Use a Mac as a Countdown Timer or Scoreboard Display: Keyboard Locked, Screen Kept On

A hackathon has forty minutes to submission and the countdown is a MacBook on a trestle table at the front of the room. A quiz night runs a two-minute timer per round from a laptop on the bar. An exam room shows the remaining time on a projector fed by the invigilator's Mac. A bake sale has a kitchen timer page open on an old MacBook Air next to the ovens. In every case the Mac is doing one job, in public, and the failure is the same: somebody leans on the table, a key gets pressed, the timer page loses focus or the screensaver kicks in, and whoever set it up is across the room with their hands full. This post is about using a Mac as a countdown timer, scoreboard or "next up" display with the keyboard and trackpad locked and the screen kept on.

Why a timer on an unlocked Mac keeps breaking

Any full-screen timer page or scoreboard app will do the display part. The problem is everything around it. macOS treats an idle Mac as one to protect: the screensaver starts, the display sleeps, and the room is looking at a black rectangle while the clock runs invisibly. Meanwhile the Mac is unlocked for anyone who wanders past: Escape drops a browser out of full screen, and a curious child at a bake sale finds Spotlight in about four seconds. The macOS lock screen (Control-Command-Q) blanks the display, which defeats the point, and the sleep settings leave the keyboard wide open. The lock the keyboard, keep the screen on post walks through that trade-off.

The fix: one visible app, everything else locked

VibeLock is a $10 menu bar app for macOS 13 Ventura or later that locks the keyboard, mouse and trackpad system-wide, hides every app except the ones you allow, and keeps the display awake while locked. A key press or a click raises VibeLock's unlock shield instead of reaching the timer, and Escape drops the shield with nothing changed. You unlock with Touch ID or your Mac login password, verified locally by macOS. It was built so developers could leave Claude Code running on a visible screen, which is the same problem as a timer on a trestle table.

The setup is the one in the presentation and classroom post, with a timer instead of slides. Make the timer page or scoreboard app full screen. Click the VibeLock icon in the menu bar, open Visible While Locked, and tick that one app (for a web timer, the browser). Leave Accessible While Locked empty. Start the countdown, then choose Lock. The room sees the timer and nothing else; Spotlight, Force Quit and Command-Q are blocked.

Set-up checklist before the doors open

1. Power. Charger in. VibeLock keeps the display awake while locked but does not override a dead battery or a closed lid. Leave the lid open, too: Touch ID is unavailable in clamshell mode.
2. Brightness. Set it before you lock. Brightness and volume keys arrive as system events that VibeLock's input tap does not intercept, so they will likely still work while locked, but do not rely on that.
3. Screensaver and lock screen settings. VibeLock holds the display awake while locked. Check your Lock Screen and Energy or Battery settings in System Settings all the same, and set the screensaver and automatic lock to Never for the day. Put them back afterwards.
4. Notifications. VibeLock hides apps; it is not a Do Not Disturb switch, and macOS still draws banners. Turn on a Focus mode so a calendar alert does not land on the scoreboard.
5. The page itself. If the timer is a browser tab, close every other tab and window first. VibeLock shows every window of an allowed app, so a second window with your inbox in it would be visible too.
6. Accessibility permission. Input blocking needs the macOS Accessibility permission, which VibeLock asks for on the first lock. Grant it at home, not in front of the room; the setup guide covers it.
7. Sound. VibeLock blocks input from people; it does not interfere with what the allowed app does on its own, so a timer alarm should play as normal. Test it once with a ten-second countdown, locked, before the event.

Timer, scoreboard or next-up: three slightly different setups

A countdown that runs itself

Hackathon deadline, exam time remaining, two minutes per quiz round. Start the timer, lock, walk away. Nobody can pause, reset or close it, and you unlock only when the event moves on.

A scoreboard somebody has to update

A scoreboard has to change every few minutes, so you have two options. The honest one is to unlock each time: touch the Touch ID sensor, update the score, lock again. One fingerprint is fast enough to do thirty times in an evening. The other is to mark the scoreboard app Accessible While Locked rather than merely visible, which lets anyone at the keyboard change the score while everything else stays locked and Command-Q stays blocked. That suits a trusted scorer and is a bad idea on an open table, because "anyone" includes the team that is losing. An accessible browser also gives them the whole web, not just your page.

A next-up or running-order display

A document or slide listing who presents next at a demo day. Same as the countdown: full screen, allow the app, lock; when the order changes, unlock with Touch ID, edit, lock. The demo loop post covers the version where the content is a looping video.

What VibeLock does not do here

• It will not start or stop the timer for you. It blocks input; it does not touch the app. Start the countdown before you lock, and unlock to change it.
• It does not stop someone closing the lid or pulling the power. Lid-close sleep is not overridden, and a long press on the power button forces a shutdown. Both land at the real macOS login screen, but the timer is gone.
• It is not a kiosk-management tool. It is a lock for a Mac you will come back to, not a way to run an unattended display for a week; the trade-offs are in the booth and lobby post. For that, macOS single-app and managed kiosk setups survive restarts and VibeLock does not try to.
• It does not hide what the timer page shows. Anything in an allowed window is readable by the whole room, so make sure the page contains only the timer.
• Trackpad swipes between Spaces are not blocked, because an event tap cannot stop them; a Space showing a hidden app is covered by the shield instead.

When not to use this

An exam room is the case that needs a pause. Many exam boards have strict rules about which devices may be present and what may be shown, and a laptop running third-party software on a projector may need sign-off. Ask the invigilator first; a wall clock they have approved beats a clever setup they have not. The same goes for any event where the audience is supposed to interact with the screen, a quiz where teams walk up and tap their answer, for instance: VibeLock swallows every click, so it is the wrong tool by definition. And if the Mac is a shared machine that people should use between rounds, log them in as a separate user instead of locking it.

Questions people ask

Will the screen stay on for the whole countdown?

While locked, VibeLock keeps the display awake. It does not override lid-close sleep or an empty battery, so keep the lid open and the charger in, and check your Lock Screen settings before the event.

Can someone pause or reset the timer?

Not from the keyboard or trackpad. Keys, clicks, scrolls and drags are swallowed before the timer app sees them; the first one raises the unlock shield and Escape dismisses it. Marking the app Accessible is the exception, and you control that.

How do I update the score without unlocking fully?

Touch the Touch ID sensor, update, and lock again from the menu bar. If someone else should update it, mark the scoreboard app Accessible While Locked and accept that anyone at the keyboard can then use that one app.

Does it work on an external display or projector?

Yes. Allowed apps work across all displays and Spaces, and the shield covers every display when it appears.