Arrival routines running after Internet drops and is restored

I’ve had internet issues the past couple days and when the connection is restored I heard my front door unlock. I looked in the notifications an I see as soon as the Internet connection came up it ran the arrival routines for my phones and for my daughters arrival sensor. I am able to reproduce this just by unplugging the ethernet from the hub.

Is the default behavior? if I’m away on vacation and my daughters zigbee arrival sensor is at home and the Internet drops my house will disarm and the front door will unlock. Seems like a major flaw to me have I missed a configuration somwhere?

You haven’t missed anything, that’s how it works. The hub doesn’t have any way of telling the difference between a reconnection because of a power restore or just a normal arrival event.

The assumption is that if you’re not home, you took your arrival sensor with you.

If you want the arrival sensor to look like it’s not home even when it is, put it in a faraday bag or wrap aluminum foil around it.

Amazon carries a bunch of these that run between five and $10. It’s a common solution for people with Airbnb or dog sitters or other people who might be leaving the fob for you but they left the home.


I don’t understand why the hub would lose connection with the zigbee device or my phone on wifi. We did not lose power just the Internet connection the hub was in contact with my phone on the local wifi and the zigbee sensor the entire time

Smartthings is a cloud-based system. Just about everything runs the logic in the cloud except for a few set ups using the official smart lighting feature.

Your phone was not in communication with the hub by Wi-Fi. The hub does not have a Wi-Fi antenna. Moreover, when the hub cannot reach the SmartThings cloud, the SmartThings mobile app cannot control anything on the hub even if it is on your local network. Unplug the hub from your router and try it. Technically, they certainly could, but that’s not how SmartThings is designed. ( feel free to call that the design flaw, many people do.)

During an internet outage, the Hub will not be able to talk to the SmartThings cloud or mobile app; you will not be notified via the app of a local event until internet is restored.

In this particular case, it is the cloud that determines whether the status of the arrival sensor device is “present” or "away. The arrival sensor pings the hub every 30 seconds. That’s literally all it does. It is the cloud that counts the number of pings and decides when too many have been missed, and at that point it is the cloud that marks the sensor as away. The number of pings that must be missed before the arrival sensor away status is set is an adjustable variable, so you can have support set it to about two minutes (3 missed check ins) to help avoid some of the phantom leaving/arriving incidents. But if your Internet is unavailable for longer than that, the arrival sensor will be marked in the cloud as away.

Then when your hub comes back online, the very next check in from the arrival sensor will be treated as an arrival, and status of the sensor will be changed to present again.

That’s why the arrival sensor being able to communicate with the hub isn’t enough to maintain the “present” status. With this, as with many things in SmartThings, it’s the cloud that does the tracking.

Thanks for the reply that is an interesting way to handle the loss of connectivity, I assumed when connectivity was restored the hub would relay the constant state of the proximity sensor and the cloud would just change its status back to present w/o triggering the arrival routines. And for the the phones I thought they would update their proximity directly to the cloud as they have the cellular connection,

This whole thing reminds me of die hard when the vault opened after the power grid was cut. So I really get to look forward to arrival routines running and disarming the house any time internet is lost for a period long enough time out proximity??

I sent this to ST support as well, its funny they told me the internet connection has not bearing on the arrival sensors presence… which is obviously not correct as seen in practice.

Luis (SmartThings)
Jan 9, 10:16 AM MST
Hey Travis,
Thanks for reaching out, sorry for the trouble. The internet connection has no bearing on the actual arrival sensors presence. I double checked the logs for the devices and hub, and the times do not match so it doesn’t look like the actual lock unlocked. It sounds like the arrival sensors device may need to be reset.
I went ahead and tried running a configure command here on my end to attempt to do that remotely, but if the behavior continues make sure to try a new battery and perform the reset processed included in this article:
Give that a shot and let us know how it goes.
SmartThings Support

Maybe I’m wrong, then, and what I described only applies to the V1 hub. Hopefully someone from staff can provide an answer. :sunglasses:

Thanks for the replies, I’ll check out the Enhanced arrival sensor DT

And @JDRoberts, I think you are correct as far as the behavior goes… that is exactly what I see from the v2 hub so nothing has changed.

Just seems like a simple logic fix with the sensors if connectivity lost then do no assume the sensors have departed and wait for Hub to comeback online.