Organizers and each station, the day before and on event day

1. Bring a charger or a power bank per station: with the screen on all day, the battery won't last to the end.
2. The day before, charge every phone to 100 percent, spares included.
3. Lower the brightness when there's no line and close what you don't use; keep only the QRnow app open.
4. The app warns you at 30 and 15 percent: at the first warning, plug in the charger; at the second, switch to the spare phone.

If a phone dies, what it already handed out isn't lost: it stays saved and goes out when it turns back on and has signal or meets another event phone.