HomematicIP Weather Station data to WeatherUnderground

Tutorials & Examples Solutions
1

I installed a HomematicIP Weather station in my backyard last fall. I am very happy with it. I was eager to share my weather station on Weather Underground, but I discovered that the HomematicIP weather station is not compatible. As a workaround I created a rule that takes the data from the weather station, and sends it to WU using HTTPGET requests. Here is the rule:

// Rule Configuration
const STATION_ID = 'mystationid';
const STATION_KEY = 'mystationkey';

// 1. Fetch data from your Items
const tempC = items.getItem('HmIPWeatherStation_Actual_Temperature').numericState;
const humidity = items.getItem('HmIPWeatherStation_Humidity').numericState;
const windKmh = items.getItem('HmIPWeatherStation_Wind_Speed').numericState;
const lux = items.getItem('HmIPWeatherStation_Illumination').numericState;
const rainTotal = items.getItem('HmIPWeatherStation_Rain_Counter'); // Use the cumulative counter

// 2. Calculate Rain Deltas using Persistence
// WU wants "Rain since midnight" and "Rain in last hour"
const now = time.ZonedDateTime.now();
const startOfDay = now.withHour(0).withMinute(0).withSecond(0);
const oneHourAgo = now.minusHours(1);

// Get the difference in mm
const dailyRainMm = rainTotal.numericState - rainTotal.persistence.persistedState(startOfDay).numericState;
const hourlyRainMm = rainTotal.numericState - rainTotal.persistence.persistedState(oneHourAgo).numericState;

// 3. Perform Conversions (Metric to Imperial)
const tempF = (tempC * 1.8) + 32;
const windMph = windKmh * 0.621371;
const dailyRainIn = Math.max(0, dailyRainMm * 0.03937); // Ensure no negative values
const hourlyRainIn = Math.max(0, hourlyRainMm * 0.03937);
const solarRadiation = lux * 0.0079; 

// 4. Construct the API URL manually
const baseUrl = "https://rtupdate.wunderground.com/weatherstation/updateweatherstation.php";

// We build the query string directly to avoid ReferenceErrors
let queryString = "?ID=" + STATION_ID;
queryString += "&PASSWORD=" + STATION_KEY;
queryString += "&dateutc=now";
queryString += "&tempf=" + tempF.toFixed(1);
queryString += "&humidity=" + humidity.toFixed(0);
queryString += "&windspeedmph=" + windMph.toFixed(1);
queryString += "&rainin=" + hourlyRainIn.toFixed(2);
queryString += "&dailyrainin=" + dailyRainIn.toFixed(2);
queryString += "&solarradiation=" + solarRadiation.toFixed(1);
queryString += "&softwaretype=openHAB_5.1_GraalJS";
queryString += "&action=updateraw";

const finalUrl = baseUrl + queryString;

// 5. Execution
try {
    // Note: in openHAB GraalJS, 'actions.HTTP' is the standard way to call this
    const response = actions.HTTP.sendHttpGetRequest(finalUrl, 5000);
    
    if (response && response.includes("success")) {
        return;
    } else {
        console.warn("WU: Upload Failed. Response from server: " + response);
    }
} catch (e) {
    console.error("WU: Communication Error: " + e);
}