Silly Electronics for Fun and Absolutely no Proft - - PowerPoint PPT Presentation

Silly Electronics for Fun and Absolutely no Proft

FlüüfffFirstfEditionf–f03/11/2017

FloerefT.fPillowcase,fDevourerfoffAutomobilesf(foere@robocow.be)

2

Disclaimer

Thisfpresentationfisfintendedfforf educationalfpurposesfonlyfandfdoesf notfreplacefindependentfprofessionalf judgement.f Thefpresenter,fnorfthefconvention,f assumefanyfresponsibilityfforfthef content,faccuracyforfcompletenessfoff thefinformationfpresented.f

3

Audience

• Basicfelectronics,ftargetedfatfcostuming.
• Thefideafisftofgetfsomethingfgoingfquicklyfandf

easily.

• Wefwillfnotfcoverf(m)anyfadvancedftopicsftoday.

– ButffeelffreeftofcomeffndfmefandfIfwillfhappilyf

discussfyourfcoolfcostumingfideas.

• Ifwillfassumefyoufhavefsomeffamiliarityfwithf

Arduinofandfsimilarfplatforms.f

– Iffnot,fdofnotfworry.fThisftalkfshouldfstillfmakef

sense.

4

WhyfthisfT alk?

• Thefinternetfisffullfoffinformationfonfhowftof

buildffunfdevices,fandfaddfcoolfefectsftof costumes.

– Muchfoffitfisfquestionableforfdangerous. – Muchfoffitfrequiresfelectronicsfknowledge.

• Basicfcostumingfgadgetryfshouldfnotf

requirefyearsfoffstudy,fnorfbefafdeathftrap.

• Iflikefmyffuzziesfcute,fcuddlyfandfalive!

5

Content

• SightsfandfSounds

Howftofaddffunfgadgetsftofyourfcostume

• Reliability

Howftofkeepftheffunfgoing

• Safety

Howftofstayfaliveftoftellfthefstory

6

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

7

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

8

Control:fArduinofandfthefLikes

• Forfdynamicfefectsfyouf

needfafprogrammablef controller.

• Therefarefmanyfeasy-to-usef
• ptionsftoday.

– Arduinof/fT

eensy

– RaspberryfPi

• Justfgofout,fbuyfafgoodf

starterfkit,fandfgo!

• Caveatfemptor:f5Vfvsf3.3Vf

logicflevels!f(Stickfwithf5Vf whenfstarting-out.)

https://www.arduino.cc/

9

LevelfShiftingfDigitalfSignals

• Itfhappensfthatftheflogicflevelsfoffyourf

microcontrollerfdofnotfmatchfthefdevicef youfarefconnectingfto.f

• 3.3Vfwasfchosenftofworkfwithf5Vfinputs.

– 3.3Vf→f5VffffOK – 5Vffff→f3.3VfNOK

Unlessfthef3.3Vfinputfisf5Vftolerant.

• Dofnotfusefresistivefdividersftofshiftfthef

levels.fThesefmess-upfsignalftiming.f (ButfOKfforfslowfthingsflikefpushf buttons.)

• Easiestftofusefarefbi-directionalfshiftersf

basedfonfMOSFET sf(e.g.fBSS138).f

– Thesefarefgoodfforf<f2fMHzfsignals. – Ifftoofslow,fusefafdedicatedflevelf

shifterfIC,fe.g.:f74LVx245fseries.

• Thesefneedfafspecifcfsignalf

directionfsetfandfrespected!

10

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

11

Sights!

12

DrivingfafFewfSmallfLEDs

• LEDsfneedfafconstantfcurrentfsource.

– Currentfrelatesftofbrightness. – T

• ofmuchfcurrentf=fboom!

– Voltageftofcurrent?fJustfafresistor.

• T
• fcalculatefthefresistorfyoufneed:

– Appliedfvoltagef(U) – LEDfforwardfvoltagefdropf(Uf) – LEDfcurrentf(I)

• Equation:fRf=f(Uf-fUf)f/fI

– Thefcurvefisfforfaf20fmAfredfLED. – (5fVf–f1.8fV)f/f20e-3fAf=f160fΩ – NearestflargerfE12fvalue:f180fΩf – Keepfthefunitsfconsistent!

• Iffyoufcan’tffndfthefdatasheetfforfyourf

LEDs,fthefvoltagefdropfisf~thefsamefforf allfsmallfLEDs.fItfdependsfonfthefcolour.

– Normalfdrivefcurrentfisf~20fmA – High-efciencyftypesfwillfrequirefless! http://www.electronics-tutorials.ws/diode/diode_8.html

13

WasfthefExamplefSmart?

• No!f

– Wefdropf~3.2fVfoverfthefresistorf=f64%fpowerfloss.

• Better:fiffwefusef2fLEDsfinfseries,fUffisfdoubledf(3.6fV)f

– Rf=ff68fΩf – Wefdropf~1.4fVfoverfthefresistorf=f28f%fpowerfloss.

• WithftwofLEDs,ftheftotalfloadfisfstillfthefsame!
• Lessfpowerfisfwastedfasfheat.f

– ThreefoffthesefLEDsfwillfjustfaboutfworkfwithf5fV.f

(Withoutfafresistor,faflittlefdimmer.)

14

DoesfthisfMethodfScale?

• No!fSeriousflimitationsfwhenfdrivenfdirectlyffromfafmicrocontroller:

– GPIOflimits

• GPIOfpinftypicalfmaximumfcurrent:f10f–f30fmAf(sourcefnotfalwaysf=fsink).
• GPIOfbankftotalfcurrentfmayfimposeffurtherflimits.
• CanfonlyfdriveftwoforfthreefLEDsfperf5fVfGPIOfpin.

–WithfblueforfwhitefLEDs,fthisfwillfgofdownftofone.f(Uffisfmuchfgreater.) –Af3.3fVfGPIOfwillfnotfbefableftofdrivefblueforfwhitefLEDsfdirectly. – MCUflimits

• T
• talfcurrentfgoesfupfquickly.f
• T

ypicalfmaximumfvaluesfaref100f–f200fmA.

– BrighterfLEDsfrequirefmuchfmorefcurrentfthanf20fmA.

• ForfmorefLEDs,fusefMOSFETfdrivers.

– Canfbefscaledftofanyftotalfdrivefcurrent. – Thesefalsofallowfafhigherfsupplyfvoltage,fseparateffromfthefMCU. – Youfcanfalsofbuyfvariousf(multi-channel)fLEDfdriversffromfvariousfvendors. – BUT,ftherefisfafsimplerfway...

15

DrivingfManyfLEDsfthefSimplefWayf DigitalfLEDfStripsf

• Fullfsoftwarefcontrolfoverfeachf“pixel”f

(RGBfLED)fcolourfandfbrightness.

• DigitalfinterfacefandfdedicatedfPWMf

driverfICfforfeachfLEDfindividually.

• Nofneedftofbuildfafcontrolfcircuitforfwiref

allfthefLEDsfyourself.

• T
• fmakefitfwork:

– Connectfaf5fVfsupply.f(Checkfthis!)

• Carefulfthatfitfhasfenoughfpower!

– Connectfyourffavouritefmicrocontrollerf

tofthefdigitalflines.

– Downloadfafsuitablefsupportflibrary.

(Buyfafstripfthatfhasfone!)

– Modifyfandfprogramfanfexample.

• Arrangedfinfafmatrix,fthesefcanfalsof

displayfsimplefanimations.f(E.g.:f winkingfsmileyfface.)

https://www.adafruit.com/

16

WhatfisfPWM?

• Pulse-WidthfModulation.
• Thefratiofbetweenfonfandfoffisf

changedf(modulated).

– Expressedfinf%fdutyfcycle.

• Thefaveragefoffthesefpulsesfinftimef

resultsfinfanfin-betweenfvalue.

• IffthefPWMfratefisffastfenoughf(orf

fltered),fthefeyefdoesfnotfperceivef thefblinking.

• Theftechniquefisfusedfaflot:

– ClassfDfaudiofamplifers. – Motorfvariablefspeedfdrives. – LEDfdrivers. – Servofpositionfencoding.

17

Demo

18

Electro-LuminescentfLights

• Unique,fcool,falmostfbiologicalfglowfefect.
• Manyfdisadvantages:

– Highfdrivingfvoltagef(butflowfcurrent)fneedsf

specialfinverterf(90f–f150fVftypical)

– Needfanfinverterfwithfcontrolfinputfiffyouf

wantftofchangefbrightnessfinfsomefway.

– Onlyfonefspecifcfcolour. – Ratherfdim.fWillfonlyfworkfwellfinfthefdark.f

(Eg:fduringfdances)

• Wouldfsuggestflookingfinto:

– ELfsheetf→fLEDfstripsfunderftheffur,forfunderf

afdifuserfsheet.f

– ELfwiref→fSide-Emittingfplasticfopticalffbre

• Drivefitffromfafpowerfulf(fewfWatt)fRGBfLED
• Variousfthicknessfofffbrefexist.
• Cheap!f(SeefAlibaba,faboutf€1fperfmeter.)

–Lightfsourcef(calledfaf“lightfengine”)fisf

extra.f3fWfversionsfarefinexpensive.

19

SomefOpticalfTricks

• ForfmorefevenfLEDflighting

– RunfmultiplefLEDfstripsfinf

parallel,fwithfafhalffLEDf spacingfofset,fforflargerf areas.

– Usefanfopticalfdifuser

• Privacyfwindowfflm.
• Thin,ftranslucentffoam.
• Frostedfplexiglass.
• Realfdifuserfflm.
• Forftinyfpointsfofflight

– 1fmmfplasticfopticalffbref

(POF)fisfinexpensive.f

– Joinfseveralfstrandsftofaf

brightfLED,forfusefafrealflightf enginefdriverfmodule.

– Feedfthefotherfendsftofwheref

youfwantflights.

– Jacketedfandfnon-jacketedf

POFfexists.

– Idea:fglowingfwhiskers!

20

SomefOpticalfTricks

• Illuminatingflargerfareas

– Useflensesfiffyoufcanfsparef

thefdepth.

– Usefafdifuserftofgetfanf

evenly-litfarea.

– Stencilsfcanfbefincorporatedf

intofthefopticalfpath.

– Usefafrayftracer.fThisfletsfyouf

testflensesfbeforefbuying.

https://arachnoid.com/OpticalRayTracer/

• Complex,fstaticfshapesfusingfdecal

– Printfonfoverheadfprojectorf

transparencyfflm.fOrfcutfoutfaf shapeffromfsomefopaquef material.

– Afdifuseflightfsourcefwillfmakefaf

bigfdiference.

– Projectingfontofafdifuserfwillfalsof

work.

– Idea:fglowingftattoofunderffur!

21

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

22

BeepsfandfBoops

• Simplefsquare-waveftones.

– Vintagef8-bitfsound. – Yourfmicrocontrollerfcanfdofthis! – But:flimitedfrangefoffexpression. – Plentyfoffexamplesfon-line,fmodifyf

asfneeded.

• Dofnotfjustfattachfafpiezofelementf

asfshownfinfmostfon-linefexamples.f

– Needsfaffewfextrafpartsftofprotectf

yourfMCUfI/Ofpinfandfthefpiezo.

– Notfloudfenoughfforfperformance.

• Usefanfexternalfamplifer!

– Afveryfbasicfinterfacefcircuitftof

lineflevelfisfsuggestedfhere.

330R ~ok

23

Demo

Image creator unknown

24

Audio

• Whatfkindfoffaudio?

– Musicforfsoundfefects?f – Characterfvoicefwithfsqueaksforfwords?

• Overcomefmufedfcostumefvoices!
• Soundfsource

– Phoneforfsimplefportablefmusicfplayer. – Therefmanyfaudiofadd-onfboards. – AnfadvancedfMCUfcanfdofanything. – Considerfhowftofcontrolfthefaudio!

• Amplifer

– Buyfanfampliferfkitforftake-apartfsomef

battery-poweredfloudspeakers.

– Class-Dfinfbridgeftopologyfpreferred! – Makefsurefit’sfbothfthermallyfandf

short-circuitfprotected.

• Loudspeaker

– Criticalftofsystemfperformance!

https://www.adafruit.com/

25

LoudspeakerfSelection

• Withflowfbatteryfvoltages,fusefaf4f

Ohmfspeakerf(iffthefampliferfallowsf this).fItfwillfbeflouder.

• Checkftheffrequencyfresponse:ffull-

rangefisfpreferredfinfmostfcases.

• Checkfthefefciency!

– MeanfSPLfinfdBfatf1W/m. – Youfwantfitfhigh,fbutfwithoutfbigf

peaksfinfthefresponse.

• Checkfthefpowerfrating.

– Sameforfhigherfthanfyourfamplifer.f – BewarefthefdiferencefbetweenfRMSf

(music)fpowerfandfratedf(peak)f power.

• Iffthefmanufacturerfisn’tftellingfyouf

thesefthingsfaboutftheirfproduct,fit’sf probablyfgoingftofbefbad…

26

LoudspeakerfDesign

• Allfloudspeakersfsoundfawfulfduef

toffront/backfcancellationfefects.

• Usefafsoundfboardforfproperlyf

sealedfboxfenclosure.

– Bothfmustfhavefsufcientfsizeftof

work.fAreaf/fvolumefmatters.

– Stuffboxesfwithfdampingf

materialsfforfbetterfbass.

– Boxesfmustfbefwellfsealed,fbutf

notfentirely.f(Ambientfpressuref equalisationfisfneeded.)f

• I’vefwrittenfmorefaboutfthisfinfthef

FlüüffBoardfOnefuserfmanual.f

– Youfarefwelcomeftofafpdffcopy!

www.robocow.be

27

Demo

This is what we’re building in the electronics workshop after this talk.

28

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

29

Motion!

Gmork - Acrylic painting by Bruce White

30

Fans

• Helpfkeepfyoufcoolfandfbreathfoutsidefair.
• MostfPCffansfrunfoff12fV.f5fVftypesfexist.
• Theflargerftheffan,fthefslowerfitfcanfspinf

forfthefsamefairffow.

– Tinyffansfsoundflikefhornetsfonfspeed.f

Thisfcanfbefaudibleftofyourfaudience.

– Therefarefveryfquietftypesfonfthef

market.fCheckfthefdBfratings!

• Speed-controlledffansfcanfbefuseful:

– Lessfbatteryfdrainfwhenfslower. – Lessfnoisefwhenfslower. – Canfstillfaccessffull-blastfwhenfneeded.

• Don’tfforgetfaboutfprotectivefgrills!
• Mostffansfarefaxialffans.fHigherfpressuresf

canfbefhadfwithfcentrifugalftypes.

http://www.ebmpapst.com/

31

ServofMotors

• Motorfwithfafreductionfgearftrain,fdriver,fandf

angularfpositionfsensor.

– Lotsfofftorque,fbutfnotfthatffast. – Don’tfover-stressfthemforfyou’llfbreakf

gears.

• Addfspringsfandfreleasefsystemsftofyourf

mechanismftoftakefoverloads.

• Metalfgearsfarefstronger.

– Quitefnoisy.

• Mostfaref5fVfcompatible.

– Verify,fasftherefarefvariations. – Therefarefaffewfvariationsfonfthef

connectionfplugsfasfwell.

• Localffeed-backfallowsfforfaccuratefangularf

position,fvelocityfandfaccelerationfcontrol.

– ControlfisfviafafPWMfpulseftrain. – However,fnofreporting-backftofMCUfoffthef

actually-achievedfangle.

• Costumingfidea:fmakefyourffacialfexpressionf

changeable! Images: www.robotpark.com

32

LinearfMotors

• AfordablefunitsfarefDCfmotorsfwithfaf

transmission.

– Veryfstrong,fbutfalsofveryfslow.

• Usefulfforfactuatingflarge,fheavyfcostumef

features,fsuchfasfwings.

• MostfhaveflargerfDCfmotorsfinside.f

– Drivefthemfusingfanf“H-bridge”fdriver,forf

afmanualfreversingfswitch.

– Useflimitfswitchesfiffyoufdon’tfneedfthef

fullfactuatorftravel.fTherefisfaflotfoffforce!

• Therefarefsmall,fRCfservo-typefunitsfoutf

therefthatfwillftakefafPWMfpositionfandf havefthefdriverfbuilt-in.f(E.g.fActuonix)

– Usefulfforfsmallffeatures,fsuchfasfearsf

andftailfwags.f(Iffyoufcan’tfusefregularf servos.)

• Makefsurefnofbodyfpartsfgetftrapped!

33

PositioningfAccuracy

• Mostfmotorsfprovidefnofpositionforfanglefinformation.
• Stepperfandfservofmotorsfareffeed-forwardfsystemsftofthefMCU.

– Steppersfarefblindffeed-forwardfsystemsfandfmissedfstepsfarefnotfrecoveredffrom.f – RCfservosfwill,fiffpossible,fachieveftheirfintendedfpositionfdueftoflocalffeed-back. – Bothfmayfneverfactuallyfachievefthefcommand.f(Notfenoughftorqueftofmove,f

transmissionflinkagefslip,fetc…)

– Wrongfassumedfpositionfmayfcausefthefmechanismftofbefover-drivenfandfbroken! – Orfyoufjustfend-upfwithfyourfanimatronicsfinfafsillyfstate...

• Iffyoufwantftofknowfthefactualfposition,fyoufhaveftofaddfsensorsftofyourfMCUfandf

linkfthemftofthefmechanism.

– End-of-runfswitches.f(Basicfprotectionfandfpositionfcalibration.) – Digitalfencoder.f(Bothfabsolutefandfrelativefoutputfexists.) – Analogfpotentiometer.f(Bestfusefafspecialftypefforfthis.) – Capacitive/magnetic/opticalfdistancefsensors.

34

Motorsf–fGeneralfIssues

• Motorsfneedfmuchfpowerfandfhaveftofbefdrivenffromfafdedicatedfpowerf

stage.f

– Somefmotorsfhavefthisfbuilt-in.f(e.g.:fcomputerffans,fRCfservos)

• Voltagefstabilityfonfthefpowerfbusfcanfsuferfdueftoflargefpeakfcurrents.

– Thisfcanfcrashfthefmicrocontrollerfandfmessfwithfotherfdevices. – Knowfthefdiferencefbetweenfrunningfcurrentfandfstart/stallfcurrent.

• Motorfcoilsfcanfgenerateflargefback-EMFfpulses.fCommercialfdriversfaref

protectedfagainstfthesefwithfdiodes.f(Don’tfforgetfthisfiffyoufrollfyourfown.)

• MotorsfwithfbushesfcanfgeneratefaflotfoffEMIf(interference).f

– Thisfcanfgetfintofyourfaudiofsystem.f – Filterfcapacitorsfmayfbefneededfonfthefmotor.

• Therefarefmanyfkindsfoffmotors,feachfwithfdiferentfdrivingfrequirements.

– Buyfthefappropriatefdriverfmodulefforfyourfmotor. – Makefsurefitfhasfshort-circuit/over-current,fandfthermalfprotection!

35

Demo

36

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

37

Interaction

?

Not a whole lot has been done with interactive costumes yet...

38

Switches

• Simplestftypefoffsensor:

– Onforfof. – But:ftheyfbounce...fAflot!

• Usefsoftwarefdebounce.
• OrfafspecialfIC.f

(E.g.:fMC14490,fMAX6816)

• SimplefRCfsolutionsfdon’tfworkf

well,fevenfiffrecommendedf everywhere.

• InterfacefwithfanfMCUfisfeasy:fpull-

upfresistorfandfswitchftofgroundf (plusfaflittlefextra).

– Thisfinverts,fjustfswap-backfinf

software.

– Makesfwiringfmorefnoisefimmune!f

(Usefshieldedfwire.)

39

ResistivefSensors

• Inexpensivefforce,flight,ftemperature,f

anglefandfpositionfsensorsfavailable.

• Needftofconvertfresistanceftofvoltagef

forfthefanalogfADCfinput.

– Resistivefdividerfisfeasiest.

• Potentiometersfareftheirfownfdividers.f
• Placefsensorfinfground-sidefoffdivider:

– Canfeasilyfusefshieldedfcablefforf

betterfnoisefimmunity.

– Mayfneedftoffipfdirectionfinf

software.

• Thesefsensorsfarefoftenfnotflinear.f

– Look-upftablefwithfinterpolation. – Correctingfequation. – Ignore.fQuitefoften,flinearityfnotf

important.

40

CostumingfIdeas

• Nosefthatfactuallyfboops.
• Colouredfspotsfthatfchangeflightingfcolourfwhenfaudiencefpokesfthem.
• ControlfLEDfbrightnessfbasedfonfambientflightflevelf(sofphotographsfdof

notfoverexpose).

• Managefcostumefefectsfwhilefperforming.

– Controlfsoundsfandfaudiofplay-back. – Controlfofffacialfexpression.

• Hiddenfsensorsftofsetffeaturesfoffyourfownfcostumefwithoutfbreakingfthef

magic.f(E.g.:fmagneticfswitchesfinfstrategicflocationsf&fmagnetfinfglove.)

– Controlfventilationflevel. – Controlfaudiofloudness. – Controlffacialfexpression. – T

urn-off(orfatfleastfreduce)flightsf&fsoundsfwhenfsittingfinfanfaudience.

41

SightsfandfSounds

• Control

Arduinofandftheflikes

• Sights

LEDsfandfelectro-luminescentffoils

• Sounds

Beepsfandfaudio

• Motion

Fans,fmotors,fandfservos

• Interaction

Buttonsfandfsensors

• Power

Sourcesfandfconversion

42

PowerfSources

• Batteries

– Batteriesfarefdangerousfthings! – LiPofbatteriesfarefespeciallyfdangerousfthings!

• NEVERfUSEfNAKEDfLiPofCELLS!fTheyfneedfspecialf

precautions.f(DiscussedfinfSafety.)

• Proposal:fusefgood-qualityfUSBfpowerfbanks.fThesef

arefencased,fprotectedfLiPofcellsfandfmuchfsafer.

– Issue:fonlyf5V,f1forf2fAf(thus,f5forf10fW). – Iff5forf10fWfisn’tfenoughftofrunfyourfsuit,fandfyouf

can’tfsplitfthefload:

• ProtectedfLiPofpackfinfsuitablefLiPofbatteryfbagf

andffre-wallf+fotherfsafetyfmeasures.

• NiMH,fLiFePO4,falcaline,fPbfgellfcells.
• Alwaysffusefanyfnon-protectedfbattery!
• DC/DCfconverters.

– ThesefwillfefcientlyfconvertfandfregulatefDCf

voltagesftofotherfDCfvoltagesf(neff>0.8).

– “Buck”fconvertsfdown,f“boost”fconvertsfup. – Thinkfpowerfin,fpowerfout.

• 5Vfff1Af=f5Wfffinf→f12Vf0.4Af=f5Wfffout.
• 12Vf1Af=f12Wfinf→f5Vfff2.4Af=f12Wfout.
• Pf=fUf*fIf(ignoringflosses)

43

CostumefPower

• Thinkfoffhowfmuchfpower,fhowflong.fThinkfinfWattsffrst,fthenfconvertftofAhf

tofselectfthefbattery.

• Plan-outfyourfpowerfsystemfandfsuitfcomponents.

– Tryftofreducefthefnumberfoffdiferentfsupplyfvoltages. – Thinkfoffhowfthefwiringfwillfrunfinfthefsuit,fandfwhereftofplacefconnectorsf

(E.g.:ftoftakefthefheadfoffforfbreaks.)f

• Avoidfhavingfseparatefbatteryfpacksfforfeveryfsinglefthing.

– Whilefaftotalffailurefwillfbeflessflikelyfwithfdistributedfpower,... – Managingfthisfisfaflogisticsfnightmarefandfgettingfitfwrongfwillfresultfinf

partialffailuresfwhilefperforming.f(Arefallfthefcellsffresh?fDofIfhavefallfthef variousfAA,fAAA,f9Vfcellsfwithfme?fHowflongfdoesfeachfgizmoflast?)

– Youfneedftoftakefbreaks,fusefthisftofswapfbatteries.fIffitfisfjustfthefonef

powerfbank,fthisfisfafno-brainer!fHavefanotherfonfafcharger.

• Makefsurefthefbatteryfisfeasilyfswappablefandfejectable.f
• SeefthefsectionfonfSafety!

44

Content

• SightsfandfSounds

Howftofaddffunfgadgetsftofyourfcostume

• Reliability

Howftofkeepftheffunfgoing

• Safety

Howftofstayfaliveftoftellfthefstory

45

ThefCostumefEnvironment...

• Isfafharshfmistressfindeed!

– Constantfmotion. – Regularfhigh-velocityfimpacts. – Lotsfoffwireffexing. – Highfhumidity. – Chargefbuild-upfonfsyntheticfeverything.f

(Untilfthefhumidityfkicks-in...)

• Consumerfgoodsfarefnotfdesignedfforfsuchfabuse…
• Herefarefsomeftipsftofimprovefreliability!

46

EnclosuresfandfPCBs

• Putfyourfelectronicsfinfafprojectfboxf

andfsecurefeverythingfproperly.

– Firstflinefoffdefence. – Willfkeepfthingsffromfshortingfout,f

beingfcrushed,forfgettingfloose.

– Givesfyoufafbaseftofattachf

connectorsfandfstrainfrelieffto.

– Helpsfkeepfsweat,fbeer,fcoinsfandf

keysfoutfoffthefcircuits.

• Don’tfusefbreadboards!fSolderf

everythingfonfafsolderboard!

• Seriously,fthisfisfafbasicfminimum!
• Makefthefboxfbigfenough.
• Hot-gluefnon-lockingfconnectors.

47

ConformalfCoatings

• Condensationfcanfcausefproblems:

– Partialfshortsfresultingfinfrandomfbuttonf

presses,fsensorfreadings,fMCUfissues...

– Long-termfelectrolysisfdamage. – Fungalfgrowth.

• Cleanfthefboardfafterfsoldering.

– Thisfwillfhelpfreducefconductivityfandf

• xidationfissues,fasfsolderffuxfisfaggressivef

andfcanfbefre-activatedfbyfmoisture.

– Preferablyfusef“safewash”fasffuxfremover. – Followfthefmanufacturer’sfinstructions!

• Whenfboardfisfcleanfandfdry,fapplyfthef

coating.f

– Afpossiblefalternativefisfclearfpolyurethanef

varnish.f(Butfnofguarantees!)

– Carefulfnotftofcoatfswitches,fconnectors,forf

anythingfelsefthatfhasftofmakefcontactforf move.

– T

ape-offsuchfareasfwhenfspray-painting,forf justfusefafbrushftofapplyfthefproduct.

– CoatfbothfsidesfoffthefPCB!

48

ProperfConnectors

• ArduinofpinfheadersfarefmeantfforfSQUAREfpins,f

notfROUNDfwires.

– Sofwhyfdoesfeveryonefkeepfdoingfthis?fItfisfnotf

reliable.f(Andfprooffthatftheyffailedfkindergarten!)

• Afconnectorfmakesfafgas-tightfunionfbetweenftwof

metalfsurfaces.

– Thisfisfwhatfkeepsfthefconnectionffromfoxidizingf

andfbecomingfunreliable.

– Matingfthefconnectorfalsofscrapes-off

contaminantsffromfthefsurfaces.

– Iffthefsurfacesfdofnotfmatefwell,fwithfthefrightf

shapefandfcontactfpressure,fthefcontactfwillffailf soonerfratherfthenflater.

– Metallurgyfmatters:fDofnotfbuyfAufoverfCu,fbutf

Au-Ni-Cu.fThefnickelfbarrierflayerfisfimportant!

• Connectorsfcostfmoney.fButftheyfhelp:

– Managefthefunitsfinfthefsuit. – Insurefreliablefconnections. – Makefmaintenancefsimpler.

• Wirefthemftidilyf(usefheat shrink!)
• Usefdiferentf#fpinsfandfgenderftofpreventfwrongf

connections.fChoosefgenderfsofpowerfplugsfcanf notfshortf(femalefpinsfonfthefbatteryfside).

49

JoinsfWiresfProperly

• Wirefjointsfarefoftenfpoorlyfmade,f

andfcausefintermittentffaults.

• Alsofanfimportantffrefhazardfwithf

high-currentfcircuits!

• Usefafsolderedflinemanfsplice.

– Willfalsofworkfwithfstrandedf

conductors.

– NASAfapproves!f(P

.f71) NASA-STD-8739.4Af–f2016-06-30

– Thisfdocumentfshowsfeveryfotherf

methodfasfwell,fandfhowftofdof them.fAfveryfusefulfmanual.

• Useftwoflayersfoffheatfshrink!

50

StrainfRelief

• Wirefconnectionsfwillfbreakfwhenf

repeatedlyffexedfoffpulled.

• Tinnedfwiresfbreakfveryfeasily.

– Don’tftinfwiresfforfusefinfscrewf

connectors,fusefwirefendfferrulesf instead!

• Strainfrelieffisfveryfimportantfforf

reliability.

• Usefcablefglands,forfthefstrainf

relieffintegratedfinfthefconnectorf housing.

• Simplyfsecuringfafwirefaflittlef

distanceffromfafsolderfjointfwithfaf nylonfcableftieftofafsupportfwillf alsofhelpfaflot. Solder Screw

51

WirefHarnesses

• Nofmysteryfconnectionsfandfrandomfwiresf

thatfgetfpulled-loosefduringfperformance.

• Thinkfoffthefdevicesfandfwiresfinfyourf

costumefasforgansfandfthefmammalianf nervousfsystem.

– Layfitfoutfasfsuch,fasfanfintegralfpartfoffthef

costume.

– Thinkfoffhowfyoufwillfmovefandfbend. – Thefbrainfmayfnotfbefinfthefhead!

• Also,fthinkfoffhowftoftakefitfallfoutftofwashf

yourfcostume!

– Afwiringfharnessfwillfmakefthisfeasy:fallfthef

wiringfbecomesfonef“thing”,fwithfthef variousfdevicesfconnectedftofitfviaf separablefconnectors.

• Spiralfwrap,fcorrugatedfwiringfharnessftubes,f

nylonfwovenftubes,felectricalftape,fetc…f Therefarefmanyfproductsfonfthefmarketftof makefafnicefharness.

• Keepfitffexiblefandfexperimentfbeforef

committingftofaftechnique.

52

ESDfProtection

• Youfcanfeasilyfgeneratef20fkVfandfmore,f

justfbyfshufingfoverfafcarpet.

– Whilefdry,faffursuitfisfanfambulant,ffufyf

electrostaticfgenerator.

• Manyfcomponentsfhavefsomefprotectionf

againstfElectro-StaticfDischarge,fbutfnotf enough.

• UsefextrafESDfprotectionfonfanyfMCUfpinf

thatfconnectsftofoutboardfwires,fforfbothf analogfandfdigitalfpins.

• Thisfisfafcomplexftopic!fOnlyfafbasicf

protectionfisfshownfhere,fusablefforfMCUf digitalfandfanalogfpinsf(0ftof5fVfrange).

– Thisfisfnotfcomprehensive,fbutfwillfhelp. – SimplefprotectionfusingfafTVSfdiodefandf

thefESDfdiodesfbuiltfintofthefchip.

– Seriesfresistorfalsofhelpsfagainstfoutput-

to-outputferrorsfandfaccidentalfshorts.

– Rxfdependsfonfthefapplication.f1Kfwillf

• ftenfworkffne.

53

PowerfBusfDecoupling

• Sourcesfhavefaffnitefimpedancefand/orf

arefcurrentflimited.

– Loadfchangesfhavefanfefect. – Heavyfloadf(peaks)fcanfde-stabilizef

yourfpowerfbus.

– Motorsfandfaudiofamplifersfarefthef

usualfcause.

• Voltagefdipsfandfgroundfpotentialfswingsf

canfcrashfyourfMCUforfdisturbfotherf digitalfdevices.

• Decouplefthefsupplyftofsensitivefdevicesf

(MCU)ffromfthefpowerfbusfwithfaf Schottkyfdiodefandfaflocalfbuferf capacitor.fThisfisfoftenfveryfefective.

• Starfgroundingfisfalsofusefulftofkeepf

groundfpotentialfswingsfinfcheck.

• Addingfafbigfcapacitorf(e.g.:f1000fµF)fatf

thefpointfoffafheavyfloadfcanfalsofhelp.f (Butflargefin-rushfcurrentfatfstart-up!)

54

Content

• SightsfandfSounds

Howftofaddffunfgadgetsftofyourfcostume

• Reliability

Howftofkeepftheffunfgoing

• Safety

Howftofstayfaliveftoftellfthefstory

55

SafetyfRisksfoffAddingfGadgets

• Thefrisksf(non-exhaustive)f

discussedfinfthisfsection:f

– Electrocution – Fire – Mechanical

56

SafetyfRisksfoffAddingfGadgets

• Thefrisksf(non-exhaustive)f

discussedfinfthisfsection:f

– Electrocution – Fire – Mechanical

57

Electrocution

• Thefriskfisfaflethalfvoltagefappearingfonfthefcostumefelectronicsfdueftofaffaultyf

powerfsupplyforflightningfstrike.fAsfyoufarefwearingfthem,fyoufcannotfdisengage.

• Thefriskfoffhighfvoltagesfisfalsofpresentfthroughfotherfelectricalfconnections.

(Suchfasfphoneflines,fnetworkfcables,faudio/videofsystems,fetc…)f

• Simplefmitigation:fBatteries Only!

– Nofmains-poweredfenergyfsourcefisfallowedfwhilefwearingfthefcostume.f

Thus,fnofadapters,fchargers,fbenchftopfpowerfsupplies,fetc...fmayfbefin-use!

– Nothingfmayfbefconnectedftofanythingfthatfisfnotfexclusivelyfbatteryfpoweredf

itselffandfisolatedffromfoutsidefsystems.

– Nofelectricalfconnectionsftofoutsidefsystemsf(suchfasfphoneflines,fnetworkf

cables,faudio/videofsystems,fetc…)farefallowed.f

– IffyoufneedftofsendfaudioftofthefDJ/PAfsystem,fusefafwirelessfapproachf(e.g.f

Bluetooth),forfhold/stickfafmicrophonefinffrontfoffyourfcostumefloudspeakers.

• CarefulfwithfCCFL/ELflightingfandftheirfinverters.fCurrentsfshouldfbeflowfenoughf

tofbefsafe,fbutfemployfgoodfelectricalfsafetyfpracticesfasfnothingfisfguaranteed.f Also:fRFfburnsflastflongfandfhurt.

58

SafetyfRisksfoffAddingfGadgets

• Thefrisksf(non-exhaustive)f

discussedfinfthisfsection:f

– Electrocution – Fire – Mechanical

59

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

60

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

61

ElectricalfFire

• Over-heatingfdueftofshorts,foverloads,fpoorfcooling,fcomponentffailures,fetc...

– Componentsfcanfoverheatfandfburn,fevenfatflowfcurrents. – Wiresfcanfoverheatfandfcauseftheirfinsulationftofcatchffre. – Sparkingfisfalsofpossible.

• Thesefheatfsourcesfcanfignitefcombustiblefmaterialsf(suchfasfwirefinsulation,fcostumef

materials,fyourfhair,fetc…)

• Fusesfarefyourffrstflinefoffdefence,fbutfnotfsufcient!f(Fusingfisfanfadvancedftopic!)

– Batteryffusesfgofrightfatfthefbattery,ftofprotectfthefwiringffromfcatchingffre.

• Keepfdevicesfawayffromfcombustiblefmaterials.

– Usefconnectorsfwithfshells. – Enclosefyourfelectronicsfinfprojectfboxes. – Usefstructuralfsupportsftofkeepfcostumefmaterialsfawayffromfelectricalfparts. – Installfnon-combustiblefandfthermally-isolatingflayersfiffnecessary.

• Workfcleanly!

– Usefheatfshrinkftofisolatefthings. – Makefproperfwirefjoints.f(Solderedf“linemanfsplice”,fdoubleflayerfheatfshrink.) – Usefmaterialsfratedfforfthefintendedfuse.f(Observefcurrentfratings,fvoltagefratings,fetc...)

62

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

63

BatteryfFire

• Considerfallfbatteriesfasfdangerous.

– Highfshort-circuitfcurrentsfcauseffre,fbatteryfover-heating. – Hotfchemicalsfcanfventfout,forfresultfinfafchemicalffre. – H2fisfafcommonfby-productfoffoverheatingfcells... – Batteryffusesfarefonlyfaffrst-linefoffdefence.

• WithfLiPo,fonlyfusefprotectedfcells,fandfshieldfthemffromfmechanicalfharm.f
• MuchfpreferredfarefgoodfqualityfUSBfpowerfbanks.
• LiPofchemistryfcanfexperiencefthermalfrunawayfatfanyftime…
• ALWAYSfkeepfanyftypefoffLiPofcellfinfafLiPofexplosionfandffre-prooffbag!f
• KeepfthefbagfEXTERNALftofyourfcostume!
• Makefsurefyoufcanfeasilyfdetachfthefbagf(pull-freefconnectorfonfthefwire)!
• Useffrewallfstructuresf(e.g.fNomexflayers,fmetal,fetc...)

64

BatteryfFire

65

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

66

MaterialsfFlammability

• Mostfcostumefmaterialsfarefpolymersforfpolymerfblends.

– Nylon,fspandex,fpolyester,fpolycotton,ffoams,fresins,fglues,f... – Manyfhaveflargefsurfacefareasf(imitationffur,ffeece). – Stufngfisfoftenfpolyurethaneffoam.

• Allfthesefmaterialsfignitefeasilyfandfburnfexceptionallyfwell.f

– Somefemitftoxicffumes. – Manyfalsofmelt.f→fThisfisfveryfbadfnewsfforfburnfwounds!

• Flamefretardantsfarefoffvitalfimportance!

– Theyfmakeftheffrefself-extinguishfandfkeepfitffromfspreading.

• Howfdofyoufknowfiffyourfcostumefisfproperlyftreated?

– Onlyftwofpracticalfways:

• Havefthefmaterialfinformationfforfeveryfpartf(tofwhichfstandards).
• T

estfeachfmaterialfwithfafgasf(butane/propane)ftorch.f(Outside,fandfhavefmeansftof extinguishfaffrefatfhand.)fTheffrefshouldfstopfwhenftheffamefisfremoved.

– Bestftoftestfsamplesfoffallfthefmaterialsfused.

• But,fnofguaranteefthatftherefwon’tfbefmaterialfandfstructurefinteractions.
• Bewarefoffthefweakestflink!fOffonefmaterialfburnsfwild,fthefwholefcostumefisfunsafe.

67

MaterialsfFlammability

68

MaterialsfFlammability

• Initialfmaterialfconclusions:

– Goodfqualityffurfappearsfproperlyffamefretardant. – Cheapffurfdefnitelyfisfnot! – Foamsfarefafproblem.fYoufmustfdefnitelyftestftheffoamfinf

yourfcostume!

• Don’tfwearfnormalfunderclothes!

– Theyfburnfandfmeltfintofyourfskin. – BuyfNomexf(andfsimilarfmaterials)! – Gofshopfatfmotorsportsfplaces,fthey

havefthisfstuffforfdriverffrefsafety.

• Firesfseemftofbuildfslowlyfwithfgood-qualityfmaterials.f

Therefisfsomeftimeftofextinguishforfescape.

69

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

70

Escapability

• You’refonffrefandfcan’tfputfitfout.fTherefareftoxicffumesfbuilding-

upfinsidefthefcostume.fNowfwhat?

• Designfthefcostumefsofitfcanfbefescaped!f

– Accessftoffreshfair!f(removablefheadfpiece?) – Quickfegressffromfthefcostume!

• Noffddlyfthings.fYoufhaveftofgetfoutfinfseconds,fevenfwhenf

panicking.

• Yourfunderclothesfmayfnotfcatchffreforfmeltfasfyoufdofthis!
• ConsiderfVelcrofescapefseams,fanfescapefknifefthatfyourf

handlerfcarries,fripablefseams,fetc…

• Canfyoufquicklyfdisposefofflargefcostumeffeaturesfduringfanf

evacuation?f(E.g.:fwings.)

• Havefafplanfandftestfit!

71

Fire

• Electricalffre
• Batteryffre
• Materialsffammability
• Escapability
• Fireffghting

72

FirefFighting

• Thefgoodfnews:fmostfofftheffrefhazardsfmentionedfarefeasilyfextinguished.

– Small,frechargablefLiPofbatteryffresfcanfbefextinguishedfwithfwater. – Mostfoffthefotherfmaterialsfarefalsofreadilyfextinguishfwithfwater.

• Whenfonffre:

– STOPf–fDROPf–fROLL – Dofnotfrun!fYoufmayfhaveftofbringfafpersonftofthefgroundfifftheyfarefpanickingf

andfrunningf(legfsweep).

– Havefthefusualffreffghtingfdevicesfonfhand:

• Water
• Firefblanketsf(yourfhandlerfcanfcarryfthese!)
• Firefextinguishersfarefafmixedfbag.fYoufarefaimingfatfafperson...
• Water-basedfisfbest!
• CO2,finfafpinch,fbutfnotfonfthefskinforffacefdueftofcooling!fSufocationfhazard!
• Powder:fDofnotfuse!fVeryfirritatingftofmucousfmembranesf(lungs!)
• Dofnotftakefclothesfthatfhavefalreadyfburnedfoffunderfanyfcircumstances.fCoverf

burnedfareasfwithfsterilefcotton.

73

SafetyfRisksfoffAddingfGadgets

• Thefrisksf(non-exhaustive)f

discussedfinfthisfsection:f

– Electrocution – Fire – Mechanical

74

Mechanical

• Actuatedfmechanismsfcanfgetfbodyfpartsftrappedfinfthem.f

Yours,fandfyourfaudience!fMindftiny,fcuriousffngers!

– Forcesfcanfbefhigh,fedgesfsharp…

• Bewarefofflongfhair,fscarves,fetc…fgettingfcaughtfonf

spinningfaxlesf/ffans.

• Makefsurefthatfeachfdangerfareafisfappropriatelyfshielded.
• Sharpfstructures:fbothftofyourfaudiencefandfyourself:fwhatf

iffyouffall-downfinfyourfsuit.fIsftherefanythingfthatfcanf impalefanyone?f(E.g.:fscrews,fhorns,fclaws,fspikes,fetc...)

• Areftherefthingsfthatfcanfgetfyoufentangledforfstrangled?f

(E.g.:fwires,fropes,fetc…)

75

Safety:fWrap-Up

• Thefimportantfrisksfarefquitefeasilyfmitigated.
• But,fyoufhaveftofconsiderfyourfcostume,fitsf

materials,fandfusagefcarefully.

• Therefwillfbefsomeflimitations.

– Beingfcreativefmeansfworkingfbothfwithfandf

aroundfthoseflimitations!

– Usually,ftherefisfafknownfsolution.

• Don’tfpinchfpennies!

– Dofitfwell. – Scale-downfthefambitionfuntilfyoufcanfdofitfwell.

76

ThefEnd!

• Manyfcoolfcostumefideasfarefleftf

unexplored.fThisfisfthefwildffrontier!

• Dofthemfwellfandfit’llfbefsafefandf

fun!fIt’sfnotfhard,fandfhelpfisfaround!

• But,foffcourse,ftherefarefSofManyf

DumbfWaysftofDiefnotfdiscussedfinf thisftalk…fOverftofyou,fMetrofTrains!

77

DumbfWaysftofDie!

“Dumb Ways to Die” PSA by Metro Trains, Melbourne, Australia