I'm trying to control a stepper motor with my Duemilanove. It's one of the motors available from SparkFun: https://www.sparkfun.com/products/10551?
But I cannot get it to behave. Setting aside the driver (I'm trying to use a SN754410 as detailed here: http://arduino.cc/en/Reference/StepperBipolarCircuit
) issues that I'm having, just hooking up the motor to the Arduino isn't working. I'm powering it with 12V, as necessary, and have the four wires from the stepper going into pins 8-11. But when I load and run any of the programs in the stepper library (StepOneRevolution, etc.) the motor simply 'shakes' - it twitches forward slightly, then back, and it's not nearly an entire step, as this motor is supposed to be doing a 7.5 degree step angle. I've switched voltage supplies, sketches, and everything else I can think of, but I can't get this motor to 'step.' (I also know it's not the motor, as I have several of them and they all respond the same.) Can anybody offer me some advice or some additional reading material? I'm stumped here, and my Google-fu has failed me thus far.