This compact pill box will store 31 days worth of pills. Just twist the cover open until you find your next pill. Day-of-the-week markers on the end let you know if you've missed a day. The cover can be locked closed to prevent accidental opening, and there is also a hollow core for bulk pill storage.
UPDATE: I've reworked some of the overhangs so that it now prints and operates much more smoothly
The parts print without support, but the spiral ridge on the box will have a somewhat lumpy surface. This can be sanded or worked smooth with the cover.
The box is designed for fairly small pills (<10mm). You should be able to scale it up somewhat for larger pills.
After printing, screw the cover onto the body and work back & forth with a little force to smooth out the operation. Then snap the sliding dove-tail locking piece into place as shown.
To fill, open the cover to the last position and then start filling each position through the window in the cover. Spare pills can be stored in the hollow core. To get your pills, hold the cover with the window facing up and then unscrew the body until you see your next pill.