It looks like this should all function well on a 5v power supply, and the torque rating of the motor seems reasonable for my needs.
I do have a couple questions though:
The motor specifies .670mA for each phase, but the Leonardo only specifies 40mA per I/O pin; how can I make up the gap of amperage?
The motor is 3.8V rather than 5V, is it as simple as putting resistors in the path to power the motor and reduce voltage to 3.8V, and should that be done in between the Arduino and stepper driver, or the stepper driver and the motor?
For a stepper motor, you have to look at the current.
The stepper motor driver has a current limiting, so you need to set the driver for the maximum current of the stepper motor.
The Arduino controls the stepper motor driver.
The stepper motor driver controls the stepper motor.
That is by the way a nice youtube movie. You can see it is speeding up and slowing down. So there is some kind of acceleration/ramp.
EDIT, That movie might not be using steppermotors for the motion at all. Just one on top of the tower.
It's probably a very expensive bit of equipment, far more than what I need but the overall design is what I'm after - XYZ motion on a gantry setup - fancy acceleration not required :]
If the Arduino only feeds 40mA to the stepper driver, how does the stepper driver get 670mA to run the motor, I guess is what I'm getting at.
That link to the Pololu driver, click on 'pictures', click on 'Minimal wiring diagram...'.
You see that the logic power supply is for the Arduino.
And the motor power supply is for the motors.
Don't think that acceleration for a stepper motor is fancy. Keep in mind that you may need it. A stepper motor is not very powerful, it can not move something at once with full speed.
If you want fast motion from the stepper then a low voltage driver will
disappoint.
Something like an A4988 driver from 24V is much more normal for this sort
of motion control. Such a driver controls the motor current and acts as
an automatic buck regulator but has the high voltage available to overcome
back-EMF at higher speeds.
The video doesn't make it clear if that's a belt or leadscrew system, the speed
suggests belt though. That's probably the first big decision...
I had been thinking belt drive for this project. It seemed the most straight forward and easy to work with. Any other suggestions, given the end-goal type system I pictured above? I'm definitely open to reshaping or tuning things as needed, this is my very first Arduino ANYTHING and I want to say 'I can tackle anything' but I also don't want to jump in and be foolhardy on something I'm new at.