Syncs an external temperature sensor to a Sonoff TRVZB.

sonoff_trvzb_external_temp_sync.yaml

blueprint:
  name: Sonoff TRVZB External Temp Sync (Fixed)
  description: >
    Syncs an external temperature sensor to a Sonoff TRVZB. 
    This version fixes the 'UndefinedError' by mapping inputs to variables.
  domain: automation
  input:
    external_temp_sensor:
      name: External Temperature Sensor
      description: The sensor that provides the actual room temperature.
      selector:
        entity:
          domain: sensor
          device_class: temperature
    trv_external_temp_input:
      name: TRV External Temperature Input
      description: The 'number' entity of the Sonoff TRV (e.g., number.trv_external_temperature_input).
      selector:
        entity:
          domain: number
    trv_sensor_selector:
      name: TRV Temperature Sensor Select
      description: The 'select' entity of the Sonoff TRV (e.g., select.trv_temperature_sensor_select).
      selector:
        entity:
          domain: select

# This section maps the inputs to variables so the templates can access them
variables:
  temp_sensor_entity: !input external_temp_sensor

mode: single

trigger:
  - platform: state
    entity_id: !input external_temp_sensor
  - platform: time_pattern
    minutes: "/30"
  - platform: homeassistant
    event: start

condition:
  # Verify the sensor is a valid number before proceeding
  - condition: template
    value_template: "{{ is_number(states(temp_sensor_entity)) }}"

action:
  # 1. Force the TRV into 'external' mode
  - service: select.select_option
    target:
      entity_id: !input trv_sensor_selector
    data:
      option: "external"

  # 2. Send the temperature value to the TRV
  - service: number.set_value
    target:
      entity_id: !input trv_external_temp_input
    data:
      # We use the variable 'temp_sensor_entity' here instead of '!input'
      value: "{{ states(temp_sensor_entity) | float(0) }}"