This repository contains the production firmware for the Ultimate Hacking Keyboard (UHK) family, including the UHK60, UHK80, and companion modules (trackball, trackpoint, keycluster) plus a USB dongle. It implements the complete embedded software stack for a highly configurable split ergonomic keyboard: USB HID and Bluetooth LE HID transport, a rich macro engine with layers, chording, autoshift, sticky modifiers, and secondary roles, per-key RGB backlighting, OLED display with LVGL-based UI, battery management, and inter-device communication (UART, I2C, SPI). The firmware supports two hardware generations via conditional compilation (legacy NXP MCUXpresso SDK on the right half, Zephyr RTOS on the device half and dongle). Architecturally, the codebase is organized into distinct compilation targets: the right-hand keyboard half (right/), the left-hand half and dongle (device/), shared libraries (shared/), and peripheral modules (trackball/, trackpoint/, keycluster/). Central design patterns include an event-driven main loop with an event scheduler, a postponer system for delayed key actions, a versioned binary configuration parser, a lock-free messenger queue for inter-device messaging, and a double-buffered HID report pipeline. The firmware exposes a large USB vendor command set for reconfiguration, debugging, and firmware updates, and includes an embedded test suite that simulates key inputs and validates USB reports. The code demonstrates strong engineering craftsmanship with clean abstractions, extensive use of state machines, and careful resource management in a constrained embedded environment. While the dual-platform support introduces some conditional compilation complexity, the core modules are well-isolated and many patterns (event scheduler, postponer, UART parser, config parser, double buffer) are directly reusable in other embedded projects. The repository is actively maintained with a comprehensive test suite and CI pipeline, though the Zephyr migration is ongoing and some legacy code paths remain.
EmuFlight is a real-time embedded flight controller firmware for multirotor drones, forked from Betaflight/Cleanflight. It runs on STM32F4/F7/H7 microcontrollers, providing sensor fusion (gyro, accelerometer, barometer, GPS), PID control, motor mixing, telemetry, and on-screen display. The architecture is bare-metal with a cooperative scheduler, modular driver abstraction (vtable patterns for serial ports, displays, VTX, sensors), and a persistent parameter group (PG) configuration system. Key data flows: sensor inputs → Kalman/dynamic notch filters → PID → mixer → motor outputs; RC input via various protocols; telemetry/blackbox logging output. External dependencies include STM32 HAL, CMSIS DSP, and MAVLink libraries. The codebase is well-structured with unit tests (Google Test) and CI, though it retains some legacy drivers and conditional complexity from the Betaflight lineage.
Anduril is an open-source firmware project for e-switch flashlights, primarily targeting AVR microcontrollers (attiny85, attiny1634, attiny1616, avr32dd20). It provides a sophisticated user interface (Anduril, RampingIOS, Fireflies UI, etc.) built on the SpaghettiMonster event-driven state machine framework. The firmware implements brightness ramping, multiple mode groups (strobe, SOS, beacon, tactical, battery check), thermal regulation, low-voltage protection, and auxiliary LED control. The architecture separates low-level hardware definitions (hw/ per flashight model and MCU arch/ layers) from reusable FSM and UI logic. Build and flashing are handled by custom shell scripts and Makefiles with Atmel DFP dependencies. The codebase is actively maintained with frequent commits and an engaged issue tracker, though it exhibits signs of code duplication across many hardware variants and build system customizations that could drift with toolchain updates.