Fusion/Sensoren/en
Fusion shows two kinds of sensors: the internal environment sensor in the case and external sensors on Wi-Fi that report via MQTT (e.g. ESPHome). Which sensors appear on the display is set in the web interface at http://wettercube-fusion.local/sensoren (card "Sensoren" on the start page). Home Assistant is not required, only an MQTT broker.
Internal sensor (AHT20 + BMP280)
| Module | AHT20 (temperature, humidity) + BMP280 (pressure) on one board, 4 pins: VDD, SDA, GND, SCL |
| Connection | the board's I²C bus (on the S3 development board the I²C connector, SDA 8 / SCL 9), 3.3 V supply |
| Addresses | AHT20 0x38, BMP280 0x77 (or 0x76); they do not collide with the touch controller or the board's IO chip
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| Measurement | every 30 seconds; the BMP280 measures in forced mode to keep self-heating low |
| Display | detected automatically (searched again every 60 s) and shown as "Temperatur", "Luftfeuchte", "Luftdruck" in the room "Gehaeuse" |
Correction (offset): Inside the case the sensor is warmed by display and processor, so temperature reads too high and humidity too low. A correction can be entered per sensor and is added to the measured value. The easiest way is "Abgleich" (calibrate): read a reference thermometer, enter the value, and the Fusion computes the offset itself. Humidity is limited to 0–100 % after the correction.
Pressure: The internal pressure is converted to sea level using the entered altitude, so it is comparable with weather maps and the weather data.
External sensors via MQTT (ESPHome), step by step
What is it? MQTT is like a bulletin board in your home network: your sensors (e.g. ESPHome) pin their readings there and the WetterCube reads them. The board (technical term "MQTT broker") usually already runs in your smart home, in Home Assistant as the add-on "Mosquitto broker". You only need its IP address. If you have no such sensors, just ignore this.
Open http://wettercube-fusion.local/sensoren. The page guides you in three steps:
- Connect: enter the IP address (e.g.
192.168.178.20) and press "Verbinden". Find the IP address in your router under "Heimnetz" (home network) or in Home Assistant under Settings → System → Network. A number is more reliable than a name. Only if the hub asks for a password, open "Ist die Zentrale mit Benutzername und Passwort geschützt?". The status line tells you in plain words whether it worked: Verbunden (connected), Anmeldung abgelehnt (check user name/password) or Nicht erreichbar (check address and WiFi). - Choose sensors: once connected, all sensors announcing themselves on the network appear (this can take up to a minute). Tick them and press "Ausgewählte hinzufügen". WiFi signal and uptime are hidden; "auch technische Werte zeigen" shows them.
- What the WetterCube shows: the selection with name, room and current value. Name and room can be edited, the tick hides a sensor, × removes it. Kachel (tile) decides which values appear together in one tile (see below). Then "Speichern". The values appear on the sensor page of the display.
Combining values in one tile: enter the same name in the Kachel field of several sensors (e.g. "Wohnzimmer" for the temperature, humidity and pressure of a room) and the display shows them together in one tile, each value with its own icon and name. If the field stays empty, the sensor gets its own tile as before. Two buttons save typing: Pro Raum zusammenfassen (combine per room) uses the room as the tile name (only if the room has several sensors), Alle einzeln anzeigen (show all separately) clears all tile fields. When adding from the search, a tick combines the values of the same device automatically (on by default, can be changed any time). The order of the tiles and of the values inside follows the sensors' order (advanced settings).
Icon, correction, order, calibration, altitude and adding by hand (MQTT topic) are under "Erweiterte Einstellungen zeigen" so the page stays simple for beginners.
Nothing shows up? ESPHome only sends via MQTT if the sensor's configuration has a mqtt: section (with the hub's address). If ESPHome is connected only through the Home Assistant API, it sends no MQTT values. Discovery is announced when the sensor starts; restart the sensor once.
Password: it stays on the device and appears neither in the log nor in the settings backup. Recommendation: create a separate read-only account for the WetterCube (example below).
Important with ESPHome: deviations that are corrected in the ESPHome code with a filter (offset:) are already subtracted in the values sent. The correction in the Fusion then stays at 0, otherwise it is corrected twice. Value and raw value are shown side by side in the table.
The topic of an ESPHome sensor is normally <node name>/sensor/<name>/state (payload: the number as text), availability <node name>/status (online/offline). A sensor with no message for 15 minutes or reporting offline is treated as unavailable.
Backup: the sensor list and the broker address are part of "Einstellungen sichern", the password is not.
Rooms for the airing traffic light
For the airing traffic light to recognise a room, a temperature and a humidity sensor need the same room (column "Raum"). The traffic light appears as a strip at the top of the sensor page.
Limits and warnings
In the column Warnen unter / über (warn below / above) you can enter a lower and/or upper limit per sensor (for example humidity above 65 %); leaving it empty means no warning. If the value is beyond the limit for more than a minute and a half, an alarm starts: the tile on the sensor page gets a red border with a red value, the hint tile of the main screen shows the sensor (room, name, value; "+n" for several) and, if ntfy is set up, a message reaches your phone (see Einstellungen). The alarm only ends when the value is a small margin inside the limit (2 % of the limit, at least 0.3), so it does not flicker at the limit. If a sensor is silent for more than 15 minutes, its alarm no longer applies. The hint tile can be switched off under Anzeige → "Hinweise auf dem Hauptscreen". /log shows the number of limits and active alarms.
Sensor page
The "Sensoren" page (after air quality) shows per tile either a single sensor with icon, name, room, value and status dot or, if you combined sensors in the web UI, a tile name with one row per value (icon, name, value). The status dot is green when all values of the tile are current, red when at least one is offline or stale, gray while nothing has been received yet. Up to 16 sensors fit; from nine tiles they become compact, tiles with several values may be taller. The web UI lets you pick the icon per sensor (thermometer, humidity, pressure, wind, pollen, UV, raindrop, …), otherwise the firmware picks it by unit.
Many sensors: several pages. If not all tiles (sensors and switches) fit on one page, the sensor page splits into pages. How many tiles go on one page, you set in the web interface under Anzeige → "Sensor-Seite: Kacheln pro Seite": 12 (compact, default) or 8 (larger and easier to read). At the bottom between the home and next buttons you then see "< 1 / 2 >": tapping turns the page (after the last page back to the first), and so does swiping left or right on the tiles. If a sensor on another page has an alarm, a red dot appears next to the page indicator. You set the order of the tiles in the web interface as before, the switch tiles come after the sensors.
The wind (Open-Meteo) is not on this page but in the wind container of the main screen: an arrow turns smoothly to the wind direction (it points where the wind blows), with direction and speed next to it.
Switch tiles
After the sensor tiles, the same page shows switch tiles with which you switch devices in your smart home (light, socket). Setup and examples: Home Assistant and switches.
On the display
The screens for this will be designed in PicoPixel later. Matching icons (thermometer, humidity, wind, pollen, pressure, UV and more from the Meteocons, MIT) are in the repository as PNG under assets/icons/meteocons/. The firmware provides the visible sensors in the chosen order (room, name, value, unit, online/offline) through sensorenAnzeige().