Never lift the toilet seat or get into any arguments over the matter ever again, simply use foot to push foot pedal down and seat goes up, but not all the way so that it doesn't get left up.
Print time a bit long but well worth the wait to never lift the seat again.
0- use ABS
1- print stl files 1 and 2 with no supports at 80% or higher infill @ 200 microns
2- print stl file 3 twice with supports only for wheel at 80% or higher infill @ 200 microns
First, You’ll need any hot glue gun & ABS filament segments & ~7 ft of heavy duty thread or shoelaces might work in a pinch.
1- Clean up all part holes if needed with a small round file.
2- use clippers to snip 4 segments of ABS filament the width of the foot pedal
3- put the small square parts inside foot pedal and thread each segment of ABS through
4- use hot glue gun to secure ABS segments to foot pedal
5- use hot glue gun to secure assembled foot pedal feet parts to floor
6- Snip 4 segments of ABS filament the width of assembled pulley wheel
7- use hot glue gun to secure 2 segments of the filament through each of the pulley wheel parts
8- use hot glue gun to secure one pulley to the top right of tank and the other midway between middle of seat in up position and first pulley.
9-use hot glue gun to secure the seat attachment to the seat
10- use thread and tie a knot to seat attachment and feed it up through the pulleys making sure the thread coming over the top of the top right pulley towards you
11- feed thread down to the foot pedal and tie the most complex of knots as possible making sure the thread is VERY taught or this trick won’t work.
12- Never lift the seat again with your hands and seat returns to down position when foot is lifted!
13-enjoy a peace of mind