GACDLMaterials:

TheIntoxilyzer9000ThomasEWorkmanJr.

Introduction:TomWorkmanisanattorneyandexpertonbreathtestingmachines.Hehas testified extensively in Georgia. He recently undertook a technicalreview of the Intoxilyzer 9000, working with Bubba Head and JanSemenoff. As a result, bothheand Jan Semenoff cannowovercome thegovernment’s objections based upon lack of experience with thisparticularmodelIntoxilyzer.Tom’sCVcanbeobtainedfromhiswebsite,whichis:HTTP://WWW.COMPUTERS-FORENSIC-EXPERT.COM/CV.PDFThomasWorkman120IngellStTaunton,MA02780Thomas.e.workman@verizon.net1(508)822-7777

Topicsofdiscussion:1. Radiofrequencyinterference2. Electronicinstability3. Breathexhaustissues4. Touchscreeninstability

Article©2017ThomasE.Workman,Jr.Photographs©2017CounterpointJournal(PhotographsbyJanSemenoff&TomWorkman)

Radiofrequencyinterference

The detector circuitry consists of two sets of circuits, one on themotherboardandtheotheronaseparatesmallcircuitboardtowhichaflexibleantennaisattached.Thisdevicedoesnotusetheheaterwireasanantenna,aspreviousmodelshademployed.

Figure1-TheantennaecircuitboardinsidetheIntoxilyzer9000.

Thesensitivityofthedetectorisadjustedwithavariableresistor,calledarheostat(showninthephotoabove–thewhitecubewithanorangedotofsealantpaintonit).Thisislocatedonthesmallcircuitboard,andappearstobeafactorycalibratedfeature.Therheostatissealedwithadabofsealant,sothatit isnotfieldconfigurable. Thelidofthedevicehasattachedtoitatapesealthatbearsinstructionsthat ifbroken,thewarrantyisvoided.

Testing with a cellphone, RFI is only reported when the cellphone isapproximately two inches from the antenna, located on the left sidetowardtherearoftheunit. Readingsareeffectedwhenacellphoneislocatedinotherpositions,buttheRFIdetectioncircuitryiscalibratedtonot detect a cellphone that is close to the device, unless it is withininchesoftheantenna.

Figure2-Theantennaeislocatedunderneaththemanufacturer'slabelontheleftsideoftheIntoxilyzer9000.

TheRFIdetectionmechanismshouldbecalibratedtodetectcellphonesandotherelectronicradiodevicesthatarewithinfeetofthedevice,notinches. The failure to properly configure the detector renders itessentiallyineffective.

Electronicinstability

In order to develop a measurement, the Intoxilyzer 9000 mustsignificantly amplify the signal generated at the detector.Measurements are made relative to a ground signal, which must bestable, and a voltage supplied to the components in the amplificationcircuit,whichalsomustbestable.

Figure3-ThetestpointsonthemotherboardoftheIntoxilyzerModel9000.

Themotherboard of the I9000 has a set of test points (shown above,circledinred)designedtopermitthemonitoringofthevariousvoltagesused by the electronic circuitry. By utilizing an oscilloscope and aprobe that touches the pads designed to permit monitoring of theessential signals on the board, the stability of the ground and 5 voltsupply was monitored. Both of these essential levels had significantnoise,orcontamination,thatwouldimposesignificantdifficultieswhencomponents were powered to amplify the signal developed by thedetectorswithintheI9000.Seetheoscilloscopeimageonthenextpage.

In monitoring the measurement made by the I9000 throughout thesample from a simulator, it was noted that large deviations werepresent in the value displayed on the screen, when in fact theconcentration supplied did not vary to cause the measurementvariances. Whentheairblankssuppliedair fromasimulator, theunitsimplykeptdrawingairuntilanacceptablesamplewasprovided.Ifthisphilosophy, selecting a point to report themeasurementwhich variessignificantly frommoment tomoment, thena reportedvalue canvarysignificantlyfromthepropervalue,andnoonewouldknow.

Figure4-OscilloscopedisplayshowinginternalnoisegeneratedbytheIntoxilyzer9000.

Anexaminationofthevarioussides,back,topandbottomoftheI9000revealsthattherearenoregulatorystickersplaceduponthedevice.AregulatorytickerwouldbepresentiftheI9000wascertifiedtobesafetooperatebyhumanoperators,e.g.anUnderwritersLaboratorysticker.

Breathexhaustissues

Onesourceofcorruptedmeasurementsistheintentionalblockingoftheexhaustbytheoperator. Whentheexhaustisblocked,traditionallybyplacingafingerovertheholethroughwhichthebreathisexhausted,themeasurementprocesscanbeinterferedwith.The Intoxilyzer 9000has amodification that prevents interference byusinganoperator’s finger toblock theexhaustport,highlighted in thered circle below. Thismodification features a steel platewith a holethat is aligned to be in line with the exhausted air, but is slightlyremovedfromthechassis,sothatiftheholeintheplateisblocked,aircanstillescapeintheareabetweentheplateandthechassis.

Figure5-theexternalexhaustportlocatedattherearoftheIntoxilyzerModel9000.

Unfortunately, a simple wooden pencil with a sharp point can beinsertedintotheexhaust,andthesameeffectcanbeachieved.Hadthehole in the plate been repositioned a short distance from the exhaustfrom the chassis, interference would have been extremely difficult toachieve.

Touchscreeninstability

Inoperatingtheunit,theselectionofinputonthetouchscreenprovideddifficultyinselectingoptionsorpositionsonthetouchscreen.Assumingthe unit was properly calibrated by CMI prior to shipment, and theobservation that the test sequence number was “2” when we beganworking with the unit, the I9000 has an unstable circuitry problemholdingcalibrationofthetouchscreenmechanism.

Figure6-ThetouchscreendisplayontheIntoxilyzerModel9000.Thedisplaywasdifficulttouseandneededcalibration.

Whenadevicefailstoholdcalibrationinoneareaofoperation,itcallsintoquestiontheabilitytoholdcalibrationinmoresophisticatedareasof operation, such as measuring the level of ethanol in the breathsample.SeeanupcomingarticleontheIntoxilyzer9000byThomasE.WorkmaninVolumeTwoofCounterpoint–TheJournalofScienceandtheLaw.