RASPBERRY PI3+ installation

[Meganetpr]

Hello,

I'm trying to install with the pip install mppsolar command , but return and error. Was able to install using the venv option , but my chrontab can't send the commands. If do manually on terminal works fine. Prefer is possible to do a normal installation. Otherwise what should be the correct format on crontab to send the command?

mega@mega:~ $ pip install mppsolar
error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
python3-xyz, where xyz is the package you are trying to
install.

If you wish to install a non-Debian-packaged Python package,
create a virtual environment using python3 -m venv path/to/venv.
Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
sure you have python3-full installed.

For more information visit http://rptl.io/venv

note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.
hint: See PEP 668 for the detailed specification.

[18616505009]

Hello @Meganetpr,

I understand the two core issues you are running into. The pip install error is due to a system-level security measure, and the crontab failure is a classic pathing problem with virtual environments.

1. The externally-managed-environment Error
   The error message you received is not a bug in mppsolar; it is a security feature based on PEP 668 introduced in modern Linux distributions. The system is preventing you from installing packages globally (sudo pip install...) because it could lead to dependency conflicts and potentially break system utilities that rely on Python.

Recommendation: Your decision to use a virtual environment (venv) is the correct and safest practice. We only need to fix how crontab uses it.

2. The crontab Pathing Solution
   crontab runs in a minimal environment that does not automatically "activate" your venv or know the path to the mpp-solar command-line executable.

While you could edit your crontab to manually source the venv activation script, I recommend a more robust and cleaner solution for data collection tasks:

Recommended Approach: Use a Python Script as a Bridge
Instead of trying to get crontab to call the mpp-solar command-line tool, you should:

Write a dedicated Python script (e.g., mpp_collector.py).

Inside this script, directly call the functions of the underlying mppsolar Python library to execute commands (like QID, PS) and retrieve the data.

In your crontab, execute this Python script using the absolute path to the Python interpreter within your venv.

Why this is better:

Reliability: It bypasses the complexity of managing environment variables and shell activation within crontab.

Flexibility: The script can immediately receive the structured data (Python dictionaries) from the library, allowing you to easily add logging, error handling, or immediately push data to MQTT/database services.

Best Practice: This is the standard, most maintainable way to integrate Python libraries into automation systems.