dewpoint_ventilation/dewpoint.yaml

#<<: !include secrets.yaml
esphome:
  name: dewpointfan

esp32:
  board: esp32doit-devkit-v1
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:
  password: !secret ota_password

ota:
  - platform: esphome
    password: !secret ota_password

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  use_address: dewpointfan.fd

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Dewpoint Fan Fallback Hotspot"
    password: !secret ota_password

mqtt:
  id: mqtt_client
  topic_prefix: dewpoint
  discovery: false
  broker: mqtt.fd
  port: 1883

i2c:
  sda: 21
  scl: 22

display:
  - platform: lcd_pcf8574
    dimensions: 20x4
    address: 0x27
    update_interval: 10s
    lambda: |-
      it.printf(0, 0, "Fan: %s", id(fan_relay).state ? "ON" : "OFF");
      it.printf(0, 1, "Temp I/O: %.1f/%.1f", id(inner_temperature).state, id(outer_temperature).state);
      it.printf(0, 2, "Hum I/O: %.1f/%.1f", id(inner_humidity).state, id(outer_humidity).state);
      it.printf(0, 3, "Dew I/O: %.1f/%.1f", id(inner_dew_point).state, id(outer_dew_point).state);
sensor:
  - platform: dht
    pin: 25
    model: DHT22
    temperature:
      name: "Inner Temperature"
      id: inner_temperature
    humidity:
      name: "Inner Humidity"
      id: inner_humidity
    update_interval: 10s
  - platform: dht
    pin: 26
    model: DHT22
    temperature:
      name: "Outer Temperature"
      id: outer_temperature
    humidity:
      name: "Outer Humidity"
      id: outer_humidity
    update_interval: 10s
  - platform: template
    name: "Inner Dew Point"
    unit_of_measurement: °C
    id: inner_dew_point
  - platform: template
    name: "Outer Dew Point"
    unit_of_measurement: °C
    id: outer_dew_point
  - platform: template
    id: fan_state_temp
    name: "Fan state"
    lambda: |-
      auto calc_dewpoint = [](float temp, float humidity) {
        float A = 17.27;
        float B = 237.7;
        float alpha = ((A * temp) / (B + temp)) + log(humidity / 100.0);
        return (B * alpha) / (A - alpha);
      };
      uint8_t fan_state = id(fan_state_temp).state;
      float inner_dewpoint = calc_dewpoint(id(inner_temperature).state, id(inner_humidity).state);
      float outer_dewpoint = calc_dewpoint(id(outer_temperature).state, id(outer_humidity).state);
      id(inner_dew_point).publish_state(inner_dewpoint);
      id(outer_dew_point).publish_state(outer_dewpoint);
      float deltadp = inner_dewpoint - outer_dewpoint;
      if (deltadp > 6.0) {
        fan_state = 1;
      }
      if (deltadp < 5.0) {
        fan_state = 0;
      }
      if (id(inner_temperature).state < 10.0) {
        fan_state = 0;
      }
      if (id(outer_temperature).state < -10.0) {
        fan_state = 0;
      }
      if (fan_state == 1) {
        id(fan_relay).turn_on();
      } else {
        id(fan_relay).turn_off();
      }
      id(mqtt_client).publish_json("sensor/dewpointfan", [=](JsonObject root) {
        root["inner_temp"] = id(inner_temperature).state;
        root["inner_humidity"] = id(inner_humidity).state;
        root["outer_temp"] = id(outer_temperature).state;
        root["outer_humidity"] = id(outer_humidity).state;
        root["inner_dewpoint"] = inner_dewpoint;
        root["outer_dewpoint"] = outer_dewpoint;
        root["fan_state"] = id(fan_relay).state;
      });
      return fan_state;
    unit_of_measurement: ""
    update_interval: 30s

switch:
  - platform: gpio
    name: "Relay"
    id: fan_relay
    pin: 13

captive_portal: