Ibuilt a tiny Unix‑like 'OS' with shell and filesystem for Arduino UNO (2KB RAM)

KernelUNO v1.0

A lightweight RAM-based shell for Arduino UNO with filesystem simulation, hardware control, and interactive shell.

Features

• Virtual Filesystem - Create files and directories in RAM (/dev, /home) - Hardware Control - GPIO management with pin mode configuration
• System Monitoring - Memory usage, uptime, kernel messages (dmesg)
• 22 Built-in Commands - From basic file operations to hardware control
• Interactive Shell - Real-time command execution with input buffering
• LED Disco Mode - Fun easter egg for testing GPIO

Hardware Requirements

• Arduino UNO (or compatible board with ATmega328P)
• USB cable for programming
• LEDs and resistors (optional, for GPIO testing)

Installation

1. Clone or download this repository
2. Open KernelUNO.ino in Arduino IDE
3. Select Board: Tools → Board → Arduino UNO
4. Select Port: Tools → Port → /dev/ttyUSB0 (or your port)
5. Compile & Upload: Sketch → Upload
6. Open Serial Monitor: Tools → Serial Monitor (115200 baud)

Alternative with arduino-cli:

arduino-cli compile --fqbn arduino:avr:uno . arduino-cli upload --fqbn arduino:avr:uno -p /dev/ttyUSB0 .

Commands

Filesystem Commands

• ls - List files in current directory
• cd [dir] - Change directory
• pwd - Print working directory
• mkdir [name] - Create directory
• touch [name] - Create file
• cat [file] - Read file contents
• echo [text] > [file] - Write to file
• rm [name] - Remove file/directory
• info [name] - Display file information

Hardware Commands

• pinmode [pin] [in/out] - Set pin mode
• write [pin] [high/low] - Write to pin
• read [pin] - Read pin value
• gpio [pin] [on/off/toggle] - GPIO control
• gpio vixa [count] - LED disco mode (easter egg)

System Commands

• uptime - System uptime
• uname - System information
• dmesg - Kernel messages
• df / free - Free memory
• whoami - Current user (hardcoded root)
• clear - Clear screen
• reboot - Restart system
• help - Show all commands

Usage Examples

# Navigate filesystem cd home mkdir myproject cd myproject touch notes.txt echo Hello World > notes.txt cat notes.txt # Hardware control pinmode 13 out gpio 13 on gpio 13 toggle read 2 # System info uname uptime dmesg df # Fun mode gpio vixa 10

Memory Usage

• Program: ~38% of 32KB flash
• RAM: ~85% of 2KB SRAM (optimized)
• Filesystem: 10 files/directories max
• DMESG buffer: 6 messages

Specifications

• Board: Arduino UNO (ATmega328P)
• Clock: 16 MHz
• Serial Baud: 115200
• Filesystem: RAM-based (no EEPROM)
• Storage: Volatile (resets on power cycle)

Technical Details

• Char-array based input buffer (32 bytes max)
• Safe path concatenation to prevent buffer overflow
• Kernel message logging with timestamps
• Real-time GPIO operations
• Efficient memory management

Limitations

• No persistent storage (EEPROM/SD)
• Limited file size (32 bytes content per file)
• Maximum 10 files/directories
• PATH limited to 16 characters
• Single user (root)

TODO / Future Enhancements

• EEPROM persistence
• PWM/analog control
• SD card support
• File size display
• More GPIO features

License

BSD 3-Clause License - See LICENSE file for details

Author

Arc1011 (Arc1011)
Created in 2026.

Contributing

Feel free to fork, modify, and improve! Send PRs for:

• Bug fixes
• Performance improvements
• New commands
• Code optimization

// The descriptive files (i.e., README and QUICKSTART) were written by Claude AI (with minor tweaks). Why? Because if I had done it myself, it would have ended up as a few lines of incoherent gibberish that wouldn't tell you anything.//