A door sensor and its tamper switch answer two different questions. The sensor asks: is the door open. The tamper asks: is the sensor still installed and honest. Confusing the two produces the two most common complaints about tamper-equipped sensors, which are false alarms during installation and silence after a battery pull that the owner assumed would be detected.
What the tamper switch actually watches
The tamper is a small mechanical or optical switch held closed by the sensor's own cover, or by contact with the mounting surface. Opening the case, prying the sensor off the wall or removing the battery opens the switch, and the device reports a tamper event instead of an open/close event.
That is its whole job. It detects the sensor being neutralized, not the door being forced. A thief who unscrews the frame does not touch the sensor on the door leaf. A thief who smashes the sensor has already triggered the entry event. The tamper covers the quieter third case: someone removes the cover to pull the battery, and the sensor would otherwise die without a word.
Why installation is the false-alarm factory
A tamper switch held closed by mounting pressure creates a sequencing problem. Pair the sensor on the bench, carry it to the door, and the moment it leaves your hand the tamper circuit may open, because the device is no longer pressed against anything. The hub logs a tamper alarm during what the installer considers normal work.
Well-designed hubs handle this with an installer mode that suppresses tamper events for a window, or the sensor latches tamper state and reports it as status rather than siren. Cheap implementations sound the alarm. The workaround that never fails: enroll and test the sensor in its final position, pressed against the final surface, with the final adhesive or screws. Bench enrollment followed by mounting is where the noise comes from.
Mounting method changes what tamper is worth
Adhesive-mounted sensors can be pried off without opening the case, and whether the tamper fires depends on whether the switch is in the cover or the base. Screw-mounted sensors with a base tamper switch fire reliably when unscrewed, which makes them the right choice for ground-floor exterior doors, shared entrances and anywhere a sensor is reachable by a stranger.
In a rental or a shared building, tamper reporting has a second use that has nothing to do with burglary: it tells the owner that a tenant or a contractor removed the sensor, which is a maintenance fact, not a security one. Notifications should be configured accordingly. A tamper alert routed to a siren at 3 a.m. is a different decision from one routed to a log.
Battery removal is the case that matters most
The attack that tamper exists for is quiet and slow: open the cover, pull the battery, wait, come back. A sensor without tamper reporting fails this test completely. A sensor with tamper reporting fails it too if the tamper event only reaches the local hub and nobody sees the log.
So the specification that matters is not "has tamper switch" but "tamper events push a notification to the app". Cloud-connected devices do this natively. Local-only alarm systems do it only if the panel is monitored or the event triggers a siren. When comparing sensors and alarms, the tamper line in the datasheet needs the follow-up question: where does the event go.
What to ask before you order
Four questions cover the feature. Is the tamper switch in the cover or the base, because that decides which removal methods it catches. Does a tamper event push a remote notification or only a local log. Is there an installer or arm-delay mode that suppresses tamper noise during mounting. And does the sensor latch tamper state while it is off the wall, so the hub knows an enrolled device spent the afternoon in a drawer.
A door window sensor manufacturer answers these from the product definition rather than from memory. The tamper behavior on XingLiao sensor lines is documented per model, and project-specific questions about notification routing go here.
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