Using a Mac as a Baby Monitor or Security Camera Viewer Overnight

An old MacBook on the dresser, or a Mac mini wired to a spare monitor, makes a surprisingly good screen for a camera feed. The nursery camera's web dashboard, a baby-monitor app that runs on the Mac, the doorbell camera's live view, a browser tab playing an RTSP or HLS stream: all of them want the Mac to stay lit and stay on that one window from bedtime until morning. A Mac is built to do the opposite. It dims, it sleeps, and every key and click it receives does something. This post is about making a Mac behave like a dumb screen for the night, with VibeLock doing the part macOS cannot.

Why the normal lock screen is the wrong tool

The obvious move is to lock the Mac. A locked Mac ignores your toddler, but it also blanks the display or covers it with the login screen, and the feed is gone. The macOS lock screen has no concept of a machine that should keep showing something while nobody is allowed to touch it.

Why “never sleep” alone is not enough either

The second move is to set the display to never turn off and add a hot corner that disables the screen saver. That fixes the display and does nothing about input. The keyboard still types, the trackpad still clicks, and a camera viewer is a fragile thing to leave in front of a live keyboard. A sleepy tap at 3 a.m. hits the space bar and pauses the stream. The cat walks across the keyboard and the browser is on a different tab. A toddler discovers that Command-Q makes the picture go away. Any of those and you wake up to a blank screen having heard nothing. An unattended viewer needs both halves: the display held on, and the input dead.

What VibeLock does while the feed is on screen

VibeLock is a $10 one-time menu bar app for macOS 13 Ventura or later, about 2 MB, native Swift, signed and notarized by Apple. When you lock it, a system-wide event tap swallows every key, click, scroll and gesture, including Spotlight (Command-Space), Force Quit (Command-Option-Escape) and Command-Q. It hides every app except the ones you allow and re-hides any that try to come back, keeps the display awake, refuses to quit, and covers fullscreen apps on other Spaces with an opaque shield. It works across all Spaces and displays, so a Mac mini on an external monitor is covered the same as a laptop. Unlock with Touch ID, or type your Mac login password into VibeLock's own shield, verified locally through macOS OpenDirectory. It needs only the Accessibility permission.

The setup

The one decision is which of VibeLock's two trust levels to give the camera app or browser.

• Visible means the app stays on screen but cannot be touched. This is the right default for a camera feed: the stream plays, the window is never hidden, and nothing done at the keyboard or trackpad reaches it.
• Accessible means the app can be used while locked. Choose this if you want to pan, zoom or switch cameras in the night without unlocking. Be clear about what it means: anyone who can reach the Mac can use that app too. For a nursery camera that is usually fine; for a browser with your email in another tab, it is not.

VibeLock pre-allows developer tools (Terminal, iTerm2, Warp, Ghostty, kitty, Alacritty, WezTerm, Claude desktop, ChatGPT/Codex and VS Code), none of which you want on screen tonight. Untick them from the menu bar and tick the camera app or browser; everything else is hidden when you lock.

Audio: set it before you lock

VibeLock blocks all keyboard input while locked, and that includes the volume keys on the top row, so the volume you lock with is the volume you have all night. Before locking, play the stream, set the Mac's volume where you want it, check the feed is not muted inside the app or tab, then lock. If you need to adjust it without unlocking, mark the camera app accessible so its own volume control works.

When the stream drops

Web dashboards and browser viewers sometimes lose the stream and show a reconnect button. With the app marked visible, that button cannot be clicked without unlocking. Two options: mark the viewer accessible, so a tap on reconnect works while everything else stays locked, or keep it visible and unlock with Touch ID when needed, which takes a second.

Privacy, in two separate pieces

VibeLock makes no network calls and has no accounts. It does not see, record or transmit the video; it only governs the Mac's input and display. The feed itself is the camera vendor's business: where the stream goes and who can log into the dashboard are questions for the camera's own settings. VibeLock is about the Mac not being touched; the camera's privacy is about the camera.

Honest limits

• VibeLock does not record, does not send alerts, and does not detect motion or sound. It is not a monitoring product. It keeps a window on screen and kills the keyboard; that is all.
• Use a Mac with the lid open or an external display. A MacBook with the lid shut is not a screen, whatever software is running.
• A dedicated baby monitor has things a Mac does not: a battery parent unit you can carry, a radio that does not depend on Wi-Fi, out-of-range warnings. A Mac viewer is a good second screen, not a replacement.
• If the camera app crashes or logs you out, no lock can fix that. Test the feed for an hour before trusting it for eight.

A checklist for the night

1. Plug the Mac in. A display held on all night on battery is a display that goes dark at 4 a.m.
2. Open the camera app or browser tab, confirm the live view is playing, size the window.
3. Set the Mac's volume and check the feed is unmuted.
4. In VibeLock, untick the pre-allowed developer apps and tick the camera app or browser as visible (or accessible if you want to pan, zoom or reconnect without unlocking).
5. Lock from the menu bar. Try a key and a click to confirm nothing happens.
6. In the morning, Touch ID or your password unlocks it.

When not to bother

If the Mac is in a room nobody enters at night and no pets roam, “never sleep” in the display settings does the job on its own, and you can save the $10. If you will be tapping between four cameras all evening, lock when you go to bed, not before. And if what you actually need is an alert when the baby cries or someone is at the door, that is the camera's job and your phone's, not the Mac's.

This is the same pattern as the other “Mac as a screen” posts here: the digital photo frame, the office wall dashboard and keeping a video playing while the Mac is locked. A camera feed adds the stakes of a sleeping child or an empty house. If small hands are the main worry, the toddler-proofing post goes deeper on that side of it.