User Manual

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JJ604
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4
AddingFrSkytoaSpektrumDX8
4
NiMHwiththealternative7.2VLiPopackwhichissoldasanaccessory(orthemuchcheaper
HobbyKingequivalent).TheDX8isdesignedforit,includesthecorrectchargecircuitryandit
willdoubletheoperatingtimeaswell.TheDX8lowvoltagealarmwillgoofflongbeforethe
FrSky
stopsfunctioning.
Thesignalproblemisalittlemoresubtle.IfyoulookatthesignalcomingoutoftheDX8
trainerjackitlookslikeTrace1.The“0‐“markeriszerovolts.The8controlpulsesare
negativegoingfromabout0.7Vpositiveto2.6Vnegative(3.3Vlogic).
Howeverwhenyou
connecttheFrSkymodulethevoltagelevelsshifttoTrace2.Thepulsesnowgofrom6.1vto
2.8V.TheFrSkyinputdiscriminateslogic0fromalogic1at1.65Vsoneverseesanypulse
input.Addinga47kpulldownresistortotheoutputof
theDX8solvestheproblemand
resultsinTrace3,aseriesof3.3Vtozeropulses.
ThenextpostshowshowIaddedanFrSkyDTHmoduleinternallybutconnectedtothe
externaltrainerportandanFLD‐02LCDdisplaytogiveafullFrSkytelemetrysystemthat
can
beswitchedatwillbacktoacompletelyunmodified(exceptforthecaseholes)DX8.
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