You may have come across the term “PID control,” and while this proportional-integral-derivative control method does a great job of smoothing out oscillations, where does one get started? 

One solution would be Mr Innovative’s demo device, showcased in the video below. In it, a DC gear motor is able to smoothly rotate an arrow overlaid on a protractor by a certain number of degrees.

Input is via a Bluetooth smartphone interface, and an encoder is used for feedback to the commanding Arduino Uno. Everything is fastened together by 3D-printed parts, and if you’d like to try your own PID experiment, code and print files are linked in the video description.