I want to build an dual extruder for my Prusa I3 an therefor I´ve bought geared stepper motors. Since I don´t plan to replace all other stepper motors as well, I´m trying to figure out how to use 12V and 6V stepper motors together on a RAMPS board. Another issue could be, that my RAMPS is powered with 12V, so there isn´t any voltage left for regulate them.

Any ideas?