Installation and Setup

Installation and Setup

A door sensor stops reporting but still reads "closed". A temperature sensor freezes on a plausible number. A coin cell slides under 10 percent while every dashboard shows it green. Home Assistant cannot tell you, because a device that stopped talking looks exactly like a device with nothing new to say.

Device Sentinel watches for that. It learns how often each of your devices normally reports, then looks for when they stop. No timeouts to guess at, no list to maintain.

It takes about five minutes to install and starts learning immediately.

Before You Start

This integration is tested on Home Assistant 2026.5.0 or newer, and HACS. Nothing goes in configuration.yaml, now or ever.

Installing

Device Sentinel is not in the default HACS store yet, so it is added as a custom repository.

One click, if you already have HACS:

That opens HACS on your own instance with the repository already filled in. Download it, restart Home Assistant, then go to Settings, Devices and Services, Add Integration and search for Device Sentinel.

By hand, if you would rather:

1. Open HACS, click the three-dot menu, and choose Custom repositories.
2. Paste https://github.com/TheThinkingHome/device_sentinel, choose the Integration category, and click Add.
3. Find Device Sentinel in HACS and download it.
4. Restart Home Assistant.
5. Go to Settings, Devices and Services, Add Integration, and search for Device Sentinel.

Setup requires nothing at all. There is one instance, no options dialog, and every setting has a working default behind the Configure button for later. It starts watching your hardware the moment you add it.

Press the Three Enable Buttons

Open Settings, Devices and Services, Device Sentinel. Look for the three buttons in the Configuration section: Enable Battery, Enable Signals, and Enable Last Seen. Press all three. Many integrations ship their battery, link-quality and last-contact sensors turned off, so the readings exist on your devices but nothing in Home Assistant is recording them. Device Sentinel requires that these entities be enabled because it can only learn from what is switched on. Each button turns on every disabled entity of its kind, including any you disabled yourself, so if there is one you want left off, do not press that button. The log names every entity each press enabled.

Set Your Home Assistant URL

This one is worth doing now too, and it is a Home Assistant setting rather than a Device Sentinel one.

Go to Settings, System, Network, and look under Home Assistant URL. There are two fields: Internet, the address that reaches your house from outside, and Local network, the address you use on your own wifi.

Device Sentinel builds and sends reports to your phone and email with links to the reports it creates. If your Home Assistant URL is not properly configured these reports will only be able to be viewed when logged into your home Wi-Fi network.

What You Will See, and When

Straight away. Every device in your registry is being watched. Discovery is automatic and there is nothing to add. Low battery detection is live from the first reading, with the default threshold set at 20 percent.

Within minutes. Three files appear:

• /local/device_sentinel/daily_brief.html is a report detailing what is wrong now, and what happened over the last day, in plain language. It arrives by email too, once you tell it where to send it.
• /local/device_sentinel/signal_report.html names the devices whose radio link is worse today than it usually is, worst first.
• /local/device_sentinel/battery_report.html is a chart and table displaying every device's battery level and rate of decay.

All three are good dashboard cards. Point a Webpage card at those addresses; they never change.

Over the first week. Freeze detection turns itself on device by device, as each one learns its own rhythm. A device added years from now does the same thing on its own. There is no learning mode to switch off and no global timer.

So an empty-looking report on the first day is the integration working, not failing. It has nothing to report yet because it has not yet seen your house misbehave.

Where Things Are Kept

Two folders, created for you.

• config/www/device_sentinel/ holds the three pages above, plus a dated copy of each going back fourteen days.
• config/device_sentinel/ holds three Markdown files for when you want to look deeper: what has been learned per device, which devices are watched and why, and a record of every unusual silence.

Trying Pre-Releases

Most releases are published as pre-releases while they are proven, and HACS hides those by default. You do not need them; this section is for anyone who wants to help test.

Under Settings, Devices and Services, Entities, set the Status filter to Disabled. Filter to show Device Sentinel entities, find the Pre-release entity, and enable it. In HACS, choose Redownload, then Need a different version?.

With that switch off you are only ever offered fully released versions, and the main branch is not visible.

Next

Notifications and Daily Brief is where you show Device Sentinel where and how to send push notifications and emails.

Exclusions and Muting is where integrations and devices that are not important to you can be muted from push notifications and reports.