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Sparky's Projects

Current Projects

Transit Tracker

A DIY customizable public transit arrivals board displaying real-time transit information. Built using the open-source Transit Tracker project by Eastside Urbanism, deployed on dma.computer infrastructure.

How to interact with it at dma.computer:

Press a button: A 15-key Stream Deck next to the sign switches which route it shows. Top row, left to right: Link, Bus 8, Bus 10, Bus 12, Streetcar. The live route lights up bright with a white border; the rest stay dimmed. Bottom-right key blanks the display.
View the display: The transit board is on the network at transittracker-display.user.dma.computer (10.20.110.197)
API endpoint: Real-time feed data available at http://transittracker-pi.int.dma.computer:3000/feeds
API host: Hosted on transittracker-pi.int.dma.computer (10.20.100.80)
Configure the display: Use the web configurator to customize which routes and stops are shown. Configurator routes by default through the upstream OneBusAway-backed feed; the local API runs a sibling GTFS-static feed (st_gtfs) for more accurate end-of-day train counts.

Current feed config:

kcm — King County Metro (GTFS-static)
st — Sound Transit via OneBusAway (legacy)
st_gtfs — Sound Transit via GTFS-static + GTFS-RT (used by the display; gives true "trains remaining today")

The board shows arrival times for local transit agencies and updates automatically. Perfect for checking your commute before heading out!

Route presets:

Preset	Routes	Stops
Link	1 Line + 2 Line	Capitol Hill, both directions
Bus 8	KCM 8	E John St & Broadway, both bays
Bus 10	KCM 10	E Pine St & 12th Ave, both directions
Bus 12	KCM 12	E Pine St & 12th Ave, both directions
Streetcar	First Hill Streetcar	Broadway & Pike-Pine, both directions

Home Assistant control:

You can do everything the Stream Deck does from Home Assistant, which is handy if you are not standing next to the sign.

select.transit_tracker_cycling_transit_preset — switches the route preset
switch.hangout_transit_tracker_cycling_display_power — blanks the display without cutting power
number.hangout_transit_tracker_cycling_display_brightness — brightness, 0-255

The Stream Deck talks to these entities over the Home Assistant REST API. It runs as a container on the same Pi as the API, and it mirrors Home Assistant, so switching a preset from either place updates both.

Troubleshooting:

If the sign shows "no upcoming arrivals" for some routes but not others, the routes that break usually share a feed. Work through these in order:

Query the API for a broken route and for a route on the same feed the sign never asks for. If the second one works, the data is fine and something is caching empty results.
Check for a stuck feed sync: SELECT feed_code, locked_at, now() - locked_at FROM sync_lock; A row older than a few hours is stale, and it blocks that feed from syncing again until you clear it.
Check the data has not aged out: SELECT feed_code, min(start_date), max(end_date) FROM calendar GROUP BY feed_code; and compare to today. GTFS feeds expire, and an agency service change replaces them.
To force a sync: docker exec transit-tracker-api-api-1 node dist/cli sync --force --feed <code>
A sync run this way is invisible to the running API for up to 12 hours, because schedule results are cached in memory as well as in Redis. Restart the API container to pick them up: docker restart transit-tracker-api-api-1

Repos:

API: github.com/sparkyfen/transit-tracker-api (fork of tjhorner/transit-tracker-api)
ESPHome firmware: github.com/sparkyfen/esphome-transit-tracker
Stream Deck controller: github.com/sparkyfen/streamdeck-transit

ESP32 Transit Tracker (WhereTrain)

A real-time transit tracker that displays Sound Transit Link Light Rail train positions on a physical LED map. The system uses an ESP32-S3 microcontroller to poll live transit data and render animated train movements across an addressable LED strip. Originally designed for /dev/hack Seattle.

Hardware:

Microcontroller: ESP32-S3 (WROOM-1-N8R8) with 8 MB PSRAM and 8 MB flash
Display: 76 SK9822 (APA102-compatible) addressable RGB LEDs in a single chain
PCB: JLCPCB-manufactured, with an expansion connector breaking out unused GPIO, UART pins, and LED access points for external LED strings

How it works:

Polls the OneBusAway API for live Sound Transit train positions
Renders smooth crossfade animations showing train movements between stops on the LED strip
API key can be requested from Sound Transit at oba_api_key@soundtransit.org

Development:

Repository: codeberg.org/sparkyfen/wheretrain
Build environment: ESP-IDF 5.x (Nix supported) — cd wheretrain && nix develop && idf.py build flash monitor
Configuration: WiFi credentials in network.c, API key in main.c
Recovery: Hold BOOT while powering on, then release and flash with idf.py flash
License: CC BY-NC-SA 4.0

Status: Active development. Contributions and feedback welcome — reach out to Sparky on Zulip or check the repo.

TRMNL E-Ink Dashboard

**Deprecated.** The space runs a different e-ink display now. This section stays for reference. Do not use it as current documentation.

A 7.5" e-ink display dashboard that serves as a distraction-free information display. TRMNL uses a privacy-focused design where the device polls for updates rather than allowing external access to the local network.

How to interact with it at dma.computer:

What it shows: Customizable layouts featuring calendar, weather, news, stocks, and 794+ other plugins
Updates: The display refreshes only when new information is available, preserving battery life (6+ months on a charge)
Plugin ecosystem: Supports integrations with Google Calendar, Home Assistant, weather stations, and community-created plugins
Developer friendly: Create custom plugins using HTML/JSON in under 5 minutes

Learn more at usetrmnl.com

Completed Projects

Coming soon