I saw the motion sensor mounts available and wanted something a little more universal. This is designed to install with a single screw, and can be mounted either normal or turned 90 degrees left or right.

If you don't over-tighten the screw, you can easily remove it for changing the beam direction or replacing the battery.

The Xiaomi sensor just pushes into the holder, and can be popped out again the same way. I found it to be a perfect fit.

I used PETg for the slight flexibility.