https://github.com/adafruit/adafruit_circuitpython_dht

CircuitPython support for DHT11 and DHT22 type temperature/humidity devices
https://github.com/adafruit/adafruit_circuitpython_dht

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Last synced: 9 months ago
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CircuitPython support for DHT11 and DHT22 type temperature/humidity devices

• Host: GitHub
• URL: https://github.com/adafruit/adafruit_circuitpython_dht
• Owner: adafruit
• License: mit
• Fork: true (mrmcwethy/Adafruit_CircuitPython_DHT)
• Created: 2017-09-18T19:18:29.000Z (almost 9 years ago)
• Default Branch: main
• Last Pushed: 2025-01-16T18:46:11.000Z (over 1 year ago)
• Last Synced: 2025-01-19T18:54:44.670Z (over 1 year ago)
• Topics: hacktoberfest
• Language: Python
• Size: 166 KB
• Stars: 187
• Watchers: 22
• Forks: 64
• Open Issues: 15
• Metadata Files:
  • Readme: README.rst
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

          

Introduction

============

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CircuitPython support for the DHT11 and DHT22 temperature and humidity devices.

Dependencies

=============

This driver depends on:

* `Adafruit CircuitPython `_

Please ensure all dependencies are available on the CircuitPython filesystem.

This is easily achieved by downloading

`the Adafruit library and driver bundle `_.

.. note::

     This library uses the `pulseio` module in CircuitPython. As of CircuitPython 7.0.0, `pulseio` is

     no longer available on the smallest CircuitPython builds,

     such as the Trinket M0, Gemma M0, and Feather M0 Basic boards.

     You can substitute a more modern sensor, which will work better as well.

     See the guide `Modern Replacements for DHT11 and DHT22 Sensors

     `_

     for suggestions.

Installing from PyPI

====================

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally `from

PyPI `_. To install for current user:

.. code-block:: shell

    pip3 install adafruit-circuitpython-dht

To install system-wide (this may be required in some cases):

.. code-block:: shell

    sudo pip3 install adafruit-circuitpython-dht

To install in a virtual environment in your current project:

.. code-block:: shell

    mkdir project-name && cd project-name

    python3 -m venv .venv

    source .venv/bin/activate

    pip3 install adafruit-circuitpython-dht

Usage Example

==============

Hardware Set-up

----------------

Designed specifically to work with the Adafruit DHT series sensors:

* Adafruit `DHT22 temperature-humidity sensor + extras `_

* Adafruit `DHT11 temperature-humidity sensor + extras `_

.. note::

    DHT11 and DHT22 devices both need a pull-resistor on the data signal wire. This resistor is in the range of 1k to 5k

* Please check the device datasheet for the appropriate value.

* Be sure that you are running the Buster Operating System.

* Make sure that your user is part of the ``gpio`` group.

Known Issues

------------

* The library may or may not work in Linux 64-bit platforms.

* The Raspberry PI Zero does not provide reliable readings.

* Readings in FeatherS2 does not work as expected.

.. note::

     Using a more modern sensor will avoid these issues.

     See the guide `Modern Replacements for DHT11 and DHT22 Sensors

     `_.

Basics

-------

Of course, you must import the library to use it:

.. code:: python

    import adafruit_dht

The DHT type devices use single data wire, so import the board pin

.. code:: python

    from board import 

Now, to initialize the DHT11 device:

.. code:: python

    dht_device = adafruit_dht.DHT11()

OR initialize the DHT22 device:

.. code:: python

    dht_device = adafruit_dht.DHT22()

Read temperature and humidity

------------------------------

Now get the temperature and humidity values

.. code:: python

    temperature = dht_device.temperature

    humidity = dht_device.humidity

These properties may raise an exception if a problem occurs.  You should use try/raise

logic and catch RuntimeError and then retry getting the values after at least 2 seconds.

If you try again to get a result within 2 seconds, cached values are returned.

Documentation

=============

API documentation for this library can be found on `Read the Docs `_.

For information on building library documentation, please check out `this guide `_.

Contributing

============

Contributions are welcome! Please read our `Code of Conduct

`_

before contributing to help this project stay welcoming.