Oil heater control unit uses outside temperature to turn on standby mode when the outside temperature reaches defined value (18degC).

An Arduino board listens for a temperature change and sets digital potenttiometer that is connected to an oil heater's control unit.

Board: Seeed Studion XIAO ESP32C3 Digital pot: PmodDPOT from DIGILENT

• 8-bit resolution
• 60Ohm - 10kOhm range
• controlled through SPI

This action runs when outside temperature changes and sends it to the device:

- id: NEW_ID
  alias: Outside temperature changed
  description: ''
  trigger:
  - platform: state
    entity_id:
    - weather.home
    attribute: temperature
  condition: []
  action:
  - service: number.set_value
    target:
      entity_id: number.oil_heater_outside_temperatur
    data:
      value: '{{ state_attr(''weather.home'', ''temperature'') }}'