Indeed, I have been doing this for the past week: put both the Fibaro Motion Sensor and Samsung SmartThings Motion Sensor side-by-side to see the results.
I would rather not post pictures of my bathroom right now but I can report the following observations.
I tried the sensors in the following locations:
- on a mini-shelf on top of a toilet paper roll holder, aimed directly at the bathroom door
- in a corner with the shower (aimed 45 degrees downward)
- on the ceiling, above the glass/metal divider between the shower and the rest of the room
- on the wall, above the glass/metal divider between the shower and the rest of the room
- on the bathroom vanity counter
This bathroom has a bath/shower with a sliding glass door between the shower and the rest of the bathroom. The sliding glass door has a metal frame on top and an additional void space of about 18 inches between the frame and the ceiling. The shower side is tiled while the rest of the bathroom is painted drywall. Opposite the shower is a vanity that occupies the entire east side of the room (the vanity could hold three sinks, but there is only one sink close to the door). Above the vanity is
a wall-to-wall mirror that goes up about 3 feet from the vanity; above the mirror is a window that goes to the ceiling (about 2 and a half feet high, 5 feet wide). The toilet is on the south side, and the bathroom door is on the north side right next to the shower door.
There are two sets of Lutron light switches: one is a dimmer (PD-5NE) and one is a switch (PD-6ANS). The switches are in the same 2-gang bank. The 2-gang bank is right next to the bathroom door, above the sink on the north wall. To test activation, I set SmartThings automations that automatically turned the lights on or off when each sensor was activated.
Overall, I am much more pleased with the Samsung SmartThings Motion Sensor (“SST”) than the Fibaro Motion Sensor (“Fib”). The SST activated very consistently and almost instantly as one would expect. In fact, when pointed directly at the door from the toilet paper holder mini-shelf, the SST activated its programmed lights before I came into view of the sensor. The motion of the door was sufficient to activate the SST (or the SST is so sensitive that it could detect my body through the door, which seems unlikely). In contrast, sometimes the Fibaro would activate only after I opened the door and set foot in the bathroom; other times the Fibaro would not activate at all unless I went right up to it next to the toilet.
Neither sensor performed at all through the sliding glass door between the shower and the rest of the bathroom. When I stuck my hand through the sliding glass door and waved it around, the SST activated with less body parts exposed. The Fibaro required a significant amount of arm. When I was down on the floor, I could see the sensors quite clearly (when mounted on the ceilings and walls) in the east wall mirror, but the sensors did not activate. Once I stuck my hand up beyond the threshold of the metal frame for the sliding glass door, however, the sensors activated. Again, the SST activated almost immediately while the Fibaro required waving around a bit.
In this particular environment, the SmartThings Motion Sensor is the clear winner to me: it just works. The shower door test was disappointing though because one reason why I replaced the Acuity Brands WSD 2P WH switch on the wall with this new setup is to make sure that the lights do not turn off while someone is taking a shower. This test made it pretty clear that PIR sensors do not work through glass, so either the sensor needs to be mounted on the ceiling above the metal frame (so it can capture both sides), or one needs two sensors.
I thought that maybe the SST had an advantage over the Fib because there is a SmartThings Outlet (2018) on the other side of the wall that might repeat the Zigbee signal more consistently and reliably. However, I unplugged the outlet and experienced similar results, so Zigbee vs. Z-Wave probably does not make a difference in this case.
Also: do not use packaging tape for these tests, as it left a colored residue on the drywall and tile that now I have to figure out how to remove. I probably should have used painters tape instead.