This is a Python module that allow accessing LaCrosse WS3500 weather station.

It is provided with an exporter for Prometheus and a command line tool to read the panel values.

This is derived from the work on this site : http://www.morichon.eu/python_WS3500.php

Programs an tools

read_pannel.py

$ python2 read_panel.py
Recording interval : 5 minute(s)
Forecast is Cloudy with Decreasing trends

Value                | Current    | Minumum                        | Maximum
=====================X============X================================X===============================
Internal Temperature |  +22.7     |  +18.7     on 2017-09-02 08:22 |  +29.0     on 2016-12-28 11:05
Internal Humidity    |   51 %     |   28 %     on 2017-03-14 15:42 |   66 %     on 2016-06-23 21:32
External Temperature |  +23.8     |  -22.0     on 2018-01-10 01:38 |  +40.0     on 2016-06-24 14:18
External Humidity    |   47 %     |   26 %     on 2018-04-22 14:32 |   89 %     on 2016-10-26 13:30
Dewpoint             |  +11.7     |  -23.1     on 2017-12-05 19:36 |  +23.3     on 2016-08-26 13:13
Relative Pressure    | 1018.9 hPa | 1041.9 hPa on 2016-12-27 22:02 |  985.0 hPa on 2017-12-11 13:02

daemon.py : Web server and Prometheus exporter

Starting the script directly

$ python2 daemon.py --device /dev/ttyUSB0 -P 1234 -H 0.0.0.0
2018-05-26 19:24:39,153 - WS3500 - INFO - [fetcher] starting thread
2018-05-26 19:24:39,154 - WS3500 - INFO - [fetcher] opening device
 * Serving Flask app "WS3500" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://0.0.0.0:1234/ (Press CTRL+C to quit)

Fetch Duration

Due to the protocol, the fetch duration is quite chaotic. The length of the initialize "U" buffer impact greatly on stability and reliability of operation.

With a "U"*150 buffer, I obtain quite stable fetch duration, oscillating mainly between 3.6 and 6.4 seconds.

But each day, a deviation is observed in the early hours. like here at 6am where fetch duration deviated to two minutes.

Status Page

The status page allow you to see the last fetched data. It looks like this :

If there is any problem, you obtain an error message instead :

Using docker

You can use docker interactively

$ docker run -ti --rm --device /dev/ttyUSB0  ws3500  bash -l