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

offline-devices-notifier.yaml

blueprint:
  name: Offline Devices Notifier
  description: Notifies for switches, sensors, and binary sensors
  #By 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: Select what time to run the check
      default: '10:00:00'
      selector:
        time: {}
    day:
      name: Day to run the check on
      description: Select when to run the check
      default: "0"
      selector:
        select:
          options:
            - label: "Monday"
              value: "0"
            - label: "Tuesday"
              value: "1"
            - label: "Wednesday"
              value: "2"
            - label: "Thursday"
              value: "3"
            - label: "Friday"
              value: "4"
            - label: "Saturday"
              value: "5"
            - label: "Sunday"
              value: "6"
    exclude:
      name: Exclusions
      description: Select what to exclude from the check
      default: []
      selector:
        target: {}
    actions:
      name: Actions
      description: Action your notification. {{offline_devices}} will replaced with the name of any offline devices
      selector:
        action: {}
  source_url: https://gist.github.com/robertbeal/5b1d051dd095dc7258c89ee0b196e220
variables:
  day: !input 'day'
  exclude: !input 'exclude'
  offline_devices: >-
    {% set result = namespace(offline_devices=[]) %}
    {% set domains = ['sensor', 'binary_sensor', 'switch'] %}
    
    {% set excluded_entities = exclude | selectattr('entity_id', 'defined') | map(attribute='entity_id') | list %}
    {% set excluded_devices = exclude | selectattr('device_id', 'defined') | map(attribute='device_id') | list %}
    {% set excluded_areas = exclude | selectattr('area_id', 'defined') | map(attribute='area_id') | list %}
    {% set excluded_labels = exclude.label_id | default([]) %}
    
    {% for domain in domains %}
      {% for entity in states[domain] | selectattr('state', 'eq', 'unavailable') %}
        {% set device_id = device_id(entity.entity_id) %}
        {% set device_name = device_attr(device_id, "name") %}
        {% set device_area = area_id(device_id) %}
        {% if 
          entity.entity_id not in excluded_entities and
          device_id not in excluded_devices and
          device_area not in excluded_areas and
          device_name not in excluded_labels
        %}
          {% set result.offline_devices = result.offline_devices + [entity.entity_id] %}
        {% endif %}
      {% endfor %}
    {% endfor %}
    
    {{result.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