First Time Stepper Motors

Support Motor controllers/drivers and motors
1

I am working on a remote controllable camera mount. I have successfully built and tested the mount using continuous rotation RC servos to drive it. Though it works, I was looking to open up the range of speed and precision. So I am upgrading my gearboxes to use Stepper motors instead.
I have ordered here 2x 1204 motors and 2x T834 drivers.
My question is, If I turn off the power after use, then move my mount by hand (thereby manually turning the stepper motor axl in the process) does a stepper motor return to it’s last known position or a set starting position when power is restored or does it simply start where it is?

My fear is, use the mount, then power it off. manually move the mount to remove SD card or batt from camera, power the mount back up and it wants to jump back in to it’s last position which could cause damage to the camera if (say) batt compartment open or a charger cable is on the camera.

Though I am fairly certain that without additional sensors telling the system where the mount is currently oriented at startup, and no soft-conditions in place to defining a start position, the Stepper will just start where it is. But again, I do not know which is why I am asking.

Thanks in advance!!

2

A stepper motor has no memory, nor does the driver. All motion is relative to the starting shaft orientation, and your program can count steps from that point, assuming that the motor is correctly sized for the system and does not skip steps.

There are two common methods to determine absolute shaft orientation (or ultimately, output position). Most commonly, people drive the motor to an endstop at startup, then count steps from there. Driving into an endstop will not damage a stepper.

The other method is to use an absolute shaft angle encoder, or an absolute position sensor for linear stages. Those are expensive and thus less common.

3

excellent… all I needed to know.
stuff arrived today :slight_smile: