Can it do this?
Includes ability to step less than step size without losing track of total.
Detect torque spike when you get to end of travel.
Turns off coils between steps for motor with gears that do not need holding torque.
Cooler running with 12v.
Can sleep when moving slow.
Enhanced performance using 12v supply with 5v motor.
Here's a summary and some help to get you started:http://arduino.cc/forum/index.php/topic,89159.0
From above link:
Here is a brief summary of the code.
It can spin a full size DSLR on it's shaft without bearings at 30RPM!
Ramping up and slowing down to prevent bouncing.
It can measure torque to detect an abnormal load or error.
It works without blocking or waiting or interrupts.
Enhanced performance using 12v without warming up the motor.
And much more!
Sounds like an advert, but it's all for Free.
Hardware is $4.
Here's the code:https://gist.github.com/sbright33/4178431