I found the following on Amazon customer comments. This really helped me with the issue I thought I was having. I hope this helps others that are new Smart Things like I am.
Initial impression is good, though the manual is a bit confusing
ByPatrick Niemeyeron May 7, 2017
I am using this with SmartThings. Setup was fairly straightforward, but with a couple things that were a bit unexpected.
First - setup is through a custom device handler. This isn’t surprising and it’s pretty well documented in the instructions (there is a tinyurl to the config for the Smart Things DH).
Next, though - after you pair the motion detector with your hub, it spends 90 seconds or so in “walk mode” (as the directions call it). During this time, the red beacon lights up every time the sensor detects motion and every time motion starts/stops, it gives you feedback about what it is able to see. This is presumably to help you ensure that the device will detect motion in your desired installation spot. But I was confused about the device for a while because it gives so much info in this mode.
After the “walk mode” trial is complete, the device does seem to still work, but it changes its behavior in two significant ways that made me think it wasn’t working: first, the LED no longer lights up to give visual feedback about it detecting motion. This is actually fine, but I had learned to expect the “LED-when-motion-is-detected” behavior during setup.
Next, when in normal operation mode, the device only tells you there is motion once within a 3 minute window. So it detects motion and if there is motion again two minutes later, it won’t tell you (again) “motion detected.” Like the last item, this is fine (the manual indicates this is a battery saving feature, which I can believe) but again, I had grown accustomed to the “you get ‘motion detected’ any time there is activity” (which is how the SmartThings motion sensors work and how this device worked while it was still in “walk mode.”)
These are OK behaviors, really, but I was confused by the device behavior during setup (since it behaves differently than the SmartThings motion sensor and it seems to behave differently from itself when comparing “during setup” to “during normal operations”) so I think it’s a bit confusing. Otherwise, it seems to work well.
The device has an internal, removable “look down” tab that you can pull off that will allow it to use the lower field of view when looking for motion.