SkyGlance

Desk-side aviation weather at a glance. SkyGlance turns a Pimoroni Badger 2040 W into an always-on e-ink board that shows the current METAR for any ICAO airport — temperature, flight category (VFR / MVFR / IFR / LIFR), wind, visibility, cloud layers, and a 24-hour Zulu observation time.

The device talks directly to aviationweather.gov over HTTPS. No server, no API key, no account — flash it, set your Wi-Fi SSID and an ICAO identifier, and it runs.

 +------------------------------------------------+
 | KLBB Lubbock                          22:00Z   |  ← header
 | -----------------------------------------------|
 |                                                |
 |   91F                          VFR             |  ← hero
 |                                                |
 | -----------------------------------------------|
 | WIND 200 5kt G15  91/46                        |  ← scale-2 body
 | CLD FEW050  vis 10SM                           |
 | ALT 29.92  DA 6572                             |
 +------------------------------------------------+

Three zones, all readable at desk distance:

• Header (scale 1): ICAO code + city name on the left, observation Zulu time on the right.
• Hero (scale 5): big Fahrenheit temperature, big flight category. IFR / LIFR render as a white-on-black inverted block — instant visual cue conditions are bad.
• Body (scale 2): three labeled rows
  • WIND direction / speed / gust + temp/dewpoint pair
  • CLD cloud layers in METAR short form + vis in statute miles
  • ALT altimeter setting (inHg) + DA density altitude + CEIL when overcast/broken layers are present

The status page (button C) shows battery, Wi-Fi, station, and local sunrise/sunset times. The Details page (button B) shows altimeter, dewpoint, spread, DA, PA, plus the raw METAR text. One more B press from there shows the TAF forecast for the current station.

Dark mode overnight: between 22:00 and 06:00 local time (via TIMEZONE_OFFSET), the whole panel inverts — black background with white foreground — so it isn't blasting light across a desk at night.

The DA value is the current density altitude in feet, computed from the station elevation + altimeter setting + observed temperature. It's what your airplane thinks the air feels like for takeoff performance. Press B for a full details page (altimeter, dewpoint, temp/dew spread, DA + PA, plus the raw METAR text).

• Big temp (Fahrenheit) top-left.
• Big flight category top-right.
• Last observation time (UTC / Zulu) in the corner.
• Station, visibility, wind, cloud layers below.
• (offline) marker in the bottom-right if the last fetch failed; the previous frame stays on-screen until the next successful refresh.

git clone https://github.com/gndl00p/skyglance.git
cd skyglance

python3 -m venv .venv
.venv/bin/pip install pytest==8.3.3

.venv/bin/pytest tests -v      # 24 tests, fully offline

cp config.example.py config.py

Edit config.py:

WIFI_SSID = "your 2.4 GHz SSID"
WIFI_PSK  = "password"

# One or more ICAO airport identifiers. Press UP or DOWN on the badge
# to open the picker and switch between them; the first entry is the
# default on first boot.
METAR_STATIONS = ["KLBB", "KAUS", "KDFW", "EGLL"]

# How often to re-fetch the METAR for the currently-displayed station.
# aviationweather.gov updates hourly; 15 min is a polite cadence.
REFRESH_MINUTES = 15

config.py is git-ignored — your Wi-Fi password never leaves the device.

bash tools/flash.sh

The script copies main.py, fetcher.py, render.py, store.py, and config.py to the Pico, preserves any persisted /state.json, and triggers a soft-reset.

  +------------------------+          HTTPS          +------------------------+
  |  aviationweather.gov   |<------------------------| Badger 2040 W          |
  |  /api/data/metar       |                         | MicroPython firmware   |
  +------------------------+                         | Wi-Fi + e-ink panel    |
                                                     +------------------------+

• main.py boots, runs one fetch + render cycle, then loops every REFRESH_MINUTES. Button A forces an immediate refresh.
• fetcher.py connects Wi-Fi, hits aviationweather.gov over HTTPS, and parses the METAR JSON into a flat dict (temp °F, wind, clouds, visibility, ceiling, flight category).
• render.py paints the e-ink panel.
• store.py persists the last successful fetch in /state.json so the panel has something to show during Wi-Fi or API outages.
• On any error the previous frame stays, a small (offline) / (bad payload) marker appears, and the next refresh tries again.

Stable at ~5 KB of flash for the application plus the persisted state file. No extra dependencies beyond what Pimoroni's stock MicroPython build already ships (badger2040, requests, network, ujson).

Evaluated top-to-bottom — a 700 ft ceiling wins over 10 SM visibility.

The selected station is persisted in /state.json, so a reboot comes back to the last airport you chose.

The on-board LED briefly pulses every 20 seconds as a heartbeat, so you can tell at a glance that the firmware is still running.

Shows altimeter setting (inHg), dewpoint (°F), temp/dew spread (°F), density altitude, pressure altitude, and the raw METAR line straight from aviationweather.gov.

Fetches the TAF for the current station from aviationweather.gov/api/data/taf and word-wraps the raw forecast line on-screen. Useful for "what's the weather going to do over the next 4–12 hours?" at a glance.

main.py            entry point — first cycle, then refresh loop
fetcher.py         Wi-Fi connect, HTTPS GET, METAR parser, stale fallback
render.py          e-ink layout
store.py           /state.json persistence (read/write)
config.example.py  template (copy to config.py, never committed)
tools/flash.sh     mpremote-based deploy + soft-reset

tests/             host-side pytest suite
  conftest.py        adds tests/stubs to sys.path
  stubs/             fake Pimoroni / MicroPython modules
  fakes/display.py   FakeDisplay that records draw calls

Run the suite:

.venv/bin/pytest tests -v

Everything is mocked — no real hardware, no network. The tests/stubs/ directory provides tiny fakes for badger2040, network, requests, machine, and ujson so the modules that import them at device boot still import cleanly on CPython.

To add a feature that calls a new Pimoroni API, extend the stub in tests/stubs/badger2040.py with a no-op method — this keeps the suite runnable on any machine without a device attached.

Wi-Fi didn't connect. Verify SSID + PSK in config.py. Reset the device; if the issue persists, run a scan:

mpremote connect /dev/ttyACM0 exec 'import network, time
w = network.WLAN(network.STA_IF); w.active(True); time.sleep(1)
for n in w.scan(): print(n[0], n[2], n[3])'

The firmware uses a polling idle loop specifically because display.halt() on the Badger 2040 W is a no-op under USB power. If buttons are still unresponsive, every mpremote exec ctrl-Cs the running firmware — issue mpremote connect /dev/ttyACM0 soft-reset to restart it.

The factory Pimoroni filesystem ships a state/ directory for the stock launcher; MicroPython resolves import state to that package and shadows a state.py file. That's why the persistence module is called store.py instead of state.py.

• config.py holds your Wi-Fi password and is git-ignored. Review .gitignore after any branch-switch rebase.
• The device only makes outbound HTTPS to aviationweather.gov. No inbound listeners, no telemetry, no analytics.
• Resetting the device via BOOTSEL + drag-drop the factory firmware clears everything; run bash tools/flash.sh to restore.

• Optional second METAR tile (home / destination) with paged display.
• Battery-powered variant using halt() + badger2040.pressed_to_wake for multi-day LiPo runtime between refreshes.
• Visual alert when flight category degrades by two tiers in one cycle.
• Flash-minimising build (strip unused Pimoroni libs).

MIT — see LICENSE.

Hardware + MicroPython runtime from Pimoroni. METAR data from the Aviation Weather Center.