June 26, 2026

Monthly smart home battery health audit

On the first Monday of each month, get a calm Slack DM with every smart home device that needs new batteries, grouped by room, plus a running spreadsheet of what dies fastest.

Agentic Task

Home Assistant

Google Sheets

SlackOperationsPersonal ProductivityNotifications & AlertsDaily Digests

PromptCreate

On the first Monday of every month at 8am in my local time zone, run a battery health audit of my smart home and give me one tidy heads up instead of seven duplicate alerts. Use a monthly cron trigger.

Step 1. Use Home Assistant's List States to pull the current state of every entity. Filter down to the ones that are actually battery powered. That means anything with a numeric battery_level attribute, or any sensor whose device_class is "battery". This should catch door and window sensors, motion sensors, leak sensors, thermostats, locks, remotes, and similar.

Step 2. For each matching entity, capture the device name, the room or area it belongs to, the current battery percentage, and if possible the battery type inferred from the entity name or attributes (for example CR2032, AA, AAA). Sort them into three tiers: critical for below 15 percent, low for 15 to 30 percent, and healthy for above 30 percent. Healthy is just for the running log, not for the message.

Step 3. For every device in the critical or low tier, append one row to a Google Sheet using Append Values. Each row should include the run date, the room, the device name, the entity id, the battery percentage, the tier (critical or low), and the inferred battery type if known. Ask me which spreadsheet and tab to use the first time the workflow runs. This sheet is the long running history of which devices die fastest and which batteries I keep buying.

Step 4. If there is at least one device in critical or low, send me a single Slack direct message using Send a Message. Write it as a calm, plain English summary grouped by room. Lead with the critical devices and then the low ones. For each device, include the device name, the battery percentage, and the battery type if you inferred one. End with a one line total, for example "3 critical, 5 low, 47 healthy this month". If nothing is below 30 percent, skip the Slack message entirely. Do not send an "all good" ping.

The point of this workflow is one tidy monthly heads up plus a long running spreadsheet of household battery consumption. Do not alert per device, do not alert when nothing is wrong, and do not duplicate rows in the sheet on the same run.

Additional information

What does this prompt do?

Scans every battery powered device in your Home Assistant setup once a month, including door sensors, motion sensors, leak sensors, thermostats, locks, and remotes.
Sorts results into critical, low, and healthy so you know what actually needs attention versus what is fine.
Sends one tidy Slack DM grouped by room, naming the specific devices and the battery type when it can be inferred, and stays silent when nothing is low.
Logs every low or critical device to a Google Sheet so you build a history of which devices die fastest and which batteries you keep buying.

What do I need to use this?

A Home Assistant setup you can reach from the internet, with a long lived access token.
A Slack account you can sign in to, so the monthly heads up arrives as a direct message.
A Google account with a spreadsheet ready to receive one row per low battery device.

How can I customize it?

Change the schedule, for example to the first of the month, every other Sunday, or only during winter when batteries drain faster.
Adjust the thresholds, so critical and low match what you actually want to hear about for your devices.
Pick the destination, so the message goes to a channel for the whole household instead of a private DM, or so the spreadsheet lives in a shared folder.

Frequently asked questions

Will this find batteries in every kind of smart home device?

It looks across all of your Home Assistant entities and picks up anything that reports a battery level or is tagged as a battery sensor, which usually covers door and window sensors, motion sensors, leak sensors, thermostats, locks, and most remotes.

What if everything is fine this month?

You get nothing, which is the point. The Slack message only sends when at least one device is below the low threshold, so a quiet month stays quiet. The spreadsheet only adds rows for low or critical devices, so a healthy month adds no rows.

Can it tell me what kind of batteries to buy?

When the battery type can be inferred from the device name or attributes, like CR2032 or AAA, the Slack message includes it next to the device. When it cannot, the message just names the device so you can check it yourself.

Why a monthly audit instead of an alert for each device?

A per device alert turns into seven duplicate pings every time a sensor blips. A monthly roll up gives you one shopping list, one trip to the drawer of spare batteries, and a clean history of which devices are draining fastest.

Do I need to list every device by hand?

No. The workflow asks Home Assistant for the current state of everything and filters down to battery devices automatically, so new sensors you add later are picked up the next time it runs.

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