Loosely coupled configuration for Home Assistant

Thu, 17 Jul 2025 19:22:03 +0000

This post will be short, but I hope it prove to be useful.

My home is getting more and more connected, and the number of my automations grows each passing month. Recently, I equipped my roller shutters with connected Somfy engines so they could roll down automatically when it's too hot in summer. Spoiler: given the current heatwave, it's a boon!

I naively created the following automation configuration:

- id: '1742926520608'
  alias: Close all shutters
  description: Close all shutters if it's already hot in the morning
  triggers:
  - trigger: time                                                      #1
    at: 07:00:00
  conditions:
  - condition: numeric_state
    entity_id: sensor.saint_julien_en_genevois_temperature
    above: 23                                                          #2
  actions:
  - action: cover.close_cover                                          #3
    metadata: {}
    data: {}
    target:
      entity_id: cover.all_shutters                                    #4
  mode: single

If at 7 AM local time
The temperature where I live is higher than 23°C
Close
All shutters

Note the entity ID cover.all_shutters: it's not an out-of-the-box entity. I explicitly created a group for it:

cover:
  - platform: group
    name: "All shutters"
    entities:
      - cover.left_shutter
      - cover.middle_shutter
      - cover.right_shutter
      - cover.bedroom_shutter
      - cover.office_shutter

I copied the same approach to switch all the lights off when I leave home. I soon realized there were flaws in this approach.

While the probability of adding more shutters is pretty low, I'll likely add more smart lights in the future. Every time I add one, I'll need to put it in the group. Also, I added lights in waves; I ID'd the lights in French at first, but later switched to English. As I renamed them all in English to be coherent, I had to update my dashboard to adapt to the new IDs.

Home Assistant already has everything to cater for the above, Areas. You can–and you probably should-assign every device to an Area. Once done, you can replace the target part of the automation with a list of area_id instead of entity_id.

- id: '1742926520608'
  alias: Close all shutters
  description: Close all shutters if it's already hot in the morning
  triggers:
  - trigger: time
    at: 07:00:00
  conditions:
  - condition: numeric_state
    entity_id: sensor.saint_julien_en_genevois_temperature
    above: 23
  actions:
  - action: cover.close_cover
    metadata: {}
    data: {}
    target:
      area_id:                                                         #1
        - office
        - bedroom
        - living_room
  mode: single

Now, Home Assistant closes all shutters that are in any of these areas

Areas tend to be much more stable than individual devices. How often do you add a new area to your home? Granted, an area doesn't explicitly map to a room, but I think that's a better approach than my original one. Home Assistant will now manage every new device of the same type added to the area, e.g., if you motorize a new shutter or add a new light.

There's one drawback to this approach. UI Tiles accept only a single entity ID. Thus, if you want to use the GUI, you must create a group as I did in my first approach.

In this post, I showed how you could replace the explicit grouping of devices by areas. It's the same idea of loose coupling we have in software, but applied to Home Assistant configuration.

To go further:

Originally published at A Java Geek on July 13^th, 2025

Getting a single value from a device's state in Home Assistant

Thu, 22 May 2025 06:21:05 +0000

I recently acquired Netatmo smart radiator valves to manage my rooms' temperature remotely. I'm not skilled at manual tasks, but I could easily replace the old thermo-static valves. I then registered the smart ones in the Netatmo app. Finally, I integrated them in my Home Assistant via the dedicated Netatmo integration. Everything was very straightforward.

I noticed that each valve not only allows remote control but also offers a state with several attributes. I wanted to extract the room's temperature indicator from it. It was not as easy as I thought it was, so I want to describe how I managed to achieve it.

By default, the Netatmo valve displays a multi-valued state. To check, go to the Developer Tools > States menu. You can use a filter to find the device.

Entity	State	Attributes
climate.spare_bedroom + Valve Spare Bedroom	auto	hvac_modes: auto, heat + min_temp: 7 + max_temp: 30 + target_temp_step: 0.5 + preset_modes: away, boost, frost_guard, schedule + current_temperature: 14 + temperature: 7 + hvac_action: idle + preset_mode: frost_guard + selected_schedule: Unknown 67ab635c2dd1afb1e601a8c2 + heating_power_request: 0 + attribution: Data provided by Netatmo + friendly_name: Valve Spare Bedroom + supported_features: 401

The problem is that the above attributes are not readily usable. We must first extract them individually. For this, we need to create a sensor; head to File Editor and select configuration.yaml. Then, append the following snippet:

template:
  - sensor:
    - unique_id: sensor.spare_bedroom_temperature
      name: "Spare Bedroom Temperature"
      state: "{{ state_attr('climate.spare_bedroom', 'current_temperature') }}" #1
      unit_of_measurement: "°C"
      device_class: temperature                                                 #2

Match the pair entity-attribute above
Must be temperature to be used as a temperature sensor afterward

Click on Save.

We don't need to restart Home Assistant, but we must reload the configuration. Click on Developer Tools. Then, click on Check configuration. The new sensor should appear in Settings > Entities.

We can now set the Area via the UI to one of the existing areas, in this case, the Spare Bedroom.

Finally, we can update the Spare Bedroom area in Settings > Area > Spare Bedroom. Set the temperature sensor to the only available item, the sensor we set in the previous steps.

At this point, whenever we add the Area card to a dashboard, Home Assistant displays our newly-created temperature sensor on top of it.

You can use this approach for every State. Check them, and I'm sure you'll get new ideas. For example, every automation has a last_triggered timestamp attribute.

To go further:

Originally published at A Java Geek on May 18^th, 2025

Coder Legion - Recent posts tagged home-automation

Loosely coupled configuration for Home Assistant

Getting a single value from a device's state in Home Assistant