INDI WeatherWatcher driver is included with libindi.
Under Ubuntu, you can install the driver via:
sudo add-apt-repository ppa:mutlaqja/ppa
sudo apt-get update
sudo apt-get install libindi1
Weather Watcher driver is a flexible tool for accessing weather data from different sources. Data can be collected from a local weather station or a remote weather provider, Weather Watcher just needs a key / value file to parse these data. For example the SOLO (the device that reads from the AAG CloudWatcher and broadcast to a network) prints temperature data in a web file (url) formatted as:
where 'temp' is the key, '18.1' the value and '=' the pair separator.
- Reads weather data from filesystems or url based resources
- Data parsed: rain / precipitation, wind average, wind gusts, temperature, forecast
- Critical parameter can trigger shutdown conditions for the observatory. Critical parameters used are: Rain, Temperature and Wind (avg).
- Customizable weather parameters ranges for operation.
- Customizable warnings for each weather parameter.
For the rest of this chapter we will assume that the following weather data are available (via filesystem or web based):
All data are treated as numeric, that is WeatherWatcher driver doesn't make assumption on unit of measurement. So your wind data can be in Kph or Mph, only the threshold has to be updated.
Before connecting, in the option tab you have to set the correct data source.
For filesystem based file you have to specify the full path. E.g. /home/weather/data.txt.
Then the keywords name have to be matched correctly in the parameters fields:
- Rain, some weather stations use 'precipitation', 'precip'. But 'rain' is the most common one.
- Temperature, 'temp' or 'temperature´ are common keywords. No unit of measurements is required.
- Wind is meant to be an average of a period of time.
- Gust highest wind value over a period of time.
- Forecast not all weather station have this information.
- Separator the character separating the key from the value.
Please note that if some of the parameters are not matched they will be ignored and no error will be triggered.
In order to change the parameters, after setting the value in the option tab, save the configuration and restart the INDI driver.
Once the driver is correctly configured, save the configuration and move to Main Control tab where the overall current situation of weather data is shown.
- Connection allows to connect / disconnect from the device.
- Status shows the OK (green), WARNING (yellow) or DANGER (red) status for the three critical parameters: rain, wind and temperature.
- Weather force reading from the device.
- Update refresh reading period (in seconds) .
Parameters tab is used to read all weather data (not just critical parameters) and to set weather alerts triggered by critical parameter ranges:
For each of the three critical parameters (rain, temperature and wind), firstly a range in which the observatory can safely operate is set (OK range, marked with a green color led in main control tab).
Outside of this range it is not safe to continue observatory operations (DANGER, red color led in main control tab).
Before reaching the danger zone, Weather Watcher can issue a WARNING (yellow color led in main control tab). Weather Watcher asks for a percentage (of the OK range) to define the warning zone. Remember that in warning zone we are still in the OK range so that a shutdown procedure is not triggered yet.
Refer to the image below as an example taking in account Temperature, where the safe operation range is -30 to +30 (obviously is meant to be Celsius degree in the example, but driver doesn't care about unit of measurement).
Note: if the minimum of the parameters is set to zero, a lower warning is not issued because the driver assumes that the parameter is positive only (e.g. Wind).
Critical parameters are queried by the scheduler, so if one of the parameters (Rain, Temp or Wind) is in the danger zone, the Scheduler will trigger the shutdown procedure. As of today (4/2019) the Scheduler will prevent observation to start but will not shutdown once it has started.