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Sensors, Circuits, and Satellites revisedApril2016

DevelopedunderGSFCIRADAwardFY13-297 page 1

Sensors,Circuits,andSatellitesLesson4:DigitalCommunication

Sensors,Circuit,andSatellitesisacollectionofclassroomlessonscreatedbyNASA’sAuramissioneducationandoutreachthatexploretheelectromagneticspectrumandNASAremotesensinginstrumentsusingstudentassembledcircuits.Theselessonsintegrateinquirywithactive-learningexperiencestoengagestudentsinthepropertiesofelectromagneticenergyandremotesensing.TheinvestigationsaresequencedtohelpthelearnerconstructtheirknowledgeabouttheelectromagneticspectrumwhileofferingrealworldexamplesfromNASA.Credits:Dr.DeborahRoberts-Harris,Dept.ofTeacherEducationattheUniversityofNewMexicoGingerButcher,SeniorNASAEducationSpecialist,ScienceSystemsandApplications,Inc.DevelopedincollaborationwithlittleBitsElectonics™viaanInternalResearchandDevelopment(IRADFY13-297)awardfromNASAGoddardSpaceFlightCenterandcontinuedcollaborationunderNASASpaceActAgreementSAA5-2013-3-N15210



Lesson4:DigitalCommunicationSummary:ThislessonisademonstrationaboutelectromagneticenergyandhowthatenergyistransferredviavisibleandIRlightwavestosoundenergy(digitalsignals).Studentswillinvestigatehowthelengthofthewaveaffectshowlightenergyistransmitted.Conceptsofdigitalsignal,visible,infraredormicrowavewavesareintroduced.StudentObjectives:Studentswillanalyzethedifferencebetweenthetransmissionpropertiesofdifferentelectromagnetic(light)wavesusingadigitalsign.

KeyTerms:electromagneticspectrum,digitalsignal,visible,infraredandmicrowave.

ApproximateTime:45–60minutes

Materials:• littleBits™components:power,microphone,audiocable,brightLED,andwire

(foreaseofuse),alsoforthesecondcircuit:power,lightsensor,speaker,andwire

o ALTERNATIVEMATERIALS*–FromSection5,ActiveAstronomyEducatorGuidefromtheSOFIAmission

§ InfraredLightEmittingDiode(LED)§ 0.22μF(microfarad)Capacitor§ AudioCablewith1/8”mini-plugononeend§ 5JumperCableswithalligatorclipsonbothends§ AABattery§ AAbatteryholder§ ReceiverCircuit§ Solarcell§ Amplifier/Speaker§ AudioCablewith1/8”mini-plugononeend§ 2JumperCableswithalligatorclipsonbothends§ 9VoltBatteryforAmplifier/Speaker

• Flashlight• MP3player• Imageoftheelectromagneticspectrum• Whitetissuepaper,fabricpiecesandplasticbags• Videogamecontroller

NGSS–DisciplinaryCoreIdeas• MS-PS4-2WavesandTheirApplicationsinTechnologiesforInformation

Transfer-Developanduseamodeltodescribethatwavesarereflected,absorbed,ortransmittedthroughvariousmaterials.[ClarificationStatement:Emphasisisonbothlightandmechanicalwaves.Examplesofmodelscouldincludedrawings,simulations,andwrittendescriptions.][AssessmentBoundary:Assessmentislimitedtoqualitativeapplicationspertainingtolightandmechanicalwaves.]



• MS-PS4.3:InformationTechnologiesandInstrumentationDigitizedinformationcanbetransmittedoverlongdistanceswithoutsignificantdegradation.High-techdevices,suchascomputersorcellphones,canreceiveanddecodeinformation—convertitfromdigitizedformtovoice—andviceversa.[ClarificationStatement:Emphasisisonabasicunderstandingthatwavescanbeusedforcommunicationpurposes.Examplescouldincludeusingfiberopticcabletotransmitlightpulses,radiowavepulsesinwifidevices,andconversionofstoredbinarypatternstomakesoundortextonacomputerscreen.][AssessmentBoundary:Assessmentdoesnotincludebinarycounting.Assessmentdoesnotincludethespecificmechanismofanygivendevice.]

NGSS–Cross-cuttingconcepts• StructureandFunction:Structurescanbedesignedtoserveparticularfunctions

bytakingintoaccountpropertiesofdifferentmaterials,andhowmaterialscanbeshapedandused.

• Patterns:Graphsandchartscanbeusedtoidentifypatternsindata.

Engage:(Teachercandemo,oraskforstudentvolunteer). 1.Shineaflashlightontothelightsensorinthereceivercircuitandtryto

makeanoise. 2.Askthestudents:Whathappens?Canyoumakeanoise?

3.Guidestudentstonoticethattheflashlightwillmakeaclickingsound whenthesignal(lightwavesfromtheflashlight)isinterrupted.Whentheflashlightmovesaway,ormovesbackonyouwillgetasound-offandon.

Explain:

Sharewiththestudentsthatwhenthesensorturnsoffandon,thereisachangeinthesignaltoelectricalenergy.Thisisjustlikethebinarycodeusedbycomputersandotherdevicestoencodeinformation.Signalscanbecodedintoaseriesofpulses.Thesignalcanonlybeonoroff.Thesearecalleddigitalsignals.

Explore:

1. Puttogetheryourfirstcircuit:Transmitter(Power+Microphoneandaudiocable+MP3+BrightLED)+wireforeaseofuse

2. Puttogetheryoursecondcircuit:Receiver(Power+Lightsensor+Speaker)+wireforeaseofuse

3. PlayyourmusicandholdtheBrightLEDbitoverthelightsensorandthelightmodulates

4. NowchangebrightledtotheIRLEDbitoverthelightsensor-doesitsounddifferent?Howso?Recordyourfindingsinyourjournal.Whydoyouthinkthisishappening?

*Ifusingalternativematerials,seeset-upinstructionsonpages73-76ofSection5intheActiveAstronomyEducatorGuidetocompletesteps1&2



Explain:Firstlet’slookathowtheenergyisbeingtransmitted.Whatisthefirstenergysource?Thebattery.ThebatteryenergyistransmittedtothedatastoredelectronicallyonMP3player,thentothelight.Thelightenergyistransferredtosoundenergyatthespeaker.

SowhyisthereadifferenceinthebrightlightandtheIRlight?Recordstudentideas.

Let’stakealookattheelectromagneticspectrum(showimage).

https://science.nasa.gov/ems/01_introWeuseelectromagneticwaveseveryday.Doyouknowofanythingthatuseselectromagneticwaves?Listentostudentideas.Electromagneticwavesareemittedbymanynaturalandman-madesources.Thesewavesareapartofourdailylives,whetherweareawareofthemornot.Wearewarmedbytheelectromagneticemissionsofthesun(sunburn?)andweseeusingthepartoftheelectromagneticspectrumthatoureyesdetectasvisiblelight.Infraredlightisnotpartofthevisiblelightspectrum,butasyoucansee,stillemitswavesthatcanbedetectedbysensors,andotherinstruments.Let’stakealookattheelectromagneticspectrum(showimage).

Givestudentorpairsofstudentsacopyoftheimageabove.Havethemrecordsomeobservationsaboutthechart.Then,asktheclass-Whatdoyounoticeabouthowlightwavesarearrangedonthespectrum?Longtoshort–lefttoright.IsthereadifferencebetweentheIRwavesandthevisiblelightwaves?Whatelsedoyounoticeaboutthischart?Inthenextpartoftheinvestigationwearegoingtoinvestigatehowthelengthofthewaveaffectshowlightenergyistransmitted.Explore:Foreachtypeoflight,wewilltesthowittransmitsenergythroughthreedifferentsubstances:tissuepaper,fabricandaplasticbag(Studentscomplete“DataCollectionVisibleLightandInfraredLight”Sheet).CONNECTION:NASAcommunicateswithsatellites,astronauts,andevenRoversonMarsbydigitalsignalsusingelectromagneticwaves.(Welcometothedigitalage-digitalcommunicationispartofourdailylives.)Allthewavesthatmakeuptheelectromagneticspectrumtravelatexactlythesamespeedthroughspace,whichisthespeedoflight.



DataCollectionVisibleLightandInfraredLight

Materialbetweentransmitterandreceiver

Observationsw/brightLEDbit(visiblelight)

Observationsw/IRLEDbit(infraredlight)

Whitetissuepaper

Fabric

Plasticbag

DataCollectionMicrowaveLight

Materialbetweentransmitterandreceiver

Observationsw/microwavelight

Whitetissuepaper

Fabric

Plasticbag

Download - Sensors, Circuits, and Satellites Lesson 4: Digital ...§ Receiver Circuit § Solar cell § Amplifier/Speaker § Audio Cable with 1/8” mini-plug on one end § 2 Jumper Cables with

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