Home weather station with Raspberry Pi Pico & Kitronik Air Quality Board.
Why? To monitor and record indoor readings that will facilitate modifications for greater comfort and allergen control.
In the original setup, the server is run from a Raspberry Pi, while development takes place on a laptop. They have slightly different needs for their environment setup and so are addressed separately here.
Overview:
- Environment setup on Mac/Linux computer
- Environment setup on Raspberry Pi
- SQLite Database
- Raspberry Pi Pico W + Kitronik Air Quality Board
- Development Server
- Deploying to Production
Once it is set up and running, graphs will begin to generate on the Visualise page:
Use pyenv to change the python version for the project directory.*
pyenv install 3.11.10
pyenv local 3.11
* Python 3.11 in this case to match the Raspberry Pi that will host the server for continuous data logging
Ensure the following is in your ~/.zshrc:
export PATH="/Users/username/.pyenv:$PATH"
eval "$(pyenv init -)"
To set up poetry environment:
poetry shell
poetry install
After this point, continue to SQLite Database.
Raspberry Pi model 1B: Raspbian GNU/Linux 12 (bookworm)
Pillow requires zlib and libjpeg. Install with:
sudo apt install libjpeg-dev zlib1g-dev
This project requires numpy to be installed with apt. See the section Known issues with numpy for more detail.
sudo apt install python3-numpyvenv is used instead of poetry on the Raspberry Pi. It is lighter weight and works well to lock down the version of numpy due to the problems listed below.
A requirements.txt is generated with poetry from a Mac/Linux computer and then used by venv on the Raspberry Pi. See the Development section for more details on generating the requirements.txt.
ssh into the Raspberry Pi, and from the weather-station directory, run the following:
python -m venv --system-site-packages .venv
source .venv/bin/activate
pip install --prefer-binary -r requirements.txt Note: --prefer-binary directs pip to use piwheels versions of packages if they are available. This saves time on compilation.
After this point, continue to SQLite Database.
Some issues may be encountered with numpy throwing a ChefInstallError when running poetry install on a Raspberry Pi.
If numpy appears to install correctly, it can be tested by opening Python and trying to import numpy. If it mentions the following error and fails to import then a system installation of numpy must be used:
libf77blas.so.3: cannot open shared object file: No such file or directory
The solution is to make numpy available globally rather than installing it with pip in the venv.
pip3 uninstall numpy # remove previously installed version
sudo apt install python3-numpySee https://numpy.org/devdocs/user/troubleshooting-importerror.html#raspberry-pi
From the src directory, initialise the SQLite database with:
flask --app server init-db
The database will appear in the instance directory as weather.sqlite
- Copy scripts from
rp2onto Raspberry Pi Pico. - Change constants at the top of the copy of
main.pyon the Pico:
SERVER_URL = 'localhost'+'/data'
WIFI_NAME = 'Wifi_name'
WIFI_PASSWORD = 'Wifi_password'
From this point see Development Server or Deploying to Production as required.
- To run the server go to the
srcdirectory and execute:
flask --app server run --debug --host=0.0.0.0
If running the development server from the Raspberry Pi, remove the --debug option
These instructions are written for a server that is run from a Raspberry Pi.
Start Gunicorn WSGI server from src directory using:
gunicorn -c server/gunicorn_config.py server:gunicorn_appSet up the config server/gunicorn_config.py:
bind="127.0.0.1:8000"
workers=2Install the nginx HTTP server:
sudo apt-get install nginxSet up a symbolic link to the at
/etc/nginx/sites-enabled/weather-station.config:
cd /etc/nginx/sites-enabled/
sudo ln -s /home/{username}/Code/weather-station/src/server/nginx/weather-station.config .
Nginx can be started with:
sudo systemctl start nginxChanges made in the configuration file will not be applied until the command to reload configuration is sent to nginx or it is restarted. To reload configuration, execute:
sudo nginx -s reloadThe last step is to automatically run the server on startup.
This is done with thesystemd system and service manager, which is used by Raspberry Pi.
For Gunicorn we will need a new service that systemd can run.
(Nginx has already created its own service on installation.)
Create a new file weather-station.service for systemd in the folder /usr/lib/systemd/system:
[Unit]
Description=Weather Station
After=multi-user.target
[Service]
WorkingDirectory=/home/{username}/Code/weather-station/src
ExecStart=/home/{username}/Code/weather-station/.venv/bin/gunicorn -c server/gunicorn_config.py server:gunicorn_app &
[Install]
WantedBy=multi-user.target*Gunicorn is started with & so that it runs in the background.
Finally, both Gunicorn and nginx must be started and enabled so that they can run automatically at startup of the Raspberry Pi:
sudo systemctl start nginx
sudo systemctl enable nginx
sudo systemctl start weather-station
sudo systemctl enable weather-station(If needed the services can be stopped with sudo systemctl stop {service}.)
Setup is now complete!
- Update the
pyproject.tomlas required - Run
poetry installto install new packages - Run
poetry lockto update lock file - From within the
weather-stationdir, generate arequirements.txt:
poetry export --without-hashes --format=requirements.txt > requirements.txt- Copy over to the Raspberry Pi (via
scporgit) and install using:
source .venv/bin/activate
pip install --prefer-binary -r requirements.txt - The
rp2directory mirrors the scripts that will go onto the Raspberry Pi Pico.