A fullscreen timer turns any display into a countdown everyone in the room can read — a projector during a workshop, a TV backstage, the laptop facing a speaker. Because a browser can fill any screen it is connected to, the only setup a fullscreen timer really needs is a page worth filling it with.
This guide uses MaestroTimer: create a timer, open its viewer link on the display, go fullscreen, and control the countdown from a different device entirely.
Create the timer
Start in the room — the container every screen and controller connects to.
The steps:
- Create a room in MaestroTimer and add a timer.
- Give it a name, and optionally a speaker and notes — on a stage display, the name tells the presenter which segment this countdown belongs to.
- Choose the direction: count down toward zero, or count up for open-ended segments where elapsed time is the number that matters.
- Set a wrap-up threshold so the fullscreen display changes its appearance as time runs low — readable from the back of the room without anyone announcing it.
Fill the screen
The viewer is the display view — no controls, just the countdown.
The steps:
- Open the room's viewer link in a browser on the device driving the display. Every view in MaestroTimer is a link.
- Press F11 on Windows and Linux, or Cmd+Ctrl+F on macOS, to enter fullscreen. Only the timer remains.
- On a TV or projector, either connect a laptop over HDMI or open the link directly in the screen's own browser — a smart TV, a streaming stick, or a Raspberry Pi in kiosk mode all work, because each is just a browser.
- Disable the device's sleep timeout for events longer than its screensaver delay.
Three ways to start it
A fullscreen display is often across the room — or across the building — from the person running it, so the timer offers three triggers.
Manual is the default: press start in the controller. Linked timers chain a rundown, each starting the moment the previous one ends. Scheduled timers begin at a set time of day on their own — a countdown to a published start time runs on the fullscreen display with nobody touching anything.
Control it from another device
The display device never needs touching once it is fullscreen. Open the controller view on a phone or laptop: start, pause, and time adjustments appear on the big screen immediately.
Messages reach the same screen — a bold, colored, or flashing note beside the countdown for wrap-up cues or schedule changes. And before the event, the room's live connections view lists every attached device, so you can confirm the projector's browser is receiving without walking over to it.
FAQ
How do I make a timer fullscreen in the browser?
Open the viewer link and use the browser's fullscreen mode — F11 on Windows and Linux, Cmd+Ctrl+F on macOS. The viewer fills whatever size the screen has.
Can I show the fullscreen timer on a TV without a laptop?
Yes, if the TV can open a web page: a built-in smart-TV browser, a streaming stick with a browser, or a small computer like a Raspberry Pi behind the screen all display the viewer link directly.
Does the display need to be touched during the event?
No. All control happens in the controller view on another device, and the fullscreen display updates live — including wrap-up color changes and messages.
Can several screens show the same fullscreen timer?
Yes. Open the same viewer link on every display; all of them stay in sync because they show the same room, and the live connections view lists each one.
Fill your next screen with a timer
MaestroTimer runs in the browser: open the viewer link on any display, go fullscreen, and control the countdown from your phone. Wrap-up colors, messages, and a live connections view are built in.