pyjoulescope-driver 2.2.2

Joulescope™ driver

Joulescope Driver

Welcome to the Joulescope™ Driver project. Joulescope is an affordable, precision DC energy analyzer that enables you to build better products.

This user-space C library communicates with Joulescope products to configure operation and receive data. The first-generation driver introduced in 2019 was written in Python. While Python proved to be a very flexible language enabling many user scripts, it was difficult to support other languages.
This second-generation driver launched in 2022 addresses several issues with the first-generation python driver including:

1. Improved event-driven API based upon PubSub for easier integration with user interfaces and other complicated software packages.
2. Improved portability for easier language bindings.
3. Improved performance.

For more information, see:

• source code
• documentation
• pypi
• Joulescope (Joulescope web store)
• jls (Joulescope file format)
• forum

Python Installation

The python bindings work with Python 3.9 and later. To use the python bindings, ensure that you have a compatible version of python installed on your host computer. Then:

python -m pip install pyjoulescope_driver

For Ubuntu, you will also need to install the udev rules.

You can then run the pyjoulescope_driver python entry points:

python -m pyjoulescope_driver --help
python -m pyjoulescope_driver scan
python -m pyjoulescope_driver info
python -m pyjoulescope_driver info * --verbose

Note that you may need to change "python" to "python3" or the full path.
You can also use a python virtual environment.

Building

Ensure that your computer has a development environment including CMake.

Windows

Install cmake and your favorite build toolchain such as Visual Studio, mingw64, wsl, ninja.

macOS

For macOS, install homebrew, then:

brew install pkgconfig python3

Ubuntu 22.04 LTS

For Ubuntu:

sudo apt install cmake build-essential ninja-build libudev-dev

You will also need to install the udev rules. If you are using a modern Linux distribution managed by systemd, using tag-based rules is most likely the right choice:

$ wget https://raw.githubusercontent.com/jetperch/joulescope_driver/main/72-joulescope.rules
$ sudo cp 72-joulescope.rules /etc/udev/rules.d/
$ sudo udevadm control --reload-rules

If your system is not managed by systemd or your user is not assigned a proper login seat (as may be the case when logging in via SSH), using group-based rules is necessery (note that the plugdev group must exist/be created and your user must belong to it):

$ wget https://raw.githubusercontent.com/jetperch/joulescope_driver/main/99-joulescope.rules
$ sudo cp 99-joulescope.rules /etc/udev/rules.d/
$ sudo udevadm control --reload-rules

Common

cd {your/repos/joulescope_driver}
mkdir build && cd build
cmake ..
cmake --build . && ctest .

This package includes a command-line tool, jsdrv:

jsdrv --help
jsdrv scan

Build python bindings

Install a compatible version of Python 3.9 or later. To install the pyjoulescope_driver dependencies:

cd {your/repos/joulescope_driver}
python -m pip install -U requirements.txt

You should then be able to build the native bindings:

python setup.py build_ext --inplace

You can build the package using isolation:

python -m build

Depending upon your system configuration, you may need to replace "python" with "python3" or the full path to your desired python installation.

On Windows, you may be prompted to install the Microsoft C++ Build Tools.