grblHAL/core is an embedded firmware for real-time CNC motion control, derived from the original grbl 1.1f project. It interprets G-code (RS274/NGC) and executes motion planning with acceleration/jerk profiles, driving stepper motors via a hardware abstraction layer (HAL) that supports many 32-bit MCUs (ESP32, STM32, RP2040, i.MX RT, etc.). The architecture is modular: a plugin system allows adding spindles, I/O expanders, kinematics (CoreXY, delta, polar, wall plotter), networking, and custom M-codes. Key subsystems include a G-code parser, motion planner with look-ahead, stepper ISR with Bresenham and AMASS, state machine, settings registry with NVS persistence, virtual file system, and cooperative task scheduler. Communication streams (serial, TCP, WebSocket, Modbus) are multiplexed. The codebase is highly optimized for real-time constraints, uses extensive conditional compilation for configurability, and provides reusable patterns such as function-pointer-based HAL, callback chaining, and abstracted I/O. While some internal coupling exists, many modules (crc, regex, utf8, string utilities, PID, expression evaluator, task scheduler) are self-contained and extractable.
This repository is a bare-metal custom bootloader and graphical recovery environment for the Nintendo Switch (Tegra T210/T210B01). It boots Horizon OS, Linux4Tegra, and third-party payloads by decrypting and patching the encrypted HOS boot chain (package1, package2, package3), deriving console keys from TSEC/EKS data, and applying version-specific binary patches. It also provides emuMMC creation and migration, eMMC and SD card tools, USB gadget modes (mass storage and HID), AutoRCM, fuel gauge/thermal diagnostics, and a full hardware bring-up path including display, touch, Joy-Con input, DRAM training, and power management. The code clearly reflects the bootloader's actual production role: a user-triggered payload running from RCM on real Switch hardware, with a text TUI in the main bootloader and a separate LVGL-based graphical frontend called Nyx. Architecturally, the repo is organized into a hardware abstraction layer called BDK (Board Development Kit), the bootloader core, the Nyx GUI application, and dynamically loadable ELF modules for DRAM training and SDRAM LP0 sleep state. The BDK provides drivers for SoC peripherals, power management ICs, storage controllers, the security engine, USB, input, and display, all written as bare-metal C with direct MMIO register access and no OS dependencies. The bootloader uses an INI-based configuration system, a small graphics console, and a module loader that can load ELF shared objects from SD or eMMC. Nyx is a separate application built on a heavily customized fork of LittlevGL v5, with custom themes, fonts, resource packing, and hardware tools. The code demonstrates strong embedded systems skill: meticulous hardware register definitions, retry and error-counting logic in storage drivers, cryptographic key derivation routines updated through many firmware generations, and carefully structured patch tables for firmware signatures. The main weaknesses are the aging bundled libraries (FatFs and LVGL forks are old and diverged from upstream), duplicated graphics implementations between bootloader and sample module, and a large amount of hardcoded hardware-specific constants and addresses. This is not general-purpose software; it is tightly coupled to Tegra X1 hardware and the Nintendo Switch modding ecosystem, but the BDK driver organization, ELF loader, INI parser, list macros, and compression utilities are genuinely reusable in other low-level projects.
openHASP is an embedded firmware framework for home automation touch panels, built around LVGL for GUI rendering. It provides a configurable dashboard for controlling IoT devices via MQTT, with support for ESP32, STM32, and other microcontrollers. The system features hardware abstraction layers for displays and touch controllers, modular services (MQTT, HTTP, FTP, Telnet, WireGuard VPN), OTA updates, and a JSON-based configuration system. It integrates with home automation platforms like Home Assistant through auto-discovery and state topics, while offering local UI interaction via touchscreen. The architecture separates concerns into HAL, GUI, networking, storage, and services, enabling cross-platform deployment.
JetKVM is an open-source KVM-over-IP device firmware that enables remote keyboard, video, and mouse control over a network. The system is built as a full-stack embedded application: a Go backend orchestrates hardware interfaces (USB gadget emulation for HID, mass storage, audio, serial console), video capture and encoding (H.264/H.265 via Rockchip MPP), WebRTC streaming, OTA updates, MQTT integration, and network management. A React/TypeScript single-page application provides the web-based KVM console with real-time video, keyboard/mouse input, virtual media mounting, serial terminal, and device settings. The architecture separates a native C/C++ layer (LVGL UI, video pipeline) from the Go application via gRPC and a Unix socket, enabling failsafe mode and modularity. The codebase demonstrates strong engineering practices: extensive E2E tests against real hardware, a comprehensive OTA update system with GPG signature verification, a custom HID RPC protocol over WebRTC data channels, and a transactional USB gadget configuration system. While tightly coupled to Linux and Rockchip hardware, many internal packages (sync wrappers, confparser, changeset, playout delay interceptor) are well-isolated and could be reused in other Go projects.
CherryDAP is an embedded firmware project that implements a CMSIS-DAP v2.1 debug probe (DAPLink) based on the CherryUSB stack and ARMmbed DAPLink reference code. It supports SWD and JTAG debugging protocols, a USB-to-UART bridge (CDC ACM), and optional features like SWO trace, custom HID commands, and a UF2 bootloader for firmware updates. The repository contains multiple hardware-specific projects targeting different microcontrollers (HPMicro HPM5301, Bouffalo Lab BL616, Espressif ESP32-S3) and two commercial probe variants (HSLink-Lite and HSLink-Pro). The HSLink-Pro variant adds advanced capabilities: programmable target voltage, NeoPixel LED, multi-function button, settings persistence via FlashDB, and a two-slot bootloader for fail-safe upgrades. The core DAP protocol handling is shared across all projects, while each platform provides its own pin configuration, I/O drivers (GPIO bit-bang or SPI-based protocol emulation), and USB descriptors. The architecture follows a monolithic firmware pattern per project, with a main loop that processes USB requests and handles UART data forwarding. The codebase demonstrates solid embedded engineering practices, including SPI-based protocol emulation for high-speed SWD/JTAG, a clean separation of protocol logic from hardware abstraction, and a feature-rich bootloader. However, there is notable code duplication across projects (e.g., SWD/JTAG I/O files, USB2UART implementations) which increases maintenance burden. The repository is actively maintained with recent commits, CI workflows, and documentation.
SensESP is an embedded firmware framework for ESP32 microcontrollers that enables building custom marine sensors that communicate via the Signal K protocol. It provides a complete pipeline from physical sensor reading (via Arduino libraries or built-in ADC/digital inputs) through data transformation (30+ composable transforms like linear scaling, moving average, hysteresis, curve interpolation) to publishing over WebSocket to a Signal K server. The framework includes a full web-based configuration UI (Preact/Bootstrap) served directly from the device, WiFi/Ethernet provisioning with captive portal, OTA updates, and a REST API for device management. Architecture follows a reactive dataflow pattern: sensors produce typed values that flow through transform chains to consumers (Signal K output, UI, logging). The core is built on ReactESP event loop, with observable/value producer/consumer abstractions enabling type-safe connections. Notable components include a TOFU certificate pinning system for secure Signal K connections, a circular log buffer with snapshot cursor for the web UI, and a smart switch controller supporting local and remote actuation with double-click sync. The codebase is well-structured with unit tests for transforms, metadata, and networking components, though some deprecated APIs and a large god object (SensESPApp) indicate areas for refactoring.
This repository provides an ESP-IDF component framework (esp-openclaw-node, esp-openclaw-talk, esp-openclaw-room-node) for building IoT devices that connect to the OpenClaw gateway via WebSocket. It implements device identity (Ed25519), session persistence, command dispatch, and WebRTC audio (Talk). The room-node component adds a full voice-interactive display client with LVGL-based animated face, Canvas (image/A2UI rendering), camera snapshot, file access, and real-time diagnostics. The codebase includes multiple board-specific examples (M5Stack Tab5, Waveshare AMOLED, ESP-BOX-3, M5Stack Dial) that demonstrate reuse of the core components. Strong engineering practices are evident: extensive host-based unit tests (with fake SDK headers), CI pipelines that verify cryptographic signatures and component patches, firmware packaging with provenance manifests, and a component registry release process for versioned distribution. The architecture cleanly separates concerns via board adapter abstractions and config structs, making the core components reusable across different ESP32 hardware.
This repository contains the K3NG Arduino CW Keyer, a highly configurable firmware for generating Morse code (CW) in amateur radio operations. The system runs on a wide range of Arduino-compatible microcontrollers (AVR, SAM, STM32, ESP32, Raspberry Pi Pico) and supports multiple input methods including paddles, straight keys, PS2 keyboards, USB keyboards (via MAX3421E USB host shield), and game controllers. It emulates the Winkey protocol for integration with logging software like N1MM+ and provides advanced features such as a CW decoder (using Goertzel algorithm), a built-in web server for remote control, beacon mode, practice/training modes, and SO2R (single operator two radio) support. The architecture is a monolithic Arduino sketch with extensive conditional compilation: over 20 hardware-specific configuration files (keyer_features_and_options_*.h, keyer_pin_settings_*.h, keyer_settings_*.h) allow tailoring the firmware to specific boards and feature sets. The main entry points are the standard Arduino setup() and loop() functions, with the web server module (k3ng_keyer_webserver.ino) providing HTTP-based control. External dependencies include the USB Host Shield library (for USB keyboard/controller input), Adafruit LiquidCrystal and TwiLiquidCrystal libraries (for LCD displays), and a PS2 keyboard library. The codebase is well-structured for its domain but carries significant complexity due to the sheer number of configuration combinations and bundled third-party libraries.
This repository provides a complete custom firmware solution for the Sonoff NSPanel smart home touch panel, tightly integrated with Home Assistant via ESPHome and a Home Assistant Blueprint. The firmware is built on ESPHome, a platform for ESP32-based devices, and uses a Nextion display for the user interface. The architecture is modular: a core set of YAML configuration files defines hardware drivers (Wi-Fi, display, relays, buttons, temperature sensor) and page definitions (home, weather, climate, light, cover, alarm, media player, utilities, etc.). Optional add-on YAML packages extend functionality for cover control, climate thermostat, TFT upload, and Bluetooth proxy. The companion C++ component library (in `components/nspanel_ha_blueprint/`) implements the communication protocol between the ESP32 and the Nextion display, handles page logic, and fires Home Assistant events via the ESPHome API. The Blueprint (`nspanel_blueprint.yaml`) allows users to configure all entities and customizations without writing code. Prebuilt firmware binaries are provided for quick flashing. The project is actively maintained, with a large community and frequent releases, though it has significant duplication across HMI variants and some deprecated add-ons.
This repository provides embedded firmware for the ESP8266 that bridges Chinese solar inverters (Voltronic/Axpert, PIP, EASUN, Deye, Anenji, Must PV/PH18) to MQTT and a local web interface. It communicates with inverters via RS232 serial (using proprietary ASCII protocols like PI30, PI18) or RS485 Modbus RTU, parses real-time status (grid, battery, PV, loads, faults), and publishes structured JSON to configurable MQTT topics including Home Assistant auto-discovery. The firmware also hosts a full web-based configuration portal with captive portal for WiFi setup, OTA updates, a live JSON endpoint, and LED status indication. Architecturally, it is a monolithic embedded application written in C++ for the PlatformIO build system. Key entry points are `src/main.cpp` (setup/loop), the web server endpoints, MQTT callbacks, and the serial/Modbus polling loop. The code is organized into a serial protocol handler (`PI_Serial`), an abstract Modbus device layer (`modbus_device`) with concrete implementations, a settings manager using EEPROM with versioning and fallback, and a chunked HTML serving mechanism to avoid heap fragmentation on memory-constrained ESP8266 devices. Notable strengths include the modular Modbus device interface that allows adding new inverter models by subclassing and providing register tables, and the auto-detection logic that probes protocols in sequence. The web UI is built with Bootstrap and jQuery loaded from CDN, and the project actively supports Home Assistant integration and multiple hardware configurations (Wemos D1 Mini, ESP-01, WiFi dongle). While the code is well-structured for an embedded project, it relies on dynamic `String` objects and large JSON documents on a limited memory platform, which could cause heap fragmentation over long periods. The license (CC BY-NC-ND 4.0) restricts commercial use and derivative works, limiting community contributions.
This repository provides an alternate firmware for the Ornament & Crime (O_C) Eurorack module, running on a Teensy 4.0 microcontroller. It implements a modular audio processing platform where individual 'engines' (synthesizers, drum machines, effects, sequencers, CV generators, and utilities) are compiled as separate .bin files and dynamically loaded via the udynlink linker. The firmware features a 128x64 OLED UI, two encoders/buttons, MIDI I/O, CV/gate handling, and a modulation routing system. The codebase is a hybrid of custom engine code and extensively vendored third‑party DSP libraries from Mutable Instruments (plaits, rings, marbles, peaks, streams, braids), open303 (TB‑303 emulation), MSFA (DX7 FM synthesis), SAM (text‑to‑speech), soundpipe, Faust‑generated models, and others. The architecture is monolithic with a plugin‑style engine API (setup/process/draw), and the build system uses a custom shell script and Python tools. While the API is explicitly marked as unstable and the code contains some hacks (e.g., #define private public), the DSP components are of high craftsmanship and many are reusable in other audio projects. The project is actively maintained by a single developer and has a small but engaged community.
This repository contains custom open-source firmware for Quansheng UV-K1/K5 V3 handheld ham radios, built around the PY32F071 MCU. It is a fork in the lineage DualTachyon → Egzumer → F4HWN → this project, adding features gated by compile-time flags (ENABLE_FEAT_F4HWN_*, ENABLE_NOAA, ENABLE_DTMF_CALLING, etc.). The firmware is bare-metal C (no RTOS in the application code despite CMSIS-RTOS2 RTX5 being vendored), with a main-loop architecture and an overlay app system using an app_api_t struct of function pointers. The build system uses CMake presets, per-app build.sh scripts, and a Docker wrapper (compile-firmware.sh) producing .elf/.bin/.hex artifacts. A pack_app.py script packs raw binaries into .app blobs. The repository vendors a large CMSIS_5 tree (~20k+ files), most of which is unused DSP/RTOS/validation code, bloating the repo. The README explicitly warns that flashing can brick radios, and overlay apps run with full privileges (no MPU). Notable engineering patterns include the overlay app API (function-pointer-based, placed in .text.entry section), an LL I2C driver mirroring STM32 LL conventions, and extensive conditional compilation. However, the codebase shows drift: deprecated compile-with-docker.sh retained as a forwarding shim, repetitive per-app build scripts, vendored CMSIS that may be outdated, and a license placeholder in the CMSIS bundle. Maintenance is active with recent commits, but the fork lineage and vendored dependencies create ongoing merge/upstream complexity. This is purely an embedded application repository - no datasets, ML models, or research artifacts are present.
This repository provides the firmware for a LoRa-based APRS iGate/digipeater station running on ESP32 microcontrollers. It bridges amateur radio APRS packets between LoRa RF and the internet (APRS-IS), and can also operate as a digipeater, TNC (KISS), weather station, and GPS tracker. The firmware includes a full web-based configuration UI, live map, MQTT integration, syslog, OTA updates, and support for dozens of hardware variants (Heltec, TTGO, etc.). The code is organized into modular C++ namespaces (LoRa_Utils, DIGI_Utils, APRS_IS_Utils, etc.) and uses a JSON-based configuration store. While the project is actively maintained, it shows some technical drift through vendored esptool binaries, dependency on older libraries (ElegantOTA), and heavy use of compile-time conditionals across board variants. The architecture is a classic embedded monolith targeting a single firmware binary, with strong hardware abstraction via pinout headers and a common configuration object. Several components—such as the KISS protocol encoder/decoder, the NetworkManager abstraction, and the Configuration class—are well-isolated and potentially reusable in other ESP32/ham radio projects.
ESPAtherma is an embedded firmware application (PlatformIO/Arduino) for monitoring and basic control of Daikin Altherma heat pump systems via an ESP32 or ESP8266 microcontroller. In production, it connects to the heat pump's X10A serial port, queries specific register addresses (reverse-engineered Daikin I and S protocols), converts raw bytes into human-readable values using configurable label definitions, and publishes the data over MQTT to a Home Assistant instance. It also provides Home Assistant MQTT auto-discovery for seamless integration. The architecture is a single-threaded loop: setup reads model-specific definition files and MQTT/WiFi config, then repeatedly queries registers, converts data, and publishes to MQTT. Key entry points are `src/main.cpp`, `include/comm.h` (serial query), and `include/homeassistant.cpp` (discovery payload generation). External dependencies include PubSubClient, ArduinoJSON, and board-specific libraries (M5Unified for M5Stick). The project also includes reverse-engineering scripts, serial log dumps, and a heat pump emulator, making it a hybrid of embedded application and protocol research. However, the primary usage and codebase character are that of an IoT monitoring/control application.
This repository provides firmware for ESP8266/ESP32 microcontrollers to interface Mitsubishi Heat Pumps (HVAC units) with MQTT and Home Assistant. The firmware runs on the ESP board, which connects to the heat pump's serial interface using the SwiCago/HeatPump library, and exposes a web interface for configuration and control, as well as MQTT topics for integration with smart home systems. It supports Home Assistant MQTT auto-discovery, Prometheus metrics, OTA firmware updates, and multi-language web UI. The architecture is a monolithic Arduino sketch with separate header files for configuration, HTML templates, JavaScript, and language strings. Key entry points are the setup() and loop() functions in mitsubishi2mqtt.ino, which initialize WiFi, MQTT, the heat pump connection, and a web server. Data flows: the ESP reads heat pump status via serial, publishes state to MQTT, subscribes to command topics, and serves a web control panel. External dependencies include the HeatPump library, ArduinoJson, PubSubClient, and the ESP8266/ESP32 Arduino core.
This repository implements the OpenSplitDeck, a split wireless game controller system designed to emulate Steam Deck input. The core functionality resides in embedded firmware built on the Zephyr RTOS, running on Nordic nRF52840 microcontrollers (Seeed Xiao BLE). The architecture consists of two controller halves (Left/Right) communicating via a custom Enhanced ShockBurst (ESB) wireless protocol, with a central dongle translating this data into USB HID reports using the S-Input protocol for Steam compatibility. The project also includes open-source hardware designs, including PCB schematics (Altium) and 3D CAD models (STL) for the enclosure and mechanical components. The codebase demonstrates solid embedded engineering practices, utilizing Zephyr's Device Tree, Kconfig, and modular driver architecture. Key features include deep sleep power management, capacitive trackpad integration (Azoteq IQS7211E), IMU sensor fusion (LSM6DS3), and DRV2605 haptic feedback. However, the repository exhibits hybridity between software and hardware engineering, with significant portions dedicated to mechanical design assets (STL files) and PCB documentation. While the firmware is well-structured, the inclusion of binary CAD files in Git and legacy Arduino code alongside the Zephyr implementation introduces maintenance complexity and potential drift. The project is actively maintained with recent commits and a substantial user base (1000+ stars), indicating a mature open-source hardware initiative. The firmware handles complex real-time constraints, including wireless latency optimization and multi-threaded sensor polling. Despite the high quality of the core logic, the repo hygiene regarding binary assets and mixed legacy code prevents a higher score, though it remains a valuable reference for embedded gaming peripherals.
The LoRa_APRS_Tracker is an embedded firmware application for ESP32-based hardware designed to function as an APRS (Automatic Packet Reporting System) tracker and transceiver. It integrates GPS tracking, LoRa radio communication, Bluetooth (Classic and BLE) for smartphone TNC connectivity, WiFi for wireless configuration, and support for various environmental sensors to telemetry data. The application features a menu-driven interface via OLED/TFT display and physical controls (buttons, joystick, touch, or keyboard), allowing users to configure beacon settings, view received packets, and manage messages. The architecture follows a modular utility pattern where distinct hardware and software components (e.g., GPS, LoRa, display, power management) are encapsulated in separate namespaced modules, each with setup and loop functions called from the main firmware loop. Configuration is managed through a hierarchical JSON-based system stored in SPIFFS, enabling persistent storage of user settings such as beacon profiles, LoRa parameters, and WiFi credentials. A built-in web server serves a responsive configuration portal (using Bootstrap) for initial setup and advanced settings via WiFi AP. Key capabilities include APRS beaconing with MIC-E encoding, two-way messaging, Winlink email integration over radio, digipeating, weather telemetry encoding, and power-saving features like GPS and LoRa module shutdown. The firmware supports numerous hardware variants through conditional compilation and variant-specific pin definitions, allowing the same codebase to compile for different ESP32 boards with various LoRa modules and sensors.
This repository is a large collection of bare-metal firmware projects for STM32 microcontrollers (F0, F1, F3, G0, G4 families), authored by Edward V. Emelianov. It contains dozens of independent example and application projects covering USB CDC virtual serial ports, CAN bus gateways, sensor drivers (BMP280, MLX90640, DHT22, DS18B20, etc.), stepper motor control, servo control, LED displays, and more. The code is written in C with direct register access (no HAL) and uses a custom USB stack with ring-buffer-based I/O. Each project is self-contained with its own main.c, hardware initialization, and command parser, typically communicating over USB or UART with a simple text-based protocol. The architecture is monolithic per project: a main loop processes periodic tasks (ADC sampling, sensor reads, CAN message handling) and responds to commands received via USB or UART. Key entry points are the main.c files in each project directory. Data flows involve sensor acquisition (ADC, I2C, SPI), optional processing (median filtering, dew point calculation), and output via USB CDC, CAN, or UART. External dependencies are minimal: only an ARM GCC toolchain and the STM32 CMSIS-like headers provided in the inc/ folder. The repository also includes KiCad PCB designs and gerber files for many projects, indicating a full hardware+software development cycle. While the code is functional and covers a wide range of embedded use cases, it suffers from significant code duplication (ringbuffer.c, usb.c, strfunc.c are copy-pasted across many projects) and lacks a centralized library or build system. Deprecated folders and multiple versions of similar projects (e.g., chronometer_v2, chronometer_v3) add clutter. The repository is best viewed as a personal collection of working examples and prototypes rather than a polished framework. However, several components (ring buffer, string utilities, USB stack) are well-implemented and could be extracted for reuse in other STM32 projects.