▁and ▁other ▁factors . ▁Some ▁vehicles ▁also ▁use ▁the ▁trip ▁computer ▁to ▁allow ▁own ers ▁to ▁change ▁certain ▁aspects ▁of ▁vehicle ▁behavior , ▁e . g . ▁how ▁the ▁power ▁lo cks ▁work , ▁but ▁in ▁most ▁cars ▁" setting ▁prefer ences " ▁is ▁now ▁done ▁through ▁a ▁center ▁screen ▁also ▁used ▁for ▁the ▁backup ▁camera ▁and ▁radio . ▁ ▁Some ▁trip ▁computers ▁can ▁display ▁the ▁di agnostic ▁codes ▁that ▁mechan ics ▁use . ▁This ▁is ▁especially ▁useful ▁when ▁the ▁mechan ic ▁wants ▁to ▁see ▁the ▁codes ▁while ▁driving ▁the ▁car . ▁In ▁ 2 0 0 4 , ▁Linear ▁Log ic ▁developed ▁the ▁Sc an G au ge , ▁which ▁at ▁the ▁time ▁was ▁the ▁only ▁easily ▁installed ▁( via ▁O BD II ) ▁access ory ▁that ▁worked ▁as ▁a ▁trip ▁computer , ▁ 4 ▁simultane ous ▁digital ▁gau ges , ▁and ▁a ▁di agnostic ▁trouble - code ▁reader . ▁This ▁device ▁has ▁available ▁ 1 2 ▁different ▁measurements ▁which ▁can ▁be ▁used ▁as ▁the ▁ 4 ▁digital ▁gau ges . ▁The ▁units ▁of ▁measure ▁can ▁be ▁independently ▁selected ▁between ▁miles / km , ▁gall ons / lit ers , ▁Cel si us / F ahren heit , ▁and ▁P SI / k Pa . ▁ ▁In ▁ 2 0 0 8 , ▁the ▁O BD u ino ▁project ▁announced ▁a ▁low - cost ▁DI Y ▁trip ▁computer ▁design ▁using ▁the ▁O BD II ▁interface ▁and ▁the ▁Ar duino ▁h ob by ist ▁micro controller ▁platform , ▁released ▁under ▁the ▁G PL