Slap Your MacBook.
It Screams Back.
Five seismology-grade algorithms detect your slap. Your screen shakes. Your brightness flashes. Your trackpad buzzes. And it plays one of 130+ sound effects scaled to how hard you hit it.
Everything Your MacBook Never Asked For
More features than the $7 paid app. All free, all open-source.
Screen Shake
Your entire screen physically rattles on impact. Every window, the dock, menu bar — everything jolts.
Brightness Flash
DisplayServices private API dims your actual hardware backlight on impact. Works over fullscreen apps.
Trackpad Haptic
Your trackpad buzzes when you slap. Multiple intensity levels — single tap to triple buzz.
Dynamic Volume
Logarithmic scaling: gentle taps play quiet whispers, hard slaps trigger full-volume screams.
Screen Flash
White overlay flash on impact with adjustable intensity. Because your laptop deserves to feel the pain too.
Escalation Tracking
Keep slapping and sounds escalate through increasingly intense files with a 30-second decay half-life.
USB Moaner
Plug or unplug a USB device and it moans. Same voice packs, no slapping required.
Per-Effect Sliders
Every effect has its own intensity slider in the menu bar. Dial each one exactly how you want.
Launch at Login
Installs as a LaunchAgent. Always running, always listening. No .app bundle needed.
Seven Moods of Protest
Your open-plan office will have questions.
Wildly Overengineered Slap Detection
Five concurrent signal processing algorithms vote on whether you actually slapped your laptop. Democracy, but for physical abuse.
High-Pass Filter
Strips out gravity so we only see sudden impacts. First-order IIR filter at alpha=0.95.
STA/LTA Ratio
Classic seismology algorithm. Compares short-term vs long-term energy at 3 timescales. Literally used to detect earthquakes.
CUSUM
Cumulative Sum change-point detection. Catches sustained shifts in mean acceleration that other detectors miss.
Kurtosis
4th statistical moment — measures signal peakedness. Sharp impacts have extremely high excess kurtosis.
Peak/MAD
Median Absolute Deviation outlier detection. More robust than standard deviation. Finds the spike in the noise.
MenuBarExtra (SwiftUI)
└─ SlapController
├─ AccelerometerReader ← IOKit HID, ~125Hz
├─ SlapDetector ← 5 algorithms vote
├─ AudioPlayer ← AVFoundation
├─ ScreenShaker ← CGS private API
├─ BrightnessFlash ← DisplayServices
├─ HapticFeedback ← NSHapticFeedback
├─ ScreenFlash ← AppKit overlay
├─ USBMonitor ← IOKit notifications
└─ SettingsStore ← UserDefaultsWhy did we make this?
We were bored, didn't want to pay $7, and thought it would be a fun challenge anyway. Turns out reverse-engineering an app, implementing earthquake detection algorithms, and calling private macOS APIs is a pretty good weekend.
Get It Running
Three commands. That's it.
Not comfortable with git?
Click the green Code button on GitHub → Download ZIP, unzip it, open Terminal, drag the folder into Terminal to cd into it, and run make install.
Requirements
- • macOS 14.6+ (Sonoma or newer)
- • Apple Silicon MacBook (M1 / M2 / M3 / M4 / M5)
- • Xcode Command Line Tools (
xcode-select --install)
Pre-built binary (no Xcode needed)
Download the latest release from GitHub Releases, unzip, and run ./install.sh
Why MacSlapApp?
| Feature | MacSlapApp | SlapMac ($7) |
|---|---|---|
| Detection Algorithms | ✓ | ✓ |
| Voice Packs | ✓ | ✓ |
| Screen Shake | ✓ | ✗ |
| Brightness Flash | ✓ | ✗ |
| Haptic Feedback | ✓ | ✗ |
| Per-Effect Sliders | ✓ | ✗ |
| Dynamic Volume | ✓ | ✓ |
| Escalation Tracking | ✓ | ✓ |
| USB Moaner | ✓ | ✓ |
| Launch at Login | ✓ | ✓ |
| Open Source | ✓ | ✗ |
| Price | Free | $7 |
FAQ
Your MacBook has feelings now.
Free forever. Open source. No license. No DRM. Just vibes.