ModernSensorsX.WuWhatinthiscourse……ExtendyourknowledgeinopticsandelectronicstoarealmofapplicationCaseStudy:exemplarymodernsensorsAlittlebitofEntrepreneurshipeducationWhatarewegoingtocover?Human/AnimalSensorsSensorPerformanceCharacteristicsStrainGaugeBasicsCapacitiveSensorsandAccelerometer(ADXL50)Piezoelectric/PressureSensorsThermometers/FlowSensorsRadiationSensors;IRSensorsInductiveandMagneticSensors(HardDiskread-writehead)SoundingMeasurementChemicalSensorsGyroscopesAlookatmodernsensorsElectronicNoseWhatcanmodernsensorsdo?Detect2,4,6-trichloroanisole(TCA)inwinearomaatpart-per-trillionlevelsinseconds(10-12)(ZnosebyElectronicSensorTechnology)AromaticcompoundsinwineElectronicNoseAvaporanalysissystemforhomelandsecurityafter9-11DetectsuspiciousgasesOlfactoryimageChemicalfingerprintsElectronicNoseHowdoestheNoselooklike?Sensorhead-BigsizeMoreworkneedstobedoneforittobedeployedinarobotPowerconsumptionChannelnumber/flexibilityIndustry’sSmallestAccelerometerSize:4x4x1.45mm3Manufacture:AnalogDeviceADXL32xfamilyofiMEMS(integratedmicroelectromechanicalsystem)accelerometersFuturepackage2x2x0.9mm3Operatingcondition:powersupplies2.7Vconsumeonly450μAcanbepower-cycledforevengreaterbatterylifeThetypicalnoiseflooris200μgperrtHz,allowingsmalltiltchangestobesensedusingthenarrowbandwidths(<10Hz)typicalofhumanmotion

TodayAccelerometersWhatcanmodernsensorsdo?DetectlinearaccelerationwithhighprecisionforindustrialandmilitaryapplicationsMiniatureAccelerometer,ColoumbiaResearchLabPyroelectricInfraredRadialSensorProductDescriptionModel:

D203SEncapsulationType:

TO-5WindowSize:

4×3mm2SpectralResponse:

5-14μmOutputSignal[Vp-p]:

≥3300mVSensitivity:

≥3100V/WDetectivity(D*):

1.4×108cmHz1/2/WNoise[Vp-p]:

<70mVSupplyVoltage:

3-15VOperatingTemp:

-30-70oCApplication:securitysystems,burglaralarms,visitoracknowledgement,lightswitchcontrolandintellectualizedtoy,etc.IntroductionWhatcanmodernsensorsdo?Detectbrainwavetocontrolcomputermouse(2006)…..IntroductionModernSensorsarepenetratingintoourlife:Medical:Angioplasty,InfusionPumps,BloodPressure,KidneyDialysis,RespiratoryAutomotive:TirePressure,MAP,FuelandEngineControlSystems,BarometricIndustrial:PortableGauges,Manometers,AltitudeMeasurements,Barometry,WaterDepthConsumer:iphone,ipad,…ieverything

MajorIndustryPlayersAnalogDevices

ColumbiaResearchLabs

Capacitec

EG&GICSensors

Endevco

Humphrey

KistlerInstruments

LucasNovasensor

MTIInstrumentsInc.

PCBPiezotronic

QuantumResearchGroup

Raytek

SensorsMagazine

SiliconDesigns

StrainMeasurementDevices

SummitInstruments

Thermometrics

VishayIntertechnology

YellowSpringsInstruments

Sensor:ADefinitionAsensorisadevicethatreceivesastimulusandrespondswithanelectricalsignal.(maybeopticalinnearfuture)Thetermstimulus:Thestimulusisthequantity,property,orconditionthatissensedandconvertedintoelectricalsignal.Thepurposeofasensoristorespondtosomekindofaninputphysicalproperty(stimulus)andtoconvertitintoanelectricalsignalwhichiscompatiblewithelectroniccircuits.Wemaysaythatasensorisatranslatorofagenerallynon-electricalvalueintoanelectricalvalue.Example:LevelElectricalsignalTheinformationisperceivedbythesensor,whichconsistsoftwomainparts:thesighttubeonthetankandtheoperator’seye,whichgeneratesanelectricresponseintheopticnerve.Thesighttubebyitselfisnotasensor,andinthisparticularcontrolsystem,theeyeisnotasensoreither.Onlythecombinationofthesetwocomponentsmakesanarrow-purposesensor(detector),whichisselectivelysensitivetothefluidlevel.Biologicalsensors–anintroductionPhysicallimitstothemeasurementofcertainsignalTemperaturefluctuationinfiniteobjectsHeatcapacityormassAirspeed/turbulenceLimitedbyenvironmentaldisturbanceAudiobackgroundnoiselimitshearingcapabilityBroadbandaudionoiseinjungleLightdetectionNumberofphotonsNocturnalanimals’visionislimitedbyscarcityofphotonsFlickerofstarlightBiologicalsensors–anintroductionNaturalevolutionaryprocessinnatureAremarkableefficientfilter(adaptation)Somehigh-performanceexamplesChemicalsensingofpheromonesinmothsUltrasoundsensinginbats(predators)andmoths(prey)Visioninpredators:cats,birdsLow-performanceTiltsensinginhumansTactilesensing

HumanSensoryCapabilitiesSystemissuesSignalconditioningWiringTimeresponseandhysteresisPackagingSoftware/hardwaretradeoffsHumanSensors:MechanoreceptorsExperimentNoticehowyourfingertipsenselocation,roughness,thicknessandtemperatureRateofadaptationTherateatwhichthemechanoreceptorpulseratereturnstonormalafterachangeinstimulusSensorswithadaptationdonotprovideinfoaboutstaticsignals-onlyaboutchangingsignalsAtime-varycontactforceonthetactilesensorsallowthesensingstaticquantity-roughnessPurposetoStudyMechanoreceptorsUltimategoalforyou:replicateorevenimprovethesysteminarobotHumanSensors:MechanoreceptorsNosingletypeofmechanreceptorcanaccomplishallthefunctions!Multi-layeredMulti-structuredVariousresponserateExtremelydifficulttoreplicateduetoChannelnumbers/densityComplextopologyLeadingtostudyoftactilesensorarrayResistivetouch-screenCapacitivetouch-screenOpticaltactilesensor/skinMechanoreceptors-categoryThemechanoreceptorsinyourskinmaybeseparatedintodistinctcategoriesFastadaptation:<0.1sec

PacinianCorpusclesModerateadaptation:1secMeissner’scorpusclesHairfolliclereceptorsSlowadaptation:10-100secRuffiniendingsMerkel’scellsTactiledisksAdaptationCurvesforSensoryReceptorsFastAdaptationPaciniancorpusclesSomatosensoryreceptorsofhandsandfeetDetectcharacterasexpressedbyafirm,confidenthandshake,anindecisiveloosegrip,oranover-zealousbone-crusherRespondstopressure,anymechanicalstimulusthatcausesdeformationofcorpusclesurroundingthesingleafferentnervefiberNamedforFilippo

Pacini,a19thCenturyItaliananatomistwhodedicatedhiscareertomicroscopicresearch,Paciniancorpusclescandetectvibrationsandtouch

intermsoffrequency,duration,andintensity

PaciniancorpusclesThesecorpusclesexistwithinmuscles,joints,andsubcutaneoustissuesthroughoutthebody.Thepaciniancorpuscleconsistsofasinglenervefiber,theterminalregionofwhichisenclosedinamulti-laminatedconnectivetissuecapsule.Thenerveismyelinated(Havingamyelinsheath)exceptfortheterminalregionwithinthecapsule,whichisnonmyelinated

ModerateAdaptationMeissner’scorpuscleegg-shapedreceptorsconsistingofamassofintertwinedfibers.locatedonhairlessskin,betweenthedermisandepidermisthatinformthebrainexactlywheretheskinistouched.Meissner'scorpusclesareconcentratedinthefingertipsandpalms,lips,andtongueAdaptationtostimulusThenerveterminalwithinthepaciniancorpuscleissensitivetomechanicalcompression,whichcausesittodepolarize.Thisdepolarization(thegeneratorpotential)increasestoamaximumandthenreturnstotherestingpotentialeventhoughthemechanicalstimulusisstillapplied.Sucharesponseisreferredtoasphasic.Theprocessbywhichthemagnitudeofthegeneratorpotentialdecreases,evenwhenthestimulusismaintained,iscalledadaptation.Meissner’scorpuscleAnexampleofasensorynerveending:Meissner'scorpusclelocatedinthepapillarylayerofthedermisovoidinshapecomposedofasensorynervefiberthatisenclosedwithinacapsuleofconnectivetissue.aspecializednerveending,atouchreceptor,andisalsotermedatactilesensorycorpuscleDowehaveopticalcounterpart?TheMeissnercorpuscleisalooselyencapsulatedsensoryreceptorinthedermalpapillaeofglabrousskin

Topology:Meissner’scorpusclesMostofthesecellsarecontactedbyoneterminalbranchofoneofthreetofiveaxonsthatendinthedome

SensordistributionSignalgroupingResolutionSlowAdaptation

Ruffinicorpuscles1mmfusiform(spindly)structurewithathincapsuleorientedparalleltothesurfaceoftheskinhavebundlesofcollagenfiberscoursingthroughthemwhicharepenetratedbytheaxonsoftheafferentnervessheathedbyconnectivetissueandcontaininterlacednetworksofnervefibers.detecttemperatureandpressureRuffini'sendingsarealsofoundinthejoints,wheretheysignalhowfarthejointhasrotated.OurTouchPerceptionSystemNerveFiberClassificationTheAa(I)fibresaremotora-fibresandproprioceptorsfromtheannulospiralendingsofmusclespindles(Ia)andfromGolgitendonorgans(Ib).TheAb(II)fibresconductdiscretetouchandfinepressuresignalsfromcutaneoustactilereceptors.TheAg(II)fibresaremotorfibrestomusclespindles.Theyhavetheirorigininthespinalcord.TheAd(III)fibrestransferpainsensations,declineinskintemperatureaswellascrude,passivetouchanddeeppressure.TheBfibres(III)areautonomicpreganglionic

fibres.TheCfibres(IV)areunmyelinatedandleadpain,touchandsignalsfromheatreceptorsfromtheskin.TheCfibreshavenomyelinsheath.YourMechanoreceptorsProbingyourhandwithatoothpick,trytolocatethemostsensitiveregionsthemostsensitivemechanoreceptorsarelocatedinthefingertips,whereskinindentationsassmallas6micronsaredetected

Howareyoursensorsdistributed?OutputSignalofmechanoreceptorsIntheformofastreamofvoltagepulsesAmplitudeofsignalpulsedensityDigitalratherthananalogAnalogoustoTTLpulsesHuman-ComputerinterfaceVirtualRealityglovecontrolsremotelyarobot'smovementsthroughherownandbyseeing,hearing–evenfeeling–theenvironmentitworksinTactileSensors:Oureffort1996,MEMScapacitive2008,SensorSkin:16sensors/cm2(asopposeto1500inhumanfingertip),organicFETmadeofcarbonchainstocreatealarge,flexible,potentiallyultra-lowcostpressure-sensorarrayTactilesensorarrayonwaferFlexibletactilesensorarrayOpticaltactilesensorMechanisms:totalinternalreflection,surfaceplasmonresonance,…HumanSensorySystem:AuditorySystemHowitworks?Soundwavepressuredeflectseardrum,andthestructuresattachedtoitMiddleear:vibrationtransfer&attenuationInnerear:anacousticspectrumanalyzer,individualmechanoreceptorsconfiguredfordetectionofparticularaudiofrequenciesOneeffectoftheshapeofthespiraldiaphragmisthattheresonantfrequencyisafunctionofpositionalongthespiral.anyparticularacousticsignalfrequencywillproduceamechanicaloscillationintheinnerearataparticularphysicallocation.

HumanSensorySystem:SmellSensingIntheuppernasalcavitythemucousmembraneisyellowandtermedtheolfactorymembrane.Itcontains100millionbipolarneuronscalledolfactorycells.Theycontainhairsorolfactorycilia.Theolfactorycellsaresmellreceptors.Theyworkastelereceptors,Theolfactorytractthentransmitstheolfactorysignalstotheolfactory