isl_climatestatio.yaml

esphome:
  name: isl_climatestatio
  platform: ESP8266
  board: nodemcuv2

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

  # Optional manual IP
  manual_ip:
    static_ip: 192.x.x.x
    gateway: 192.x.x.1
    dns1: 192.x.x.1
    dns2: 8.8.8.8
    subnet: 255.255.255.0

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Isl Climatestatio 10"
    password: ""

captive_portal:

# Enable logging
logger:

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

ota:
   password: !secret ota_password
   safe_mode: True
   
web_server:
  port: 80
  auth:
    username: admin
    password: !secret web_server_password

i2c:
  sda: 5
  scl: 4
  scan: False
  id: bus_a
  
globals:

#The load resistance on the board. Value in KiloOhms
  - id: RLOAD
    type: float
    restore_value: no
    initial_value: '1.025'

#Calibration resistance at atmospheric CO2 level. Outdoor calibration data
  - id: RZERO
    type: float
    restore_value: no
    initial_value: '35.429'

#Atmospheric CO2 level for calibration purposes. Outdoor CO2 level during calibration. Usually 450, but it's better to clarify.
  - id: ATMOCO2
    type: float
    restore_value: no
    initial_value: '450'

#Parameters for calculating ppm of CO2 from sensor resistance
#  Exponential regression:
#  GAS      | a      | b
#  CO       | 605.18 | -3.937  
#  Alcohol  | 77.255 | -3.18 
#  CO2      | 110.47 | -2.862
#  Tolueno  | 44.947 | -3.445
#  NH4      | 102.2  | -2.473
#  Acetona  | 34.668 | -3.369
  - id: PARA
    type: float
    restore_value: no
    initial_value: '110.47'
  - id: PARB
    type: float
    restore_value: no
    initial_value: '-2.862'

#Parameters to model temperature and humidity dependence
  - id: CORA
    type: float
    restore_value: no
    initial_value: '0.00035'
  - id: CORB
    type: float
    restore_value: no
    initial_value: '0.02718'
  - id: CORC
    type: float
    restore_value: no
    initial_value: '1.39538'
  - id: CORD
    type: float
    restore_value: no
    initial_value: '0.0018'
  - id: CORE
    type: float
    restore_value: no
    initial_value: '-0.003333333'
  - id: CORF
    type: float
    restore_value: no
    initial_value: '-0.001923077'
  - id: CORG
    type: float
    restore_value: no
    initial_value: '1.130128205'

# Here you need to indicate the supply voltage of the MQ135 sensor. It can be measured with a voltmeter. Please note that the rated power will not always be accurate.
  - id: volt_resolution
    type: float
    restore_value: no
    initial_value: '5.14'

# 1 for Exponential, 2 for Linear
  - id: regression_method
    type: int
    restore_value: no
    initial_value: '1'

sensor:
  - platform: htu21d
    temperature:
      name: "Temperature htu21d"
      id: htu21d_temperature
    humidity:
      name: "Humidity"
      id: htu21d_humidity
      filters:
      - lambda: if ((id(htu21d_temperature).state)>=0) {return (id(htu21d_humidity).raw_state + (25.0 - id(htu21d_temperature).state) * (-0.15));} else {return id(htu21d_humidity).raw_state;}
    update_interval: 30s
    
  - platform: adc
    pin: A0
    name: "Gas ADC"
    update_interval: 1s
    filters:
      - multiply: 3.3 # for NodeMcu ESP8266 v3 Lua
    accuracy_decimals: 4
    unit_of_measurement: V
    id: sensor_volt

  - platform: template
    #Linearization of the temperature dependency curve under and above 20 degree C
    #below 20degC: fact = a * t * t - b * t - (h - 33) * d
    #above 20degC: fact = a * t + b * h + c
    #this assumes a linear dependency on humidity
    #getCorrectionFactor
    name: "Correction Factor"
    lambda: |-
      if (id(htu21d_temperature).state<20) {
        return (id(CORA) * id(htu21d_temperature).state * id(htu21d_temperature).state - id(CORB) *
          id(htu21d_temperature).state + id(CORC) - (id(htu21d_humidity).state - 33.) * id(CORD));
      } else {
        return (id(CORE) * id(htu21d_temperature).state + id(CORF) * id(htu21d_humidity).state + id(CORG));
      }
    update_interval: 10s
    accuracy_decimals: 6
    id: correction_factor

  - platform: template
    #Get the resistance of the sensor, ie. the measurement value @return The sensor resistance in kOhm
    # RS = [(VC x RL) / VRL] - RL
    # RS_air = ((5.14*1.0)/sensor_volt)-1.0 Calculate RS in fresh air 
    #getResistance
    name: "Resistance"
    lambda: |-
      return ((id(volt_resolution)*id(RLOAD)/id(sensor_volt).state) - id(RLOAD));
    update_interval: 5s
    accuracy_decimals: 3
    unit_of_measurement: kOm
    id: resistance
    
  - platform: template
    # Get the resistance of the sensor, ie. the measurement value correctedfor temp/hum @return The corrected sensor resistance kOhm
    #getCorrectedResistance
    name: "Corrected Resistance"
    lambda: |-
      return (id(resistance).state / id(correction_factor).state);
    update_interval: 5s
    accuracy_decimals: 3
    unit_of_measurement: kOm
    id: corrected_resistance

  - platform: template
    # Get the ppm of CO2 sensed (assuming only CO2 in the air). The ppm of CO2 in the air
    #getPPM
    name: "PPM CO2"
    lambda: |-
      if (id(regression_method)==1) {
        return (id(PARA) * pow((id(resistance).state / id(RZERO)), id(PARB)));
      } else {
        return (pow(10, (log10(id(resistance).state / id(RZERO)) - id(PARB)) / id(PARA)));
      }
    update_interval: 5s
    unit_of_measurement: ppm
    id: ppm_co2

  - platform: template
    # Get the ppm of CO2 sensed (assuming only CO2 in the air), corrected  for temp. The ppm of CO2 in the air
    #getCorrectedPPM
    name: "Corrected PPM CO2"
    lambda: |-
      if (id(regression_method)==1) {
        return (id(PARA) * pow((id(corrected_resistance).state / id(RZERO)), id(PARB)));
      } else {
        return (pow(10, (log10(id(corrected_resistance).state / id(RZERO)) - id(PARB)) / id(PARA)));
      }
    update_interval: 5s
    unit_of_measurement: ppm
    id: corrected_ppm_co2

  - platform: template
    # Get the resistance RZero of the sensor for calibration purposes. The sensor resistance RZero in kOhm
    #getRZero
    name: "RZero"
    lambda: |-
      return (id(resistance).state / pow((id(ATMOCO2) / id(PARA)), (1./id(PARB))));
    filters:
      - sliding_window_moving_average:
          window_size: 15
          send_every: 1
    update_interval: 5s
    accuracy_decimals: 3
    unit_of_measurement: kOm
    id: r_zero

  - platform: template
    # Get the corrected resistance RZero of the sensor for calibration purposes. The corrected sensor resistance RZERO in kOhm for ATMOCO2 level
    #getCorrectedRZero
    name: "CorrectedRZero"
    lambda: |-
      return (id(corrected_resistance).state / pow((id(ATMOCO2) / id(PARA)), (1./id(PARB))));
    filters:
      - sliding_window_moving_average:
          window_size: 15
          send_every: 1
    update_interval: 5s
    accuracy_decimals: 3
    unit_of_measurement: kOm
    id: corrected_r_zero