home-assistant.io/source/_integrations/htu21d.markdown

title, description, ha_category, ha_release, ha_iot_class, ha_domain, ha_platforms

title	description	ha_category	ha_release	ha_iot_class	ha_domain	ha_platforms
HTU21D(F) Sensor	Instructions on how to integrate a HTU21D Temperature and humidity sensor into Home Assistant.	DIY	0.48	Local Push	htu21d	sensor

This integration is deprecated and will be removed in Home Assistant Core 2022.4.

For more information see: Architectural Decision Record 0019.

The htu21d sensor platform allows you to read the temperature and humidity from a HTU21D sensor connected via I2c bus (SDA, SCL pins).

Tested devices:

• Raspberry Pi

Configuration

To use your HTU21D sensor in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
sensor:
  - platform: htu21d

{% configuration %} name: description: The name of the sensor. required: false default: i2c_bus type: string i2c_bus: description: I2c bus where the sensor is. required: false default: 1 (for Raspberry Pi 2 and 3) type: integer {% endconfiguration %}

Customizing the sensor data

Give the values friendly names and icons, add the following to your customize: section.

# Example configuration.yaml entry
customize:
  sensor.htu21d_sensor_temperature:
    icon: mdi:thermometer
    friendly_name: "Temperature"
  sensor.htu21d_sensor_humidity:
    icon: mdi:weather-rainy
    friendly_name: "Humidity"

To create a group, add the following to your groups section.

# Example configuration.yaml entry
group:
  ambient_sensor:
    name: HTU21D Environment sensor
    entities:
      - sensor.htu21d_sensor_temperature
      - sensor.htu21d_sensor_humidity

Directions for installing smbus support on Raspberry Pi

Enable I2c interface with the Raspberry Pi configuration utility:

# pi user environment: Enable i2c interface
$ sudo raspi-config

Select Interfacing options->I2C choose <Yes> and hit Enter, then go to Finish and you'll be prompted to reboot.

Install dependencies for use the smbus-cffi module and enable your homeassistant user to join the i2c group:

# pi user environment: Install i2c dependencies and utilities
$ sudo apt-get install build-essential libi2c-dev i2c-tools python-dev libffi-dev

# pi user environment: Add homeassistant user to the i2c group
$ sudo addgroup homeassistant i2c

# pi user environment: Reboot Raspberry Pi to apply changes
$ sudo reboot

Check the i2c address of the sensor

After installing i2c-tools, a new utility is available to scan the addresses of the connected sensors:

/usr/sbin/i2cdetect -y 1

It will output a table like this:

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- 23 -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: 40 -- -- -- -- -- UU -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- 77

So you can see the sensor is present at the 0x40 address (there are more i2c sensors in that Raspberry Pi).