Smart Home Monitor - Alarm only when two sensors go off

I’ve been using SmartThings for a “soft” home security system, getting notified on the phone when there’s any activity at home while I’m away. So far due to concerns about reliability (both triggering alarms and automatically disarming based on presence sensors), I have not yet hooked it up to sirens.

One problem is that I keep getting spurious alerts from my motion sensors. At least once a week I get one or two reports of motion indoors that then goes away.

I understand that consumer hardware may do this occasionally, and I’d be OK with it, if there was a way for the Smart Home Monitor to deal with it gracefully. As I have a number of motion sensors and door sensors around, I’d be perfectly happy with something like requiring two independent sensors to trigger before raising an alarm, i.e.:

  • When one sensor goes off, enter a “warning” state for x minutes (optionally notifying the user but without setting off the sirens)
  • If another sensor trigger while in the “warning” state, go to red alert

Is anything like this being worked on? Is there a better way of doing it?

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You can do something like this with Mike Maxwell’s app. Basically require 2 or more real motion detectors to detect motion before doing anything.


I was not aware of this one, that’s extremely useful and will probably solve the false alert problems. This also means that I can apply the extra logic for the motion sensors, but keep the (significantly more reliable) open/close sensors as is, triggering on a single one.


in the burglar alarm/security alarm domain, this feature is called cross-zoning. But recently seems like multiple ST motion sensors are indicating false motion around the same time, so cross-zoning would not eliminate the false alarm in my case

My motion sensors will false trigger with no one in the house if they get hit by direct sunlight through a window