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Device Sentinel watches your hardware. It detects frozen devices (silent but showing a healthy value), unavailable devices, and low batteries, by learning each device's own reporting rhythm and setting per-device freeze windows automatically. Every detection reaches a problem list you act on, and a daily brief writes it up in plain language and emails it on its schedule.
Everything runs on sensible defaults from the moment it is installed. There is one thing to configure: for alerts to reach your phone, Device Sentinel must be told where to send them, on the Notifications and Daily Brief screen.
- Installation and Setup: what you need, the five minutes it takes, and the one Home Assistant setting worth getting right first.
Open Settings, then Devices and Services, then Device Sentinel, then Configure.
- Notifications and Daily Brief: where alerts go, quiet hours, and when the daily brief is sent.
- Global Exclusions: hardware you never want judged or reported, by anything.
- Low Battery: the low threshold, how far ahead a falling cell is flagged, and battery-only excludes.
- Signal Strength: how weakening radio links are judged against a line just above each device's own learned floor, and the colored dwell chart that puts the whole fleet on one page. Three sliders tune it.
- Freeze Detection: how long a device may go quiet before it is called frozen, unavailable, or unknown. Set by two grace sliders.
- Advanced: settings most people never need to change.
- Maintenance Mode: the button you press before working on hardware, so your repairs are not learned as a device's normal behavior.
- How Device Sentinel Learns: the rhythm, the windows, and why there is no fixed timeout anywhere.
- The Device Page: what every sensor and button means.
- The Daily Brief: the report written for a person, every day, in plain language, and emailed on its schedule.
- The Battery Report: which cells are going to be low, which is the question a percentage cannot answer.
- The Signal Dwell Chart: each device's signal against its own history, and how to tell a bad room from a bad day.
- The Diagnostic Reports: the three diagnostic files behind all of them.
- The Problem List: how a detection reaches the list, and what the checkbox does.
- The Bridge and Broker Sensors: the coordinator sensor and the MQTT broker sensor, and what each state means.
- What Is Recorded About Your House: restarts, broker outages, coordinator outages and integration reloads, and why a device's silence is explained by them.
- Built to Be Efficient: how writing is kept down, and what to set on an SD card.
- FAQ and Troubleshooting
Device Sentinel recognizes four and can read one. These pages say what each gets, and what would change that.
- Zigbee2MQTT: fully read. Pairing windows, bridge outages, and a second opinion on every freeze verdict.
- ZHA: detected only. What is known, what is unverified, and the captures that would change it.
- Z-Wave: detected only. What is known, what is unverified, and the captures that would change it.
Open an issue at the issue tracker and attach your diagnostics: Settings, Devices and Services, Device Sentinel, then the three-dot menu, then Download Diagnostics. The diagnostics carry the learned state and settings in effect and answer most questions without a screenshot. Notification targets are redacted automatically.