Lumen

Real-time hardware monitoring for macOS. Two interfaces: a GPU-rendered dashboard (raylib) and a terminal UI.

Written in Zig, direct Mach kernel, IOKit, SMC, and libproc calls.

What it monitors

• CPU — total and per-core usage via host_processor_info
• Memory — used/wired/compressed via host_statistics64 (matches Activity Monitor's formula)
• GPU — utilization and VRAM via IOAccelerator PerformanceStatistics (no root needed)
• Network — download/upload bandwidth via getifaddrs
• Disk — usage via statfs
• Battery — charge, health, time remaining via IOPowerSources
• Temperature — CPU/GPU temps via SMC (supports both Intel sp78 and Apple Silicon flt formats)
• Processes — top 8 by CPU% via libproc

Build

Requires Zig 0.15.2+.

# GUI version (raylib window)
zig build run

# TUI version (terminal)
zig build tui

Binaries go to zig-out/bin/lumen and zig-out/bin/lumen-tui.

GUI controls

Key	Action
Tab	Focus panel (zooms to full screen)
Tab (again)	Cycle to next panel
Esc	Return to grid
S	Screenshot to ~/Desktop/lumen_*.png
Q	Quit

TUI controls

Key	Action
Q	Quit
Ctrl+C	Quit

Dependencies

The GUI uses raylib for rendering; the TUI uses mibu for terminal control and raw ANSI escape sequences.

• raylib-zig (devel) — GUI rendering
• mibu — terminal raw mode and cursor control
• Fira Code — embedded at compile time

Platform

macOS only. Tested on Apple Silicon (M4 Max). Intel Macs should work but are untested.

License

MIT