Eddy's Snippets

A collection of my small (and sometimes not-so-small) C utilities for Linux and embedded systems — a personal toolbox built from real‑world projects in astronomy, laboratory automation, and embedded development. Some are battle‑tested, others are experimental or deprecated.

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Overview

This repository contains a wide variety of C code snippets, full utilities, and helper libraries that I have developed over the years for different tasks. The common thread is pragmatic C on Linux — tools for serial communication, Modbus control, sensor interfacing, network proxies, embedded optimization, and more.

The repository is intentionally modular. Each subdirectory typically contains an independent utility or library with its own build system (plain Makefile or CMakeLists.txt). Some modules rely on my common helper library snippets_library (also known as usefull_macros).

🔍 Quick Navigation

• Active / Maintained → ESP8266, I2Csensors, modbus_params, serialsock, stringHash4MCU_
• Mature / Stable → HSFW_management, thread_array_management, USBrelay
• Deprecated / Archive → Trinamic, Socket_CAN, NES_webiface
• Algorithmic / Embedded Helpers → _snippets, table_sincos, stringHash4MCU_, Zernike

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Modules

ESP8266 - Description: A simple TCP server based on AT‑commands for the ESP8266 Wi‑Fi

module. The code is written to be as close to the MCU as possible, making it lightweight and easy to port.

• Status: Active
• Key Files: esp8266.c, esp8266.h, main.c, serial.c, CMakeLists.txt

I2Csensors

• Description: A complete library for reading data from various temperature, humidity, and pressure sensors over I2C.
• Supported Sensors: AHT10, AHT15, AHT21b, BMP180, BMP280, BME280, SHT3x, SI7005.
• Features: Unified API with sensor status tracking, support for both single‑shot and periodic measurements, and example programs included.
• Build: CMake (with DEBUG and EXAMPLES options). After installation, use #include <i2csensorsPTH.h> and link with -li2csensorsPTH.
• Status: Active
• Documentation: See I2Csensors/README for full API reference and usage examples.

HSFW_management

• Description: A command‑line utility to manage Edmund Optics high‑speed filter wheels (HSFW). It allows you to check/change turret positions, list connected devices, and rename wheels or filters stored in EEPROM.
• Features: Supports operation by filter name, wheel ID, or serial number; includes a “list‑all” mode to dump all EEPROM information.
• Status: Mature (marked for possible code review)
• Documentation: See HSFW_management/README and the usage examples in the module’s description.

MLX90640_test

• Description: A test implementation for the MLX90640 thermal camera sensor. Currently processes example data from Melexis and is used to debug calculation errors in the temperature conversion algorithm.
• Status: Experimental / Almost deprecated
• Note: The sensor driver is not yet fully functional; the main purpose is to test and verify the mathematical model offline using CSV data.

NES_webiface

• Description: A web interface for managing the Nesmith Echelle Spectrograph (NES). Built on top of pusirobot and liboninon.
• Status: Deprecated (almost deprecated)

Raspberry

• Description: Raspberry Pi–specific code.
• Contents: MPU-6050-log/ — a utility to log data from an MPU‑6050 accelerometer/gyroscope sensor.
• Status: Archive

SSL_Socket_snippet

• Description: A client/server example demonstrating an SSL‑protected TCP socket connection with mutual certificate verification (server checks client certificates).
• Features: Complete example with CA and client/server certificate files, command‑line option parsing, and separate client/server implementations.
• Status: Stable (reference implementation)

Socket_CAN

• Description: A CANbus message retranslation utility between two different CAN networks (BTA bus ↔ Dome bus). Includes SSL support for secure communication and example udev rules.
• Components: soccanserver and soccanclient with mutual TLS authentication.
• Status: Deprecated (marked as almost deprecated)

TeAmanagement

• Description: Client/server management utility for "Telescope Analyzer" (TeA) stages.
• Status: Archive / Unmaintained

Tetris

• Description: A classic CLI Tetris implementation using terminal graphics.
• Features: Full game logic with keyboard controls, score tracking, and a terminal display buffer.
• Status: Stable / Complete

Trinamic

• Description: Older code for managing Trinamic stepper motor drivers.
• Submodules: SHA_client/, SHA_client_cmdline/ (Shack‑Hartmann sensor clients), client/, websock_simple/.
• Status: Deprecated (almost deprecated)

USBrelay

• Description: A utility to control Chinese USB relay modules (HID‑based). Includes device autodetection and udev rules for permission setup.
• Status: Mature
• Documentation: See the Makefile and the module’s README (if present).

Zernike

• Description: A implementation of wavefront decomposition and reconstruction using Zernike polynomials (up to 100th order). Supports both standard (n, m) and Noll indexing notations.
• Functions: zernfunR(), zernfunNR(), Zdecompose(), Zcompose(), set_prec().
• Status: Archive / Algorithmic reference

_snippets

• Description: A collection of miscellaneous small C code snippets, including:
  • AVX examples
  • B‑trees
  • Bresenham circle drawing
  • C‑style function overloading tricks
  • USB reset
  • CLI color output
  • Bit counting
• Status: Archive / Personal reference

cmakelists_

• Description: A set of reusable CMakeLists.txt and Makefile templates for different project configurations (e.g., debug/release, library/executable, cross‑compilation).
• Contents: Several CMakeLists_regular_XX.txt variants, Makefile, Makefile_dbg_rls, and helper scripts.
• Status: Reference / Active

modbus_params

• Description: A command‑line tool and network server for interacting with Modbus RTU devices. It uses a human‑readable dictionary that maps register addresses to mnemonic codes.
• Features:
  • Read/write holding registers by address or code.
  • Periodic dumping of selected parameters to a TSV file.
  • TCP/UNIX socket server for remote control.
  • Aliases (macros) and verbose logging.
• Dependencies: libmodbus, usefull_macros, pthread.
• Status: Active
• Documentation: See modbus_params/README.md for command‑line options and server protocol.

modbus_relay

• Description: A simple utility to manage Chinese Modbus relay boards. Includes a basic web interface (web_management/ subdirectory) for remote control.
• Features: Supports multiple relay board types (including a non‑standard 4‑relay board based on STM8S003) and command‑line operation.
• Status: Active

serialsock

• Description: A lightweight TCP/UNIX socket‑to‑serial proxy that allows multiple simultaneous clients to read from and write to a single serial (TTY) device. It runs as a robust daemon with automatic child respawning.
• Features:
  • Up to 30 simultaneous TCP clients.
  • Configurable baud rate, device path, and exclusive access.
  • Daemon mode with PID file and logging.
  • Signal‑safe cleanup.
• Dependencies: usefull_macros (provides command‑line parsing, serial port handling, socket management, and logging).
• Status: Active
• Documentation: See serialsock/Readme.md for full usage.

stellarium_emul

• Description: An emulator for the Stellarium telescope control protocol, designed to control a 10‑micron mount.
• Features: Daemon mode, command‑line options, and socket‑based communication.
• Status: Archive

stringHash4MCU_

• Description: A tool for testing and generating hash functions suitable for string command parsing on microcontrollers.
• Components: hashtest.c (test different hash functions on a dictionary), hashgen.c (generate source/header files from a dictionary), and helper scripts (runtest, mktestdic).
• Use Case: Convert string commands to integer hashes for efficient parsing on resource‑constrained MCUs.
• Status: Active

table_sincos

• Description: A generator for lookup tables to compute sin() and cos() using integer arithmetic on MCUs. Includes a fast integer square root implementation.
• Usage: Run gentab <precision> to generate a table; compile with -DMAX_LEN and -DDATATYPE to customize.
• Status: Stable / Reference

thread_array_management

• Description: A library for managing named thread lists with FIFO message passing between threads.
• Status: Mature
• Example: Includes a test program (test.c) demonstrating usage.

usb_reset

• Description: A small utility to reset a USB bus (useful for recovering stuck USB devices).
• Status: Stable

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Common Dependencies

Many modules rely on my common helper library: snippets_library (also known as usefull_macros). This library provides:

• Command‑line parsing (sl_parseargs)
• Serial port (TTY) handling (sl_tty_t)
• TCP socket management (sl_sock_open)
• Daemonisation, PID file handling
• Logging macros (LOGMSG, LOGWARN, LOGERR, etc.)

To build any module that depends on it, first install libusefull_macros:

git clone --depth=1 https://github.com/eddyem/snippets_library.git
cd snippets_library
mkdir build && cd build
cmake ..
make
sudo make install

Then return to the module directory and build (usually with make).

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Building a Module

Most modules can be built by simply running make in their directory. For CMake‑based modules (like I2Csensors):

mkdir build && cd build
cmake ..
make
su -c "make install"   # optional

Some modules have additional configuration options (e.g., DEBUG, EXAMPLES) that can be passed to CMake.

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License

This repository is provided under the GNU General Public License v3 or later. Individual modules may contain their own license headers; the GPL license applies unless otherwise stated.

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Contributing

This is primarily a personal collection, but issues and pull requests are welcome. If you find a bug or have an improvement, please open an issue first to discuss it.

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Disclaimer

Use at your own risk. Some modules are marked as deprecated or “almost deprecated” — they may contain bugs, rely on outdated interfaces, or lack proper documentation. Always review the code before using it in a production environment.