How to set up an event countdown timer

Anything that runs a browser is a candidate display, which turns hardware planning into an inventory walk.

The common options:

Where cables are involved, plan them like the AV crew does: HDMI is fine for short runs but is usually the first thing to fail, so carry spares; long throws across a large venue are SDI territory — locking connectors, hundreds of feet — with an HDMI-to-SDI converter at the computer end. A browser-based display shrinks this problem, because a device sitting at the screen needs network, not video cable.

• A laptop connected to a TV or projector over HDMI — the simplest stage or room display.
• A smart TV or streaming stick opening the link in its own browser — no computer needed behind the screen.
• A tablet on a stand — a lectern-sized confidence monitor.
• A Raspberry Pi in kiosk mode — the permanent, silent installation.
• Your production software — OBS and vMix accept web pages as inputs when the countdown should be part of a stream.

The timer setup happens once, in the browser, before touching any screens.

The steps:

1. ✓Create a room — the container every screen and controller connects to. One room per event; for a multi-track venue, one room per stage, so each track's rundown advances independently.
2. ✓Add a timer per segment: doors, opening, each talk, breaks, closing. Names, speakers, and notes make the list a running order rather than a pile of durations.
3. ✓Set wrap-up thresholds on speaker segments so displays change appearance as time runs low.
4. ✓Decide the starts: manual for flexible moments, linked so segments advance automatically, scheduled for anything tied to the clock — doors at 18:00 starts itself.

Each display opens one link. The viewer shows the clean countdown for stages and rooms; the agenda shows the running order for backstage and crew areas; the moderator view adds messaging for a host's tablet.

Open the link on each device, make it fullscreen, and disable the device's sleep timeout. That is the entire per-screen installation — no software, no accounts on venue hardware, nothing to license.

The beginner mistake is discovering a dead screen during the opening speech. The room's live connections view prevents it: every connected device appears in a list, so the room owner or an admin confirms the stage monitor, the lobby screen, and the greenroom tablet are all receiving — from one seat, before doors. The list is sent to owners and admins only, so this check is not the operator's to run.

You can rename a connection to match your plan — "Lobby screen" instead of "Viewer 1" — but the name only lasts while that browser stays connected. A reload gives the device a default name again.

Do one rehearsal pass: start the first timer, watch it change at a wrap-up threshold, send a test message, and check it lands on the stage display.

Two venue habits make the check trustworthy: put production devices on their own Wi-Fi network (or SSID) rather than sharing the attendee network that will saturate at doors, and run this verification well before the event — a missing screen found two hours out is a fix, not an incident.

During the show, control lives in the controller view on a phone, tablet, or the front-of-house laptop. Start and pause segments, add time when a talk runs long, and send messages — bold, colored, or flashing — to the stage without a sound.

When the schedule bends, adjust the live timer and every display follows. Open-ended segments — Q&A, networking — run in count-up mode so elapsed time stays visible without a deadline glaring at anyone.