Auto-arm explained: when your phone secures itself
If your phone lies still and unattended for a while, it arms itself. Unlocking disarms it. How it works and who it is for.
The hardest part of a phone alarm system is not the siren but arming it. If you forget to secure the phone when you get up in a café, you gain nothing from it. That is exactly what auto-arm is for: your phone recognises by itself when it is unattended.
The idea in one sentence
If the phone lies still with the screen off for an adjustable time and has not moved from its spot either, it arms itself. If someone then touches it, the owner has a few seconds to unlock it; otherwise the siren sounds.
The process step by step
In the viewer you set, for each phone, how many minutes of stillness it should wait before arming, for example 10. The default is “off”. The phone then watches in the background with its motion sensor whether it is lying still, and uses its position to notice whether you are moving away from the spot. Someone riding in a car with the phone counts as attending to it, as does someone using it. When the quiet time is up, the phone asks the server to arm it.
If you pick it up later, you feel a short double buzz. You now have, adjustable and by default about 12 seconds, to unlock the phone. If that works, it is disarmed automatically without you having to enter a password. If not, the siren sounds and everyone in the household gets the message.
Why unlocking is enough
Someone who can unlock a phone with a PIN, pattern or fingerprint is, as a rule, the owner. That is the same assumption the phone itself rests on. That is why this shortcut may only apply to phones that armed themselves. A phone armed by hand, for example a backpack guard, still requires signing in again with a password or Google to disarm.
What you need for it
A screen lock that is set up, the location permission “Always” and battery optimisation switched off. In addition, the phone needs a connection to the server when arming, because the state is kept there.
When it gets annoying, and how to avoid that
If you keep the phone in your trouser pocket for a long time and hardly move, for example in the cinema or in a meeting, it could be mistaken for unattended. So choose a quiet time that suits your daily life: shorter if the phone often lies on the table, longer if you sit a lot. And test the function at home before you rely on it. Settings that are too sensitive can be changed in the viewer, as can the triggers: if movement alone is too much for you, let only a change of place or the charging cable trigger it.
Limits
If the thief knows your PIN, unlocking does not help. If he switches the phone off at once, it cannot be reached. And a phone lying still in power-saving mode sometimes accepts remote commands with a delay. The honest limits are covered in the article Phone alarm system: the honest limits.
