Unit ENV-IV ESPHome Component

Unit ENV-IV reads temperature, humidity, pressure, and derived environmental data.

1. Component Overview

Item	Information
Product Name	Unit ENV-IV
SKU	U001-D
Main Function	Temperature, humidity, and pressure detection
Communication Interface	I2C
Default I2C Address	SHT40: `0x44`; BMP280: `0x76`
ESPHome Components	`sht4x`, `bmp280_i2c`, `template`, `absolute_humidity`
ESPHome Version Requirement	/

2. Component Description

Including Official Components

Unit ENV-IV uses the official SHT4X sensor for temperature and humidity, and the BMP280 sensor for pressure and temperature. Altitude, absolute humidity, and dew point are derived values calculated from the raw data.

Unit ENV-IV configuration example:

yaml 
sensor:
  - platform: sht4x
    temperature:
      id: sht40_temp
      name: "Temperature"
    humidity:
      id: sht40_humi
      name: "Relative Humidity"
    address: 0x44

  - platform: bmp280_i2c
    temperature:
      name: "BMP280 Temperature"
      id: bmp280_temp
      oversampling: 16x
    pressure:
      name: "BMP280 Pressure"
      id: bmp_pressure
    address: 0x76

You can also create derived entities such as altitude, absolute humidity, and dew point using empirical formulas. Append the following entries to the existing sensor list. The calculated results are for reference only:

yaml 
sensor:
  - platform: template
    name: "Altitude"
    lambda: |-
      const float STANDARD_SEA_LEVEL_PRESSURE = 1013.25; //in hPa, see note
      return ((id(bmp280_temp).state + 273.15) / 0.0065) *
        (powf((STANDARD_SEA_LEVEL_PRESSURE / id(bmp_pressure).state), 0.190234) - 1); // in meter
    update_interval: 15s
    icon: 'mdi:signal'
    unit_of_measurement: 'm'

  - platform: absolute_humidity
    name: "Absolute Humidity"
    temperature: sht40_temp
    humidity: sht40_humi

  - platform: template
    name: "Dew Point"
    lambda: |-
      return (243.5*(log(id(sht40_humi).state/100)+((17.67*id(sht40_temp).state)/
      (243.5+id(sht40_temp).state)))/(17.67-log(id(sht40_humi).state/100)-
      ((17.67*id(sht40_temp).state)/(243.5+id(sht40_temp).state))));
    unit_of_measurement: °C
    icon: 'mdi:thermometer-alert'

Notice

To calculate altitude accurately with the BMP280 pressure sensor, first obtain the standard sea-level pressure for your location and the current day. Replace the global constant STANDARD_SEA_LEVEL_PRESSURE, for example with a real-time value obtained from the Internet or from a fixed sensor via MQTT.

3. Reference Example

After adding the device to the Dashboard, you can view sensor data in Home Assistant.

Monitor the temperature trend.

Notice

Because the BMP280 also has a temperature sensor, two temperature curves are shown.

Monitor pressure changes.

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Unit ENV-IV ESPHome Component

1. Component Overview

2. Component Description

Including Official Components

3. Reference Example

4. Related Links

5. Related Video

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