thickskull - courses.physics.illinois.edu
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ThickSkull
ECE445Fall2016DesignReview
JosiahSpears jnspear2 Xingyang(Xandy)Liu xliu141
TA:JohnA.Capozzo
October4,2016
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ContentINTRODUCTION....................................................................................................................................3
MOTIVATION/STATEMENTOFPURPOSE...........................................................................................................3EXISTINGSOLUTIONS....................................................................................................................................3PROBLEMSWITHEXISTINGSOLUTIONS;OURSOLUTION......................................................................................4OBJECTIVES.................................................................................................................................................5
DESIGN.................................................................................................................................................6BLOCKDIAGRAM..........................................................................................................................................6SENSORMODULE.........................................................................................................................................7DATATRANSMISSIONMODULE.....................................................................................................................12DATAPROCESSINGMODULE........................................................................................................................13POWERMODULE.......................................................................................................................................14
REQUIREMENTSANDVERIFICATIONS.................................................................................................14
REQUIREMENTSANDVERIFICATIONSPOINTTABLE............................................................................17
TOLERANCEANALYSIS........................................................................................................................18
COSTANDSCHEDULE.........................................................................................................................20COSTANALYSIS..........................................................................................................................................20SCHEDULE.................................................................................................................................................21
ETHICSANDSAFETY............................................................................................................................23ETHICS......................................................................................................................................................23SAFETY.....................................................................................................................................................24
CITATIONS..........................................................................................................................................24
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IntroductionMotivation/StatementofPurposeOne of the biggest issues facing the game of American football is that of concussions.ConcussionscanbefoundonalllevelsofAmericanfootball,inchildrenstartingfromtheageof10, through high school, college and especially the pros. In the article, “Concussions AmongUnitedStatesHighSchoolandCollegiateAthletes,”theOhioStateresearchgroupconcludedthatover300,000headtraumainjuriesfromsportsoccurintheUSannually[1].Thearticlealsostatesthatparticipationinsportsisthesecondleadingforheadtraumaforpeoplefromtheages,15-24 [1]. Asmoreandmore researchhasbeen conducted,playingwith concussionshasbeenshowntobedetrimentaltoaplayer'shealth,andcouldpotentiallyhavealastingadverseimpactonhisorherhealthgoingforward.Havingasystemtohelpcollect,time-log,storeandtransmitpertinentrealtimedatarelatingtoadiversesetofconcussionsymptoms(inthiscasefour)willhelpdoctorsandresearchscientistsintheirquesttobetterunderstandconcussionsandmakequickerin-gameconcussionanalysisanddiagnosis.ExistingSolutionsSeveralexistingattemptstoatleasthelpmitigatethisproblemarecurrentlyonthemarket.FourmajorproductsthattriedtosolvethisproblemaretheRiddleSRS,RiddleInsite,ShockboxandChecklightbyReebok.TheRiddleSRSemploysHITS,asoftwaredevelopedatVirginiaTechandDartmouthCollege,tomeasuretheimpactofrealtimegamehitsandtopredict likelihoodofconcussion based on themagnitude of the hit. They use iMemsMotion Signal Processing tocalculatelinearacceleration,andcompiledataaboutthelocation,directionanddurationofthehit.Theyusewirelesscommunicationstosenddatatothesideline[2].TheRiddleInsite,isamoresensitive,moreexpensiveversionoftheRiddleSRS.Itcontainsthemostsensitivemeasurementsystemofcollisions[2].Theyemployalightweightfive-zonesensoranduseared-yellow-greenLEDsystemtovisiblyshowhowhardeachhitwas[3].TheShockboxsolutionusesBluetooth to communicate to a systemon the sidelines. It is aportable sensorsystemthatcanbeplacedinanyhelmet.ItusesSCAT,SportsConcussionAssessmentTool,tokeeptrackof thenumberofhitsandhowhardeachhitwas.However, thisdatacanonlybeaccessedafterthegame,whichdoesnotpreventplayersfromplayingwithaconcussionduringthegame.LikeSRS,theymeasure linearandrotationalacceleration.Theymakesurethatthepeak acceleration does not reach over the 70-100 g threshold, which is where majority ofconcussionsfall[4].Thelastcompetitor,ChecklightbyReebok,measuredtheaccelerationoftheheaddirectly.Italsorecordedthenumberofhitstakenbytheplayer.TheyusedHIC,HeadImpactCriteriatomeasureimpact,onlymeasuringlinearacceleration.However,sincethestartoftheproject,webelievethatChecklighthasbeenremovedfromthemarket[5].
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ProblemswithExistingSolutions;OurSolutionAlthoughthemarketforheadtraumadatacollectionseemsquitecrowded,everysinglesolutionmentionedabovehasseveredifficultiesproducingon their claims.CNNdida studyofRiddleInsite.TheresultsshowedthattheInsitestruggledtosignalahardhit,havinganinaccuracy30%[6]. It is important tokeep inmindthat this is themostsensitivesensingsystem. Ifasystemcannotbetrustedbyplayersanddoctorsalike,howcanitbringanyvalue?Anotherissuewithseveralofthedesigns,especiallyShockbox,isthatthesensorswerejustplacedinsidethehelmet[4].Thismayallowittobeusedwithanyhelmet,butitchangesthefeelofthehelmetsfortheplayers.Sportsisallaboutcomfortabilityandrepetition.Ifthedesigninfringesonthis,thenmanyplayers,especiallypros,willnotwanttouseit.The biggest issue that the ThickSkull team has with all of the existing solutions is how onedimensionaltheyare:theyonlymeasurethemagnitudeofthehitorthenumberofhits.Everyplayer’sbodyisdifferentthantheotherandwillrespondtohitsdifferently.Somanyfactorsgointoconcussionsandthebodyreactsbygivingoffmanysignsthatcanbemeasuredandcollected.Ourteamagreesthatthemagnitudeofhitsshouldbeconsideredaswellasthenumberofhits,sincemany pro players become concussed during routine tackles, because of the buildup inimpact.Butweneedmuchmoredata, so thatwecanhaveabetterunderstandingofhowaconcussionaffectsaperson,andtoincreasethelikelihoodofidentifyingsituationswhereplayersmaybeatriskofbeingconcussed.Ourmissionistoincreasetheamountofdatacollectedandthetypeofdatacollectedinreal-time.Weplantoprocessthisdataandpresentitinaclearandmeaningful way so that it can be used by doctors when they diagnose concussions and byresearchesastheytrytounderstandmoreaboutconcussionsandtheirlastingeffectsonhumans.
Webelieveweshouldmeasureforwell-definedconcussionsymptoms,sinceaplayer'sbodywillgiveoffspecificsignsthatitispotentiallyconcussed.Firstweplantotaketwoheartbeatmeasurements.Thefirstoneisrestingheartrate.Weplantomeasureforaplayer’srestingheartrate,rightbeforethestartofthegame,duringhalftimeandafteragame.Aplayer'srestingheartratedecreasingfromthepreviousmeasureisaconcussionsymptom.Additionally,anincreaseinexercisingheart rate isalsoakeysymptomofconcussions.Weplan tocontinuouslymonitorheartrateduringagame(whiletheyareonthefield)andtakeatime-averageofthis.Ifthereisasharpincreaseordecreasecomparedtothetime-averagevalue,thenwewillflagthatpersonas needing further checked. Dr. Kevin Jackson, who does research on concussion effects onfootballplayersattheUniversityofIllinoisconfirmedthatthesemeasurementsaresymptomsofconcussionsand that compilingandprocessing thisdatawouldbring value tohis andothersresearchinthisarea[7].Weplantomeasurethesefoursymptoms-numberofhits,magnitudeoflinearandrotationalaccelerationofhits,restingheartrateandexerciseheartrate-andincorporatethemintoasinglePCB design so that we can incorporate them into a comfortable aesthetically alternative toexisting.We decided to embed this system into the helmet tomaintain the same feeling asnormalhelmetsthatplayerscurrentlyuse.Theacceleration,andhitnumberdatathatisgatheredbythehelmetwillbeimmediatelytransferredtowhatwecallourdataprocessinghub,whichison the sideline. Since the heart rate is measured almost continuously, we will store a
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conglomerateofdataonthehelmetPCBbeforewesendittothehub.Thedatatransferwillbedone using Bluetooth technology. We will incorporate existing antennas along with customFPGAsonboththehelmetanddataprocessinghubtoallowforcommunicationbetweenthehelmet and the sideline hub. At the sideline hub, the data is stored and processed and theresultingprocesseddataisstored.Wewilluseanalgorithmtotakethisdataandmakeapredictionastowhethertheplayerisinjeopardyofbeingconcussed.Theplayercanthenbebroughttothesidelineandbeadministeredaquickpsychologicevaluationbasedonastandardquestionnaire,developedbypsychologistandneuroscientists.Wethenwillclearlypresentthetestresultswithandaconglomerationofthefourtypesofdatasothatadoctorcanusethisextrainformationtohelphimmakeadecisionastowhethertheplayershouldgobackintothegame.Aresearcherorneurologistcouldusetheresultsofknownconcussedplayerstoplayersperceivedtonotbeconcussedtolearnmoreaboutthehumanbodyreactsandfunctionswhenitisconcussed[7].ObjectivesGoals/objectives
• Createahardwarecircuitthatwilladdvaluetoheadtraumadetection(thisisfocusedtowardfootballplayers)
• Createthiscircuitsmallenoughsothatitcanfitwithoutanoticeabledifferenceinthefeelandeaseofuseforplayerscomparedtoexistingmainstreamhelmets
• Measurefourdatapointsofconcussionsymptoms,twomorethanexistingsolutions• Transferthisdatafromhelmetstoasidelinemodule• Present this data in a processed and organized manner so that it can be used by
researchesanddoctorsinconcussionstudiesandprognosis.Features
• Measurelinearaccelerationofhits• Measurerotationalaccelerationofhits• Measurenumberofhits• Measurethedifferenceinrestingheartrateoftheplayer,atthestartofthegame,at
halftime,andattheendofthegame• Measurethedifferenceinexercisingheartrate,toseeifwecandetectspikesinheart
ratecomparedtothetimeaverage• AnalogtoDigitalconversioninsidethehelmet• Temporarydatastorageinsidehelmet• Thisdatacanbecommunicatedbetweenhelmetanddataprocessinghubinreal-time• Thisdatacanbestoredandprocessedintheprocessinghubonthesideline• Timelogsthisdata• PresentsthisdatainanclearformatusingaGUIsothatdoctorsandresearcherscaneasily
accessthedataandanalyzeit
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Note:Manyofthegoalsinthisprojectarealsofeatures.Becauseourprojectistryingtoaidresearchesthedifferencebetweengoalsandfeaturesismuddledatbest.
DesignBlockDiagram
Figure1HardwareblockdiagramoftheSystem
Thesystemconsistsoftwosubsystems:thehelmetandthehubatthesideline.Thehelmetisembeddedwithasensormodule,transmissionsideofthedatatransmissionmodule,andapowermoduleforthehelmet[Figure1].Thehubconsistsofadataprocessingmodule,receptionsideofthedatatransmissionmodule,andapowersupplymoduleforthehub.
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Figure2Softwarelevelgeneralflowchart
Thesoftwaresideofthesystemisimplementedintwosubmodules:processor(helmet)submoduleandprocessor(hub)submodule.Theprocessor(helmet)submoduleobtainsdigitizedpulsewaveand3-axisaccelerationfromthepulsesensorsubmoduleandaccelerometersubmodule.Thenfromthesedigitaldata,BPMiscalculatedandaccelerationsarefilteredandonlyaccelerationsofthehitsarekept.Thepre-processeddataisthentransmittedthroughdatatransmissionmoduletotheprocessor(hub)submodule.Theprocessor(hub)submodulethenstoresthedatapointsandprocessesthemwithalgorithm.TheresultsarepresentedontheGUI.SensorModuleTheobjectiveofthesensormoduleistomeasuretherawdataaswellastopre-processtherawdataintomeaningfulldatapointsreadytobesenttodatatransmissionmoduleinthehelmet.Itincludesthreesubmodules:accelerometersubmodule,pulsesensorsubmodule,andaprocessorsubmodule(helmet).Theaccelerometersubmoduleandpulsesensorsubmodulecollectpulsewavesandaccelerationinrealtimerespectively.Therawdataisthensenttotheprocessorsubmodule(helmet)inSPIandI2Cprotocolsrespectively.Theprocessorsubmodule(helmet)thenpre-processestheserialdataandcalculatestheheartbeatrate(BPM)andforceofthehit.Thepre-processeddataisthensenttothedatatransmissionmodule.
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AccelerometerSubmodule
I/O Name DescriptionInput ACCELERO_SCL AccelerometerI2CserialclocksignalOutput ACCELERO_SDA AccelerometerI2Cserialdatasignal
Table1I/Otableofaccelerometersubmodule
Figure3Accelerometersubmoduleschematic[8]
The3-axisaccelerometersensesthelinearaccelerationinthreedirections:x,y,z.TheanalogdataisthenconvertedtodigitaldatathroughaninternalADC.Thenthedigitaldataissenttotheprocessor(helmet)throughI2Cprotocol[8].WechooseH3LIS331DLSTMicroelectronicsbecauseitsfeaturesmeetourrequirements.Someresearchesindicatethat86%ofimpactsinfootballarebelow50gandthatconcussionspredominantlyfallinarangebetween70–100g.Andaseverehitcouldbeashighas150g[4].TheH3LIS331DLaccelerometerisabletomeasurewiderangeofaccelerationupto±100g/±200g/±400g,whichissuitableforourcause.Its3-axissensorsenseslinearaccelerationinx,y,zdirections.Throughouralgorithm,wecanalsocalculaterotationalacceleration,anotherdatapointweareinterestedin.Theoutputdataratecanbeashighas1kHz,whichmeanstheaccelerationreadingisupdatedevery1millisecond.Thisisfastenoughtotracktheaccelerationsofhits.
Features ValuesSensortype 3-axissensingSupplyvoltagerange 3.3Vto5VDCCurrentrating Typical300μA
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Accelerationscale ±100g/±200g/±400gOutputdatarate 0.5Hzto1kHzOutputdatawidth 16bitCommunicationprotocol I2CserialdigitaloutputinterfacePackage 3×3×1mmTFLGAOperatingtemperature -40°Cto+85°CShocksurvivability 10000gTypicalApplications Shockdetection
ImpactrecognitionandloggingConcussiondetection
Table2FeaturesofH3LIS331DLaccelerometer
PulseSensorSubmodule
I/O Name DescriptionInput PULSE__CLK SPIserialclockInput PULSE_SPI SPIserialdatainInput PULSE_CS SPIchipselectOutput PULSE_IN SPISerialdataoutput
Table3I/Otableofpulsesensorsubmodule
Figure4Pulsesensorsubmoduleschematic[9]
ThepulsesensorsubmoduleincludesagreenLED(AM2520ZGC09),aminiaturesurface-mountambientlightphotosensor(APDS-9008),anoperationalamplifier,andanAnalogDigitalConverter.
Features ValuesSupplyvoltagerange 1.6Vto5.5VOperatingtemperature -40°Cto85°CResponsivity ExcellentSensitivityvariation Lowacrossvariouslightsources
Table4FeaturesofAPDS-9008lightphotosensor
Features Values
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Supplyvoltagerange 2.7Vto5.5VCurrentrating 5nAtypicalstandby;550μAactivemaxOutputdatawidth 10bitSamplingrate 200kspsmaxCommunicationprotocol SPIOperatingtemperature -40°Cto+85°C
Table5FeaturesofMCP300210-bitADC
TheoperatingtemperaturerangeforthegreenLEDandtheambientlightphotosensoriswellbeyondthetemperatureoftheworkingenvironment,thusmakingthesepartssuitableforourproject.ThesamplingrateistheADCisalsohighenoughtocapturetheanalogsignals.Theanalogsignalcapturedbythelightsensorisfilteredbyhigh-passfilterandtheACsignalisamplifiedandnormalizedbytheoperationalamplifier.ThentheoutputoftheamplifierisfedintotheAnalogDigitalConverter,afterwhichthedigitalsignalissenttotheprocessor(helmet)submoduleviaSPIprotocol.
Figure5AmplifiedandNormalizedpulsewave
TocalculateIBI(InterBeatInterval),weneedtoknowtheexacttimewhenabeathappens.Variousheartresearchershavedifferentdefinitionsaboutwhichreferencepointshouldbeusedtoindicateapulse[9].Inourproject,wechoosethe50%ofthewaveformamplitudeontherise.Thisreferencelevelstartsatmid-level(V/2),andgetsconstantlyupdatedfromtheprevious50%level. Atimerisusedtokeeptrackoftheintervaltimebetweenpulses,andtheintervaltimeisstoredintoanarray.Tomitigatetherelativeerrorinmeasurement,wetaketheaverageof10consecutiveIBItorepresenttheinstantaneousheartrate.
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Tomitigatenoisesignalbetweenpeaksandfalsereadingondicroticnotch,weonlystartlookingforpulse200msafterthelastpulse.Weassumeheartbeatratewouldnotbeover300bpm,whichtranslatesto200msIBI.Thisgraphshowstheoutputofthepulsesensorafterithasbeenfiltered,amplifiedandnormalizedaroundacenterlevel(around2.5V).Thisdecisionallowsfordistinctdifferencestobepickedupeasieronthegraph,becausethedifferencebetweenthepeakandthetroughofthepulsewaveismaximizedandcuttingoffofthevaryingsignalisavoided.Processor(Helmet)Submodule
I/O Name DescriptionOutput ACCELERO_SCL AccelerometerI2CserialclocksignalInput ACCELERO_SDA AccelerometerI2CserialdatasignalOutput PULSE__CLK SPIserialclockOutput PULSE_SPI SPIserialdatainOutput PULSE_CS SPIchipselectInput PULSE_IN SPISerialdataoutput
Table6I/Otableoftheprocessor(helmet)submodule
Figure6Processor(helmet)submoduleschematic[10]
Features ValueLogicElements(LEs) 4608M4KRamblocks 26TotalRAMbit 119808
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Embedded18x18Multipliers 13PLLs 2MaxuserI/Opins 142
Table7FeaturesofEP2C5T144
Aprocessorisembeddedinthehelmet.ThesensorssenddigitaldatatotheprocessorthroughI2CorSPIprotocols.TheprocessorthencalculatestheBPMfromthepulsesensordatainputandobtaintheaccelerationofthehitsfromtheaccelerometerdatainput.Theresultingdataisthensenttodatatransmissionmoduletobetransmittedtothesidelinehub.DataTransmissionModuleThedataistransmittedthroughadatatransmissionmoduletothedataprocessingmoduleandarestoredthereforanalysis.Thedatatransmissionmoduleconsistsofalong-rangeBluetoothtransmitterandreceiver,suchthatdatacanbetransmittedtothesidelinehubfromanywhereofthefootballfield,whichis160ftx360ftinsize.
Figure7Placementofthehubandthefurthestdistancefromtheplayertothehub[11]
Theoptimumlocationofthehubwouldbethecenterofthelongside,fortheareawithcertainradiuscoversmostofthefield.Thefurthestdistanceisbetweenthehubandthefurthercornerofthefield.Itsdistanceis:
160$ + (360/2)$ = 240𝑓𝑒𝑒𝑡 ≈ 73𝑚TheWirelesslong-rangeBluetoothtransmitterandreceiver(SparkFunBluetoothMateGold)hasrangeupto100m,whichisbeyondourrange.
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Features ValuesOperatingvoltage 3.3Vto6VOperatingcurrent 25mAaverageCommunicationspeed 2400-115200bpsOperatingTemperature -40°Cto70°C
Table8FeaturesofSparkFunBluetoothMateGold
DataProcessingModuleThedataprocessingmoduleconsistsofthreesubmodules:datastoringsubmodule,processor(hub)submodule,GUIsubmodule.Theprocessorreceivesthedatafromthetransmissionmoduleandstoresinthedatastoringsubmodule.Theprocessoralsoanalyzesthedatathroughanalgorithmanalyzingtheimpactsandheartbeatresponsesandstorestheresultsinthedatastoringunit.Finally,adetailedreportontheimpactsispresentedthroughaGUIsubmodule.Processor(Hub)SubmoduleTheprocessoratthehubreceivesdatafromthedatatransmissionmodule.Itstoresthedataintothedatastoringmoduleandalsoanalyzesthestaticdataaswellasthedynamicdataviaanalgorithm.TheresultoftheanalysisisstoredinthedatastoringmoduleandsenttoGUIforpresentation.ThecoreoftheprocessorisanFPGA,whichprocessesthedataatahighprocessingrateandhastheabilitytocommunicatewithitsperipherals.DataStoringSubmoduleThissubmoduleisalargememorywherethedatacollectedandtheanalysisresultsarestored.Dataisstoredandretrievedbytheprocessorforfurtheruse.Thememoryisdynamicallyallocatedtoaccommodatemultiplehelmet.GUISubmoduleTheprocessorpresentstheBPM,accelerationofeachhits,andanalysisresultsintheGUIsubmoduleforaclearandinteractivepresentationoftheresults.A9.7-inchLCDscreenisusedforgraphicalpresentationoftheprocesseddata.
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PowerModule
Figure8Powermoduleschematic[10]
Thehelmetandthehubarepoweredbytwopowermodulesindividually.Thepowermoduleinthehelmetincludesalight-weight,small-sizerechargeable5Vbattery.Itprovidespowerfortheothermodulesinthehelmet.Thepowermoduleinthehubincludesarechargeablebattery,aswellasanAC-DCconverter,whichallowsthehubtocontinuefunctioningwhenbatteryisbeingcharged.Thehelmetispoweredbya5VrechargeableLi-ionbattery.The5Vpowersupplyisregulatedinto3.3Vand1.2Vwithvoltageregulatedtopowerothermodules.Thebatteryinthehelmetisprotectedbyfoamtocushiontheimpact.
RequirementsandVerifications
EquipmentandRequirements Verifications
Accelerometer 1) Measurelinear
accelerationwithaccuracyofatleast80%
2) Measureaccelerometerreadingwithina10mstimeperiodwithlessthan5%error
LinearAcceleration1.) Takethehelmetwiththeaccelerometerinitand
dropitfrom3feethigh.(Useatapemeasureoryardsticktocalculatethisdistance.)
2.) Therearetwodifferentwaystochecktheaccelerationvalue.Ifourcompletedesignworks,thenwecancheckthevalueoutputontheGUIandcompareittothetheoreticalvalueof1g.Ifourcompletedesigndoesnotwork,thenwecanconnecttheFPGAoutputpins73,74,75,76,79,80,81,86,87,88,89,90,91,92,93,94tosixteenLEDsonabreadboard.EachLEDwillcorrespondtoabit,with
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alitLEDrepresentingaoneandanon-litoneazero.Simpleconversionfrombinarytodecimalvaluewillgiveusthedesiredresult.CompareValuesoftheoretical(1g)toactualandcalculatetheerror.Timingrequirement1) Wespecificallychoseachipthatwouldmeasure
anaccelerationpeakassmallas1ms,muchsmallerthanthe10msrequirement.However,tobesurewewilltake100differentrunsoftheexperimentlistedinpart1ofthelinearaccelerationverification.Ifanimpactisnotreportedin95ormoreofthedrops,thenourtimingisnotaccurateenough,andtherearecertainaccelerationjumpsthatouraccelerometersarenotabletodetect.
Pulsesensor 1) Measureheartbeat
withanaverageaccuracyof90%forbothrestingandexercisemeasurements
1) WewilluseanoximeterfromMcKinleytomeasureaperson’sheartrate.Theoximeterisattachedtoaperson’sindexfinger.Liketheaccelerationmoduletherearetwowaysoftesting.ToprovemodularfunctionalityiffullsystemisnotworkingwewilldisplaythecalculationsfromtheFPGAinsidethehelmet(pins96,97,99,100,101,102,103,104,112)toabreadboardwithtenLEDs.
Processor(Helmet) 1.) Processorrunsat90%
of50MH2.) ItHas2GBofmemory3.) PulseSensorDatais
stored,ProcessedandsenttoBluetoothmoduleinbetween.9-1.1s
1) UsebuiltinAlteraTimeQuesttoverifythattheclockdrivingtheFPGAchiphasa90%valueof50MH
2) Makesurethattheexternalmemoryisa2GBsize.Wedonothavetomeasureexactly,becauseourdesigndoesnotuseclosetoall2GB.
3) Analyzetheclockdrivingalloftheprocessesinvolvedinpulsesensordatastorage,processingandtransmissiontotheBluetoothmoduleusingAlteraTimeQuest.Addallofthecalculatedtimestogetherandchecktoseeifvaluesarewithinrange.
Powermodule(Helmet) 1) Powerthe
accelerometerbetweena2V-3Vpowersupplyand30-40μAcurrent
1) Useoscilloscopetoviewthethreevoltageoutputsofthepowermoduleunderzeroloadcondition
2) Connect10kOhmresistoracrossthe2.5Vvoltageoutput,30kOhmresistoracross5Vvoltageoutput,1MOhmacross3Vtomodelfullloadcondition
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2) Powerthepulsesensorwith4.5-5.5Vpowersupplyand2-6macurrenteach
3) PowerAlteraCycloneIIFPGAwith4.5-5.5Vpowersupply
4) PowertheBluetoothmoduleatpowersupplyof2.5V-3.5Vat1.3-3.9μA
3) Forbothzeroloadandfullloadconditions,thevoltagewaveformsshouldhavevoltagerippleof±1.5%voltageripple(ADP2116)
Wirelessdatatransmissionmodule
1) Antennaerelay’sdataata90%accuracyrate
2) Errordetectis95%accurate
1) ConnecttheoutputdatafromtheFPGAonthehelmet,pins(114,115,118,119,120,121,122,125,128,129,132,133,134and135)toLEDsonthebreadboard.ConnecttheinputsoftheFPGAhub(pins114,115,118,119,120,121,122,125,128,129,132,133,134and135)toLEDsonthebreadboard.ComparethisvaluesoftheLEDS.Theyshouldbothmatch.Thistestwillbedone50times.TheLEDSneedtomatch45timesormoretofulfillthisrequirement
2) Checkwhenthereisanerror,bycomparinginputtooutput,andthencomparethattoourerrordetectionoutput
Processor(Hub) 1) Processorrunsat90%
of50MH2) PulseSensorDatais
stored,ProcessedandsenttoGUImoduleinbetween.9-1.1s
3) Simultaneouslyaccelerometerdataisstored,processedandsenttoGUImoduleinbetween.9-1.1s
1) SamprocessasmentionintheProcessorhelmetmodule
2) SamemethodasverificationthreefromProcessor(helmet)section
3) Sameastwo
Datastoragemodule(onHub) 1) Datastoredtimeis
between.5-.7s2) Datastorageis4GB
1) SamemethodasverificationthreefromProcessor(helmet)section
2) Makesurethattheexternalmemoryisa4GBsize.Likeonthehelmet,wedonothavetomeasure
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exactly,becauseourdesigndoesnotuseclosetoall4GB.
GUImodule 1) Makessurethatthe
GUImoduledisplaysthecorrectdatainthecorrectformat100%ofthetimeontheRaspberryPiLCD’’touchscreen
2) PresentaquestionnaireontheGUI
1) RuntheGUIalgorithmandcomparethedesireddataandpresentationwiththedesign.Ifthereareanydiscrepanciestheseneedtobetakencareofbeforethefinalproductisreleased.
2) ConfirmsthatthequestionnairecanbeseenandansweredonanLEDscreenorphone
Powermodule(Hub) 1) PowerRaspberryPi
LCD’’touchscreenwith4.5-5.5Vpowersupply
2) PowerAlteraCycloneIIFPGAwithexternalstoragewith4.5-5.5Vpowersupply
3) PowertheBluetoothmoduleatpowersupplyof2.5-3.5Vat2.2-2.6μA
1) Useoscilloscopetoviewthethreevoltageoutputsofthepowermoduleunderzeroloadcondition
2) Connect30kOhmresistoracross5Vvoltageoutput,1MOhmacross3.3Vtomodelfullloadcondition
3) Forbothzeroloadandfullloadconditions,thevoltagewaveformsshouldhavevoltagerippleof±1.5%voltageripple(ADP2116)
RequirementsandVerificationsPointTableModule PointsAccelerometer 5PulseSensor 5Processor(Hub) 7.5Powermodule(Helmet) 5WirelessdataTransmissionModule 5Processor(Hub) 7.5DataStoragemodule(Hub) 5GUIModule 5PowerModule(hub) 5
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ToleranceAnalysisThisprojectisaboutcollectingmoredatatohelpresearchersanddoctorsinconcussionstudyanddiagnosis.Althoughseveralaspectscancontributetoconcussion-likesymptoms,theprimaryfactorincausingconcussionsarethehits.Thushitdetection,calculatedusingouraccelerometer,isthemostimportantpartofourproject.Ifweareunabletodothisaccuratelytoacertainpoint,thenourprojectdoesnotaddmuchvalue.Ourcompetitorsarelessthan70%accurateindetectinghardhits[6].Withtime,moneyandtechnologyrestrictionsimprovingonthisaccuracyisquitedifficult.Addingourheartbeatsensormeasurementsdoeshelpmitigatesomeofthisinaccuracy.However,wedoplantoimproveonthisexistingaccuracy.Baseduponcalculationsandtheaccelerometerdatasheetwebelievethatwecanmeasureaccelerationata20%tolerance.Beforeweexplainhowwereachourhardhitaccuracycalculation,weneedtofirstexplainwhatresearchesdefineasahitandahardhit.Onewayofclassifyingahitandahardhitisbygroupinghitsintotheiraccelerationvalues.Ingeneral,ahitisdefinedasacollisionresultingina20gaccelerationorhigher.Ahardhithasanaccelerationof50gorhigher[12].Figure1showstheclassificationofhitsbasedontheiraccelerationvalues.
Figure1:GraphshowingtheClassificationofHitsBasedonAcceleration[12]
Withanaccelerationtoleranceof20%inmind,wemustcalculatetheminimumvalueinthe50gandaboverangethatwillstillbeconsideredahardhit,assumingmaxerroranddecreasingerror(errorsubtractedfromactualvalue).Wedonotcareaboutvaluesthatareincreaseerrors(errorisaddedtoactualvalue)inthisrangebecausetheywillstillbecomputedasahardhit.Ourcalculationswillnotexceed100g,sincetheprobabilityabovetheseaccelerationvaluesisverylow,thusinaccuratelyskewingouraccuracyresults.Belowisthecalculationofthemaxvaluewhereerrorisfound.
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𝑥 −𝑥5 = 50𝑔
45 𝑥 = 50
𝑥 =2504 = 62.5𝑔
Therangeofvaluesthatwillnotregisterashardhitsiftheerrordecreasesfromtheactualvalueisbetween50g-62.5g.Calculatingtheerrorpercentageofhitsinthe50-100rangeisfoundbelow.
x =62.5 − 50
50 = 25%
𝑥 = $;%$= 12.5%
(assumingerrorisaslikelytobepositiveasnegativeandthatpositiveerrordoesnotcauseanerror)
Nowwemustcalculatetheerrorcausedfromwhenahitisbelow50gaccelerationbutiscalculatedasahardhitbecauseofpositiveerror.Althoughthiserrorislessofanissueastheaboveerroritisstillerror.Theprocedureusedtocalculatetheabove50gvalueswillbeusedbelowaswell.
Calculationformaxvaluewhereerrorisfoundforbelow50g.
𝑥 +𝑥5 = 50𝑔
65 𝑥 = 50
𝑥 =2506 = 41.6667~41.5
Therangeofvaluesthatwillregisterashardhitsiftheerrorincreasesfromtheactualvalueis41.5-50g.Calculatingtheerrorpercentageofhitsinthe50andbelowrangeisfoundbelow.
x =50 − 41.5
50 = 17%
𝑥 = =>%$= 8.5%
(forsamereasonasintheabove50grange)Calculatingtotalerrorisdonebyaddingtheerrorcalculationofboththeaboveandbelow50granges.
12.5% + 8.5% = 21.5%hardhiterror
Itisimportanttokeepinmindthatmostconcussionhitsarewithinthe70-100grange[12].Ourdevicehasa100%accuracywithinthisrange,asverifiedbythecalculationsintheabove50gcategory.
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Takingintoaccountthatouroverallerroris21.5%,whichis8.5%betterthanourexistingcompetition,andthatourerrorduringtherangewheremostconcussionsoccuris0%,the20%toleranceforouraccelerometerisjustifiedandwellwithintheobjectivesofthisproject.
CostandScheduleCostAnalysisLabor
Name Hourlyrate($/hr)
Totalnumberofhoursinvested(hr)
Totallabor($)
JosiahSpears 32.2 240 19,320
Xingyang(Xandy)Liu 32.2 240 19,320
Totallabor($) 38,640
Parts
Parts Count Price($)
Total($)
Pulsesensor 1 10.00 10.00
SeeedstudioGrove-3-AxisDigitalAccelerometer(±400g) 1 34.99 34.99
EP2C5T144AlteraCycloneIIFPGAMiniDevelopmentBoard 2 21.90 43.80
RaspberryPiLCD’’touchscreen 1 64.95 64.95
AnalogDeviceADP2116DC-DCmulti-outputregulator 2 2.50 5.00
SparkFunBluetoothMateGold 2 34.95 69.90
USB2.0maleto5.5mm/2.1mm-5VDCPowerCableBarrelConnectorJackPlug
1 4.78 4.78
GeeetechAlteraUSBBlaster 1 8.99 8.99
Total 242.41
GrandTotalLaborcost+partscost=$38,640+$208.41=$38,848.41
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Schedule
Week Task Responsibility
9/12 Finalizeprojectproposal Contactprofessorswithexpertiseinantenna/communications PrepareforMockDesignReview Eagleassignment
JosiahSpears
Finalizeprojectproposal Contactbioinstrumentprofessor PrepareforMockDesignReview Eagleassignment
XandyLiu
9/19 OrderFPGAsandantennas Schematicdesignforthesensormodule PCBlayoutforbothpowermodules
JosiahSpears
Orderaccelerometerandpulsesensor PCBlayoutdesignforthesensormodule Schematicdesignforbothpowermodules
XandyLiu
9/26 Schematicdesignforthedataprocessingmodule PCBlayoutforthedatatransmissionmodule
JosiahSpears
PCBlayoutdesignforthedataprocessingmodule Schematicdesignforthedatatransmissionmodule
XandyLiu
10/3 FPGAdesignrelatedtodatastorageinsidethehelmet JosiahSpears
FPGAdesignrelatedtointeractionwithsensorsandantennae XandyLiu
10/10 Solderingassignment Test/Debugofsensormoduleonthebreadboard ProgramtheFinitestatemachineofFPGAandtesttomakesureitworksConfigureFPGAinteractionwithDAC
JosiahSpears
Solderingassignment Test/Debugofpowermoduleonthebreadboard Testingtheinteractionsbetweenthepowerandsensormodules
XandyLiu
10/17 BuildtheFPGAcodeformemorystorageandretrieval Startonindividualprogressreports
JosiahSpears
22
Startonindividualprogressreports ImplementthememorywiththeFPGAandsensors
XandyLiu
10/24 CodeGUIforinterfacebetweenuseranddevices Finishindividualprogressreports
JosiahSpears
Finishindividualprogressreports Buildpowermoduleandconnecttohelmetmodule R&VSecondTable
XandyLiu
10/31 Test/DebugtheentiredataprocessingmoduleConfigureBluetoothonhelmetmodule
JosiahSpears
Test/Debugtheentiredataprocessingmodule Learnaboutwirelessdatatransmissionprotocols
XandyLiu
11/7 IncorporatedatatransmissioninFPGAdesignofsensormodule R&VTableFinal
JosiahSpears
IncorporatedatatransmissioninFPGAdesignofdataprocessingmodule Testing/Debuggingthedatatransmissionmodule
XandyLiu
11/14 Test/Debuginterconnectionandcommunicationbetweenindividualmodules
JosiahSpears
Test/Debugtheentiresystemsothatitproducesthedesiredproduct
XandyLiu
11/21 Write Introduction and Research of project into Paper Put this part into the Presentation
JosiahSpears
WorkonPresentation StartonFinalPaper
XandyLiu
11/28 FinishPresentation ContinueworkonFinalPaper
JosiahSpears
FinishPresentation ContinueworkonFinalPaper
XandyLiu
12/5 FinishPaper• Introduction• Verification• Conclusion
JosiahSpears
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FinishPaper• Design• Cost• Reference
XandyLiu
EthicsandSafetyEthicsTheThickSkullProjectisaffectedbythefollowingethicalstandardsfoundintheIEECodeofethics[13].Ourteamtakesthefollowingethicalstatementsextremelyseriouslyandhavecarriedthemouttothebestofourknowledge.Wetakeprideinthefactthatwehaveandwillcontinuetoupholdthemandunderstandthatnotfollowingthemreflectspoorlyonusaselectricalengineers,soon-tobeUIUCgraduates,andmembersofourglobalsociety.
[1]Toacceptresponsibilityinmakingdecisionsconsistentwiththesafety,health,andwelfareofthepublic,andtodisclosepromptlyfactorsthatmightendangerthepublicortheenvironment
[3]Tobehonestandrealisticinstatingclaimsorestimatesbasedonavailabledata.[4]Torejectbriberyinallitsforms[5]Toimprovetheunderstandingoftechnology,itsappropriateapplication,and
potentialconsequences.[6]Tomaintainandimproveourtechnicalcompetenceandtoundertaketechnological
tasksforothersonlyifqualifiedbytrainingorexperience,orafterfulldisclosureofpertinentlimitations.
[7]Toseek,accept,andofferhonestcriticismoftechnicalwork,toacknowledgeandcorrecterrors,andtocreditproperlythecontributionsofothers.
[9]Toavoidinjuringothers,theirproperty,reputation,oremploymentbyfalseormaliciousaction.
[10]Toassistcolleaguesandco-workersintheirprofessionaldevelopmentandtosupporttheminfollowingthiscodeofethics.
Ethics[1]appliestoourprojectinmanyways.Bycreatinghelmetadd-ons,ourdesign
couldpotentiallydecreasethesafetyofhelmetsandcouldpresentmoresafetyhazards,withtheinclusionofbatteries.Wemustdisclosethepotentialsafetyhazardswithourdesignandletthepublicknowthestepswehavetakentoalleviatethem.Ethics[3]isrelevanttoourprojectbecauseitdiscussesthefactofmakingfalseclaims.Forourprojectwecannotclaimthatourproductisgoingtosolveconcussionsorpredictthem.Becauseoutprojectdealsinaverypoliticalarena,concussions,therecouldcomeatimewherewewouldbebribedsothatwestopourproductionorinsteadbeforcedtofalselyreportoutresultsorcapabilities,ethics[4].Ethics[5]appliestousbecausewebelievepartofourmissionistoshownon-engineeringsportsleadersthepossibilitiesoftechnologyandsciencetocreatesaferenvironmentsin
24
sports,whilekeepingthemrealisticoncurrentabilitiesandlimitations.Ethics[6]appliestousbecauseifdonehaphazardlyorignorantly,ourdevicecouldimmediatelyorfuturisticallydamagelives.Anyengineeringproject,mustincludeethics[7],wherewemustalwaysgivecredittooutsideresourcesandusetheiradvicetoimproveourproject.Ethics[9]goeshandinhandwithethics[1].Sinceourdesignmodifiessafetyhelmets,thiscouldincreaseinjuriesifwedonotmakeconsumersawareofthedifferencesandneededprecautions.Ourultimategoalistoaddvaluetotheconcussionfieldinneuroscience,whichwillallowustoenactethicscode[10].
SafetyEachmemberofourteamhasreceivedtheGeneralLaboratorySafetyandElectricalSafetycertificatesinordertousethelabsintheECEB.Ourprojectdoesnotdealwithlargeamountsofpowerdistributionorgeneration,sincethehighestamountofvoltagecapacityneededis5-5.5V.1)Battery
• Makesurethattheoperatingtemperatureforpowersupplyisbetween0degreeto45degreesCelsius.
• DonotputtheLithium-ionbatteryunderwaterorfire.Donotcompress,dismantle,orprickthebattery.
• Thebatteryiswell-cushionedinsidethehelmetsoastoreducetheimpactonthebattery.
• Makesurethetwoterminalsarenotshortatanytime.• Goodinsulationwithinthehelmetfromthehumanbodyorotherelectronicdevices.
2)Theproduct• Theproductisforbiddentobetestedonhumansubjectsotherthantheteammembers.
Citations[1]
S.K.F.C.L.C.R.W.D.R.D.C.LukeM.Gessel,"ConcussionsAmongUnitedStatesHighSchoolandCollegiateAthletes,"JournalofAthletcTraining,vol.42,no.4,p.495–503,2007.
[2]
Riddell,"riddellIQ,"Riddel,[Online].Available:http://www.riddell.com/riddell-iq.[Accessed10September2016].
[3]
Riddel,"RiddleInsite,"[Online].Available:http://www.riddell.com/InSite#whatitis.[Accessed14September2016].
[4]
Shockbox,"FootballHelmetSensors,"[Online].Available:http://www.theshockbox.com/football-sensors/.[Accessed14September2016].
25
[5]
Reebok,[Online].Available:http://www.reebok.com/us/checklight/Z85846.html.[Accessed14September2016].
[6]
S.Smith,"Headimpactsensors:On-the-fieldplaceboordanger?,"21November2013.[Online].Available:http://www.cnn.com/2013/11/15/health/youth-head-sensors/.[Accessed14September2016].
[7]
D.K.Jackson,Interviewee,[Interview].26September2016.
[8]
STMicroelectronics,"H3LIS331DLMEMSmotionsensor:low-powerhigh-g3-axisdigitalaccelerometer,"September2013.[Online].Available:http://www.st.com/content/ccc/resource/technical/document/datasheet/3e/48/02/c7/a4/e6/41/bb/DM00053090.pdf/files/DM00053090.pdf/jcr:content/translations/en.DM00053090.pdf.[Accessed2October2016].
[9]
J.MurphyandY.Gitman,"OpenHardware,"[Online].Available:http://pulsesensor.com/pages/open-hardware.[Accessed2October2016].
[10]
OpenImpulse,"EP2C5T144AlteraCycloneIIFPGADevelopmentBoard,"4May2011.[Online].Available:https://www.openimpulse.com/blog/wp-content/uploads/wpsc/downloadables/EP2C5T144-Altera-Cyclone-II-FPGA-Development-Board-Diagram.pdf.[Accessed2October2016].
[11]
A.Haley,"FootballFieldDimensionsandGoalPostSizes:AQuickGuide,"15June2015.[Online].Available:http://www.stack.com/a/the-dimensions-of-a-football-field.[Accessed13October2016].
[12]
Shockbox,"Research,"[Online].Available:http://www.theshockbox.com/helmet-sensors-technology-for-concussion-management/shockbox-helmet-sensors-research/.[Accessed14September2016].
[13]
IEEE,"IEEECodeofEthics,"[Online].Available:http://www.ieee.org/about/corporate/governance/p7-8.html.[Accessed16September2016].
[14]
MicrochipTechnologyInc.,"2.7VDualChannel10-BitA/DConverterwithSPISerialInterface,"2007.[Online].Available:http://ww1.microchip.com/downloads/en/DeviceDoc/21294C.pdf.[Accessed2October2016].
[15]
AvagoTechnologiesLimited,"APDS-9008MiniatureSurface-MountAmbientLightPhotoSensorDataSheet,"7November2008.[Online].Available:http://docs.avagotech.com/docs/AV02-1169EN.[Accessed2October2016].