Badges and signage
Print four hundred badges once.
A badge is printed a week before the event and it's the one thing every attendee carries all day. Its QR should be worth scanning at nine, at two, and the Tuesday after.
Scan it
The same idea, on a card you could clip to a lanyard.
This is a real badge code running a conference day on a loop: check-in first thing, morning sessions, lunch, the afternoon tracks, the reception, then feedback and slides once the rooms go dark. Scan it whenever you like and you'll land where the schedule says people should be.
The strip is the week in your time zone. Each shade of bronze is a different rule doing its job.
Right now this code sends people to the menu.
At 4:00 PM it switches to happy hour.
Shown in your time zone. The café keeps Chicago time.
Open where it points right now or scan it. Same code, every day of the year.
The worked example
One badge, a whole event.
Dated windows, highest priority wins. Set before the print deadline; edit from the back of the hall if the keynote runs long.
Signage too
The sign on the door says what's in the room.
Room signs
One code per room, on a schedule that follows the program. Scan the door and get this session, then the next one, then "this room is closed."
Posters
Tickets until it sells out, then the waitlist, then the photos. The poster stays up for weeks; the link changes three times.
Sponsor booths
The offer during the show, the follow-up after. Give the sponsor a code and keep the print deadline.
In bulk
Four hundred codes is a spreadsheet, not an afternoon.
Import codes from a CSV, put them on a shared schedule, and print them as sheets on a badge or label layout. Tag them by track or by sponsor so a thing with 400 codes isn't 400 rows to scroll past.
An event pass turns on the big-event limits for 30 days and then drops back to free, which is what an event actually needs.