Hello, I have decided that no matter how many times I ask, people will always leave my bedroom door open. Therefore, I have decided to try my hand at a DYI project to create an automatic door closer. I'm aware these already exist but I'm also doing this because I've always been interested in robotics and figured this would be a fun way to get my foot in the door. The main things that I am struggling with is deciding how much voltage my motor will need, and what type of motion my motor will need to use. My door weights about 60 pounds and the motor will only need enough force to close it close it shut. I do not need it to open the door. How can I calculate this? Will the angle in which the door is open affect the power needed?