Two taps
The whole display goes to the clipboard. There is no crosshair and no confirmation dialog.
A menu bar app for Apple Silicon.
Two taps.
Screen copied.
Knock the palm rest twice and the whole display lands on your clipboard. Three taps and you drag out the part you wanted. No crosshair, and no screenshot file left on the desktop.
macOS 14 or later. Apple Silicon only. Not notarized yet, so the first launch needs a right-click.
- 800 Hz
- sensor sample rate
- 0.35 g
- rejected as a bump
- 80 °/s
- minimum rotation
- 250 ms
- pause after a key
Two gestures, no modes.
There is no button to find and nothing to switch into. The count is the mode.
Three taps
The screen dims and you drag a box. Esc cancels. Whatever you framed ends up on the clipboard.
Tap the palm rest or the top case. The lid is deliberately not a target.
It can tell a tap from a bump.
Every Apple Silicon MacBook has a Bosch accelerometer behind the SPU, sampling at about 800 Hz. MacAccel reads it through IOKit and filters the signal down to the band where the chassis rings.
A fist on the table moves the machine by 1.2 g or more. A tap on the chassis stays under 0.3. Bumps that reach it through a mattress get caught by rotation instead, because a tap applies torque and a jolt through the bed mostly does not.
Four taps inside half a second is a run of knocks, so it stops listening for a moment. Taps within 250 ms of a keystroke are dropped before they are counted.
- 0.35 g
- anything harder is treated as a surface impact
- 80 °/s
- rotation below this is a bump, not a tap
- 150 ms
- settle time before a soft tap counts
- 400 ms
- gesture commit, so a stray third tap cannot fire
Two minutes, one right-click.
-
1
Move it to Applications
Unzip
MacAccel-0.1.zipand drag the app into/Applications. Running it from Downloads works too, but Applications is tidier. -
2
Open it once with a right-click
The app is not notarized, so a double-click gets a warning. Right-click, choose Open, then confirm. After that a normal launch works.
-
3
Grant two permissions
Input Monitoring is for the accelerometer. Screen Recording is for the screenshot. Both are tied to the app's signature, so you grant them once. Relaunch after granting.
No prompt? Add the app by hand in System Settings › Privacy & Security, then quit and reopen it.
The awkward ones.
Does it work on Intel Macs?
No. Intel MacBooks have no motion sensor that macOS exposes to apps, so there is nothing to read. Apple Silicon only, macOS 14 or later.
Will it fire while I type?
Taps within 250 ms of a keystroke are discarded, and the timing comes from the system rather than from watching your keys. The app never sees what you type, only when the last key went down.
Why does a screenshot tool want Input Monitoring?
The accelerometer is a HID device, and macOS gates HID access behind Input Monitoring. It is not used to read keystrokes. Without it the sensor does not open at all.
What happens if I bump the desk?
A hard jolt is rejected by the shock check, and a bump through a mattress is usually rejected by the rotation check. Four knocks in half a second are treated as a run, not a gesture.
Does it send anything anywhere?
No network code. No analytics, no update check, no account. Recordings used for tuning stay on the machine that made them.
Can I change how hard I need to tap?
Yes. Settings has four levels, from Gentle to Very firm, plus toggles for the shutter sound and for bump rejection. Firm is the default.