Questions, bugs, or a room where detection needs tuning — write to andrei.costin.neagoe@gmail.com. Please include your device model and iOS version.
The spare phone becomes the Sentry. The phone you carry becomes the Companion. Both devices must be signed into the same Apple Account — that is the whole pairing step. To use a phone on a different Apple Account, show it the QR code under Setup → Family access.
Plug it in, turn the volume up, set a disarm PIN, and enable Guided Access so a stray tap cannot leave the app. The checklist links straight into the Shortcuts automations that reopen Hotel Sentry if power blips or if you text it a code word.
Choose a sensitivity, set the exit delay long enough to walk out, and tap ARM. The screen goes near-black; a small dot shows the state. The first minute after the exit delay is calibration — the app is learning the room.
The sentry sends a heartbeat every five minutes; after two missed beats it is marked offline. Check the phone is still charging, the app is still in the foreground, and it has network. Force-quitting the sentry app will always show as offline — that is by design.
Pressure detection needs a phone with a barometer (iPhone 6 and later) and a closed room — a propped-open window or a running extractor fan bleeds the pressure blip away. Try High sensitivity, and make sure calibration finished (the dot stops pulsing amber).
Drop to Low sensitivity. Corridor noise and loud air conditioning are the usual causes. The event log shows exactly which signals scored, which makes it easy to see what set it off.
iOS will not let an app raise the hardware volume. Turn the volume up before arming — the setup checklist has this as a step.
Newly installed apps sometimes take a while to appear. Launch Hotel
Sentry once, reopen Shortcuts, and search rather than scrolling. If it is still absent,
use the action Open URLs with hotelsentry:// instead.
Alerts travel by push, with a 30-second poll as a fallback and a direct Bluetooth link when the phones are near each other. On hotel Wi-Fi that occasionally means a short delay rather than an instant banner.
Hotel Sentry is an extra pair of eyes, not a security guarantee. It does not replace a door lock, a hotel safe, or contacting hotel staff and local authorities if you believe someone has entered your room.