Hi. . .umm, not quite sure what your level of electronics expertise is but. . . you are not going to find a -5V source to tap from the vehicle. I'd suggest adding both a positive and negative voltage regulator to your circuit board and power the whole thing off +12V from the car. You won't find negative voltage regulators at radioshack. You'll have to get them from either a real electronics store or online at places like Digikey or Mouser. |