10/13/17: I improved the mount to make it more universal, please see the improved version here: https://www.thingiverse.com/thing:2585156 The ring is the same between the two models so that part can be reused if you want to change out the mounts.
I am still staying in a handicap accessible apartment and needed to find someplace to put my trash in the bathroom. I could have purchased a trash can but this seemed like a fun project to draw up.
The mount piece slides over the grab bar. The ring part screws onto the mount using two #8 x 1" sheet metal screws. The ring has an upper and lower annulus that help guide the trash bag and hold it securely. On the back right is a toothed peg that sticks out so you have someplace to secure the extra part of the bag too.
I designed this for use with standard 13 gallon kitchen trash can bags.
Print both with EVERYWHERE supports just as the parts are laid out in the STL files.
I used the Polymaker PLA High Speed print profile provided by lulzbot (see attached).
This is designed for a 38mm grab bar, 1 5/16" from the wall.