Today i found great project on Youtube, that's called Toroid coil winding machine from youtuber Mr. Innovative

Toroid coil is a kind of transformer that has ferrite core in circle shape. So, winding copper wire for it is always a challenged for human. Today, most of toroid coil is done by machine which not cheap. Surprisingly, a youtuber can make this kind machine in easy way

Main case for machine is made from wood. A motor is used to rotate main circle that goes through circle ferrite core. Coil of copper wire is attached on main circle, so it can go through the ferrite core.