I've recently bought a stepper from Sparkfun
I am attempting to do the MotorKnob tutorial http://www.arduino.cc/en/Tutorial/MotorKnob
The stepper is a bipolar, and I hooked everything up correctly (checked multiple times) and copied the code correctly.
The motor follows the motion of the pot fine, but it vibrates when the pot is not being turned. Also, I have an external power supply (24v). I run that through a 7512 voltage regulator that powers my Arduino as well as the stepper. However, I noticed after about 10 seconds of running, the 7512 is very hot.
I checked the current through the motor wires, and the coils were pulling like 3 amps!! I have no idea why. The datasheet states a coil resistance of about 34 ohms, and with 12 volts I should be right around the rated current of 330 mA.
I even tried a few different resistors on the coil wires (up to 220 ohm!) and it seemed to have very little (if any) effect on the current draw.
What is going on? This is the first stepper I've played with, so hopefully I've missed something simple.
If everything is running correctly, I should be well under the rated current for the 7512, which I believe is around 1 amp.
Thanks in advance for the help.