Real-time departures
Select a Swiss stop and request trains, trams, buses, ships, cableways, or any combination supported by the API.
ESP32 • Swiss public transport API • ST7789
Swiss Transit Tracker
A configurable departure board for Swiss public transport. Pick a station or stop, choose API modes like train, tram, bus, ship, or cableway, then prioritize the lines and destinations you actually care about.
- 4
- rows shown
- 60s
- refresh cycle
- 120s
- watchdog
12:34 IR27On time
13:02 B50On time
13:17 T8+1 min
14:03 S3On time
ESP32 board
Wi‑Fi connected microcontroller
USB-C power
5V input for simple mounting
ST7789 display
Color rows for any selected mode
Departure UI
Four sorted public-transport departures
Watchdog
120s hang protection
JSON pipeline
Filtered fields and user rules
Drag to rotate • Scroll to zoom
What it does
A compact board built for reliable glanceable departures.
Delay state at a glance
Green blocks mark departures that are on time. Red blocks show delays above one minute, capped at two digits.
Custom route filters
Prioritize destination text and exact line labels, or hide non-matching departures for a focused board.
Night brightness
Uses the HTTP date header to dim the ST7789 backlight late at night and restore normal brightness during the day.
Data pipeline
Modes and filters are chosen before the display logic runs.
The sketch asks the transport API for up to eight departures using your selected transport modes. ArduinoJson keeps only the fields the UI and custom filters need, reducing parse pressure on the ESP32.
01
Wi‑Fi
Reconnect tries before failing cleanly
02
Selected modes
transportations[]=bus
03
User filters
Destination and line rules
04
Sorted display
Best four matches shown
const char* TRANSPORTATION_TYPES[] = {"train", "bus"};
const char* DESTINATION_FILTERS[] = {"basel", "laufen"};
const char* LINE_FILTERS[] = {"S3", "B50"};
const bool ONLY_SHOW_FILTER_MATCHES = false;
filter["stationboard"][0]["to"] = true;
filter["stationboard"][0]["category"] = true;
filter["stationboard"][0]["number"] = true;
filter["stationboard"][0]["stop"]["departure"] = true;
filter["stationboard"][0]["stop"]["delay"] = true;RAM discipline
Static buffers, bounded rows, predictable work.
JSON document bytes
StaticJsonDocument<9216> holds the filtered stationboard data after parsing.
Filter bytes
StaticJsonDocument<512> stores the ArduinoJson filter schema.
Payload reserve
The response string reserves room up front to reduce repeated heap growth.
Bounded display work
Temporary arrays inspect up to eight API rows, then render the best four matching rows.
Reliability
The watchdog turns bad network states into visible recovery.
The board resets the task watchdog around long network and parse steps. If Wi‑Fi, HTTP, or JSON handling fails, the display shows the reason briefly before the ESP32 restarts into a clean state.
1
Feed WDT
esp_task_wdt_reset() before and after blocking work.
2
Classify failure
wifi, http, json_nomemory, or body validation errors.
3
Show reset reason
The ST7789 prints
RESET: with the failure message.
4
Restart cleanly
ESP.restart() recovers from a stuck or corrupted runtime state.
Build shots
Small enough for quick mounting, bright enough to read across the room.
Build details
Hardware, libraries, and setup steps.
Display pinout
| ST7789 pin | ESP32 pin |
|---|---|
| MOSI | GPIO 6 |
| SCLK | GPIO 7 |
| CS | GPIO 14 |
| DC | GPIO 15 |
| RST | GPIO 21 |
| BL | GPIO 22 |
Quick setup
- Install ESP32 board support in Arduino IDE.
- Add ArduinoJson, Adafruit GFX, and Adafruit ST7789.
- Set
STATION,ssid, andpassword. - Choose
TRANSPORTATION_TYPESfor train, tram, ship, bus, or cableway. - Adjust destination and line filters for the departures you want.
- Flash the sketch and power the board through USB-C.