This project implements a (realtime) data-plotter for sensor-data. Under the hood, it uses Matplotlib, but instead of programming the plot yourself, you just need to describe the data/plot using a configuration file.
Basic assumption is that you either have the data already in CSV-format in a file, or you can read the data from a device (e.g. serial-line). One column should have timestamp data (usually in ms), the other columns represent the sensor-data.
Use the following commands to install the data-monitor:
git clone https://github.com/bablokb/py-datamon.git
cd py-datamon
sudo tools/install
If your system is not Debian-based, you should edit the install
commands within tools/install to your needs.
This will copy the python-script py-datamon.py and some support classes
to your system and will create a python-virtualenv with prerequisite
packages. It also copies the shell-script py-datamon, which will
start the python-script from within the virtualenv.
In addition, you might have to install a suitable GUI-backend (TkInter, Qt5) with python-bindings for Matplotlib. You usually do this using the package-manager of your distribution (on PiOS this was already preinstalled).
To test the program, run these commands:
# create test-data (takes 20 seconds)
tools/sincos-data.py 0.1 200 | tee testdata.csv
# create plot with 3x2 subplots, one value each
/usr/local/bin/py-datamon -c sincos3x2x1.json testdata.csv
# or all values in a single subplot
/usr/local/bin/py-datamon -c sincos1x1x6.json testdata.csv
To test the live-monitoring, use
tools/sincos-data.py 0.1 | \
/usr/local/bin/py-datamon -c sincos6x1.json -
Read the full documentation for all the details.
If you wonder where those json-files are: these sample files are
part of the project and are in /usr/local/lib/py-datamon/configs.
Configuration files don't have to be there, just pass the path to
your file to the -c-option.
If you don't provide an explicit configuration-file, the program
first tries to use a configuration with the the ".csv"-suffix of the
data file replaced by ".json". If this file does not exist, it
uses the file default.json from /usr/local/lib/py-datamon/configs.
The formal definition of a configuration-file is documented in doc/config.md. You have to define
- how many subplots you want
- how many values should be plotted together in each subplot
- which columns of the csv map to which value
- define titles and labels
The best strategy is to take one of the sample configuration files, copy it and adapt it to your needs.
Note that Matplotlib allows you to define every aspect of a plot. The config-files don't expose the full power of Matplotlib. If you need to create publication-ready plots, you might be better of programming Matplotlib directly. But for simple data-visualization py-datamon should be flexible enough.