Automatic doorcloser for people who cant close the door after themself

Hello. One day my mom did leave the door open again and i called after her to close it. She got me an annoyed glare and said something like that: "why doesnt close this door on its own alredy?!" And bam door closed, she out and my mind processing.
I didnt have my 3d printer for long and i wanted to try to do something usefull, instead the printing nice thingiverse files to test the printer.

So I tested if i could come up with something and so i started constructing. First i measured our doo