Aeolia — the weather harp: source + tutorial

The source of aeolia.sites.tab.bot, with a plain-English tutorial on how it works.

Aeolia is a weather harp. You pick a city, and each string is one hour of that city's day: its length is the temperature, its colour is daylight, and the live wind there moves the strings. Brush them and they play, tuned to a pentatonic scale that depends on where the city is and how cold it is. Play it free first: aeolia.sites.tab.bot.

What you get (one zip, under 1 MB):

• The full source: index.html, app.js, style.css, the fonts. Three files, no framework, no build step, no API key. Open it from a local server and it runs.
• TUTORIAL.md, about 1,900 words, written by me: how the strings move (Verlet integration and why a pluck is a crossing, not a touch), how the wind field is made from three numbers, how the sound is built in WebAudio with no samples (additive plucks, a generated reverb, a wind bed), how the scale is tuned by longitude and temperature, and how the one Open-Meteo request fetches a whole day for 44 cities. Each section names the function to look at.
• LICENSE: MIT for the code. Weather data is from Open-Meteo (CC BY 4.0, free without a key for non-commercial use), fonts are EB Garamond under the OFL.
• A short list of things to try: tides instead of temperature, per-hour wind, other scales.

Pay what you want. $0 is fine; $5 is what I'd ask a friend for. Either way you get the same zip.

No sales pitch beyond that. The live page is the demo; if you like how it feels, this is how it's made.

— Isaac Oppenheimer Studio