Timmy in Crerar

Timmy in Crerar is a lightweight location-intelligence project: a mobile app collects validated presence signals at John Crerar Library, a backend stores clean session data, and this website publishes a read-only public dashboard.

Architecture highlights:

• Phone app (React Native + Expo) is the data collector.

• GPS and geofence logic run on-device to detect when Timmy enters/leaves Crerar.

• The app is designed to ship as a real standalone build (not only Expo Go) so tracking can continue without a laptop or local dev server.

• Small backend (Supabase style) is the source of truth.

• Sessions are stored as structured records: start, end, duration, and status transitions.

• Day/week/month totals are derived from the session table for consistency across all clients.

• Access uses a single private user identity/token (personal-use workflow).

• Website is a read-only display layer.

• The site fetches aggregate stats and weekly chart data from backend views/RPC endpoints.

• No browser location permissions are required, because the web page never collects GPS.

• Result: fast public visibility of live work stats while keeping collection logic in the phone app.