Hanging Ceiling Fire-Alarm Mount Bracket

After getting a new 3D printer, I wanted to add some safety to my basement printing area by adding a fire alarm. I have a suspended ceiling, which doesn't make it easy to mount fire alarms. So I designed a slip on bracket that would allow me to use the standard mount bracket that came with the fire alarm. Each part of the bracket assembly slides over the suspended ceiling metal frame structure. It is design to work in a corner of one of my 4x2 foot sections. The 4 holes (1 in each bracket) allows the fire alarm bracket to be mounted, so the alarm can easily be slipped into place.
My initial version did not include the hex nut slot, but added that because it makes it easier to install the screws from below. If you don't need the hex nut slot- just flip the bracket over and use the flat side up above the ceiling.