powermonitor 0.0.2

macOS power monitoring tool with auto-updating TUI

Power Monitor

macOS power monitoring tool with auto-updating TUI for real-time battery and charging status.

Status

Fully Migrated to Python: Complete TUI implementation with auto-updating display, IOKit/SMC FFI, and SQLite history tracking.

Features

• 🖥️ Auto-updating TUI with 3-panel layout (Textual framework)
• ⚡ Real-time monitoring - Updates every 2 seconds automatically
• 📊 Live power metrics - Voltage, amperage, wattage, battery %
• 📈 Historical visualization - Power chart and statistics
• 🔋 Battery tracking - Capacity, charging status, charger info
• 💾 SQLite persistence - Automatic background data logging
• 🎯 IOKit/SMC access - Direct macOS API integration via ctypes
• 🔄 Auto-fallback - Graceful fallback to subprocess-based collection

Installation

Install with uv (recommended)

uv tool install powermonitor

Install with pipx

pipx install powermonitor

Usage

Launch the TUI

# Single command launches auto-updating TUI
powermonitor

The TUI displays:

┌─ powermonitor ──────────────────────────────┐
│ Real-Time Power                           │
│ ⚡ 45.2W / 67W    🔋 72%    ⚡ Charging   │
│ 20.0V × 2.26A                             │
├───────────────────────────────────────────┤
│ Statistics (Last 100 readings)            │
│ Avg: 42.3W  Max: 55.1W  Min: 12.4W       │
├───────────────────────────────────────────┤
│ Power Chart (Last 60 readings)            │
│     55W ┤      ╭──╮                       │
│     45W ┤  ╭───╯  ╰──╮                    │
│     35W ┤──╯         ╰─                   │
│         └───────────────────               │
│ [q] Quit  [r] Refresh  [c] Clear History │
└───────────────────────────────────────────┘

Keyboard Controls

• q or ESC - Quit application
• r - Force refresh data
• c - Clear history (with confirmation)

Development Mode

# Run with verbose collector info
uv run python -c "from powermonitor.collector import default_collector; collector = default_collector(verbose=True); print(collector.collect())"

# Test data collection
uv run python -c "from powermonitor.collector import default_collector; print(default_collector().collect())"

Requirements

• macOS: 12.0+ (Monterey or later)
• Python: 3.13+ (uses modern type hints)
• Dependencies: textual, rich, textual-plotext (auto-installed by uv)

Architecture

TUI Layout (3 Panels)

1. LiveDataPanel (green) - Real-time power data

   • Status: ⚡ Charging / 🔌 AC Power / 🔋 On Battery
   • Power: watts_actual / watts_negotiated
   • Battery: percentage, capacity (mAh)
   • Electrical: voltage, amperage
   • Charger info (if available)

2. StatsPanel (cyan) - Historical statistics

   • Time range (earliest/latest)
   • Average/min/max power
   • Average battery percentage
   • Based on last 100 readings

3. ChartWidget (blue) - Power over time

   • Line chart with 60 data points
   • Shows actual power and max negotiated power
   • Auto-scales based on data

Data Collection

powermonitor uses two collectors with automatic fallback:

1. IOKitCollector (preferred) - Direct IOKit/SMC API via ctypes

   • Reads 7 SMC sensors: PPBR, PDTR, PSTR, PHPC, PDBR, TB0T, CHCC
   • Most accurate power readings (PDTR sensor)
   • Zero overhead (no subprocess)

2. IORegCollector (fallback) - Subprocess-based

   • Executes ioreg -rw0 -c AppleSmartBattery -a
   • Parses plist output using Python's plistlib
   • Works on all Macs without special permissions

Database

All readings automatically saved to SQLite:

Default location: ~/.powermonitor/powermonitor.db

Custom location (via environment variable):

export POWERMONITOR_DB_PATH=/path/to/custom.db
powermonitor

Schema:

CREATE TABLE power_readings (
    id INTEGER PRIMARY KEY,
    timestamp TEXT,
    watts_actual REAL,
    watts_negotiated INTEGER,
    voltage REAL,
    amperage REAL,
    current_capacity INTEGER,
    max_capacity INTEGER,
    battery_percent INTEGER,
    is_charging INTEGER,
    external_connected INTEGER,
    charger_name TEXT,
    charger_manufacturer TEXT
);

Project Structure

powermonitor/
├── pyproject.toml              # uv project config
├── uv.lock                     # Dependency lock file
├── src/
│   └── powermonitor/
│       ├── cli.py              # Entry point
│       ├── models.py           # PowerReading dataclass
│       ├── database.py         # SQLite operations
│       ├── collector/          # Data collection
│       │   ├── base.py         # PowerCollector protocol
│       │   ├── ioreg.py        # Subprocess collector
│       │   ├── factory.py      # Auto-fallback logic
│       │   └── iokit/          # IOKit/SMC FFI
│       │       ├── bindings.py # ctypes bindings
│       │       ├── structures.py # SMC data structures
│       │       ├── parser.py   # Binary parsing
│       │       ├── connection.py # SMCConnection
│       │       └── collector.py # IOKitCollector
│       └── tui/                # Textual TUI
│           ├── app.py          # powermonitorApp
│           └── widgets.py      # Custom widgets
└── tests/
    └── fixtures/               # Test data

Development

Code Quality

# Type checking
uv run ty check .

# Linting
uv run ruff check src/

# Auto-formatting
uv run ruff format src/

# Run all checks
uv run ty check . && uv run ruff check src/ && uv run ruff format src/

Testing

# Run tests (when available)
uv run pytest

# Manual testing
uv run powermonitor

Performance

• Memory: <50MB RAM
• CPU: <1% when idle
• Update interval: 2 seconds (configurable)
• Database: Indexed for fast queries

Migration Notes

• To: Python TUI with unified auto-updating interface
• Reason: Better rapid development, easier maintenance, similar performance for 2s intervals
• Preserved: All data collection logic, database schema, SMC sensor access (via ctypes)

License

MIT