Departure Board S3

A live departure board on a 64×32 LED matrix, powered by an Adafruit MatrixPortal S3. It cycles between three feeds:

• Trains — next departures between two UK stations (default: Hockley → London Liverpool Street), with platform, delay/cancellation status, and minutes to departure
• Buses — next departures from a chosen UK bus stop, filtered to a specific route and direction (default: the Arriva 7 towards Rayleigh)
• Overhead aircraft — the nearest plane to your location, with callsign, route (for airliners) or aircraft type (for light aircraft), altitude, and distance

The clever bit: it hides departures you can't actually catch. Set how long it takes you to reach the station and the bus stop, and anything leaving sooner than that never appears.

Total build cost: about £30. No subscriptions.

Hardware

Part	Notes
Adafruit MatrixPortal S3 (or compatible)	Plugs directly onto the panel's HUB75 socket
64×32 RGB LED matrix panel, HUB75, 1/16 scan	P4 (256×128mm) or P3 both work
USB-C power supply, 2A+	A phone charger brick is fine; the board powers the panel
Panel power cable	4-pin plug to panel, spade terminals to the MatrixPortal's screw standoffs

This is where I got things: https://www.printables.com/model/514658-led-matrix-frame-for-32x64-p4-led-panel-adabox-16 - 3D printed frame https://a.aliexpress.com/_EImZCKq - Matrix S3 https://a.aliexpress.com/_EQDTfFM - P4 Display

Assembly: push the MatrixPortal onto the panel's input HUB75 socket, screw the spade terminals onto the +5V and GND standoffs (peel the protective stickers off first!), plug the 4-pin end into the panel, and power the MatrixPortal over USB-C. No soldering.

The sketch keeps brightness at 50% by default, which is comfortable indoors and well within USB power limits for text.

Software setup

1. Install the Arduino IDE 2.x and add ESP32 board support (Boards Manager → search "esp32" by Espressif).
2. Install two libraries via the Library Manager:
   • Adafruit Protomatter (accept the dependencies, e.g. Adafruit GFX)
   • ArduinoJson (v7.x)
3. Select the board Adafruit MatrixPortal ESP32-S3 and set Tools → USB CDC On Boot: Enabled.
4. Open departure_board_s3_public.ino, fill in the config (see below), and upload.

Upload tips for the S3: if the port refuses to open, hold BOOT, tap RESET, release BOOT to enter the bootloader, then reselect the (possibly new) COM port and upload again. The first upload attempt sometimes fails at the reboot step; running it a second time usually works.

Configuration

Everything lives in the CONFIG block at the top of the sketch.

WiFi

#define WIFI_SSID      "your-network"
#define WIFI_PASSWORD  "your-password"

2.4GHz only (the ESP32-S3 can't see 5GHz). Guest networks with captive portals won't work.

Trains — Realtime Trains (free)

1. Register at https://api-portal.rtt.io (free for personal, non-commercial use).
2. Copy the long refresh token (starts eyJ...) into RTT_REFRESH_TOKEN. The sketch automatically exchanges it for short-life access tokens and refreshes them as needed.
3. Set TRAIN_ORIGIN and TRAIN_DEST to your stations' three-letter CRS codes (find them on realtimetrains.co.uk).
4. Set TRAIN_LEAD_MIN to how many minutes it takes you to reach the station — trains leaving sooner are hidden.

Buses — TransportAPI (free tier)

1. Sign up at https://developer.transportapi.com and create an app to get an app_id and app_key.
2. Find your stop's ATCO code on https://bustimes.org — it's the number in the stop page's URL (e.g. bustimes.org/stops/15001101515). Count the digits carefully; a truncated code returns HTTP 400.
3. Set BUS_LINE and BUS_DEST_MATCH to your route number and the destination text that identifies your direction of travel.
4. Set BUS_LEAD_MIN to your walking time to the stop.

Important: the TransportAPI free tier allows only 30 requests per day, which is why the sketch polls buses hourly and uses scheduled (nextbuses=no) rather than live times. Repeatedly rebooting the board while testing will burn through the quota (each boot fetches once) and return HTTP 429 for the rest of the day.

Aircraft — airplanes.live + adsbdb (free, no key)

Set LAT/LON (and the matching LAT_STR/LON_STR strings) to your location, and RADIUS_NM to the search radius in nautical miles (5–15 is sensible). Airliner callsigns get a route lookup (e.g. LHR>JFK); light-aircraft registrations show the aircraft type instead.

How it behaves

On boot: wifi... → loading → then pages rotate every 5 seconds. The plane page only appears when an aircraft is in range. Trains refresh every 60s, planes every 10s, buses hourly (free-tier quota).

Colours: amber for normal departures, red for delays and cancellations, green for routes/types, an asterisk marks a live (rather than scheduled) bus estimate.

The board derives UK local time itself from NTP + explicit BST rules, so times stay correct year-round regardless of the device timezone.

Troubleshooting

Symptom	Likely cause
Page stuck on "loading"	That feed's fetch is failing — check the Serial Monitor (115200) for the HTTP code
[RTT token] no token / 401	Refresh token clipped when pasting — recopy it in full
[BUSES] HTTP 400	ATCO code wrong or truncated
[BUSES] HTTP 429	Daily 30-request quota spent — resets next day
[HTTP] 404 ...adsbdb...	Harmless: light aircraft have no route to look up
Board USB connect/disconnect loop	Bootlooping firmware — hold BOOT, tap RESET, erase-flash and re-upload
No serial output after upload	USB CDC On Boot not enabled, or wrong monitor baud (use 115200)
WiFi connects but no data	Captive-portal guest network, or 5GHz-only SSID

Notes

• Realtime Trains data is for personal, non-commercial use; public-facing use requires visible credit to Realtime Trains.
• Aircraft data comes from the community ADS-B network via airplanes.live, with route enrichment from adsbdb.com.
• Bus data via TransportAPI; stop lookups courtesy of bustimes.org.

Built at East Essex Hackspace.

License

MIT — see LICENSE.