I am sitting here in office and my wife is at work. Just got a text alert that there is a motion in the second floor hallway. Just one text alert though. Have switched all the lights on and watching the motion tile on the dashboard… Appears to be none thereafter. It’s a first generation ST motion sensor.
Pray to god, its a false alarm. ADT shows no motion.
I’ve had this happen to me a number of times in the past - thought about installing a camera for verification of the movement…
I am thinking about a camera too. It is kind of spooky. It just happened for a minute. The activity shows just one entry for a minute. Reported it to support too. The wife is freaking out. 
Consider whether a sudden change in light intensity may have occurred - cloud masking the sun through a window, bird flying by the window, etc. I have these too, but I also have enough other motion sensors in the house that I can pretty much deduce that a single second floor motion report is false unless I see motion elsewhere in the house around the same time…
Just came back home and it was a false alarm and the device is just 3 months old with 88% battery left on it. The intensity of light does not change there in the hallway during the day and does not have any window or anything as such next to it. Will try reinserting the batteries. In order to get to my second floor hallway, a person has to pass thru couple of other sensors and of course ADT sensors too. Will let support know if it happens again (hope not). 
Infrequently I have had false triggers like this (perhaps every 2nd or 3rd month). I have multiple sensors at home, though, so I’ve learned that unless more than 1 triggers that it is probably a false alarm. Of course if someone smashes a window and only goes into the room with that window they win…
While we are at this, what in your opinion is a decent zwave motion sensor supported by ST? I need one for the basement to trigger a light! With no offense to ST zigbee sensors. 
I am very happy with the Aeon Multis.
I’m happy with the Aeon Multis and with the SmartThings sensors. I also have two Schlage Z-Wave Sensors (Schlage RS200HC Home Motion Sensor) that give me just a bit more coverage. I have them mounted in a corner (they come with nice corner mount brackets) and, with a 90 degree corner, I get complete room coverage.
Thanks a lot! So, aeon multi it is this time! I like the ST’s too and have two of those but wanted a zwave this time!
Just ordered one! I desperately needed one for the basement.
People are not imagining this. It really is happening, at least with the first generation motion sensors. I have one that is on external power that is in a closed room unaffected by light and it has triggered 4 times in the last month. It is located about 30 foot from the hub. Maybe it is the same gremlin/ghost that opens my garage door in the middle of the night, or turns on lights for no reason. Grrrr.
Dug out another one… The battery was again at 88% when this happened just like mine. So, at least three cases here when it happened at battery level 88%. It may be a coincidence though. Eh?
Had another one of the false motion alarm early morning at 2:00 AM.
I had a false alarm yesterday at 9:15am. No one was home and sun does not affect this one either. It is a gen1 ST motion sensor.
Second one for me in two weeks period. It’s a generation 1 motion sensor too. IT turned on all the motion activated lights even though we were in bed. My text alerts are not set for night mode.
I have been getting a motion alert about one every 3 or 4 minutes when I’m out for about 20-30 minutes. It really freaks my wife out. First generation ST motion sensor too.
I tried repositioning the sensor to no avail.
Say, has anyone on this thread attempted to tinker with the sensitivity of the ST motion sensors? I can’t find any settings for that, but I suspect it could address the problem.
I’ve had 6 first-gen ST motion detectors installed for several months now. On average, I would estimate that one or the other of them seem to generate a false alarm 3-4 times per week – including one in a hallway that is not directly exposed to any windows. Whether they’re on battery or plug power, whether they face a window or not - none of that seems to matter. All of them seem to have sent false alarms at some point or another. It’s weird. I have one Aeon Multi that doesn’t appear to have done this, as far as I can recall.
Right now, based on my experience, I wouldn’t buy another ST motion, but in the meantime, I’m trying to get the 6 that I have to work reliably, so if anyone has managed to get under the hood, I’d appreciate hearing about it.
I’ve had 2 SmartMotion 1st gen sensors (among others) working since February. Each one has had one “False Alarm” that might have been caused by moving plant leaves (apparently the cleaning folks moved my plants when cleaning and repositioned leaves right in front of the sensors. I repositioned the plants and had no further problems)
However, last week one sensor cycled on and off for several hours and the other one caused my alarms to go off several times one night until I had to lock it out of my system. Then, a few days ago, both sensors just stopped responding. My battery level on both showed 38%, which was what I recalled it was one month ago. So, I replaced the batteries and, so far, both are recording appropriate activities.
Hopefully, it was just the batteries and a “frozen” battery level indicator.
Have read it at several places that battery level below 50 May cause it. Have no way to claim it is true or not as I am not an expert. But I have got two false alarms till date since I started this ST thing when my battery levels on the 1st generation ST motion sensor was 88%. Now I have it powered thru usb to better the zigbee mesh (?) and pretty much use it only for that purpose and use the new ones and Aeon for real stuff.