Udelej nebo si kup menic z 5V na 12V.
http://dics.voicecontrol.ro/tutorials/mc34063/
http://www.ebay.com/itm/DIY-Kit-5V-to-12V-Step-up-Power-Converter-Module-DIY-Kit-ICSK034A-/361081932929?pt=LH_DefaultDomain_0&hash=item5412290c81
http://www.ebay.com/sch/i.html?_odkw=stepup+converter&LH_BIN=1&_from=R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xstepup+converter+5+to+12v&_nkw=stepup+converter+5+to+12v&_sacat=0