This binding produces calculated meterological data based on raw observations from a weather station. Using temperature, humidity, and pressure items this binding is able to provide a range of additional metrics.
Calculations Provided
Wind Chill
Heat Index
Feels Like temperature
Humidex
Dew Point
Sea Level Pressure
Atmospheric Pressure Trend
Cardinal Wind Direction (from degrees)
High/Low temperature
Rainfall Accumulation (for stations that only report incremental accumulation)
Calculated values are automatically updated as the values they are calculated from are updated. Temperature, Humidity and Pressure items are mandatory; additional calculations will be made if Rain and Wind items are configured.
Configuration
This binding does not support auto-discovery. To create a new instance, go to the Inbox and click on “add new thing” and choose “Weather Calculations Binding”. Then, complete the configuration by providing height of the station and choosing the items you want to use as the sources for the calculated values. Additional details can be found in the readme document in the repository linked below.
Changelog
Version 3.4.1
Compiled for openHAB 3.4
Version 3.2.2
Support for multiple things. Previously adding a new Weather Calculation thing would disable any previous ones.
Version 3.2.1
Uses correct value for “Low Temperature Yesterday”
I’ve stumbled upon this binding when I tried to wrap my head around on calculating dew points based upon humidity and temperature.
While using your binding for data provided by say a web-service works like a charme it does limit the ability to just use partial available data like from a Shelly H&T sensor which only provides humidity and temperature. Provind additional input items by copying the values from the web-service is one option of course, I’m wondering if you could adjust your data-model to allow for less functionality depending on the provided input values?
Thanks for giving this binding a try and I really appreciate your feedback!
The calculations binding was originally intended to be used with a local weather station, providing derived calculations so that each binding didn’t need to provide them. Thus, it requires Temperature, Humidity and Pressure. The wind and precipitation related inputs are optional because I presumed they were not among the minimum set of data a weather station might provide. At the time, I hadn’t really thought about more limited types of sensors.
Having said that, since then, I’ve actually installed a number of local temperature and humidity sensors that I use with this, and simply use the air pressure item from my outdoor weather station (since the likelihood that pressure will differ meaningfully between indoors and outdoors over time). I think your use of a web service to provide that value is an equivalent approach.
If you don’t want to use a real pressure value at all, you could just create a dummy item that held a constant value (I think zero would probably not cause errors). A single item could be used with multiple instances of the calculation thing. The only downside is that you just wouldn’t get reasonable values for sea-level pressure and pressure trend.
I’ll have to think about making pressure optional… I’m not opposed to the idea, but I do have a concern about introducing bugs or unexpected behavior for folks who’ve been using the binding.
