Automatic door stop for carpeted floors

I am looking for feedback on this design, I've had it on my door a few months and made some changes to make this easier to operate and stronger. I am not sure if other countries do knob screw spacing different but this is sized for an American interior door. This door should have anywhere between 8mm and 22mm of clearance from the carpet to work properly and no threshold or door sweep installed, its only for interior doors with no transition below them.

The whole thing comes together with (8) 6mm M3 screws, a rubber band, and you'll need a string or wire that has very little elasticity, something that doesn't stretch with load easily, I used some inner strands from a piece of paracord but a steel wire would have worked a lot better.

You'll need to print one of each piece and (3) ‘Caps’, this is not print-in-place, the caps should face up when installing them as they are just there to keep the mechanism in place and shouldn't put any pressure on the movement, there is an offset built-in already for that. 

2 of the screws that attach the knob hardware ‘lid’ to the ‘body’ are attached from the back so this cannot be assembled once its on the door. Look carefully at the full ‘knob hardware’ stl and the pictures. 

Door installation should be simple as taking the two screws off the knob, placing this plate behind the knob and installing the screws again, place the ‘sear’ and ‘thumb’ pieces in a vertical position. Then you can install the door stop at the bottom of the door, you will need to attach your line to the loop of the ‘Stop’ and place it within the ‘frame’, then slide it under the door until it is directly vertical to the loop on the ‘bar’ above. Bring your line up niche and tight and loop it around the line tightener once or twice and adjust the M3 screw to hold it in place. Now you can install the rubber band using the loop on the Door stop ‘frame’ and the hook on the ‘stop’. Tighten your line once more.

You're done! Now you can flip the thumb latch and the rubber band should pull the ‘stop’ down and hold your door in place, more or stronger rubber bands for more holding force. Please give me your feedback, I'd love to make this easier to install or even how to explain the process better.