spank

Slap your MacBook, it yells back.

"this is the most amazing thing i've ever seen" — @kenwheeler

"I just ran sexy mode with my wife sitting next to me...We died laughing" — @duncanthedev

"peak engineering" — @tylertaewook

Uses the Apple Silicon accelerometer (Bosch BMI286 IMU via IOKit HID) to detect physical hits on your laptop and plays audio responses. Single binary, no dependencies.

Requirements

• macOS on Apple Silicon (M2+)
• sudo (for IOKit HID accelerometer access)
• Go 1.26+ (if building from source)

Install

Download from the latest release.

Or build from source:

go install github.com/taigrr/spank@latest

Note: go install places the binary in $GOBIN (if set) or $(go env GOPATH)/bin (which defaults to ~/go/bin). Copy it to a system path so sudo spank works. For example, with the default Go settings:

sudo cp "$(go env GOPATH)/bin/spank" /usr/local/bin/spank

Usage

# Normal mode — says "ow!" when slapped
sudo spank

# Sexy mode — escalating responses based on slap frequency
sudo spank --sexy

# Halo mode — plays Halo death sounds when slapped
sudo spank --halo

# Fast mode — faster polling and shorter cooldown
sudo spank --fast
sudo spank --sexy --fast

# Custom mode — plays your own MP3 files from a directory
sudo spank --custom /path/to/mp3s

# Adjust sensitivity with amplitude threshold (lower = more sensitive)
sudo spank --min-amplitude 0.1   # more sensitive
sudo spank --min-amplitude 0.25  # less sensitive
sudo spank --sexy --min-amplitude 0.2

# Set cooldown period in millisecond (default: 750)
sudo spank --cooldown 600

Modes

Pain mode (default): Randomly plays from 10 pain/protest audio clips when a slap is detected.

Sexy mode (--sexy): Tracks slaps within a rolling 5-minute window. The more you slap, the more intense the audio response. 60 levels of escalation.

Halo mode (--halo): Randomly plays from death sound effects from the Halo video game series when a slap is detected.

Custom mode (--custom): Randomly plays MP3 files from a custom directory you specify.

Detection tuning

Use --fast for a more responsive profile with faster polling (4ms vs 10ms), shorter cooldown (350ms vs 750ms), higher sensitivity (0.18 vs 0.05 threshold), and larger sample batch (320 vs 200).

You can still override individual values with --min-amplitude and --cooldown when needed.

Sensitivity

Control detection sensitivity with --min-amplitude (default: 0.05):

• Lower values (e.g., 0.05-0.10): Very sensitive, detects light taps
• Medium values (e.g., 0.15-0.30): Balanced sensitivity
• Higher values (e.g., 0.30-0.50): Only strong impacts trigger sounds

The value represents the minimum acceleration amplitude (in g-force) required to trigger a sound.

Running as a Service

To have spank start automatically at boot, create a launchd plist. Pick your mode:

Pain mode (default)

sudo tee /Library/LaunchDaemons/com.taigrr.spank.plist > /dev/null << 'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.taigrr.spank</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/spank</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
    <key>StandardOutPath</key>
    <string>/tmp/spank.log</string>
    <key>StandardErrorPath</key>
    <string>/tmp/spank.err</string>
</dict>
</plist>
EOF

Sexy mode

sudo tee /Library/LaunchDaemons/com.taigrr.spank.plist > /dev/null << 'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.taigrr.spank</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/spank</string>
        <string>--sexy</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
    <key>StandardOutPath</key>
    <string>/tmp/spank.log</string>
    <key>StandardErrorPath</key>
    <string>/tmp/spank.err</string>
</dict>
</plist>
EOF

Halo mode

sudo tee /Library/LaunchDaemons/com.taigrr.spank.plist > /dev/null << 'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.taigrr.spank</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/spank</string>
        <string>--halo</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
    <key>StandardOutPath</key>
    <string>/tmp/spank.log</string>
    <key>StandardErrorPath</key>
    <string>/tmp/spank.err</string>
</dict>
</plist>
EOF

Note: Update the path to spank if you installed it elsewhere (e.g. ~/go/bin/spank).

Load and start the service:

sudo launchctl load /Library/LaunchDaemons/com.taigrr.spank.plist

Since the plist lives in /Library/LaunchDaemons and no UserName key is set, launchd runs it as root — no sudo needed.

To stop or unload:

sudo launchctl unload /Library/LaunchDaemons/com.taigrr.spank.plist

How it works

1. Reads raw accelerometer data directly via IOKit HID (Apple SPU sensor)
2. Runs vibration detection (STA/LTA, CUSUM, kurtosis, peak/MAD)
3. When a significant impact is detected, plays an embedded MP3 response
4. Optional volume scaling (--volume-scaling) — light taps play quietly, hard slaps play at full volume
5. 750ms cooldown between responses to prevent rapid-fire, adjustable with --cooldown

Star History

Credits

Sensor reading and vibration detection ported from olvvier/apple-silicon-accelerometer.

License

MIT