Home Assistant Blueprint: Low battery level detection & notification for all battery sensors

report_zigbee_zwave_devices_gone_offline.yaml

blueprint:
  name: Report offline zigbee/zwave/battery/smart plug devices
  description: Works with Smart Plugs, ZWave, Zigbee etc (Works with ZHA & Z2M)
  #SlipperySaxophone 2024-07-12 Now detects devices that have been offline
  #Tahutipai 2024-02-21
  #Originally Based on the work of Sybx @ https://community.home-assistant.io/t/low-battery-level-detection-notification-for-all-battery-sensors/258664
  #Note: This has been upgraded to report only the Device that is offline, not multiple individual sensors within one Device
  domain: automation
  input:
    time:
      name: Time to test on
      description: Test is run at configured time
      default: '10:00:00'
      selector:
        time: {}
    day:
      name: Weekday to test on
      description: 'Test is run at configured time either everyday (0) or on a given
        weekday (1: Monday ... 7: Sunday)'
      default: 0
      selector:
        number:
          min: 0.0
          max: 7.0
          mode: slider
          step: 1.0
    stale:
      name: Days Unresponsive
      description: 'Number of days of no communication to consider a node dead. Recommended >= 2'
      default: 2
      selector:
        number:
          min: 1
          max: 365
    exclude:
      name: Excluded Sensors
      description: Battery sensors (e.g. smartphone) to exclude from detection. Only entities are supported, devices must be expanded!
      default: {entity_id: []}
      selector:
        target:
          entity:
            device_class:
              - battery
              - switch
    actions:
      name: Actions
      description: Call your notification here. {{offline_devices}} will replaced with the name of any offline devices
      selector:
        action: {}
  source_url: https://gist.github.com/slipperysaxophone/6b4c31b8f75fcb3d3817007e35384396
variables:
  day: !input 'day'
  exclude: !input 'exclude'
  stale: !input 'stale'
  offline_devices: >-
    {% set stale_date = now() - timedelta(days=stale) %}
    {% set results = namespace(offline_devices=[]) %}
    {% set devices = namespace(dev_ids=[]) %}
    {% for sensor in states.sensor | selectattr('attributes.device_class', 'defined') | selectattr('attributes.device_class', '==', 'battery') %}
      {% if sensor.entity_id in exclude.entity_id %}
        {% continue %}
      {% endif %}
      {% if "unavailable" in sensor | string %}
        {% set results.offline_devices = results.offline_devices + [device_attr(device_id(sensor.entity_id), "name")] %}
        {% continue %}
      {% endif %}
      {% set devices.dev_ids = devices.dev_ids + [device_id(sensor.entity_id)] %}
    {% endfor %}
    {% for sensor in states.binary_sensor | selectattr('attributes.device_class', 'defined') | selectattr('attributes.device_class', '==', 'battery') %}
      {% if sensor.entity_id in exclude.entity_id %}
        {% continue %}
      {% endif %}
      {% if "unavailable" in sensor | string %}
        {% set results.offline_devices = results.offline_devices + [device_attr(device_id(sensor.entity_id), "name")] %}
        {% continue %}
      {% endif %}
      {% set devices.dev_ids = devices.dev_ids + [device_id(sensor.entity_id)] %}
    {% endfor %}
    {% for switch in states.switch | selectattr('state','eq','unavailable') %}
      {% if switch.entity_id not in exclude.entity_id %}
        {% set results.offline_devices = results.offline_devices + [device_attr(device_id(switch.entity_id), "name")] %}
      {% endif %}
      {% set devices.dev_ids = devices.dev_ids + [device_id(switch.entity_id)] %}
    {%endfor %} 
    {% for device_id in devices.dev_ids %}
      {% for device_entity in device_entities(device_id)%}
        {% if device_entity | contains("last_seen") %}
          {% set last_seen = states(device_entity) %}
          {% if not as_timestamp(last_seen, default=None) or stale_date | as_timestamp > last_seen | as_timestamp %}
            {% set results.offline_devices = results.offline_devices + [device_attr(device_id, "name")] %}
          {% endif %}
        {% endif %}
      {% endfor %}
    {% endfor %}
    {{results.offline_devices|sort|unique|join('\n')}}
trigger:
- platform: time
  at: !input 'time'
condition:
- '{{ offline_devices != '''' and (day | int == 0 or day | int == now().isoweekday()) }}'
action:
- choose: []
  default: !input 'actions'
mode: single

Modifed in order to detect devices that have completely fallen off the network and have not been tagged as unavailable.