservercommand.

$ node app.jsSincethebeginning,whenevertheappisopened,asocketissetuptoreceivesignalsfromthesensoreverysecondwhichiscalleddiscoverymode.Fromthedashboard,thesensorstatusispresentedas‘Discovering..’whichmeanstheconnectionbetweenthesensorandserverisnotestablishedyet.

Picture4.Discoverymode.

Thesensorwillbeturnedonbypressingpowerbutton3forseconds.Ablinkingledlightonthesensorindicatesthatitisindiscoverymode.Whileindiscoverymode,itstartsbroadcastingitsaddress(UUID)tonearbydevices.

Picture5.Broadcastingconnectivitysignal.

Withthehelpofsensortaglibrary,thesensorwasdetectedwiththediscoveryfunction.Fromtheconsolewindow,thesensor’stypeanddevice’sIDwereprintedouttoindicatethattheyfoundeachother.

Picture6.Sensorinformationrecognizedbynodeserver.

Inaddition,anotherstepwasaddedtoverifywhetherornotwearechoosingtherightsensortoconnectto.Aftergettingdiscovered,everytimewepressanybuttononthesensor,theserverwillshowitsrecognition.Therearetwomethodstobecomeestablishedwiththeserver.Wecantakeaphysicalactiondirectlyonsensorbyholdingbothbuttonsatthesametimeor,ontheotherhand,byclickingonconnectbuttonfromthedashboard.Theindicationwillbereflectedontheserverconsole.Theuserinterface(UI)offersoptionstoenablefromonlyonetoallthebuilt-insensorsinordertoadapteveryneed.

Picture7.Sensorpanelindashboard.

Oncetheconnectionisup,temperature,humidityandlightdensitysensorsareactivatedaccordingly.Measurementsstarttofloodintonode-serverwithanintervalof1second.Atthesametime,MongoDBisalsoreceivingthosevaluesthenstoringthemwithinthecollectionnamedafterthecurrentdate.

Picture8.ResponsesfromserverwhenconnectedtoSensorTag.

Allofthoseflowsofdataarehandledbysocket.io.Bysettingupthebridgesbetweenthenodeserver,thesensortagmoduleandtheUI,thenumbersweretransferredbackandforthseamlesslybetweenthoseendswhichcreatesadataflowthroughouttheentireapp.

4.5 DataFlow

BetweenUIandserver

Afterusershavemadetheirchoicesofwhichtypeofdatatheywanttoretrievefromthesensor,asocketnamed“custom”wascreatedinordertosendthatcommandstraighttosensortagmodule.Themodulethenenablesthefollowingsensorscorrespondingly.

Figure1.DatatransferfromUItoservervia“custom”socket.

Inaddition,anothersocketwasinitializedbythenameof“valuesOut”.ThissocketisinchargeofforwardingvalueswhicharereceivedfromsensortagmoduletotheUIforpresentation.Thevaluesarepresentedingauges(meters)andingraphs.

Figure2.Socket“valuesOut”structure.

Lastly,inordertokeeptrackofhowmanysensorsareoperating,the“signal”socketiscreated.Theroleofthissocketistosynchronizeallthestatesofsensortoalltheconnectedclients.

Figure3.Socket“signal”.

Betweendatabaseserverandnodeserver

MongoDB,ontheotherhand,capturesvaluesrightaftertheyhavearrivedatthenode-server.Alongwiththetimestamp,eachentrywasinputtothedatabaseservereverysecondinadesignatedstructurewhichisexplainedinlatersection.

Figure4.Recordsaresenttodatabase.

4.6 Userinterface

Dashboard

Intermsofvisualizationofthecurrentstatus,fromthedashboard,allthevaluesareupdatedeverysecondinreal-time.Thechartinthesectionbelowisplottedinordertovisualizeeverychangesincethesensorisconnected.

Picture9.Dashboardinterface.

Report

Thispagewasintendedtopresentthedatawhichisstoredinthedatabaseserverduringthetimebeing.Wewillhavetwofieldstoselect:dateandtypeofdata.Sincethestructureofdatabaseinthisprojectwascategorizedbydate,userscanchoosewhichtypeofdatatheywanttoqueryonthatspecificdayfromtheformabovethegraph.

Picture10.Showrecordspanel.

Afterthe”SHOW”buttonwaspressed,requestsarethenforwardedtotheMongoDBcontainingthetypeofdataalongwiththedatebyuser’schoicetoextracttherecords.Afterthat,allthedatawillbeconvertedintograph-friendlydataformatthenisvisualizedbyagraphasbelow.

Picture11.Visualizedgraphofdata.

OnemoreintegratedfeatureofHighChartslibraryisthatwecanexportanygraphtovarietyofimageformatssuchasPNG,JPEGandPDF.Theseexportedimagescanbeusedforstoringorsendingbyemail.

Picture12.ExportingfeatureofHighCharts.

4.7 Database

Whenitcomestotheapplication,thedatabaseplaysanessentialrole.Forthisparticularproject,thedatabaseserverisnotonlyinchargeofstoringmeasurementsfromthesensorbutalsohandlingrequestsfromuser.Comparedwiththerelationaldatabase,MongoDBhasadifferentapproachtobuilditsownstructure.Asmentionedearlier,insteadoftables,collectionsareusedtostoreentrieswhicharecalledkeys.EachkeyconsistsofanobjectID,time,measurementsandeachcollectioncontainsrecordsforoneday.DatabaseName:sensorAppCollectionnames:namebydateKeys:

● Hour-Integer● Minute-Integer● Second-Integer● Temp-String

● Humi-String● Lux-String● Gyros-String

AnexampleofarecordindatabaseisdemonstratedinPicture13below.

Picture13.StructureofakeyinMongoDBdatabase.

5 PERFORMANCE

PerformanceplaysanimportantroleinwebapplicationsandsensorAppisnotanexception.Acharacteristicofthissystemisconstantlyretrievingvaluesfromthesensorwithatinyintervalsoaburdensomeloadofdatawillbecarriedbythedatabase.Becauseofthat,transferringsuchahugeamountofdatatoplotonthegraphbecomeschallengingforboththeserverandclient-side.Sinceeverytimeusersrequestarecordforalongperiodoftime,thedatabaseserverhastomakeaquerywitharesultcanbeuptothousandsofentriesorevenmore.Regardingthemechanismbehindit,thedatabaseserverprocessestherequestbyusersfromthedashboard,thenreturnswithanarrayofobjectsaccordingly.Beforethearrayissentbacktotheclient-side,NodeJSconvertsthevaluestochart-compatibletypesothatthechartcanpresentthoselateron.Apointinthegraphwastechnicallyrepresentedbyatimeandarequestedvaluewhichiseithertemperature,humidityorlightdensity(lux).Aspresentedinanexamplebelow,xisthetimestamp(milliseconds)andyisthetemperature(°C).

Picture14.Apointtransferredfromservertographs.

Duringtheexportingdatastagefromdatabasetoclient,anobstacle,whichisamethodoftravelingvaluesacrossthesystem,hasbeenaddressed.Sincetheamountofdataisenormous,theprocessingspeedwilldependonmanyaspectsnamelyquerying,traversing,convertingandplottingtime.Aftertryingdifferentapproaches,thefinalsolutionhasperformedwell..

Picture15.Howdataishandleduponrequests.

Theideaisthatallthecalculationaswellasconvertingjobswillbegiventotheserverwhichthentransferstheresulttothegraphwithoutanyadditionaladjustment.Aftermanyattemptsandmodifications,themostefficientwaytotransferdatafromtheservertotheUIisbyusingAjax.Ajaxcallallowsdatatraversefromoneendtoanotherwithoutrefreshingthewebpage.Therefore,userexperiencewasimproveddramatically.Ontheotherhand,queryingandinsertingentriesarehandledsimultaneouslyonthedatabaseserver.

6 ASSESSMENT

Theprojectcoversmanyaspectsofhowtoimplementareal-timewebapplicationfromscratch.Withacombinationofmanyrecenttechnologiesonthemarket,allthecomponentscooperatesmoothly.Moreover,withasimpleyetpracticaluserinterface,themonitoringtasknowhasbecomemoretransparent.Infact,therequirementsenabletheauthortolearnmoreandhaveachancetoapplyprogramingskillsaswellasachieveasignificantamountofknowledgethroughoutthemaking.Moreover,troubleshootingorproblemsolvingskillwasgainedgraduallywhilefacingobstaclesontheway.Twomonthsincludingresearchingtimeisthetotalamounttimetobuildeverythingfromanideatothefullyworkingapp.Ittook1weekatleastduringthetimelinetotestoutallthecomponentsaswellascombinethemtogether.Thefinaltestingandtuningupphasestookanotherweekinordertoensuretheoutcomemettheexpectations.

6.1 Obstacles

Althoughtheapphasbeenfunctional,therearestillproblemsthatneedtobeaddressed.Firstofall,themeasurementcompletelydependsonthesensor.Duringthedebuggingstage,theprovidedsensorhasdisplayedastrangebehavior.Forexample,thehumiditysensorrandomlysendsitspeakvalueswhichare-40degreeCelsiusand100%humiditytobeprecisetotheserverinsteadofitscurrentvalues.Despitethenewestfirmwareinstalledorfreshbatteryinstallation,noimprovementhasbeenseen.Overall,itmostlikelycouldbeahardwarefault.Secondly,theperformanceofdatabasehasitsowndownside.Theproblemcouldbeavoidedbyahighspeedconnectionbetweentheclientandtheserverwhilequeryinghistoryrecordsfromdatabase.Becauseofahugeamountofentriesfloodingintothesamesocket,itcancauselatencyinresponse.Lastly,sincetheserverdoesnothaveanyencryptionmethodtobondwith,securitymattersshouldbetakenintoaccount.Nocredentialisrequiredtoaccessthedashboardremotelysoitistotallypossibleifoutsiderswanttointerferewiththeoperationofthesystem.

6.2 PotentialFutureImprovement

Everythinghasitspositiveandnegativesideand,ofcourse,thisappisnotanexception.Aconsiderednumberoftaskshavebeenaccomplished

flawlessly.However,thereweresomeimprovementsthatcouldhavebeenmadetotakeittoanotherlevel.Firstly,technically,anaccuracyoflightdetectionneedstobeincreased.Atthemoment,theconceptoftrackingopening/closingdoormovementsintuitivelydependsonthefluctuationsofthelinechart.Theoretically,thelightingleveliscompletelydifferentatanyrandompointinthemedium.Becauseofthat,everytimethedoorwasopened/closed,thechangeswerereflectedbytheupwardordownwardtrendonthegraph.

Picture16.Lightdensitypresentation.

Secondly,anadministratormayneedananalyticalreportforalongerperiodnotjustaday.Becauseofthatdemand,theexportingrecordsfeatureshouldbeupgradedtoalargerscalewhichallowstheadministratortoreviewastatisticforaweek,amonthorevenayear.Implementationdoesnotseemtobesophisticatedafterall.However,thetransmittingspeedofrecordsacrossthenetworkshouldbetakenintoaccount.Forafullday,wehave86400recordswith1sintervaltobeexact.Ontheotherhand,roughly,2.592e+6recordsareregisteredinamonthorevenaexcessivenumbersofrecordsinayear.Inaddition,thestruggleisnotonlywiththebandwidthofnetworkbutthenumbersofconnectionsaccessingtheappinordertoexportatthesametimeisalsoachallenginngproblem.Theperformancecouldbeimprovedbyusingefficienttweakingmethods.

6.3 Limitations

Powerconsumption

Thesensorisrequiredtofunctionconstantlytokeeptrackofeveryeventinrealtime.Asmentioned,thelimitinbatterycapacityisaseriousconcern.Throughoutthetestingphrase,with1sintervalfortransmission

andtheuseofonecoin-sizebattery,thesensorlastsonlyafewdaysbeforethebatteryrunsout.Thatresultwasconductedwhenallthesensorswereenabled,namelytemperature,humidity,luxometerandgyroscope.Themoresensorsareenabled,themorepowertheappconsumes.AccordingtoMishaandheranalysis[12],thepowerconsumptionofthesensorthroughoutoperationstageswasreflectedbythetablebelow.Table10.Powerconsumption.

Currentinmilliamp(mA)

Poweringon 12

Standby 0.24

TemperaturesensorON 0.84

Temperature+HumiditysensorsON 0.92

Lightsensor(Luxometer) 0.56

Motionsensor 4.16

Barometricsensor 0.5

Allsensorson(100mssamplerate) ~5.5

Followingtheanalysis,the240mAhbatterycanonlypowerthesensorforlessthan48hourswithmaximumtransferrateorroughly240hourswithjustonlytemperatureandhumiditysensorson.ThisresultisfarfromwhatTexasInstrumentspromotesontheirwebsitewhichitcanlastforayear.Therefore,inordertoaccomplishthatrateofmaintenance,wecanuseanexternalpowersupply.Becauseoflackofphysicalinterface,thesensorneedssupportfromthedevelopmentkittoconnecttoexternalbattery(powerbank)viaUSBport.

Gyroscopeaccuracy

Becauseofthesensitivityoflightsensor(luxometer),everyminormovementofthedoorwillberegistered.Therefore,dependingonlightdensityvaluealonetodeterminedoormovementisnotpracticalinareallifescenario.However,combiningthatdatawithvaluesfromgyroscopemakesthedeterminationmuchmoreaccurate.Forexample,whenthedoorstartstomove,thegyroscopereflects3valuesfrom3-axisand,simultaneously,luxometerprovidesfluctuationsfromlightdensity.SensorTagcomeswithdifferentsensorsdedicatedtomotiondetectionsuchasaccelerometerandgyroscope.Inordertotracktheobject'smovements,inthiscaseisthedoor,thegyroscopesensorwasenabled.Thissensorhas3axisvariablessimilartoaccelerometerwhicharex,yandz.DependingonthepositiontheSensorTagwasplacedontothedoor,oneofthe3variableswouldchangeaccordinglytothedoormovements.Bycalculatingthedifferencebetween2valueswhenthedoorat2positions,wecandeterminewhetherornotthedoorisbeingopened.

Picture17.Gyroscopepresentation.

Regardingthecalculationmethod,thevaluesof3axis(X0,Y0,Z0)whenthedooratrestwereinitiallymeasuredthensubtractedwithvalues(X,Y,Z)whenthedoorstartedtomove.Thedifferencesbetweentheinitialvaluesandcurrentvaluesof3axisarecalledDelta1,Delta2,Delta3.

Delta1=|X0-X|Delta2=|Y0-Y|Delta3=|Z0-Z|

Equation1.Differenceswhensensorchangingposition.

Sincethesensorisextremelysensitive,evenasmallmovementcanmakeadifference.Therefore,aso-calledOffsetConstant(C)isalsocreatedtoexcludethosetinychancesfromalgorithm.Inthiscase0.8istheoffsetconstant.Withthat,wecandecidewhetherthedoorisopenedorclosedbycomparingDeltastoOffsetConstant(C).

Table11.SensorstatesdecidedbyDelta.

Delta1 Delta2 Delta3

>C Moving Moving Moving

<=C Atrest Atrest Atrest

7 CONCLUSION

Astheresult,afullyfunctionalmonitoringservermeetstheinitialobjectives:

• Measuresenvironmentalvariablesnamelytemperature,humidity,lightdensity,gyroscopevaluesfromtheSensorTag.

• Hasareal-timevisualizedgraphicalinterface.• High-capacitydatabaseprovidesanalyticaldatainformofgraphs

withexportingfeaturesbuilt-in.• Providesamanaginginterfacecanberemotelyaccessedwidely

fromanytime,anywhere.• Isfullycompatiblewithmostofbrowsersanddevices.

Atthetimethisthesiswaswritten,thisapproachtoSensorTagdevicesisnotpopular.Mostofrecentprojectsusemobiledeviceasarelaydevicetoforwardinformationfromsensortothe“cloud”.Usersthenhavetousewebservicefromtheproviderinwhichitisimplementedtoreviewthereceiveddata.Mostservicesdonotprovidethedatabaseextractionfeature.WiththehelpofacombinationofNodeJSserver,MongoDB,socket.ioandFront-endframeworks,wecanalmostestablishallthewebapplicationinfrastructurenotonlyinacommercialbutalsoinanindustrialenvironment.ThisappisadefiniteexampleoftheInternetofThingsinpracticewhichisatrendinembeddedprogramingnowadays.Inconclusion,theapplicationisusingallthemoderntechnologiessoitispracticalinproduction.Itrunsproperlyandmeetsalltherequirementsasexpectedeventhoughtherearestilllimitsintechnologyaswellastheexperienceoftheauthor.Inordertocompletethestack,manyskillshavebeenrequiredincludingfluencyinprogramminglanguages,manipulatingandhandlingbigdatainanetwork.Moreover,communicationbetweenphysicaldeviceandtheAPIisalsoachallenge.Allinall,thereisspaciousroomforimprovementsinthefuture.Despitethesizeofthisproject,theversatilityandpossibilityareendlessifwecankeepthefoundationandimplementspecificinfrastructureontoptosuiteveryneed.

REFERENCES

[1]TexasInstrumentsSensortag.Consulted30.3.2016.Availableathttp://www.ti.com/tool/cc2650stk#1.[2]SimpleLinkSensorTagDebuggerDevPack.Consulted30.3.2016.Availableathttp://www.ti.com/tool/cc-devpack-debug.[3]BluetoothBLE.Consulted30.3.2016.Availableathttps://www.bluetooth.com/what-is-bluetooth-technology/how-it-works.[4]MithunSatheesh,BrunoJosephD’mello,JasonKrol.2015.WebDevelopmentwithMongoDBandNodeJS.2ndEdition.PacktPublishing.E-book.Consulted5.4.2016.[5]SandeepMistry.2015.Node-sensortag.Consulted15.4.2016.Availableathttps://github.com/sandeepmistry/node-sensortag. [6]FionnKelleher.11.8.2014.Consulted20.4.2016.Availableathttps://nodesource.com/blog/understanding-socketio/.[7]RyanBenedetti,RonanCranley.2011.HeadFirstjQuery.1stEdition.O’ReillyMedia,Inc.Consulted20.4.2016[8]MongoDB.https://docs.MongoDB.com/manual/.Consulted25.4.2016[9]JoeKuan.2015.LearningHighCharts4.PacktPublishing.E-book.Consulted5.5.2016.[10]JimR.Wilson.2013.Node.jstheRightWay.ThePragmaticProgrammers.Consulted10.5.2016.[11]mLab.Consulted11.5.2016.Availableathttps://en.wikipedia.org/wiki/MLab.[12]Misha,9/6/2015.TISensorTag2Powerconsumptionanalysis.Consulted30.5.2016.Availableathttp://mobilemodding.info/2015/06/ti-sensortag-2-power-consumption-analysys/.

Appendix1

Appendix1-Applicationtree.app.jspackage.jsonbin└── wwwpublic├── images├── javascripts ├── dashboard.js ├── socket.io.js ├── sensortag.js └── report.js└── stylesheets ├── style.css └── report.cssroutesviews├── error.pug├── dashboard.pug├── report.pug└── layout.pug

Appendix2(1)

Appendix2–Sensortagmodulecodevarasync=require('async');varSensorTag=require('sensortag');//sensortaglibraryvarstatus=0;vartOn,hOn,lOn,gOn;SensorTag.discover(function(tag){ //whenyoudisconnectfromatag,exittheprogram. functiondisconnectTag() { tag.on('disconnect',function(){ console.log('disconnected!'); module.exports.dis=1; process.exit(0); }); } functionconnectAndSetUpMe(){

//attempttoconnecttothetagconsole.log('connectAndSetUp');

tag.connectAndSetUp(enableIrTempMe); //whenyouconnect,callenableIrTempMe

}functionenableIrTempMe(tempON,humiON,luxON,gyroON){

if(tempON){ console.log("Temperaturesensorisenabled!"); tag.enableIrTemperature();}if(humiON){

console.log("Humiditysensorisenabled!"); tag.enableHumidity();}if(luxON){ console.log("Luxometersensorisenabled!"); tag.enableLuxometer();}if(gyroON){ console.log("Gyroscopesensorisenabled!"); tag.enableGyroscope();}

Appendix2(2)

}functiondisableSensors(){

//disableallsensorstag.disableHumidity(tag.disableLuxometer(tag.disableIrTemperature(tag.disableGyroscope())));console.log("Disableallsensors!!!");disconnectTag();

}functionnotifyMe(tempON,humiON,luxON,gyroON){ console.log('Sensor'+tag.type+'isconnected!'); console.log('Device\'sIDdetected:'+tag.id); console.log('--------------------------------'); console.log(''); tag.unnotifySimpleKey(); if(tempON) { tag.notifyIrTemperature(tag.setIrTemperaturePeriod(1000,listenForTempReading)); } if(humiON) { tag.notifyHumidity(tag.setHumidityPeriod(1000,listenForHumidity)); } if(luxON) { tag.notifyLuxometer(tag.setLuxometerPeriod(1000,listenForLuxometer)); } if(gyroON) { tag.notifyGyroscope(tag.setGyroscopePeriod(1000,listenForGyroscope)); }functionlistenForLuxometer(){ //ListenforLuxometer tag.on('luxometerChange',function(lux)

{ //console.log('luxvalue=',lux);

module.exports.lux=lux.toFixed(1); });}functionlistenForGyroscope(){ //ListenforLuxometer vartempX,tempY,tempZ,state;

Appendix2(3)

tag.on('gyroscopeChange',function(x,y,z){ //console.log('Gyroscope:'); //console.log('x:',x.toFixed(1)); //console.log('y:',y.toFixed(1)); //console.log('z:',z.toFixed(1)); module.exports.gyro=x.toFixed(1)+"|"+y.toFixed(1)+"|"+z.toFixed(1); if(x.toFixed(1)-tempX>0.8) { state=1; } else { state=0; } module.exports.state=state; tempX=x.toFixed(1); tempY=y.toFixed(1); tempZ=z.toFixed(1); });}//Whenyougetanaccelermeterchange,printitout:functionlistenForTempReading(){

tag.on('irTemperatureChange',function(objectTemp,ambientTemp){ //console.log('\tObjectTemp=%ddeg.C',objectTemp.toFixed(1)); //console.log('\tAmbientTemp=%ddeg.C',ambientTemp.toFixed(1)); varintemp=ambientTemp.toFixed(1); module.exports.temp=ambientTemp.toFixed(1); });}//GetdatafromHumiditySensor(+Temperature)functionlistenForHumidity(){

tag.on('humidityChange',function(temperature,humidity){//console.log('\tTemperature=%ddeg.C',temperature.toFixed(1));//console.log('\tHumidity=%d%H',humidity.toFixed(1));module.exports.humi=humidity.toFixed(1);varintemp=temperature.toFixed(1);varinhumid=humidity.toFixed(1);});}//whenbuttonspressedfunctionlistenForButton(){ tag.on('simpleKeyChange',function(left,right){

console.log("Device:"+tag.type); console.log("DeviceID:"+tag.id);

Appendix2(4)

if(left){ console.log('leftbuttonPRESSED!'); } if(right){ console.log('rightbuttonPRESSED!'); } //ifbothbuttonsarepressed,disconnect: if(left&&right){ console.log("Device:"+tag.type+"withidof:"+tag.id+"connected!"); enableIrTempMe(); //tag.disconnect(); } }); }//Nowthatyou'vedefinedallthefunctions,starttheprocess:tag.connectAndSetUp( function(){ varintervalID=setInterval(function() { //console.log("Checkstatus:",status); if(status==1) { notifyMe(tOn,hOn,lOn,gOn); enableIrTempMe(tOn,hOn,lOn,gOn);

//connectedsignal clearInterval(intervalID); varsecondIntervalID=setInterval(function(){ if(status==2) { disableSensors(); clearInterval(secondIntervalID); } },1000); } },1000); console.log("SensorType:",tag.type); console.log("SensorID:",tag.id); module.exports.sta=status; module.exports.type=tag.type; tag.notifySimpleKey(listenForButton);//startthebuttonlistener);

Appendix2(5)

});});module.exports=function(s,tempOn,humiOn,luxOn,gyroOn){ status=s; tOn=tempOn; hOn=humiOn; lOn=luxOn; gOn=gyroOn;}

MONITORING ENVIRONMENTAL VARIABLES USING SENSORTAG · Picture 1. Concept of a monitoring system. 6...

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