Okay i'm starting a new project where I want run an Arduino UNO and a stepper motor which requires 12V. I would like both to be running off the same supply. Should I cut the 12v cable which will power the motor through some driver circuit, and use a voltage divider to step down to 5V for the UNO + a regulator.?
You know that you need a motor driver module or shield, to drive the motor?
You can feed 12V to the Uno jack or Vin.
I ran my stepper motor with four FETs directly from the Arduino outputs. The stepper motor was an RS 199-8299 (RS Pro Hybrid Stepper Motor 1.8°, 100mNm, 12 V dc, 400 mA, 6 Wires). Runs superbly well.
Coding a bit tricky especially for ramp up. The motor is only capable of 2.5 revs per sec whereas the Arduino could run many times faster.
12v to motor, 7805 feed to Arduino. Good! Don't forget to join all grounds together. Use a capacitor before the regulator (and a small one after) because those motors are very noisy and don't forget the back emf suppression diode across each winding
Dead_Ard
The uno has a perfectly good 5v regulator on-board - why bother with a 7805? Use the Vin.
Allan.