Quoted from branlon8:...at 0,9° per phase you‘ll have almost 400 phases per rotation so I guess you don‘t see the individual phases. What‘s the purpose of the A4988 ? - to control the current and thus the final speed? Where is the vibration damper?
400 steps is correct but even at these higher step counts, you would still see each step, especially with the circumference of the ferris wheel. That's where the A4988 driver comes in. A normal stepper driver just sends a hard step pulse to the coils which is why you hear that really loud "buzzing" in most stepper motors, There's also backlash and a few other contributors, too.
The driver I'm using has a more tapered rise and decay for the phases which makes it very quiet and the rise and decay is somewhat adjustable in that, the driver can even move the armature in 1/2 step, 1/4 step, and 1/8 step per signal pulse. Power wise, it's a little less efficient because it has to keep the coils energized while cycling through each phase but it makes for even higher "resolution" and smoother motion and in turn, less noise. Even with all this, you can still hear the motor when mounted to a rigid body so, the vibration damper (barely visible in my original post) is just two metal plates with vulcanized rubber connecting them. It isolates the motor from resonating to the mount point and does a phenomenal job of keeping it quiet. Here is a pic of what the damper looks like:
20210313_173752 (resized).jpg