The ARS-Shield is a board that can host an Arduino (i.e. UNO) module adding the capability to interface with a rotor (DC or AC) It’s compatible with K3NG rotator controller who provides the Open Code of his project at the web site:
https://blog.radioartisan.com/yaesu-rotator-computer-serial-interface/
If you enjoy the homebrew and you want to design your own rotor controler this ARS-Shield will be a piece surely you will need and appreciate.