ChronoCult: Race timing without the timing truck

ChronoCult uses phones and Bluetooth timing devices to run races: proximity-based racer detection, live timing that survives bad signal, and live tracking on a map.

Context

Grassroots races still rely on expensive timing equipment or a volunteer with a stopwatch. We wanted timing that a club could run from the phones already in their pockets.

What we built

A React Native/Expo app connected to BrakeAce timing devices over Bluetooth
Event management and automatic, proximity-based racer detection
Offline support and background processing, so timing continues with no signal or a locked screen
ChronoCult Track: live race tracking from Garmin inReach, SPOT, KML and GPX feeds on Express, SQLite and MapLibre