Hi all, I hope this thread is still live. I’m having false triggers with one particular Samsung motion sensor too. I’ve been carrying out tests now for several months. Here is what I’ve discovered.
The sensor is mounted high up in a porch on a plastered brick wall facing a window above my front door. It is mounted 15 cm above the porch external door which I keep unlocked. It is there to detect when someone enters the porch through the open door as they are facing the locked front door. It triggers a light, and notifies me on my phone that someone is at the door via the SmartThings Hub. So, when someone enters the porch, the sensor is up high behind them above the door they just came through. For that it works perfectly.
However, when a car passes by on the road outside, it triggers. There is absolutely no line of site from the road to the sensor, except by reflection on my internal front door stained glass. I am sure this is not the cause, as when I approach the front door myself, it does not detect reflected heat from me. It only activates when I step under the sensor and come into view of it. The road is 8 metres from the door. I am 1.5 metres from the door when I step in.
The sensor is triggered 70-80% of the time when a car goes by. The times it doesn’t trigger when a car goes by are when a small quiet car goes by. I have not observed it trigger at any other time.
I have tried standing outside the porch and shouting loud at the porch. I haven’t been exhaustive in the range of frequencies I’ve shouted in for obvious reasons to do with my neighbours’ concern over my mental health. I have been unable to trigger it with shouting, or banging the garden gate shut very hard. I have also tried hitting the porch wall with a large piece of wood.
My conclusion so far…
I am convinced that the device can be triggered by very slight vibration of certain frequencies. I believe my porch is a small enough cavity with the outside entrance open to accentuate certain harmonics of sound coming from the spread spectrum of frequencies of sound a car gives off as it drive sdown my road. I don’t think I can recreate either the energy level or frequency(s) required with my voice or the piece of wood without attracting an ambulance to take me away to be sectioned.
I would speculate further that it may be low frequency sound or vibration, possibly propagating through the ground rather than the air, then being amplified in my porch due to the resonant qualities of the porch cavity.
In summary,
I think you have an accidental unreliable vibration sensor that triggers at very low frequencies, as well as it being a reliable IR motion sensor.
Regards,
Rory.