THEOHIOSTATEUNVIERSITY

WirelessAccelerometerECE682

ClayCochran,TimDuly,BrandonErvin,&MikeJender

3/13/2009

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ExecutiveSummary

PurposeThisdocumentproposesthedesignanddevelopmentofawirelesscircuitnetworktorecordandanalyzetheaccelerationofsomesystem.

ProblemStatementAnalarmingstatisticthatisincreasingtodayisthenumberofstudentsnotenteringengineeringafterhighschool.Highschoolstudentswithinterestinengineeringleavehighschoolandentercollegewithlittleornoengineeringexperience.Asmallprogrammablemicrocontrollercouldbeusedtocreateafairlysimpleapplicationsuchasmeasuringaccelerationtobeintegratedintoahighschoollabsetting.

BackgroundResearchByusingtheTIeZ430rf2500WirelessDevelopmentTool,itispossibletocreateamoreuserfriendly,easytouseaccelerometer;thisdevicecouldbeusedinavarietyofwaysthathighschoolstudentswouldfindinteresting.

Oncetheaccelerometerdeviceisdesignedandbuilt,usingtheunitdiscussedjustpreviously,novelandinterestingwaystouseitintheclassroommustbedevised.Onesuchapplicationcouldbeuseonamodelrollercoaster.Inthiscase,theaccelerometercouldbeusedtoanalyzespeedsorgforcesatvarioustimesthroughouttherollercoaster.

DesignApproachWewillinvestigatewirelesstransmittersandbuyonetoevaluate.Afterwearefamiliarwiththeproduct,wewillintegratetheaccelerometertosenddata.Oncewehaveagoodmeansofsendingandreceivingaccelerationdata,thedooriswideopenforapplications.Thespiraldesignprocesswillbeused;manypartsofthedesignwillberevisited.

DesignWeplantousetheeZ430RF2500Ttosenddatafromtheaccelerometer.Ourinitialdesignincludedadigitalaccelerometerbutitwasdecidedtorevisitthedesignandwesettledonananalogaccelerometer.Itwasmucheasiertodebugandfixproblems.WeusedMATLABtorecordaccelerationintheX,Y,andZdirectionsandplotteditonascreen.WeplantoapplythissystemtoamodelrollercoasterwithCoasterDynamixandintegrateitintoahighschoollabprojectmodeledaftertheInfinityProject.

ConclusionThedesignanddevelopmentofafairlysimpleandaffordablewirelessanalogaccelerometernetworkhasimportantapplications,oneofwhichtomeasureaccelerationofamodelrollercoasterforahighschoollabsetting.

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TIPartsDiscussion

RFTransmitterandReceiver TheCC2500RFtransceiverprovidedcommunicationfromtheaccelerometerontherollercoastertothereceivernode.Itwaslowpowerwhichensuredalongerbatterylifeforthesystem.Thisisalsoimportanttoconsidersincethereareamultitudeoftransmissionsoccurring.Thecommunicationlinkprovidedsufficientdistancefromourtransmitterandreceiverperfectforusinginsidearoom.

MSP430Microcontroller TheMSP430F2274wasused.Thismicrocontrollerprovidedthenecessaryanalogtodigitalconversionaswellastheprocessingpowertoreadthedata.Onthetransmittingend,themicrocontrollerprovidedtheanalogtodigitalconversion,necessarydatamanipulation,andsetuptobesentwirelesslythroughtheCC2500.Onthereceivingend,thechipactedasameanstopassdatathroughtotheUSBportonthecomputer,whichwasreadbyourMATLABprogram.

Thisparticularmicrocontrollerwaschosenforavarietyofreasons.Itwaslowpowerwhichmeantoursystemcouldworklongerbeforechangingthebattery.ItssizewasidealforattachingtotheaccelerometerboardandforfutureimplementationinaPCBboard.

VoltageRegulator TheTPS71530wasusedtoallowdifferentvoltagestobeconnectedtothesystem.Thispartacceptedvoltagesupto24Voltsandprovidedaconstantoutputof3V;thereforenoadjustmentswereneededtomaintainthevoltagelevel.Thisensuredconsistentoperation.Thisparthadanerroror4%,whichstillprovidesacceptablevoltagesfortheaccelerometer.TheTPS71530wasdesignedtoworkwithMSP430microcontrollersandisverysuitableforourpurposes.

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TableofContents

ExecutiveSummary.......................................................................................................................................1

Purpose.....................................................................................................................................................1

ProblemStatement...................................................................................................................................1

BackgroundResearch................................................................................................................................1

DesignApproach.......................................................................................................................................1

Design........................................................................................................................................................1

Conclusion.................................................................................................................................................1

TIPartsDiscussion.........................................................................................................................................2

RFTransmitterandReceiver.....................................................................................................................2

MSP430Microcontroller...........................................................................................................................2

VoltageRegulator.....................................................................................................................................2

TableofContents..........................................................................................................................................3

Introduction..................................................................................................................................................4

Purpose.....................................................................................................................................................4

ProblemStatement...................................................................................................................................5

Scope.........................................................................................................................................................5

BackgroundResearch....................................................................................................................................6

RequirementsAnalysis..................................................................................................................................7

DesignApproach...........................................................................................................................................7

InitialDesignPlan..........................................................................................................................................7

FinalDesign...................................................................................................................................................8

ExplanationofCode................................................................................................................................10

Calibration...............................................................................................................................................11

SampleImageCapture................................................................................................................................11

ReportofWork...........................................................................................................................................12

Resources....................................................................................................................................................12

Personnel................................................................................................................................................12

Facilities,Equipment,andCosts.........................................................................................................13

Schedule......................................................................................................................................................14

DesignReview.............................................................................................................................................15

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FuturePlannedDevelopments...................................................................................................................16

Conclusion...................................................................................................................................................16

Appendix:Code...........................................................................................................................................17

CCodeUsedinIAREmbeddedWorkbench............................................................................................17

AccessPoint........................................................................................................................................17

EndDevice...........................................................................................................................................22

MATLABCodetoDisplayPlots................................................................................................................26

TableofFiguresFigure1:BlockDiagramofWirelessAccelerometerNetwork.....................................................................8Figure2:SchematicofAnalogAccelerometerEndpoint............................................................................10Figure3:SampleAccelerationinX,Y,&Z...................................................................................................11Figure4:SparkFun3DAccelerometer.......................................................................................................14Figure5:TIMSP430WirelessDevelopmentTool.......................................................................................14Figure6:TableofDesignWorktoBeCompleted......................................................................................15

Introduction

Purpose Thisdocumentproposesthedesignanddevelopmentofawirelesscircuitnetworktorecordandanalyzetheaccelerationofsomesystem.Thisistobedonebyimplementingtheuseofawirelesscapablemicrocontrollerandasmallaccelerometer.Thiscircuitwouldbevaluablebecauseitcouldbeusedforawidevarietyofprojectsandapplications.Thewirelessaccelerometernetworkcouldbeusedifdevelopmentisfairlystraightforwardtointroduceandpromoteinterestinhighschoolstudentstoengineeringbyimplementingthedevelopmentofthecircuitinaclassroom.Thisisimportantbecausemanyhighschoolstudentsarenotinterestedinengineeringprogramswhentheygraduatebecausetheyarenotexposedtothemandthinkthatitistoocomplicatedtocompletethelargenumberofcomplexscienceandmathcourses.Theaccelerometercircuitcouldalsobeusedinmanyothermorecommonengineeringapplications.Arollercoastermodeloneoftheseexamplesofaprojectthatthewirelessaccelerometercouldbeimplementedinto.Thiscouldbeusedtomeasuretheaccelerationinthreedirectionstoseehowintensetheactualrollercoasterexperiencewouldbeforsomeoneridingtheactualrollercoaster.Ifthewirelessaccelerometernetworkisfoundtobeeffectiveandfairlycompact,itwouldalsobepossibletoimplementinmanyotherextremelyimportantandmarketableapplications.

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ProblemStatementAnalarmingstatisticthatisincreasingtodayisthenumberofstudentsnotenteringengineering

afterhighschool.Astheworldcontinuestobecomemoretechnologicallycenteredandcomplex,itisimportanttomakecertainthatthereareanabundanceofpotentialengineersleavingourcountryshighschools. Highschoolstudentswithinterestinengineeringleavehighschoolandentercollegewithlittleornoengineeringexperience.Asaresult,therearealargepercentageofstudentsthatdropoutofengineeringoncetheygetintothemajorbecausetheyfeeloverwhelmedorunprepared.Furthermore,manystudentslacktheinitialinterestinengineeringbecausetheyarenotexposedtoit.Theyarediscouragedbythewaymathandsciencearetaughtandtrytoavoidafieldofstudyorcareerthatwillbeusingthesefortherestoftheirlives.Inordertocombatthis,studentsneedtobeexposedtocomplexbutachievableengineeringprojectsinhighschools.Theseprojectswillalsodemonstrateareallifeapplicationusingmathandscienceasopposedtoonlyworkingtrivialproblems.

Teachersfeelfrustratedwithteachingbecausemanylabkitsareexpensiveandoverlycomplexforthehighschoollevel.Thereforeitisimportanttomakesuretheteachersarewellpreparedandeducatedregardingengineeringlabkitssothattheycaneffectivelyteachtheirstudents.Itisjustasimportanttomakethekitslowcostsopublicschoolscanaffordthemtobeimplementedintheirlabsandprovidetheirstudentswiththesameopportunitiesasprivateschools.

SomekitsareavailablesuchastheInfinityprojectthatutilizesadigitalsignalprocessortocreatevariousprojects.Programmingadigitalsignalprocessorisfairlycomplicated,especiallyatthehighschoollevel.Thereforeanotherapproachthatiseasiertoworkwithandthatrequireslessbackgroundknowledgeshouldbeusedinthekitstomaketheprogrammoreeffective.Asmallprogrammablemicrocontrollercouldbeusedtocreateafairlysimpleapplicationsuchasmeasuringacceleration.PerhapsthiscouldbeappliedtoamodelrollercoasterapplicationsuchasaCoasterDynamixrollercoaster.Engineeringeducationwouldalsobecomplimentedbyphysicsandothersciencedisciplines.

Theaccelerometercircuitcouldalsobeimplementedintomanymoreimportantapplicationsifitisfairlyaccurate.Therearemanyapplicationssuchastestingofautomobilesandsafetyandhealthofhumanbeingsjusttonameafewthatcouldbeimprovedbytheuseandimplementationofanaccuratewirelessaccelerometernetwork.

Scope Thisreportdiscussesthedesignandimplementationofthewirelessaccelerometercircuit.Itdiscussesthedifferentpiecesofequipmentandthehardwareselectedfortheimplementationofthecircuitandhowtheywillbeconnectedandimplementedtogetthedesiredresults.Itwillonlydiscusstheapplicationsofthecircuitveryminimally.Thereismuchmoreofafocusontheactualconceptualdesignthanontheactualapplicationsoftheaccelerometernetwork.Althoughonlyasmallnumberofapplicationsarementioned,thereareunlimitedapplicationsforthiswirelessaccelerometercircuit. TheaccelerometerwasdesignedandbuiltthroughoutthecourseofthedesignseriesofECE582andECE682/683.AfairlysimpleGraphicalUserInterface(GUI)wasdevelopedinMATLABtomonitortheaccelerationreadingsintheX,Y,andZdirections.Thisprovidedawayofcollectingtheaccelerationdatasoitcouldbeusedforanalysisofthesystemlater.Thecircuitanddatacollection

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systemwascompletedandisdiscussedinadditiontothepossibleadvancementsandimprovementstothesystem.

BackgroundResearchItisessentialtocontinueemphasizingexposuretothesciencesandengineeringduringhigh

school.Amajorobstaclestandinginthewayofthisgoalisthecomplexityofmanyexistingtechnologykits.ByusingtheTIeZ430rf2500WirelessDevelopmentTool,itispossibletocreateamoreuserfriendly,easytouseaccelerometer;thisdevicecouldbeusedinavarietyofwaysthathighschoolstudentswouldfindinteresting.

TheTIeZ430rf2500WirelessDevelopmentToolisactuallyadevicewiththreemainparts.AttheheartofthedeviceistheMSP430F2274Microcontroller.Thisisaverylowpowermicrocontrollerthatincludesseveralusefulperipheralcomponents.Theseincludea10bitA/Dconverter,twogeneralpurposeoperationalamplifiers,two16bittimers,and32I/Opins.Thus,thismicrocontrollerisveryusefulforapplicationsthatrequireananalogsignaltobedigitizedandsubsequentlyprocessed.Thisisanimportantability,becauseitwouldenabletheprocessingofanalogaccelerometerdata.

AlsoincludedintheWirelessDevelopmentToolistheCS2500Transceiver.Thisisalowcostelectroniccomponentthatbothtransmitsandreceiveswirelessdata;itisdesignedespeciallyforuseinverylowpowerapplications.Itisequippedwithamodemcapableofadjustabledataratesofupto500kBaud,aswellasvariousmodulationschemes.Thereare64bitFIFOsforbothtransmitandreceive.Thiscomponentwouldallowtheaccelerometertobewireless,openingupavarietyofexcitingpossibleuses.

Lastly,andperhapsmostimportantly,theeZ430RFDebuggingInterfaceisincludedwiththedevice.ThispieceallowstheusertouseaUSBconnectiontoprogramanddebugtheattachedmicroprocessor.Thiscomponentcanbeseparatedfromtherestoftheunit.Thisisoneofthemostimportantadvantagesofthisdevice,asitallowsaccesstoaneasytouseinterfacewiththemicroprocessorandallowsstepthroughdebugging.

Alsoincludedinthedeviceisatargetboard,whichisagroupof18developmentpinsthatallowseasyaccesstotheMSP430F2274microcontroller.Thisprovidesasimplewayfortheusertoconnectvarioustypesofhardwaretothemicrocontroller,andallowsforawiderangeofusesfortheunit.

Oncetheaccelerometerdeviceisdesignedandbuilt,usingtheunitdiscussedjustpreviously,novelandinterestingwaystouseitintheclassroommustbedevised.Onesuchapplicationcouldbeuseonamodelrollercoaster.Inthiscase,theaccelerometercouldbeusedtoanalyzespeedsorgforcesatvarioustimesthroughouttherollercoaster.

CoasterDynamix,asmallcompanybasedinVirginia,makeshighqualityrollercoastermodelsthatwouldworkverywellinconjunctionwiththeaccelerometerunit.Thesewellmadescalemodelswouldexposestudentstointerestingengineeringandphysicsconceptswhichtheycouldidentifywith.

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RequirementsAnalysis Thissystemwillbeginasageneralaccelerometerdatatransmitter,andapplyittospecificapplications.Weplantoimplementthisdeviceintoaclassroomsettingforahighschoolorevenjuniorhighlaboratory,whichwouldbemoreeffectivethanacomplextoolkitthattheInfinityprojectnowhas.Furthermore,thissystemhassellingpotentialtocompaniessuchasRollerCoasterDynamixinwhichtheywantshowinrealtimetheaccelerationoftheirmodelrollercoasters. Thesystemmustbeabletotransmitaccelerationdatawirelesslytoareceiverwithinahundredmeters.Thisdatawillbestoredinamicrocontrollerandwillbeeasilyavailableforcalculations(i.e.,velocity,distance).Thewirelesstransmitsystemisrequiredtobephysicallysmall:nomorethan10cmx10cminareasothatitcanbeimplementeddiscretelyintosystemssuchasamodelrollercoaster.

DesignApproach Ourteamisusingabottomupapproachtodesigningthissystem.Wewillstartwithanaccelerometerevaluationboardtotestandcharacterize.Nextwewillinvestigatewirelesstransmittersandbuyonetoevaluate.Afterwearefamiliarwiththeproduct,wewillintegratetheaccelerometertosenddata.Thenwewillworkonthereceivedeviceandworkonhowtotalktothetransmitter.Oncewehaveagoodmeansofsendingandreceivingaccelerationdata,thedooriswideopenforapplications,andweshallapproacheachapplicationindividuallyandbranchofffromthere. Acommonthemeinourdesignapproachistakingsmallsteps.Thisway,wecanseparatetheproblemanddebugitindividually.Thisismucheasiertodoratherthanbuildingthesystemasawholeandattemptingtofixitwhensomethinggoeswrong.Alsoweintendfortheprogramstoberelativelysimplefordebuggingpurposesandforcreatingmorecomplexsystemsinthefuture. Aspiraldesignapproachwillbeusedforthedevelopmentofthesystem.Astimeprogresses,manypartsofthedesignprocesswillberevisited.Asthedesignprocessisadvanced,theactualsolutiondefinedwillchangeaswillmanyotheraspectsofthedesign.Thisiseasilyshowninaspiraldesignrepresentation.Also,thedebuggingprocesswillprovetobeextremelyimportantduetoactuallyseeingwhatthemicrocontrolleriscapableofandtheprogrammingskillsofallteammembers.

InitialDesignPlan TheinitialplanwastocreateadesignforawirelessaccelerometerimplementingTIpartsintothedesign.WeplannedtousetwoeZ430RF2500Ttargetboardsforthedesign,usingoneforthemainnodeandonefortheendpointofthesystemcollectingdatafromtheaccelerometer.Thesedevicesallowdatatobesentwirelesslybythetransceiversconvenientlylocatedoneachtargetboard.Theaccelerometerdatawasplannedtobeoutputeitherdigitaloranalogdata.Thisdecisionprovedtobethemostimportantdecisionbecauseitwasdiscoveredthatthedesignwasmucheasierimplementedusingtheanalogaccelerometer.ThedigitalaccelerometerprovedtobemuchmoredifficultduetotheSPIcommunicationscheme.TheeZ430RF2500ThasanA/Dconverterthatwastobeusedtoconverttheanalogsignalfromtheaccelerometertodigitalforsignalprocessing.Thisleadtomucheasiertroubleshootingofthecircuitduringtestingandwasmucheasiertodevelopsoftwarefor.

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Oncethesignalwasreceived,itwasplannedtobesenttoanothermicrocontrollerwherethedatawouldbecollectedforprocessing,andthensenttoacomputerforinterpretation.AfairlysimpleGUIwastobedevelopedthatwouldmakeitpossibletoanalyzethedatacollectedfromtheaccelerometerforanalysispurposes.ItwastobedevelopedtoshowtheX,Y,Zmovementonthecomputerscreenandsaveallofthedatacollected.Nextitwasplannedtoapplyaspecificapplicationtothewirelessaccelerometer.Forexample,withtherollercoaster,CoasterDynamixwouldliketoseetheamountofgsexertedonthemodelrollercoasterinrealtimeasitmovesalongthetrack.Also,itcouldbeimplementedintoasecondgenerationInfinityProjectforHighSchoolstudentstolearnmathandscience.Oncethesystemwascompleted,numerousopportunitiesforapplicationsarise,withlittleornotweaking.Figure1showstheblockdiagramfortheprojectshowingboththepossibilitiesofusingeitherananalogofdigitalaccelerometer.

Figure1:BlockDiagramofWirelessAccelerometerNetwork

FinalDesign ThefinalhardwaredesignwasfairlystraightforwardandisshowninFigure3.Ananalog3dimensionalaccelerometerwaspickedforthefinaldesignbecauseitwasmucheasiertotestandworkwiththanthedigitalaccelerometerusingSPIcommunications.ThepinslabeledX,Y,andZaretheactualanalogoutputsoftheaccelerometer.ThesepinswerethenconnectedtoanaloginputsforPortAofthemicrocontrollertargetboard.ThiskeptallofthedataconfinedtothefirstthreechannelsofPortA.Inordertoactuallyreadthedata,theSLPpinoftheaccelerometerhadtobesettohigh.Thiswasdonebyoutputtingahighvaluefrompin8continuouslyfromthetargetboard.Thiswasusingmore

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powerbykeepingtheaccelerometeractiveallofthetime,butitwaseasiestandmosteffectiveforthisapplication.

TheschematicoftheconnectionsfortheendpointisshowninFigure2below.Thisshowsthenecessaryconnectionstocollecttheaccelerationdatafromtheaccelerometerandthenprepareitforwirelesstransfertothemainnode.TheVccwireisusedtopowertheaccelerometerbysupplyingitwithapproximately3VDCfromthepowersupplyofthetargetboard.TheGS1andGS2pinsselecttheaccelerationrangefortheaccelerometer.Inthisapplication,bothpinsweresettohighinordertosetitfora+/6grangeofaccelerationdata.Thereareotherrangesthatcanbesetbychangingtheconfigurationofthesetwopins.Inordertogetthesetwopinstohighvoltage,theyaretappedoffoftheVccpoleonthebreadboard.Thegroundisobviouslythenfedfromthegroundonthetargetboardwhichissuppliedbythepowersupplyofthetargetboard.Thiswouldserveastheminusofthebattery.TheX,Y,andZpinsontheaccelerometeraretheoutputpinsfortheaccelerationinthatspecifieddirection.ThesearefedintotheanalogPORTAonthemicrocontrollertargetboardasshownbelow.TheSLPpinontheaccelerometercouldbeusedtosavepowerbyonlysendingdatawhenthevoltageatthatpinishigh.Inordertosimplifythis,itwassettohighallofthetime,whichwouldresultinashorterbatterylife,butsinceitusessuchsmallpower,itwasdecidedthateaseofdevelopmenttookprecedence.Inordertosetthishighitcouldbeapproachedtwoways.OnewaywastodirectlyconnectittotheVccpole,whiletheotherwaywastooutputahighsignalfrompin8onthetargetboardallofthetimetothatpin.

Afteraworkingprototypewasbuilt,itwasdecidedthatinordertomakethesystemmoreversatile,avoltageregulatorcouldbeusedwhichwouldacceptvariousvoltagelevelsandoutputtheconstant3Vthatthesystemrequired.TheTPS71530issuitableforthistask,acceptingvoltagesupto24Vandproviding3Voutputwithadequatecurrentforthesystem.

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Figure2:SchematicofAnalogAccelerometerEndpoint

ExplanationofCode

Themicrocontrollercodewasdividedintotwoparts,accesspointandenddevice.TheaccesspointcodeisrunonthemicrocontrollerthatisattachedtoaPCandservestogatherthedatabeingtransmittedfromtheenddevice.ThisdataisthenconditionedandsenttothePCthroughaUSBconnection.Theaccesspointcodestartsbycontinuouslyloopinguntilitdetectsasignalfromanenddevice.Onceasignalisacquiredandaconnectionismade,theaccesspointentersthedataprocessingloop.InthislooptheaccesspointcontinuouslygathersdatafromtheenddeviceandconditionsthecharacteroutputtobesenttothePCovertheUSBconnection.Theenddevicecodestartsbyinitializingthemicrocontrollerandtheprotocolsneededforwirelessdatatransmission.Theenddevicethenentersthedatagatheringloopwhereitreadstheanalogaccelerometervoltagesusingthreeseparateanaloginputs.Thevoltagesareconvertedusingthe10bitADCtodigitalnumbersrangingfrom01023.Thesevaluesarethentransmittedtotheaccesspointandnewvaluesarethenacquired.TheMatlabcodeisusedtopresenttheaccelerationdatainauserreadableform.TheMatlabcodestartsbyopeningaCOMportthatislinkedtothemicrocontrollerattachedtothePC.ThecodethencontinuouslypollstheCOMportfordataandenterseachdatareadingintotherespectiveX,YandZdatamatrices.Theadvantageofhavingseparatematricesforeachaxisisthatthedataisstored

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separatelyandcanthereforebemanipulatedlaterifnecessary.Afterasetnumberofdatapointsaregathered,thedatagatherloopexitsandtheaccelerationdataforeachaxisareplottedtogether.AllcodesareincludedintheAppendixattheendofthereport.

Calibration

Inordertotrytocalibratetheaccelerationvaluestothecorrectvalues,theaccelerometerwasplacedintheXYplanesothattheonlyforceactingontheaccelerometerwasgravityanditwasintheZdirection.Therefore,thevalueswerethennormalizedbysubtractinginMATLABbyaconstanttoaccountfortheoffsetoftheactualoutputoftheaccelerometer.ThiscalibrationwasdonebytakingtheZaxisdataandthensubtractingbyavaluetomakeitequalto1g.ThissameprocedurewasdonetomakethevaluesoftheXandYaxesequalto0gsincetheywerebothnotactedonbygravityatallandtheaccelerometerwasnotinmotion.

SampleImageCaptureFigure3showsasampleoutputofrunningtheMATLABscriptthatcapturestheX,Y,andZaccelerationanddisplaysinasubplot.Thisprovidestheenduserwithaccurate,easilyvisibleaccelerationoftheirsystem.Themaximumaccelerationineitherdirectionis6gs.

Figure3:SampleAccelerationinX,Y,&Z

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ReportofWork582

Themaingoalof582wastodefinetheproblemandrequirementsofthewirelesssystem/accelerometer.Theoveralldesignprocesswasdefinedandplanspartswereorderedduringthebreaksowecouldbeginprototypinginthebeginningof682.Asignificantamountoftimewasdevotedtodevelopingtherequirementsthattheaccelerometerandsoftwarewillhavetomeet.ThewirelesstransceiverportionofthedesignisanofftheshelfpartfromTIandthereforeitcanbeorderedattheendof582toprovidemorebuildtimein682.Attheendof582theplansanddesignshouldbesufficientenoughtobeginbuildingassoonasthepartsarrive.

682

Prototypingwasstartedasquicklyaspossible.WeusedtheMSP430RF2500andspentasignificanttimelearninghowitoperatedandhowitsentandreceiveddata.WeinitiallyorderedadigitalaccelerometerfromSparkFunbutafterreiterationofthedesignprocessdecidedtouseananalogaccelerometer.Wealsoorderedasmallcoincellbatterytopowerthesystem.

Thedesigncontinuedtoberefinedbasedupontestedconductedwiththeworkingprototype.ArobustsoftwareapplicationusingMATLABwasusedtogatherthedataandplot.Agraphofthesensorsaccelerationinrealtimewassuccessfullycompletedandgaveademonstration.

Beyond682

TheprototypewasfairlylargeonabreadboardandifwewantedtorunthemoduleonarollercoasterwithCoasterDynamixthedesignwillbeimplementedonaPCBboard.AlsothereportplanstoberigorouslyreviewedinordertosubmittoTIcontest.

Resources

Personnel TheprojectandtaskspreviouslymentionedwillbeperformedbyfourseniorengineeringstudentsatTheOhioStateUniversity.Theyeachhaveawidevarietyofskillsthatwhenintertwinedcanbeusedtosuccessfullydevelopthewirelessaccelerometercircuit.Thefollowingisalistofallteammembersandwhattheyarebringingtotheteamtoresultinasuccessfulcircuitdevelopment.

ClaytonCochran:HehasgainedexperienceinthedevelopmentanddesignprocessbyworkingasaninternwithEmersonNetworkPower:LiebertCorporationintheresearchanddevelopmentdepartment.Hehasalsocompletedawidevarietyofcourseworkincluding,microcontrollerprogrammingandcommunicationsthatwilllikelybehelpfulinthedevelopmentofthewirelessaccelerometercircuit.

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BrandonErvin:HeisaSeniorinElectricalEngineering,graduatingSpring2009,whoisfocusingonPowerSystemswithminorfocusesinComputersandControl.HeparticipatedintheFEHprogram,placing4thintherobotdesigncompetition,Spring2006.

TimDuly:HeisfocusinghisElectricalEngineeringstudiesinCommunications/DSPandElectromagnetics.HehashadexperienceprogrammingMSP430microcontrollersinaninternshipin2008.

MikeJender:HeisafifthyearelectricalengineeringstudentatTheOhioStateUniversity.Hiscourseworkconcentrationsinclude:DigitalSignalProcessing,Communications,ControlSystems,andElectromagnetics.

Facilities,Equipment,andCosts Thedevelopmentoftheaccelerometercircuitwillrequireaverysmallamountofequipmentandessentiallynospecialfacilities.Theonlyfacilitiesthatwillbenecessarywillbeaplacetomeetasagroupandaplacetobuildandtestthecircuit.Thisplaceneedstoonlyconsistofatablelargeenoughtocompletethebuildingandtestingandthenacomputercontainingthesoftwareneededtodeveloptheprogramforthemicrocontroller.Thefollowingisalistofhardwareneededtodevelopthewirelessaccelerometernetwork.

Microcontroller:TexasInstrumentsMSP430RF2500DevelopmentTool($49.00)o MSP430developmenttoolwithtargetboards(USBdevelopment)o CC2500transceiverforwirelesscommunicationso IntegratedDevelopmentEnvironmentSoftwareforcompilingthecode

SmallDigitalAccelerometer:SparkFun3DAccelerometerLIS302DL($19.95)o Selectable+/2gto+/8grangeo 8bitresolutiono Extremelysmall

SmallAnalogAccelerometer:SparkFun3DAccelerometerMMA7260Q($19.95)o Selectable+/1.5gto+/6grangeo Extremelysmall

VoltageRegulator(DigiKey)($1)o Allowsformultipleinputvoltagesupto24V

SparkFuncoincell3Vbatteriesandbatteryholder($10.00) Wiringandheadersfordevelopingthesystemwiththetargetboards($20.00)

TOTALCOST:$139.90

BothaccelerometersfromSparkFunthatwereusedareverysmall,asseeninFigure4.Theanalogaccelerometer,asmentionedearlier,hasaselectablerangeofaccelerationreadingsfrom+/1.5gto+/6g.Thisrangeofaccelerationshouldbelargeenoughformostofitsexpectedapplications.

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Althoughthedigitalaccelerometerencounteredperformanceproblemsduringthecourseoftheproject,itisourhopethatwewilleventuallybeabletoimplementadigitalversionofourproject.The8bitresolutionshouldalsoprovidethenecessaryaccuracyforthesystem,butifamoreaccurateaccelerometersystemisneededthereareaccelerometersouttherethatdohavehigherresolution.Becausethisspecificaccelerometergivesitsoutputindigitalform,itwillnotbenecessarytoperformananalogtodigitalconversiontosendthedata.

Figure4:SparkFun3DAccelerometer

ThemaincomponentofthedesignistheMSP430WirelessDevelopmenttoolshowninFigure5.ThiskitcomeswitheverythingshowninthefigureandhasaneasytouseUSBconnectiontousewithacomputer.Thiswillcomeinveryhelpfulwhiledevelopingthecodeforthemicrocontrollerandtestingthedesign.Thisdevicealreadyhasthetransceiverandthemicrocontrolleralreadyintegratedintoonedevice.Thisshouldprovemucheasierthantryingtoimplementthemonourownwhichcouldprovetobefairlydifficult.

Figure5:TIMSP430WirelessDevelopmentTool

Asseenabove,thecostoftheprojectwillbereasonablyaffordable.Also,someofthepartswillmostlikelybepaidforbyCoasterDynamixwiththeagreementthatiftheaccelerometerworks,itcanbeusedontheirmodelrollercoaster.

Schedule Accordingtotheoriginalschedule,themajorityoftheprojectwasgoingtobebuiltanddevelopedthroughthedurationof682.Theplanningfortheprojectwasmostlydoneduringthedurationof582.Therefore,thegoalwastogetthepreliminaryplanandmentalideathatweredevelopedduringthefirstquarteroftheseries,andthenactuallyimplementthedesignandideasinthelasthalfoftheseries.

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ThefollowingFigure6showstheoriginalroughtemporaryplanforthedesignprocessofthewirelessaccelerometernetwork.Itiseasilyseenthatastheprojectprogressed,thegoalwastorevisittaskstomakecertainthattheprojectwasprogressingwhereitneededto.Thistableagainessentiallyshowsthespiraldesignplan.

Week

1 2 3 4 5 6 7 8 9 10

Task

DefineSolutionApplications

DrawSchematics,Purchase

PartExploration

ComponentCommunication

Test

Debugging Figure6:TableofDesignWorktoBeCompleted

Theactualdesignprocessfollowedthisscheduleexactly.Duringthefirst6weeks,themainfocuswasonthedigitalaccelerometer.However,oncethesixthweekconcludedanditwasdecidedthatitwastoodifficulttoworkwithSPIinthisshortamountoftime,thesolutionwasredefinedtoincludetheanalogaccelerometer.Afterthiswasdecided,therestoftheplanfellintoplaceandresultedinafunctionalwirelessanalogaccelerometer.

DesignReview Afteraverybriefdesignreviewitwasdecidedthatifthewirelessaccelerometersystemisdevelopedcorrectlyandfunctioningasexpectedagyroscopeelementcouldbeaddedtothesystem.Thiswouldmakecertainthattheaccelerationreadingsareallconsistentbykeepingtheorientationoftheaccelerometerataconstant.Thereforez,x,andydirectionaccelerationwouldbeinthattruedirectiontheentiredurationofthetest.Ifthereisnogyroscopeandtheaccelerometeristestingarollercoastermodelasmentionedearlier,thedirectionsofaccelerationwillchangewiththeorientationoftheaccelerometer.Suchaswhentheaccelerometerisgoinguphillthezdirectionwillbedifferentthanthezdirectionwhentheaccelerometerisonflattrack.Thiswouldmakethewirelessaccelerometersystemmuchmoreaccurateandmorevaluable.

Thestatusreviewmeetingsprovedtobeextremelyvaluableinkeepingthegroupontrack.Itwasimportanttogetweeklyfeedbackonourprojectandtogetsuggestions.Forexample,itwasrecommendedthatweuseananalogaccelerometerafterourinitialdigitaldesignwasnotworking.Thedigitaldesignwasdifficulttodebugandwedecidedthatananalogdevicewouldbeeasiertotrackproblems,andthereforeeasiertofix.

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FuturePlannedDevelopments Sincetheonequarterofworkfordevelopmentoftheprojectwasafairlyshorttime,thereweremanyotherdevelopmentsthatcouldhavebeenapproachedfortheproject.Thesedevelopmentsarelistedasfollows:

Implementagyroscopeintothecircuittogettrueaccelerationreadingstoaccountfortherotationoftheaccelerometerduringtesting.

Developaprogramtomanipulatethedataforcalculationofvelocityandpositioninthreedimensions,possiblymodelingthemotioninthreedimensionalspace.

Minimizethesizeoftheentirecircuitbycombiningthetargetboardandtheaccelerometeroftheendpointtoasinglefabricatedprintedcircuitboard.

MakeamoredetailedanduserfriendlyGUIthatcanbeusedtosettherangeofaccelerometerandthatcanstartandstopthedatacollectionwithapushofthebutton.

Conclusion Thedesignanddevelopmentofafairlysimpleandaffordablewirelessaccelerometernetworkcouldprovetohaveextremelyimportantandendlessapplications.AwirelessaccelerometercanbedesignedusingTIcomponents,suchasamicrocontrollerandtransceiver,andanaccelerometer.Itisimportanttokeeptheelementsofthesystemphysicallysmalltomakecertainthatitcanbeappliedtomostsituationswhereaccelerationshouldbemeasured.Oneapplicationusedtodevelopthesizeandperformanceofthesystemwasamodelrollercoaster.Inthisapplicationtheaccelerometermustbesmall,lightweight,andabletomeasureupto6g.Also,ifthemicrocontrollerprogrammingisproventobefairlysimple,itcouldbeusedinahighschoolsettingtogetstudentsinterestedinthefieldsofengineeringandphysics.Thewirelessaccelerometernetworkcouldretrievedataontheaccelerationofacertainobjectandthenprovidethisdatatoacomputertoruncalculationsonthedataanddeterminemuchmoreimportantinformationaboutthesystemundertest.Thewirelessaccelerometernetworkcouldbeaveryvaluablecircuitthatcouldbeusedformanyimportantapplications.

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Appendix:Code

CCodeUsedinIAREmbeddedWorkbench

AccessPoint//Access Point File

#include "bsp.h" #include "mrfi.h" #include "bsp_leds.h" #include "bsp_buttons.h" #include "nwk_types.h" #include "nwk_api.h" #include "nwk_frame.h" #include "nwk.h" #include "msp430x22x4.h" #include "vlo_rand.h" #define MESSAGE_LENGTH 6 void TXString( char* string, int length ); void MCU_Init(void); void transmitData(char msg[MESSAGE_LENGTH] ); void transmitDataString(char msg[MESSAGE_LENGTH]); void createRandomAddress(); //data for terminal output const char splash[] = {"\r\n--------------------------------------------------\r\n ****\r\n **** eZ430-RF2500\r\n ******o**** Temperature Sensor Network\r\n********_///_**** Copyright 2007\r\n ******/_//_/***** Texas Instruments Incorporated\r\n ** ***(__/***** All rights reserved.\r\n ********* Version 1.02\r\n *****\r\n ***\r\n--------------------------------------------------\r\n"}; __no_init volatile char Flash_Addr[4] @ 0x10F0; // Flash address set randomly // reserve space for the maximum possible peer Link IDs static linkID_t sLID[NUM_CONNECTIONS]; static uint8_t sNumCurrentPeers; // callback handler static uint8_t sCB(linkID_t); // work loop semaphores static uint8_t sPeerFrameSem; static uint8_t sJoinSem; //static uint8_t sSelfMeasureSem; int run; void main (void) { addr_t lAddr; bspIState_t intState; WDTCTL = WDTPW + WDTHOLD; // Stop WDT // delay loop to ensure proper startup before SimpliciTI increases DCO

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// This is typically tailored to the power supply used, and in this case // is overkill for safety due to wide distribution. volatile int i; for(i = 0; i < 0xFFFF; i++){} if( CALBC1_8MHZ == 0xFF ) // Do not run if cal values are erased { volatile int i; P1DIR |= 0x03; BSP_TURN_ON_LED1(); BSP_TURN_OFF_LED2(); while(1) { for(i = 0; i < 0x5FFF; i++){} BSP_TOGGLE_LED2(); BSP_TOGGLE_LED1(); } } BSP_Init(); if( Flash_Addr[0] == 0xFF && Flash_Addr[1] == 0xFF && Flash_Addr[2] == 0xFF && Flash_Addr[3] == 0xFF ) { createRandomAddress(); // set Random device address at initial startup } lAddr.addr[0]=Flash_Addr[0]; lAddr.addr[1]=Flash_Addr[1]; lAddr.addr[2]=Flash_Addr[2]; lAddr.addr[3]=Flash_Addr[3]; SMPL_Ioctl(IOCTL_OBJ_ADDR, IOCTL_ACT_SET, &lAddr); MCU_Init(); //Transmit splash screen and network init notification TXString( (char*)splash, sizeof splash); TXString( "\r\nInitializing Network....", 26 ); SMPL_Init(sCB); // network initialized TXString( "Done\r\n", 6); //Some of our original code begins here BSP_TOGGLE_LED2(); // main work loop while (1) { // Wait for the Join semaphore to be set by the receipt of a Join frame from a // device that supports and End Device. if (sJoinSem && (sNumCurrentPeers < NUM_CONNECTIONS)) { // listen for a new connection SMPL_LinkListen(&sLID[sNumCurrentPeers]); sNumCurrentPeers++; BSP_ENTER_CRITICAL_SECTION(intState); if (sJoinSem) {

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sJoinSem--; } BSP_EXIT_CRITICAL_SECTION(intState); } // Have we received a frame on one of the ED connections? // No critical section -- it doesn't really matter much if we miss a poll if (sPeerFrameSem) { uint8_t msg[MAX_APP_PAYLOAD], len, i; // process all frames waiting for (i=0; i>8) & 0xFF; Flash_Addr[1]=rand & 0xFF; Flash_Addr[2]=(rand2>>8) & 0xFF; Flash_Addr[3]=rand2 & 0xFF; FCTL1 = FWKEY; // Clear WRT bit FCTL3 = FWKEY + LOCKA + LOCK; // Set LOCK & LOCKA bit } /*------------------------------------------------------------------------------ * ------------------------------------------------------------------------------*/ void transmitData(char msg[MESSAGE_LENGTH] ) {

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transmitDataString( msg ); } /*------------------------------------------------------------------------------ * ------------------------------------------------------------------------------*/ void transmitDataString(char msg[MESSAGE_LENGTH] ) { char x_string[] = {"XXXX"}; char y_string[] = {"XXXX"}; char z_string[] = {"XXXX"}; int tempx = msg[0] + (msg[1]

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/*------------------------------------------------------------------------------ * ------------------------------------------------------------------------------*/ void MCU_Init() { BCSCTL1 = CALBC1_8MHZ; // Set DCO DCOCTL = CALDCO_8MHZ; BCSCTL3 |= LFXT1S_2; // LFXT1 = VLO TACCTL0 = CCIE; // TACCR0 interrupt enabled TACCR0 = 2000; // ~1/6 second TACTL = TASSEL_1 + MC_1; // ACLK, upmode P3SEL |= 0x30; // P3.4,5 = USCI_A0 TXD/RXD UCA0CTL1 = UCSSEL_2; // SMCLK UCA0BR0 = 0x41; // 9600 from 8Mhz UCA0BR1 = 0x3; UCA0MCTL = UCBRS_2; UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine** IE2 |= UCA0RXIE; // Enable USCI_A0 RX interrupt __enable_interrupt(); } /*------------------------------------------------------------------------------ * Runs in ISR context. Reading the frame should be done in the * application thread not in the ISR thread. ------------------------------------------------------------------------------*/ static uint8_t sCB(linkID_t lid) { if (lid) { sPeerFrameSem++; } else { sJoinSem++; } // leave frame to be read by application. return 0; } /*------------------------------------------------------------------------------ * ADC10 interrupt service routine ------------------------------------------------------------------------------*/ #pragma vector=ADC10_VECTOR __interrupt void ADC10_ISR(void) { __bic_SR_register_on_exit(CPUOFF); // Clear CPUOFF bit from 0(SR) } /*------------------------------------------------------------------------------ * Timer A0 interrupt service routine ------------------------------------------------------------------------------*/ #pragma vector=TIMERA0_VECTOR __interrupt void Timer_A (void) { run = 1;}

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EndDevice//End Device File #include "bsp.h" #include "mrfi.h" #include "nwk_types.h" #include "nwk_api.h" #include "bsp_leds.h" #include "bsp_buttons.h" #include "vlo_rand.h" void linkTo(void); void MCU_Init(void); __no_init volatile char Flash_Addr[4] @ 0x10F0; // Flash address set randomly void createRandomAddress(); void main (void) { addr_t lAddr; WDTCTL = WDTPW + WDTHOLD; // Stop WDT { // delay loop to ensure proper startup before SimpliciTI increases DCO // This is typically tailored to the power supply used, and in this case // is overkill for safety due to wide distribution. volatile int i; for(i = 0; i < 0xFFFF; i++){} } if( CALBC1_8MHZ == 0xFF ) // Do not run if cal values are erased { volatile int i; P1DIR |= 0x03; BSP_TURN_ON_LED1(); BSP_TURN_OFF_LED2(); while(1) { for(i = 0; i < 0x5FFF; i++){} BSP_TOGGLE_LED2(); BSP_TOGGLE_LED1(); } } // SimpliciTI will change port pin settings as well P1DIR = 0xFF; P1OUT = 0x00; P2DIR = 0x20; //P2OUT = 0x00; P3DIR = 0xC0; P3OUT = 0x00; P4DIR = 0xFF; P4OUT = 0x00; //P2SEL = 0x07; P4OUT |= 0x08; //Sets Pin 8 (P4.3) high, turns on the accelerometer, set low to put to sleep BSP_Init(); if( Flash_Addr[0] == 0xFF && Flash_Addr[1] == 0xFF && Flash_Addr[2] == 0xFF && Flash_Addr[3] == 0xFF )

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{ createRandomAddress(); // set Random device address at initial startup } lAddr.addr[0]=Flash_Addr[0]; lAddr.addr[1]=Flash_Addr[1]; lAddr.addr[2]=Flash_Addr[2]; lAddr.addr[3]=Flash_Addr[3]; SMPL_Ioctl(IOCTL_OBJ_ADDR, IOCTL_ACT_SET, &lAddr); BCSCTL1 = CALBC1_8MHZ; // Set DCO after random function DCOCTL = CALDCO_8MHZ; BCSCTL3 |= LFXT1S_2; // LFXT1 = VLO // keep trying to join until successful. toggle LEDS to indicate that // joining has not occurred. LED3 is red but labeled LED 4 on the EXP // board silkscreen. LED1 is green. while (SMPL_NO_JOIN == SMPL_Init((uint8_t (*)(linkID_t))0)) { BSP_TOGGLE_LED1(); BSP_TOGGLE_LED2();; __bis_SR_register(LPM3_bits + GIE); // LPM3 with interrupts enabled } // unconditional link to AP which is listening due to successful join. linkTo(); } void createRandomAddress() { unsigned int rand, rand2; do { rand = TI_getRandomIntegerFromVLO(); // first byte can not be 0x00 of 0xFF } while( (rand & 0xFF00)==0xFF00 || (rand & 0xFF00)==0x0000 ); rand2 = TI_getRandomIntegerFromVLO(); BCSCTL1 = CALBC1_1MHZ; // Set DCO to 1MHz DCOCTL = CALDCO_1MHZ; FCTL2 = FWKEY + FSSEL0 + FN1; // MCLK/3 for Flash Timing Generator FCTL3 = FWKEY + LOCKA; // Clear LOCK & LOCKA bits FCTL1 = FWKEY + WRT; // Set WRT bit for write operation Flash_Addr[0]=(rand>>8) & 0xFF; Flash_Addr[1]=rand & 0xFF; Flash_Addr[2]=(rand2>>8) & 0xFF; Flash_Addr[3]=rand2 & 0xFF; FCTL1 = FWKEY; // Clear WRT bit FCTL3 = FWKEY + LOCKA + LOCK; // Set LOCK & LOCKA bit } void linkTo() { linkID_t linkID1; uint8_t msg[6]; // keep trying to link... while (SMPL_SUCCESS != SMPL_Link(&linkID1)) { __bis_SR_register(LPM3_bits + GIE); // LPM3 with interrupts enabled BSP_TOGGLE_LED1(); BSP_TOGGLE_LED2();

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} // Turn off all LEDs if (BSP_LED1_IS_ON()) { BSP_TOGGLE_LED1(); } if (BSP_LED2_IS_ON()) { BSP_TOGGLE_LED2(); } while (1) { char msg[6]; int data_x,data_y,data_z; volatile long temp; int results[3]; SMPL_Ioctl( IOCTL_OBJ_RADIO, IOCTL_ACT_RADIO_SLEEP, "" ); //__bis_SR_register(LPM3_bits+GIE); // LPM3 with interrupts enabled SMPL_Ioctl( IOCTL_OBJ_RADIO, IOCTL_ACT_RADIO_AWAKE, "" ); //read x: x is A0 which is P2.0 BSP_TOGGLE_LED2(); ADC10CTL1 = INCH_0 + ADC10DIV_2; //set ADC to A0 with clock divide of 2, we might not need the clock divide ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts //for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start __bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done results[0] = ADC10MEM; //copy ADC results to x data ADC10CTL0 &= ~ENC; //reset encode bit //read y: y is A1 which is P2.1 ADC10CTL1 = INCH_1 + ADC10DIV_2; //set ADC to A1 with clock divide of 2, we might not need the clock divide ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts //for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start __bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done results[1] = ADC10MEM; //copy ADC results to y data ADC10CTL0 &= ~ENC; //reset encode bit //read z: z is A2 which is P2.2 ADC10CTL1 = INCH_2 + ADC10DIV_2; //set ADC to A2 with clock divide of 2, we might not need the clock divide ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts //for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start __bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done results[2] = ADC10MEM; //copy ADC results to z data ADC10CTL0 &= ~ENC; //reset encode bit

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ADC10CTL0 &= ~(REFON + ADC10ON); // turn off A/D to save power /* The anaolog data is converted using the following formula: Digital = 1023*(Vanalog - Vref-) / (Vref+ - Vref-) The 1023 comes from the 10 bit ADC (2^10) For our case as it's setup, Vref- = Gnd and Vref+ = Vcc An input voltage of Vcc/2 corresponds to zero acceleration so zero accerlation is 512 in digital (1023/2 rounded up, not sure if supposed to round up) */ data_x = results[0]; data_y = results[1]; data_z = results[2]; msg[0] = data_x&0xFF; msg[1] = (data_x>>8)&0x03; msg[2] = data_y&0xFF; msg[3] = (data_y>>8)&0xFF; msg[4] = data_z&0xFF; msg[5] = (data_z>>8)&0xFF; BSP_TOGGLE_LED1(); if (SMPL_SUCCESS == SMPL_Send(linkID1, msg, sizeof(msg))) { BSP_TOGGLE_LED2(); } else { BSP_TOGGLE_LED2(); BSP_TOGGLE_LED1(); } } } /*------------------------------------------------------------------------------ * ADC10 interrupt service routine ------------------------------------------------------------------------------*/ #pragma vector=ADC10_VECTOR __interrupt void ADC10_ISR(void) { __bic_SR_register_on_exit(CPUOFF); // Clear CPUOFF bit from 0(SR) }

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MATLABCodetoDisplayPlots

%serial data capture and plot clear all s = serial('COM1'); set(s,'BaudRate',9600,'DataBits',8,'Parity','none');%,'InputBufferSize',28); fopen(s); s.ByteOrder = 'bigEndian'; l = 200; i = 2; t = []; x = []; y = []; z = []; t(1) = 0; data = fgets(s); data = fgets(s); tic data2 = str2num(data); x(1) = data2(1); y(1) = data2(2); z(1) = data2(3); while (i < (l + 2)) data = fgets(s); data = fgets(s); t(i) = t(i-1) + toc; tic data2 = str2num(data); x(i) = data2(1); y(i) = data2(2); z(i) = data2(3); i = i + 1; disp(data) end n = toc; fclose(s);delete(s);clear s x = (x - 474)./85.3; y = (y - 481)./85.3; z = (z - 478)./85.3; subplot(3,1,1) plot(t,x) axis([0 t(l) -6 6]) subplot(3,1,2) plot(t,y) axis([0 t(l) -6 6]) subplot(3,1,3) plot(t,z) axis([0 t(l) -6 6])