This is the one and only Knex door closer. I admit it is not the best but it works fine. You can even close the door from far away by adding a string to the pin.
Step 1: The Body
This is the main part. It holds the counterweight. It is possible to make the tower 1 gray rod higher to shut the door even farther.
I Know a lot of the pictures are out of order but please try your best. If you have questions feel free to ask.