QR Entrance & Exit

Access control at the gate was a paper book: name, time, vehicle, signature. It was slow at shift change, unreadable after a week of handling, and impossible to search when someone actually needed a record.

Badges with QR codes already existed, issued by a separate system. What was missing was the thing that reads them.

This is an Expo app that opens straight into the camera, scans a badge, resolves who it belongs to, and posts the movement to the existing registration service. One toggle switches the whole app between entry and exit mode, because at a checkpoint you are doing one or the other for a stretch, not alternating — the guard sets the mode once at the start of a flow rather than choosing per scan.

Scans are debounced against the last badge seen, so leaving the camera pointed at a badge does not write the same movement dozens of times.

The lesson was that the interesting part of a scanner app is not the scanning. It is the fifteen seconds of interaction around it, under bad lighting, by someone holding a clipboard.

The app talks to an internal service; endpoints and hostnames are not published.