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Wednesday, September 21st, 2022 11:06 AM

Entry sensor battery died and triggered alarm

The alarm was triggered at 1:30AM while we were sound asleep. It showed our exterior garage door had been opened. The door was locked and secured. It appeared the entry sensor battery had died and therefore the system assumed the door had been opened. I opened and closed the door a few times and the blue light did not flash. How do we avoid this in the future? There was no warning of a low battery.  

Official Solution

Community Admin


4.8K Messages

1 year ago

Hi @melislo ,

The way that the Entry Sensor works is that the only way it can trigger an alarm is if it sends an "opened" signal while your system is armed. If the battery on that sensor was dead, that means it cannot send a signal at all - so false alarms shouldn't be possible.

Of course, if an Entry Sensor's battery was low, you should also be getting a "Low Battery" warning from the system, which leads me to believe that this issue is something else.

Like the Captain, a big clue for me is that you have this sensor installed on a garage door. You did already confirm that it's installed on a regular door, not a rolling garage door. But is that door made of metal (either iron or steel)? The Entry Sensor works by detecting the smaller magnet piece. So if you place either piece on a ferrous surface, that could cause the magnet to demagnetize. That would result in that persistent "open" signal, and the sensor going in and out of function.

The solution is to add a bit of padding underneath both pieces of the sensor - perhaps pieces of wood or plastic cut to size. You just need to put a physical barrier between the sensor pieces and the metal surface.

Hope this all helps!


4 Messages

1 year ago

Our alarm was triggered at 1:30 in the morning. The keypad showed the exterior garage door had had been opened. We checked the door and it was locked and secured. It appeared the entry sensor battery had died so the system registered the door as open. I opened and closed the door a few times and the blue light did not flash. We did not get any warnings regarding a low battery. How do we avoid this in the future?  

Note: This comment was created from a merged conversation originally titled Dead Battery Triggered Alarm



5.4K Messages

1 year ago

@melislo this is a tough one, as using the entry sensor on a garage door (to be specific, a door that opens so you can drive your car in and out of the garage) is not, at this time, a manufacture's approved use of that sensor. Now that is out of the way, I and many others do use an entry sensor (motions too) to protect their garages. 

I have experienced myself low batteries causing connection issues, but never causing an alarm.  Are you sure that the gap between the entry sensor and magnet did go beyond the maximum gap? Windy that night? How do you have the entry sensor mounted? I had mine original on door hindges but now use a nylon sensor holder I purchased on Etsy that is beautiful in design and works like a champ.

There was a customer who used an entry sensor mounted on a metal band but I found that not reliable and could cause false alarms.

If you don't think the install setup was an issue, suggest calling SS support and see if they can provide any insight; of course, Simplisafe, you are more than cordially invited to add to this thread!

4 Messages

@captain11​ the sensor is used for a regular entry door from the garage to the backyard ,so a regular door not a garage door that opens for a car.

Not sure about the wind. The sensor is mounted using the stick tape that comes with it as long and extra for reinforcement. The sensor itself did not fall (which I had originally thought happened).

As mentioned, when we checked it immediately after, the blue light was not flashing so we assumed it was the battery. Later in the day it was working again and set off the alarm a second time. At this point I’m not sure what the issue is. I should mention that this sensor is a new one we recently added to the system so battery should not be an issue yet. 

11 Messages

@melislo​ Did you resolve the issue? To test for wind related issues, with your door closed, and latched as usual, push it forward and aft to check the motion. You can also arm the system, then push it forward and aft to see if there is too much movement, thereby setting off the alarm.

2 Messages

11 months ago

Pretty sure this same thing just happened to me. 5:53am. Scared the hell out of us. 

Community Admin


4.8K Messages

We definitely want to troubleshoot deeper. If you want to give us more info about that sensor, where it's located, what warning messages you see on your Keypad and/or app, we can help.


Or we would strongly recommend giving us a call at 800-548-9508. Our Support team can check on your system and resolve the issue step by step.

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