Custom sensors

Custom sensors are parameterized sensors you can add as many times as you like, with different settings. Each one has:

• Type: what kind of sensor it is
• Name: the entity name in Home Assistant
• Parameter: what to monitor (depends on the type)
• Unit: optional unit of measurement shown in Home Assistant; it marks the sensor as a numeric measurement, and a unit of °C, GB, MB/s, h, W, V, A or MHz brings the matching device class (temperature, data size, data rate, duration, power, voltage, current, frequency), so a °C sensor shows as °F where that is the custom and the unit can be changed on the entity (10.10.0+, integration 10.10.0+)
• Profile: the polling interval (fast / normal / hourly / startup)
• Tray and Svc: which role reads it

The Custom sensors tab

Add, or a double click on a row, opens the editor: it explains the chosen type, offers what the PC has (running processes, services, drives, built-in attributes, LibreHardwareMonitor values), and Test shows the value the sensor would report. Shift and Ctrl pick several rows in the list; Remove and Test then work on all of them (10.10.0+). A sensor only the service can read says so instead of a value.

The sensor editor, with one-click value testing

process_running

Checks whether a Windows process is currently running.

Field	Example
Parameter	notepad or chrome.exe
State	true / false

The .exe extension is optional. The check uses Process.GetProcessesByName(), so it matches the process name without path.

Use case: trigger an automation when a specific application starts or stops.

Name: "Chrome running"
Parameter: chrome

service_status

Reads the status of a Windows service.

Field	Example
Parameter	Spooler or wuauserv
State	running, stopped, paused, etc.

Use the exact Windows service name (not the display name). You can find it in services.msc or with Get-Service in PowerShell.

Use case: monitor whether a critical service is running (database, backup agent, print spooler).

Name: "Print Spooler"
Parameter: Spooler

disk_free

Reports the free space on a drive in GiB.

Field	Example
Parameter	D or D: or D:\
State	123.4 (GiB)

Any of the three formats work. The sensor reports as a numeric measurement with unit GiB.

Use case: alert when a data drive is running low on space.

Name: "Data drive free"
Parameter: D

built_in_attribute

Extracts a single value from a built-in sensor's attribute tree and exposes it as a standalone sensor entity.

This is the most powerful custom sensor type. Some built-in sensors (LAN IP, Active displays, GPU usage, Drive health, Event Log errors) return structured data with multiple values. The built_in_attribute type lets you drill into that structure and pull out one specific value.

Field	Example
Parameter	network_address.addresses[0].address
State	192.168.1.42

Path syntax: the parameter is a dot-separated path into the sensor's attribute JSON. Array elements use [index] notation:

sensor_key.property.nested_property
sensor_key.array[0].property
sensor_key.array[0].nested[1].value

The editor's list offers every path this PC has, with the unit filled in when it picks one; Sensor attributes lists them by sensor. Some of the paths:

Built-in sensor	Attribute path	Value
LAN IP	network_address.addresses[0].adapter	Adapter name
LAN IP	network_address.addresses[0].address	IPv4 address
Active displays	active_display.displays[0].name	Display name
Active displays	active_display.displays[0].width	Width in pixels
Event Log errors	event_log_errors_recent.events[0].provider	Source
Event Log errors	event_log_errors_recent.events[0].created_at	Timestamp
Last shutdown reason	last_shutdown_reason.reason	Reason text
Last wake reason	last_wake_reason.source	What woke the machine
Last wake reason	last_wake_reason.kind	modern_standby, sleep, hibernate or fast_startup
Sleep blocked	sleep_blocked.primary_blocker	First holder that really blocks sleep
Sleep blocked	sleep_blocked.blockers[0].name	Holder (process, service or driver)
GPU usage	gpu_usage.engines.3d	3D engine load (%)
GPU usage	gpu_usage.memory_dedicated_gb	Dedicated GPU memory in use (GB)
GPU usage	gpu_usage.adapters[0].name	Adapter name
GPU usage	gpu_usage.adapters[0].usage	This adapter's load (%)
GPU usage	gpu_usage.adapters[1].engines.3d	The second adapter's 3D engine load (%)
Memory usage	memory_usage.total_gb	Installed memory (GB)
System drive free	system_drive.total_gb	The system drive's size (GB)
Drive health	drive_health.temperature	The system drive's temperature (°C)
Drive health	drive_health.drives[0].power_on_hours	The first drive's power-on hours (h)
Drive health	drive_health.drives[1].health	The second drive's health
Audio sessions	audio_sessions.apps[0].volume	The first app's volume (%)
Camera in use	camera_in_use.apps[0]	App using the camera
Microphone in use	microphone_in_use.apps[0]	App using the microphone

Auto-create from the built-in sensors

Sensors with attributes show a + button next to their name on the Built-in sensors tab. Clicking it creates a built_in_attribute custom sensor for every attribute path of that sensor this PC has, each a separate Home Assistant entity with its unit. Clicking + on LAN IP creates three custom sensors per adapter: adapter name, adapter description and IPv4 address; on Drive health, the temperature, the health, the power-on hours and the rest for every drive. Delete the ones you do not need from the Custom sensors tab.

Example: the second network adapter's IP address:

Name: "Secondary adapter IP"
Parameter: network_address.addresses[1].address

Example: the system drive's temperature:

Name: "SSD temperature"
Parameter: drive_health.temperature
Unit: °C
Svc: on

A custom attribute sensor can only be ticked for a role that reads its built-in sensor (the drive health for the service, the active window for the app); the other box is greyed. It refreshes the shared read at its own profile: see Polling profiles.

lhm (LibreHardwareMonitor)

Reads a hardware value from a running LibreHardwareMonitor: CPU and GPU temperature, fan speed, voltage, load. The app has no vendor-specific hardware code of its own; LibreHardwareMonitor does the reading and the app asks it.

1. Run LibreHardwareMonitor and turn on Options > Remote Web Server > Run (port 8085 by default). Let it start with Windows if the sensor should always work.

2. Add a custom sensor of the type LibreHardwareMonitor. The Sensor field lists everything LibreHardwareMonitor reports, with the current value; picking one fills in the unit, and the name when it is empty.

3. The parameter is LibreHardwareMonitor's own sensor id (e.g. /amdcpu/0/temperature/2).

4. The value is null while LibreHardwareMonitor is not running.
5. The Connection... button next to the field sets a different address or port (default http://localhost:8085), and the user name and password when LibreHardwareMonitor's web server is set to ask for them.
6. No Home Assistant integration update is required.

Name: "CPU temperature"
Type: LibreHardwareMonitor
Parameter: /amdcpu/0/temperature/2
Unit: °C
Profile: normal
State: 45.5 °C

command / command_powershell / command_pwsh

Runs a program or PowerShell script and uses its output as the sensor value, for anything Windows has no built-in sensor for.

Type	Parameter	Runs as
Command (program)	A program or full command line (e.g. nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader,nounits)	The executable directly (fast, no shell)
Command (PowerShell)	An inline command or a .ps1 path	powershell.exe -NoProfile -ExecutionPolicy Bypass
Command (PowerShell 7)	Same as above	pwsh.exe -NoProfile -ExecutionPolicy Bypass

• The first non-empty line of the output (trimmed, at most 255 characters) becomes the sensor state, so format your command to print a single value. A plain number is published as a numeric value.
• Set an optional Unit (e.g. °C) to show it in Home Assistant; a unit also marks the sensor as a numeric measurement, so Home Assistant keeps long-term statistics and graphs it.
• Each run has a timeout (about 10 s) so a hung command cannot stall reporting. Pick the Normal or Hourly profile, not Fast.
• Security: you define what runs; Home Assistant only reads the resulting value, it cannot send commands. A command sensor for the service needs an administrator's approval, since the service runs as SYSTEM: Commands the service runs. No Home Assistant integration update is required for these.

Name: "GPU temperature"
Type: Command (program)
Parameter: nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader,nounits
Unit: °C
Profile: normal
State: 54 °C