Local weather goes live

Ikara now publishes its own weather — temperature, wind, rain, pressure, sun and UV from the station in the paddock, alongside the conditions inside the cabinet.

This one is about plumbing rather than radio. If you like knowing how a small remote site actually hangs together — where the data comes from, and who owns it — this is that. No radio knowledge needed.

There is an Ecowitt weather station at Spring Range. The outdoor array sits on its mast in the paddock: thermometer and hygrometer, a tipping-bucket rain gauge, an anemometer and wind vane, and a head that measures sunlight and ultraviolet. It talks on 433 MHz to a console inside the IKARA cabinet, and the console pushes the numbers up to Weathercloud every ten minutes.

Until now, seeing that data meant going and looking at it on somebody else’s website. Everything else at Ikara — the solar, the battery, the cabinet, the link — reports to Ikara. The weather is now on the same footing. There is a weather panel on the stats pages, and it is live:

What it shows

Six dials for the things that change: temperature, wind, humidity, pressure, solar radiation and UV index. The wind one is a proper compass card rather than a gauge, because a wind reading is really two numbers — how hard, and from where — and a needle on an arc can only ever tell you half of that.

Under the dials there is rainfall, the day’s extremes with the times they happened, a rolling twenty-four hour trace, and the record book for the month and the year.

A couple of small things were worth getting right rather than merely displaying. The station sits around 690 metres above sea level, so its barometer reads about 946 hectopascals. That figure is perfectly correct and completely useless for comparing against a forecast, so the dial shows the sea-level equivalent — about 1026 — and keeps the raw reading in the caption underneath. The station also reports wind in metres per second, which nobody in this country thinks in, so that gets converted too.

Inside and outside

Here is the part I did not expect to care about as much as I do.

The console’s own thermometer and hygrometer are not measuring the weather. They are sitting inside the IKARA cabinet, which means they have quietly been a fourth opinion on the equipment’s environment this whole time, alongside the BME680 and the three IKARA probes on the Environment page.

As I write this the paddock is at 14 degrees and the inside of the cabinet is at 25. That eleven degree gap is the cost of putting powered equipment in a sealed box in the sun, and it is worth being able to watch.

Those readings are on the page, in their own panel, in a different colour, under a heading that says INSIDE. Confusing cabinet temperature with air temperature would be an easy and genuinely misleading mistake, so the page goes out of its way to make it impossible.

Where the data comes from

The console feeds two places. It uploads to Weathercloud every ten minutes, and it also pushes its complete sensor set directly to the Raspberry Pi on the site LAN, every few seconds. A small receiver on the Pi catches those pushes, converts the protocol’s imperial units into sensible ones, and writes them down.

The page prefers that local feed. It is a minute old rather than ten, it does not depend on anyone else’s servers being up, and it is the only source that carries the inside readings at all.

Weathercloud has not been dropped. It is the fallback if the console or the receiver goes quiet, and it still supplies the month and year record book. The page tells you which of the two it is currently reading.

How it actually hangs together

• array Ecowitt WH-series in the paddock, 433 MHz to the console
• console HP2561 Pro in the cabinet — uploads to Weathercloud, and pushes everything to the Pi
• receiver a small service on ikarapi catches the push and logs it
• producer a script every five minutes builds one JSON file of the current state
• page the web tier just draws that file, and re-reads it every sixty seconds

That is the same shape as every other data page on this site, and it is deliberate. The web server holds no logic and makes no decisions. It renders what the site sends it. If a number looks wrong, there is exactly one place to go and look.

The Pi keeps its own history too — a fortnight of minute-by-minute readings and four months of the coarser Weathercloud record, both trimmed automatically so a weather log can never quietly eat the SD card. There is a wx command on the Pi that dumps the current conditions and the recent log to the terminal, for when I am already in a shell and cannot be bothered opening a browser.

The point

None of this is clever. It is a weather station, and weather stations have been solved for a century. But it closes a small gap that had been bothering me since the site went live.

For everything else at Ikara — the solar, the battery, the cabinet, the link — the answers were already “here” and “nobody”. Now the weather gives the same answers.