Next, let's create a virtual environment to run the Python 3 Flask application. In order to do so, we will run the following command:<\/p>\n
\r\nvirtualenv -p python3 \/home\/pi\/rpi-dht11-flask-env\r\n<\/pre>\nAfter that, we get into the virtual environment by running the following command:<\/p>\n
\r\nsource \/home\/pi\/rpi-dht11-flask-env\/bin\/activate\r\n<\/pre>\nOnce you gotten into the virtual environment, run the following commands to install the Python dependencies for the Python 3 Flask application:<\/p>\n
\r\npip install Flask==1.0.2 Adafruit-DHT==1.3.4\r\n<\/pre>\nAfter pip<\/code> finishes the installations, you will be able to run your Python 3 Flask application within the virtual environment.<\/p>\nTesting your Python 3 Flask application<\/h2>\n
Once you had installed the Python dependencies for your Python 3 Flask application, you can run it with the following commands:<\/p>\n
\r\ncd \/home\/pi\r\npython run.py\r\n<\/pre>\nYou will notice that after you ran the commands, the terminal pauses. This meant that your Flask application is ready to serve HTTP GET requests to the root endpoint.<\/p>\n
Next, use a web browser from your work computer to access the IP address of your Raspberry Pi 3. For example, if the IP address of your Raspberry Pi 3 is 192.168.1.123<\/strong>, you will type in http:\/\/192.168.1.123:12345<\/strong> into the location bar of your web browser.<\/p>\nAfter you had done so, your browser will receive a JSON object that tells you the humidity and temperature of the environment that your Raspberry Pi 3 is located at.<\/p>\n
Running the Python 3 Flask application as a background process when your Raspberry Pi 3 powers on<\/h2>\n
When you want your Python 3 Flask application to run whenever your Raspberry Pi 3 is turned on, you can depend on Supervisor. This section will show how to get Supervisor to run your Python 3 Flask application whenever your Raspberry Pi 3 is turned on.<\/p>\n
Firstly, let's create a shell script that will activate the virtual environment that we had created earlier and run our Python 3 Flask application within that virtual environment.<\/p>\n
To do so, we use nano to create a shell script at \/home\/pi\/run.sh<\/p>\n
\r\nnano \/home\/pi\/run.sh\r\n<\/pre>\nOnce the editor loads, write the following content into the editor:<\/p>\n
\r\n!#\/bin\/bash\r\nsource .\/rpi-dht11-flask-env\/bin\/activate\r\npython run.py\r\ndeactivate\r\n<\/pre>\nAfter you had included the content, type Ctrl-X<\/strong> and then Y<\/strong> to save the file.<\/p>\nAfterwards, make the shell script executable by running the following command:<\/p>\n
\r\nsudo chmod 744 \/home\/pi\/run.sh\r\n<\/pre>\nTo get Supervisor to start our Python 3 Flask application so that we can check the humidity and temperature with our Raspberry Pi 3, we first create a configuration file at \/etc\/supervisor\/conf.d\/rpi-dht11-flask-app.conf<\/code>:<\/p>\n\r\nsudo nano \/etc\/supervisor\/conf.d\/rpi-dht11-flask-app.conf\r\n<\/pre>\nAfter nano<\/code> loads, copy the following configuration codes into the editor:<\/p>\n\r\n[program:rpi-dht11-flask-app]\r\ndirectory=\/home\/pi\r\ncommand=\/bin\/bash -E -c .\/run.sh\r\nautostart=true\r\nautorestart=true\r\nstopsignal=INT\r\nstopasgroup=true\r\nkillasgroup=true\r\nuser=pi\r\n<\/pre>\nOnce you had written the configurations into the editor, run the following command to restart Supervisor:<\/p>\n
\r\nsudo systemctl restart supervisor.service\r\n<\/pre>\nWhen Supervisor runs again, it will take the configurations that you had created earlier and run your Python 3 Flask application.<\/p>\n
With that, whenever you power on your Raspberry Pi 3, you will be able check the humidity and temperature with your Raspberry Pi 3.<\/p>\n
![\"How](\"https:\/\/www.techcoil.com\/blog\/wp-content\/uploads\/How-to-read-temperature-and-humidity-from-a-DHT11-sensor-that-is-connected-to-a-Raspberry-Pi-3.jpg\")
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