The light comes with an in-line toggle in the power cord which I would plug into a smart plug and using Webcore to turn it on when motion is sensed here:
I put a motion sensor in a junction box and used a pvc tube to narrow it’s field of view. It’s pointed at my patio door. This is the view that the sensor sees:
I was going to place the red light (in the amazon link) inside the house somewhere near the door (which has miniblinds between the panes) so that if someone approaches the door at night the light will flash. (There is also a LIFX bulb in the outside fixture next to the door.)
The idea for the outdoor motion sensor came from @rscott09 here:
I would use a GoControl z-wave siren instead. This is what I use and I cut the wire to the Siren and use just the strobe light. I have the battery version which make it much more clean. Don’t think my wife would accept any exposed wire.
As for the motion sensor. That’s way too big of a box. You can use a socket plug outdoor box or better yet. Get an infared sensor and place it at the stair rails. If appearance is not a big deal then I guess your approach should work.
I have one of those lights in my bedroom and the noise of the spinning piece and brightness of the light wakes me up in time to hear my Aeon Doorbell announce the problem so I can decide whether or not to turn on an actual siren.
The light would probably be fine sitting on a kitchen counter or something, but I think it’s too big and heavy to mount on a wall.
The Fibaro Motion Sensor and Aeon Multisensor 6 are indoor/outdoor so those would work fine under your deck.
