[Sandeep_UNO] may have the project for you. As you can see in the video below (and, yes, it should have the phone rotated and it doesn’t), his Arduino uses a servo motor to dip a bubble wand ...

[Frank Herrmann] had an interesting idea to turn a geared DC motor into a servo motor assembly ... up to the motion controller upstream. The Arduino source for this can be found on the project ...