Ball Mount for Three Inch Pole

I needed to mount a weatherproof motion sensor to a lamp post, so I designed this. 

The sensor I have is Chamberlain Cwpir Weatherproof Outdoor And Alert System, which includes a plate with a ball socket.  That's great for attaching to trees or other large flatish surfaces, but it doesn't work for smaller diameter poles.

The screw that came with the sensor passes through “inner thing” and “ball socket thing” to attach to the sensor.  That whole contraption pushes on tightly to the “pole clamp”.  No adhesives were necessary in my case.  The ball joint lets you position the sensor at whatever angle you desire.

I printed with ABS.  No supports required, just orient it well on the build plate.  Fusion360 file included.  Changing the pole diameter is just one variable.