Argent OpenTracker User manual

OpenTracker
User’s Manual
PCB Revision 4





1. Introduction

TheOpenTrackerisasimple,low‐costamateurradiodataencodercapableofgenerating1200
or300baudAX.25packetsusingbothAPRS™andOpenTRACprotocols,aswellasPSK31text
beacons.ItcanbeconnectedtoaGPSreceivertoreportposition,courseandspeed,time,and
altitude,andwillalsoreporttelemetryfromitsonboardtemperatureandvoltagesensors.With
itsexpansionconnectorandeaseofreprogramming,thedevicecanbeadaptedtoawide
varietyoftasks.

Changes

PCBRevision4includessignificantchangesfromprevioushardwarerevisions.Whilethe
firmwarefeaturesandconfigurationoptionsremainthesame,thepinheaderconfigurationand
powerspecificationshavechanged.Revision4incorporatesalargervoltageregulatorcapable
ofsupplyingenoughcurrenttopowermanypopular5‐voltGPSreceiverswithoutrequiringa
heatsink.

Acknowledgements

TheOpenTrackerisfarfrombeingthefirstdeviceofitstype,andowesmuchtothosethatcame
before–inparticular,JohnHansen’sGPS‐EfirmwareanditsTAPRPIC‐Ehardware,Steve
Bragg’sHamHUD,andByonGarrabrant’sverysuccessfulTinyTrakseries.Lessonslearned
fromallofthesedeviceshavecontributedtothedesignoftheOpenTracker.TheOpenTrackeris
verysimilarinphysicallayouttotheTinyTrak3(inits‘trimmed’version),andidenticalin
connectorconfiguration,allowingenclosuresandcablestobeusedinterchangeably.Despite
theirsimilarities,though,thetwodeviceshaveverydifferentprocessorarchitectures,different
digital‐to‐analogconversionsystems,andentirelyunrelatedfirmware.TheSmartBeaconing™
algorithmusedbytheOpenTrackerwasoriginallydevelopedbyTonyArnerich,KD7TA,and
SteveBragg,KA9MVA.APRS™isatrademarkofBobBruninga,WB4APR.BrianRiley,N1BQ,
andKeriMorgret,N6TME,contributedtothismanual.
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Table of Contents
1.Introduction ............................................................................................................................................2
2.OpenTrackerAssemblyNotes .............................................................................................................4
3.ConnectorPinAssignments .................................................................................................................6
a.General ................................................................................................................................................7
b.ReceiveAdjustment ..........................................................................................................................7
c.TransmitAdjustment ........................................................................................................................7
d.LEDBlinkCodes ...............................................................................................................................8
e.ConfigurationProgram.....................................................................................................................8
f.Mainconfigurationwindow.............................................................................................................9
5.InstallingNewFirmware....................................................................................................................14
6.WeatherStationOperation .................................................................................................................15
7.TelemetryOperation............................................................................................................................ 16
8.OpenTrackerCircuitDetails...............................................................................................................17
TheoryofOperation............................................................................................................................ 18
AppendixA–TestProcedures ..............................................................................................................20
a.Measurements ..................................................................................................................................20
AppendixB–APRSsymboltables........................................................................................................21
AppendixC–CommonModifications................................................................................................. 23
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2. OpenTracker Assembly Notes

Table1–PartsList

Part Description Notes
 
U1MC908KX8MCUwithsocketReferencenotchfacesleft
U278M05VoltageRegulatorInstallfirst
U3LM335ZAligntosilkscreenoutline
R1,R710KresistorBrown‐Black‐Orange
R2220KresistorRed‐Red‐Yellow
R32.2KresistorRed‐Red‐Red
R41KresistorBrown‐Black‐Red
R53KresistorOrange‐Black‐Red
R66.8K*resistorBlue‐Gray‐Red
R8,R910KpotentiometerAlignpinstoholes
R1010MresistorBrown‐Black‐Blue
R1120KresistorRed‐Black‐Orange
JP110‐pinheaderSinglerow.100pins
C10.33uFcapacitorYellowwith“334”marking
C2‐C40.1uFcapacitorYellowwith“104”marking
C6,C718pFcapacitor“180”or“180j”marking
Q3,Q42N7000transistorAligntosilkscreenoutline
D1‐D21N914or1N4148diodeBlackbanddenotescathode
LEDRedLEDShortleadfacestowardR4
X1DB9Connector‐femaleLeftedgeofboard
X2DB9Connector‐maleRightedgeofboard
Y129.4912MHzcrystalBenddowntoPCBbeforesoldering
*A6.2Kresistor(Blue‐Red‐Red)maybesubstitutedforR6

TheOpenTrackerkitrequiresbasictointermediatelevelsolderingskills.Youwillneedalow‐
wattagesolderingiron,wirecutters,andsolder.Rosincoresolderisrecommended–neveruse
acidcoresolderforelectronics.

Reviewthepartslistandidentifythecomponentsyoureceived.Ifanyaremissingordamaged,
contact[email protected]forreplacements.Don’tworryifyourkitincludesextraresistorsor
otherpartsnotlistedabove–theseareprovidedformodificationsandalternateversionsofthe
kit.

U2isasurfacemountdeviceandshouldbeinstalledfirstforeaseofsoldering.Applyasmall
dropofsoldertoonepadandkeepitmeltedwhileyoualignthepart.Soldertheotherlegand
themetaltabatthetop,makingsurethatthesolderformsagoodjunctionbetweenthetaband
thecircuitboardforproperheattransfer.

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TheDB9connectorsshouldbesolderednext.Notethatthemaleconnectoris
installedontherightside,andthefemaleconnectorisinstalledontheleft.
Therestofthepartsmaybeinstalledinanyorder.

The16‐pinDIPsocketforthemicrocontroller,U1,isoptional,but
recommendedtofacilitatereplacement.ResistorR3isusedforPTTkeying
withcertaintypesofhandheldradios.Forotherradios,particularlymobiles
andKenwoodhandhelds,thisresistormaybeomitted.Seesection4formore
information.

Paycloseattentiontocomponentpolarity.DiodesD1andD2havetheircathodeendsmarked
withablackband.Thiscorrespondstothelineatthepointedendofthesymbolshownforthese
partsonthesilkscreen.TheLEDshouldhaveitsshortleadand/orflatedgeinstalledtotheleft,
facingD1.Themicrocontroller,U1,hasareferencenotchononeedgethatshouldfaceleftas
showninthediagrambelow.

TostraightenU1’spinspriortoinsertion,placeonerowofpinsonahard,flatsurface.Holdthe
ICbytheedgesandgentlyrollituntilthepinsreachthecorrectangle.Repeatfortheother
row,andinserttheICintoitssocketgently,makingsurethateachpinisalignedwithitshole.

Installalldiodesandresistorsvertically.Oneleadshouldbebentaroundparalleltothe
component.Forresistors,thebodyofthecomponentisinstalledoverthepadindicatedwitha
circleonthesilkscreen.

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3. Connector Pin Assignments

Table2–PinHeader1(JP1)
PinDesignatorNotes
JP1PTTInputorRelayOutSeenote#1
JP2Ground
JP3JumperUsuallyusedtoswitchconfigurations
JP4IRQSeeNote#2
JP5ADC0On‐boardtemperaturesensor
JP6ADC1On‐boarddividerprovides1/3Vin
JP7ADC2ExtraADCinputor1‐wiredatabus
JP8Vin 6.7to35VDC
JP9Vext (seeNote#3)
JP10+5VoltsDCOutputofregulatorU2

Note#1–JP1canbeusedforeitherPTTinputformicencoderoperation,orasarelaycontrol
outputifpowercontrolisenabled.Whenusedasarelayoutput,thepincanprovidenomore
than15macurrent.

Note#2–JP4pulledmomentarilytogroundwillforceanimmediatetransmit.

Note#3–IfJP8andJP9arejumperedtogether,pin4onconnecterX2(SerialPort)canbeused
tosupplyrawvoltage(Vin)toanexternaldevicesuchasaGPSreceiver,ortoreceivepowervia
aspeciallywiredcableassembly.JP9andJP10maybeconnectedtoprovideregulated5volt
poweronpin4.

Table3–DB9Female(X1)–RadioPort

Table4–DB9Male(X2)–SerialPort
PinFunction
1NoConnection
2DataIn
3DataOut
4Vext
5Ground
6NoConnection
7NoConnection
8NoConnection
9NoConnection
PinFunction
1AudioOut
2COR/SquelchInput
3PTT
4NoConnection
5AudioIn
6Ground
7Powerin
8PTTInput
9NoConnection
X2iswiredasDTEtoallowconnectiontoaGPSreceiverusingastandardcable.Anullmodem
cableisrequiredforconnectiontoacomputer.

Bydefault,theOpenTrackerexpectsGPSdatatobeinNMEA‐0183formatat4800baud.
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4. OpenTracker Setup and Operation

a. General
TheOpenTrackerradioconnector,X1,isidenticaltothatusedbytheKantronicsKPC‐3andthe
ByonicsTinyTrak3.Anycablethatwasmadetointerfacearadiotoeitherofthesedevices
shouldworkwithOpenTracker.BUXCommprovidesdetailedwiringdiagramsandpre‐
assembledcablesforawidevarietyofradiosathttp://www.packetradio.com/wiring.htm.

Mosthandheldradios(withthenotableexceptionofthosemadebyKenwood)assertPTTby
groundingthemicrophoneinput.ResistorR3isusedforthispurpose.R3shouldbeomitted
whenthetrackerisusedwithmobileradiosorwithhandheldsthatdonotusethismethodof
PTTkeying.Ifthetrackerwillbeusedwithbothmobileandhandheldradios,R3canbe
installedinthecableusedtoconnectthetrackertothehandheld.

TheOpenTrackerrequires6.7to30voltsDC.IfR11andR12areinstalled,theOpenTrackercan
measureandreportitsvoltageinputlevel.However,themeasurementrangeislimitedto6.7to
15volts.

PowermaybesuppliedatthreepointsontheOpenTrackerboard.Mostoften,itissupplied
throughpin7oftheradioconnector.Itmayalsobesuppliedthroughpin8oftheexpansion
header.Inaddition,ifajumperisinstalledbetweenpins8and9oftheexpansionheader,
powermaybesuppliedthroughpin4ofthedataconnector.

b. Receive Adjustment
TheOpenTrackercannotdecodeincomingpacketdata.Instead,itwatchesforaudioenergy
(voice,data,orstatic)toavoidtransmittingoverotherstations.Thesensitivityoftheenergy
detectisdeterminedbythetrimpotlabeled‘RX’.

Adjustthesquelchonthereceiversothatitremainsclosedunderaveragechannelconditions
withnosignalspresent.TurnRXpotentiometerallthewayupsothatitremainslighted,and
thenturnitbackdownuntilitstopsblinkingunderquietchannelconditions.

c. Transmit Adjustment
The‘TX’potentiometersetstheunit’stransmitaudiolevel.Tosetthislevelproperly,use
anotherradiotolistentotheunit’stransmittedpackets.Turnthelevelupslowlyuntilthesignal
doesn’tgetanylouder,andthenturnitbackdownuntilitgetsnoticeablyquieter.Continue
turningitdownforabout1/8turnafterthatpoint.Properaudioleveliscriticaltoensuringthe
transmittedpacketscanbereceivedanddecoded.Atransmitaudiolevelsettoohighwill
causeclippinginthetransmitter,whichresultsinsignalsthataredifficulttodecode.

Theconfigurationsoftwarealsoallowsadjustmentoftheaudiooutputlevelusingaslider
control.Seethesoftwaredocumentationfordetails.
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d. LED Blink Codes
ThetrackerreportsitsstatusthroughtheuseofasingleLEDasfollows:

ActionMeaning
RapidblinkingChannelisinuse
SingleflashReceivedvalidGPSfix
DoubleflashReceivedinvalidGPSfix.GPSmaynotbeready
LitsolidTransmittingorinconfigurationmode

Note‐IftheLEDisblinkingrapidlywhenthechannelisnotinuse,thereceivesensitivityis
probablysettoohigh.AdjusttheRXtrimpotuntiltheLEDstopsblinking.Itshouldstart
blinkingagainwhentheradioʹssquelchopens.

e. Configuration Program
TheOpenTrackerisconfiguredthroughaMicrosoftWindowsprogramavailableinthe
downloadsectionofthewebsite.Useastandardnull‐modemcabletoconnectthedevicetothe
PC.ThePCdoesnotsupplypowertothetracker,soitmustbepoweredexternally.

Connectthetrackerandstarttheconfigurationprogram.Thefirstwindowdisplayedallows
youtoselecttheCOMportthatthetrackerisconnectedto.



OverwritinganInvalidConfiguration
The‘Erasedeviceandloadnewfirmware’optionwillloadanewfirmwareimage,usingthe
defaultconfigurationsettings,withoutattemptingtoreadtheexistingconfigurationfirst.Thisis
particularlyusefulifthetrackerhasaninvalidormissingconfiguration.

TurboMode
Bydefault,theconfigurationprogramwillattempttoconnectat115,200baud.Ifyouhave
troubleconnecting,usethe‘DisableTurbo’optiontoforcetheprogramtoconnectat19,200
baud.


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WarmBootvs.ColdBoot
Iftheunitisalreadypoweredonandoperatingwhenyouclickthe‘Connect’button,the
programattemptsa‘warmboot’operationtoputthedeviceintoconfigurationmode.Ifthe
firmwarehasbeencorrupted,i.e.byafailedupgrade,itmayfailtoenterconfigurationmode.
Youcancorrectthisbyperforminga‘coldboot’‐powertheunitoffandpoweritonagainafter
clicking‘Connect’.
f. Main configuration window



ConfigurationProfiles
TheOpenTrackercanstoretwoseparateconfigurationprofiles.Theprofilecurrentlybeing
shownisselectedusingthetabsatthetopofthewindowlabeled‘Config1’and‘Config2’.

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Whenitisfirstpoweredon,theOpenTrackerwillalwaysstartoutusingtheConfig1profile.
Afterstartup,profileselectiondependsonthesettingsinthelower‐leftpaneofthe
configurationwindow.

Theconditionstotestareselectedusingthecheckboxestotheleftofeachcondition.Thecom‐
parisoncanbeeither‘>’(greaterthan)or‘<=’(lessthanorequalto).Clickingonthebutton
showingthecomparisonoperatortogglesitbetweenthesetwosettings.

TheAltitudeandSpeedvaluesarecomparedwiththoseindicatedbytheGPS.Onboardsensors
providereadingsforcomparisonwiththeTemperatureandVoltagefields.ADCInputreferstothe
unusedanalog‐to‐digitalconverterinputonJP8.Thepossiblevaluesare0to255,corresponding
toarangeof0to5volts.ThejumpersettingreferstoJP3.InstallingajumperbetweenpinsJP2
andJP3setsthe‘On’condition.TheGPSFixisconsideredinvalidifithasbeenmorethan20
secondssincethelastvalidpositionwasreceivedfromtheGPSunit.

Theselectedtestsarerunonceeverysecond.Iftheconditionsaremet,thenewprofileisloaded.
IfTransmitwhenswitchingtothisprofileischeckedinthenewprofile,apacketistransmitted
immediately.

Oncetheswitchtothenewprofilehasbeenmade,thecriteriainthenewprofiletakeeffect.
Anotherswitchwillnotoccuruntilthenewcriteriaaremet.Often,thecriteriaineachprofile
willbecomplementary.Forexample,Config1mightindicateaswitchwhenthejumperis
installed,andConfig2wouldindicateaswitchwhenthejumperisremoved.However,the
criteriamaybecompletelyindependentofeachother.

Ifthecriteriainbothprofilesaremetatthesametime,theconfigurationwillswapevery
second.Keepinmindthattheremaybeacertainamountofnoiseorjitteronanaloginputssuch
asvoltageandtemperature.

LoadingandSavingSettings

Afterchanginganyconfigurationoptions,youmustclickthe‘Write’buttontowritethe
changestothetracker’sfirmware.Youmayalsousethe‘SavetoFile’buttontosavethe
configurationoptionstoafile,whichcanbeloadedlaterusingthe‘LoadfromFile’button.

BasicConfigurationOptions

Callsign–Theradiocallsigntousewhentransmitting.Tacticalcallsignsmaybeused,butFCC
andITUrulesrequireperiodicidentification.Iftheactualcallsignisnotusedhere,besureto
includeitinthecommentfield.

Path–Thisspecifiesthedigipeaterpathtouse.Specificcallsignsmaybeentered(e.g.,
‘K6SYV‐10,K6TZ‐10’)butforAPRSoperationasetofcommonaliasesareusuallyused.A
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