Im trying to create a linear rail system to move my camera back and forth in a straight line. I will be making it a mobile unit i can take with me into the field and use it hand held. I want to use a small stepper motor like the nema 11 (could be another stepper i just dont want to have a motor with a diameter greater than about 53mm)
I will be using the Arduino Micro Pro 5v as the controller

I was planning to use the Sparkfun Easy stepper driver but come to find out it might not be able to run a stepper at higher rpm.
Also i came to find out it might need a separate power source with much higher voltage than the one i will need to use for the Arduino

So my question is what driver do i really need and how much voltage is going to be enough to accomplish my goal. It needs to be battery powered and i was hoping to connect the driver and controller to the same power source

 

Take a look at the Gecko stepper drive site, they have a Tech info on selecting a drive and the right supply voltage.
Max.

 

Here is the technical problem. The higher the speed, the lower the torque. At some high speed with some amount of mass the motor will simply stall and stop. You will need to find out where that point is. To start, stop, and run the motor you will need to create a "velocity" profile. One that works well is the trapezoid. Starting from zero velocity, you increase the velocity in a linear fashion (aka a constant acceleration), when you reach the desired velocity you continue at that constant speed (aka zero acceleration) and when it is time to stop you ramp the velocity down in a linear fashion (constant deceleration). You must be careful to avoid running at any velocity that will excite either a mechanical or electronic resonance. If you hit one by accident the motor will stall and try to move but be unable to accomplish the task. It won't hurt the motor, at least in the short term, but the first time it happens will surely be a WTF moment.

Good Luck

PS A motor with a 1.8° step size requires 200 full steps or 400 half steps per revolution. So 200 RPM is 3.33 revolutions per second or approximately 1332 half steps per second. The lower frequency mechanical resonance will occur between 200 an 500 half steps per second. The higher frequency resonance will occur around 4000 half steps per second and zero torque will be slightly higher. These estimates are highly dependent on the actual power supply and switching hardware as well as the actual inertial load and damping. To run the motors for a two axis engraving table we used a two level supply with 40V @ 4A and 8V @ 25 A unregulated. The lower voltage supply was for maintaining adequate holding torque, while the higher voltage supply was used to improve the acceleration and high speed running.

 

Normally on NEMA stepper is a label showing its V and I requirements ?

Or look up its datasheet to get power requirements.

Regards, Dana.

 

Normally on NEMA stepper is a label showing its V and I requirements ?

Or look up its datasheet to get power requirements.
Regards, Dana.

A stepper motor should not be ran at any more current than the plate rating, the only problem is the torque drops rapidly after a few hundred rpm, there have been different methods used for maintaining the current as the inductive reactance increases.
The current method is to use a much higher supply voltage and control and maintain the plate current via the PWM controller.
Max.