.. note::

    Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

    **Why Join?**

    - **Expert Support**: Solve post-sale issues and technical challenges with help from our community and team.
    - **Learn & Share**: Exchange tips and tutorials to enhance your skills.
    - **Exclusive Previews**: Get early access to new product announcements and sneak peeks.
    - **Special Discounts**: Enjoy exclusive discounts on our newest products.
    - **Festive Promotions and Giveaways**: Take part in giveaways and holiday promotions.

    👉 Ready to explore and create with us? Click [|link_sf_facebook|] and join today!

.. _py_dht11:

6.2 Temperature - Humidity
=======================================


Humidity and temperature are closely related from the physical quantity itself to the actual people's life.
The temperature and humidity of human environment will directly affect the thermoregulatory function and heat transfer effect of human body.
It will further affect the thinking activity and mental state, thus affecting the efficiency of our study and work.

Temperature is one of the seven basic physical quantities in the International System of Units, which is used to measure the degree of hot and cold of an object.
Celsius is one of the more widely used temperature scales in the world, expressed by the symbol "℃".

Humidity is the concentration of water vapor present in the air.
The relative humidity of air is commonly used in life and is expressed in %RH. Relative humidity is closely related to temperature.
For a certain volume of sealed gas, the higher the temperature, the lower the relative humidity, and the lower the temperature, the higher the relative humidity.

|img_Dht11|

A basic digital temperature and humidity sensor, the **DHT11**, is provided in this kit.
It uses a capacitive humidity sensor and thermistor to measure the surrounding air and outputs a digital signal on the data pins (no analog input pins are required).

* :ref:`cpn_dht11`

**Schematic**

|sch_dht11|


**Wiring**


|wiring_dht11|

**Code**

.. note::

    * Open the ``6.2_temperature_humidity.py`` file under the path of ``euler-kit/micropython`` or copy this code into Thonny, then click "Run Current Script" or simply press F5 to run it.

    * Don't forget to click on the "MicroPython (Raspberry Pi Pico)" interpreter in the bottom right corner. 

    * For detailed tutorials, please refer to :ref:`open_run_code_py`. 
    
    * Here you need to use the library called ``dht.py``, please check if it has been uploaded to Pico, for a detailed tutorial refer to :ref:`add_libraries_py`.

.. code-block:: python

    from machine import Pin
    import utime as time
    from dht import DHT11
    
    # Initialize the pin for the DHT11 sensor as an input
    pin = Pin(16, Pin.IN)
    
    # Create a DHT11 sensor object
    sensor = DHT11(pin)
    
    while True:
        # Measure temperature and humidity
        sensor.measure()
        
        # Print the measured temperature and humidity values
        print("Temperature: {}, Humidity: {}".format(sensor.temperature, sensor.humidity))
        
        # Wait for 1 second before the next measurement
        time.sleep(1)



After the code is run, you will see the Shell continuously print out the temperature and humidity, and as the program runs steadily, these two values will become more and more accurate.

**How it works?**

In the dht library, we have integrated the relevant functionality into the ``DHT11`` class.

.. code-block:: python

    from dht import DHT11

Initialize the ``DHT11`` object. This device only needs a digital input to be used.

.. code-block:: python

    # Initialize the pin for the DHT11 sensor as an input
    pin = Pin(16, Pin.IN)
    
    # Create a DHT11 sensor object
    sensor = DHT11(pin)

Use ``sensor.measure()`` to read the current temperature and humidity, which will be stored in ``sensor.temperature``, ``sensor.humidity``.
They are then printed out.
Finally the DHT11 sampling rate is 1HZ, a ``time.sleep(1)`` is needed in the loop.

.. code-block:: python

    while True:
        # Measure temperature and humidity
        sensor.measure()
        
        # Print the measured temperature and humidity values
        print("Temperature: {}, Humidity: {}".format(sensor.temperature, sensor.humidity))
        
        # Wait for 1 second before the next measurement
        time.sleep(1)