Exact model-family answer directory
SimpliSafe Entry Sensor troubleshooting
Choose the symptom actually shown by the serial number is inside the sensor's battery compartment. SimpliSafe Gen 3 system component; sensors reach the Base Station over SimpliSafe's own sub-GHz radio rather than Wi-Fi, so a router problem and a sensor problem are separate investigations. Monitoring plan, cellular backup and camera generation vary. Error codes remain separate records because the same characters can mean different things on another platform.
SimpliSafe Entry Sensor firmware update is stuck or failed
For the SimpliSafe Entry Sensor, power, network, storage, hub/controller and provider service should be stable.
Open record SimpliSafe · batterySimpliSafe Entry Sensor has power or battery problems
For the SimpliSafe Entry Sensor, outlet/transformer, contacts, battery temperature/condition and sleep behavior should be isolated.
Open record SimpliSafe · offlineSimpliSafe Entry Sensor is offline or unavailable
For the SimpliSafe Entry Sensor, device power, local radio/LAN, hub/controller and provider cloud should be separated.
Open record SimpliSafe · notificationsSimpliSafe Entry Sensor notifications are late, missing or excessive
For the SimpliSafe Entry Sensor, event capture, cloud processing, phone permission, Focus/background rules and alert zones are separate layers.
Open record SimpliSafe · routineSimpliSafe Entry Sensor routine, schedule or automation is not running
For the SimpliSafe Entry Sensor, trigger, conditions, controller/hub, permissions and action chain should be tested separately.
Open record SimpliSafe · shared accessSimpliSafe Entry Sensor shared users or family members cannot control it
For the SimpliSafe Entry Sensor, invitation/account, home membership, role/permission and platform region should be separated.
Open record SimpliSafe · wrong readingSimpliSafe Entry Sensor shows the wrong time, state or sensor reading
For the SimpliSafe Entry Sensor, time zone, placement, calibration, stale cloud state and sensor hardware should be separated.
Open record SimpliSafe · setupSimpliSafe Entry Sensor will not complete setup or pairing
For the SimpliSafe Entry Sensor, power, reset state, owner account, Bluetooth/local permission and supported home network should be proved.
Open record SimpliSafe · factory resetSimpliSafe Entry Sensor will not reset or needs to be reset safely
For the SimpliSafe Entry Sensor, ownership, automations, codes, recordings and physical access consequences must be recorded first.
Open recordConfirm the model first
Which units this covers, and how to tell yours is one of them
Every answer below is scoped to these model identifiers. A neighbouring model in the same line can use a different part, a different reset sequence or a different radio, so matching the identifier before following a procedure is the step that decides whether the rest of the page applies to you.
- Model numbers and patterns
- the serial number is inside the sensor's battery compartment
- What that covers
- SimpliSafe Gen 3 system component; sensors reach the Base Station over SimpliSafe's own sub-GHz radio rather than Wi-Fi, so a router problem and a sensor problem are separate investigations. Monitoring plan, cellular backup and camera generation vary.
- 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. Those symptoms have no page here for this model rather than a page that guesses.
Published specification
What is true of this model and changes how you fix it
These are the properties that decide which procedure applies. Each is read from the manufacturer’s own published figures for this model, not carried over from a sibling that shares its retail name.
- How it detects
- A 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.
- Battery
- One 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.
- Size
- 1.25 x 1.5 x 0.62 inches, peel-and-stick installation with a magnetic strip.
- Siting
- SimpliSafe specifies indoor use only. A gate, a shed door or an outbuilding is outside specification regardless of how sheltered it looks.
- Beyond doors
- SimpliSafe 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 behaviour rather than a fault.
- Power path
- Internal or removable battery. Every capability that costs current — night vision, higher stream quality, longer recordings, frequent events — is paid for in runtime, so a change in behaviour after a settings change is usually a power consequence rather than a fault. Cold weather reduces usable capacity sharply.
- Radio
- A manufacturer-specific sub-GHz radio to the base station rather than Wi-Fi. It travels further through structure than Wi-Fi does and is unaffected by router changes — which means a Wi-Fi problem and a sensor problem are genuinely separate investigations here.
Where these figures were read. simplisafe.com/entry-sensor Features list, read 2026-08-28
Manufacturer support for this product line. SimpliSafe Support — Entry Sensor Installation Guide. SimpliSafe's own Entry Sensor installation, alignment and gap-tolerance article.
Exact questions
Questions that only have an answer for the SimpliSafe Entry Sensor
Each answer below uses this model’s own published figures. The same question asked about a different model in the line has a different answer, which is why it is answered here rather than on a general page.
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.
What battery does the Entry Sensor use?+
One CR-2032 Lithium 3V coin cell, included, rated up to 5 years depending on usage. It is not an AA device, which catches people out who keep spares for the Keypad and the Siren.
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 behaviour, 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.
Structured depth, not empty permutations
Every published record carries a direct answer, scope, ordered fixes, risk notes and sources.
Device and manufacturer hubs share a consistent record system, but each answer carries the relevant controls, fault boundaries, consequences and official support entry point for that platform.
See the publication gate