Solar EV charger - how to read the DAC value (ESP8266 / MCP4725)

ESPHome
1

I have got my solar charger working with an ESP8266 receiving a value from an HA automation which it uses to set the output of a MCP4725 DAC.

What I don’t understand is how to monitor that DAC value in home assistant? I am reading through the section on lambdas and publish_state() and getting nowhere.

Any help on being able to see what the DAC is set to would be greatly appreciated.

The code from the device in ESPhome is:

esphome:
  name: evsecontroller
  friendly_name: EVSEcontroller
  on_boot:
    -  priority: 600
       then:
         - lambda: |-
             id(output_voltage).set_level(0);

esp8266:
  board: esp01_1m

# Enable logging
logger:

  # Set a global i2c connection
i2c:
  sda: GPIO4
  scl: GPIO5
  scan: true

# Set the output with default (address: 0x60 / global i2c)
output:
  - platform: mcp4725
    id: output_voltage



# Enable Home Assistant API
api:
  encryption:
    key: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
  services:
    - service: set_dac_value
      variables:
        dac_value: int
      then:
        - output.set_level:
            id: output_voltage
            level: !lambda 'return dac_value / 4096.0;'

ota:
  password: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

wifi:
  ssid: !secret wifi_password
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Evsecontroller Fallback Hotspot"
    password: "xxxxxxxxxxxxxxxxxx"

captive_portal:

And the automation that sets the DAC value according to available export power is:

- id: Solar charging optimisation
  alias: Solar charging optimisation
  trigger:
  - platform: state
    entity_id:
    - sensor.export_minus_charger_immersion
  condition:
  - condition: sun
    after: sunrise
    after_offset: '2'
  - condition: sun
    before: sunset
    before_offset: '2'
  - condition: not
    conditions:
    - condition: state
      entity_id: device_tracker.evsedac
      state: unavailable
  - condition: state
    entity_id: input_select.car_charge_mode
    state: 'Solar'
  action:
  - if:
    - condition: numeric_state
      entity_id: sensor.export_power_moving_average
      above: 1440
    then:
    - service: esphome.evsecontroller_set_dac_value
      data_template:
        dac_value: '{% set i = states(''sensor.export_minus_charger_immersion'') | int %}
                    {% if i > 3120 %} 1448
                    {% elif i > 2880 %} 1368
                    {% elif i > 2640 %} 1319
                    {% elif i > 2400 %} 1249
                    {% elif i > 2160 %} 1198
                    {% elif i > 1920 %} 1136
                    {% elif i > 1680 %} 1065
                    {% elif i > 1440 %} 1008
                    {% endif %}'
  - if:
    - condition: numeric_state
      entity_id: sensor.export_power_moving_average
      below: 1440
    then:
    - service: esphome.evsecontroller_set_dac_value
      data_template:
        dac_value: '0'
  mode: single