Exact model-family answer directory
SimpliSafe Entry Sensor troubleshooting
SimpliSafe Entry Sensor (Entry Sensor (no separate model number — the serial number is inside the sensor's battery compartment)): battery (from SimpliSafe Support); mounting; low battery message after a swap, and a fix for each symptom below.
- Battery (from SimpliSafe Support)One Duracell CR-2032 lithium 3 V coin cell, with a life expectancy of up to 5 years depending on placement and use.
SimpliSafe Entry Sensor routine, schedule or automation is not running
Open record SimpliSafe · shared accessSimpliSafe Entry Sensor shared users or family members cannot control it
Open record SimpliSafe · factory resetSimpliSafe Entry Sensor will not reset or needs to be reset safely
Open recordConfirm the model first
Which units this covers, and how to tell yours is one of them
- Model numbers and patterns
- Entry Sensor (no separate model number — the serial number is inside the sensor's battery compartment)
- Not applicable to this hardware
- This SimpliSafe Entry Sensor does not have the hardware for: will not stay connected to Wi-Fi; does not respond to voice control; will not connect through Matter, HomeKit or another platform.
Published specification
What is true of this model and changes how you fix it
- How it detectsA magnet in the smaller part of the sensor. SimpliSafe states the alarm sounds when the magnet moves more than 1.5 inches away from the sensor body. That 1.5-inch figure is the whole specification — an alignment gap wider than it produces a permanent 'open' state on a closed door.
- BatteryOne CR-2032 Lithium 3V cell, included, with up to 5 years of life depending on usage. A coin cell, not AA — so this is not a sensor whose batteries you keep spares of by accident.
- Size1.25 x 1.5 x 0.62 inches, peel-and-stick installation with a magnetic strip.
- SitingSimpliSafe specifies indoor use only. A gate, a shed door or an outbuilding is outside specification regardless of how sheltered it looks.
- Beyond doorsSimpliSafe documents using Entry Sensors on cabinets and safes, with Secret Alerts notifying quietly without sounding the alarm — which is why an unexpected notification with no alarm is often a configured behavior rather than a fault.
- MountingNeeds clean, dry surfaces and the magnet lined up within about 3/4 inch of the sensor. Retail listings give an operating range of 32 to 120 degrees F, so it is not for unheated spaces or outdoors.
- Low battery message after a swapSimpliSafe says a Low Battery notification can take up to 24 hours to clear from the app or keypad after a fresh battery goes in, so it is not on its own a sign the new battery is bad; only investigate further if it lasts past 24 hours or keeps coming back.
Where these figures were read. simplisafe.com/entry-sensor Features list
Manufacturer support for this product line. SimpliSafe Support — Entry Sensor Installation Guide. SimpliSafe's own Entry Sensor installation, alignment and gap-tolerance article.
Also read for this model. SimpliSafe Support — Testing the Entry Sensor; SimpliSafe — Entry Sensor.
Exact questions
Questions that only have an answer for the SimpliSafe Entry Sensor
My door is closed but the sensor says open.+
That is the alignment gap. SimpliSafe specifies that the alarm triggers when the magnet moves more than 1.5 inches from the sensor body, so a closed door whose two halves sit further apart than that reports open and is behaving exactly as specified. Re-seating the magnet closer is the fix, not a replacement sensor.
Can I put an Entry Sensor on a gate or shed?+
No — SimpliSafe specifies indoor use only for this sensor. An outdoor position is outside specification whatever the weather is doing, and moisture at a coin-cell contact produces intermittent faults long before it produces visible damage.
I got a notification but no alarm sounded.+
Check whether that sensor is set up as a Secret Alert. SimpliSafe documents Secret Alerts specifically to notify quietly — for cabinets, safes and private areas — without sounding the alarm. That is a configured behavior, not a failure to alarm.
Can I use it on something other than a door?+
Yes — SimpliSafe documents cabinets, safes and similar. The only real constraint is the same 1.5-inch magnet gap and the indoor-only rating, so anything that opens far enough and lives indoors works.