The screen wants to dim. The Mac shouldn't.
Overnight render. Big download. Time Machine first-time backup. You want the Mac running. You don't want the screen blasting at full brightness in your bedroom for the next eight hours.
Most mouse jigglers can't help here — they keep the Mac awake by moving the cursor, which wakes the screen. Allow display to sleep is the answer.
How it works under the hood
When Allow display to sleep is on, Shake It On stops moving the cursor entirely. Instead it holds an IOKit power assertion (specifically kIOPMAssertionTypePreventUserIdleSystemSleep) that tells macOS: "the system is in use, don't go to sleep, but the display is fair game."
macOS dims and sleeps the display normally. The Mac stays running. Background work continues. Your eyes thank you.
Enable Allow display to sleep
- Open Settings (menu bar → Settings…).
- Scroll to the General section.
- Turn on Allow display to sleep while shaking.
That's it. Notice that the "Display is off or locked" pause-when toggle automatically greys out — it doesn't apply in this mode (the display going off is the whole point).
All your conditions still apply
Allow display to sleep doesn't disable Only Shake If or Paused When. The engine still:
- Holds the assertion only while your conditions are satisfied (sustained CPU, app running, etc.)
- Releases it when a Paused When condition triggers (camera in use, Focus mode on, on battery, etc.)
- Respects your schedule
It's the same engine. Just a different "shake" mechanism.
vs. Lungo / Amphetamine / Theine
Other Mac-keep-awake apps have a similar mode. The differences:
- Lungo calls it "Display ON / Display OFF". Same IOKit assertion approach. No conditional gating.
- Amphetamine has it as a per-session toggle ("Allow display to sleep when this session is active").
- Theine has a "Lock screen allows sleep" option (related but inverted — it lets the Mac sleep when you lock).
- Shake It On wraps it in the full smart-condition engine. Allow display to sleep + sustained-CPU 75% for 1m is a one-line setup that means "stay awake while rendering, sleep immediately when the render finishes".
The classic overnight-render setup
- Allow display to sleep — on
- Only Shake If: CPU above threshold — 60% sustained for 1 minute
- Paused When: On battery (so it doesn't drain if you accidentally unplug)
- (Optional) Save as a "Render" Session for one-click switching
Hit start on the render, lid stays open, screen goes black, render completes, Mac sleeps when CPU drops back. Wake up to a finished export.