NimbusOS 🌩️

A lightweight, feature-rich Real-Time Operating System (RTOS) for Arduino with networking, storage, and display capabilities.

🚀 Features

Core OS Features

• Cooperative Multitasking: Support for up to 6 concurrent tasks
• Priority-based Scheduling: 4 priority levels (IDLE, LOW, NORMAL, HIGH)
• Task Management: Suspend/resume capabilities
• Pseudo-preemptive Protection: Tasks automatically yield after max runtime
• Inter-task Messaging: Built-in message passing system
• Power Management: Low-power mode support

Hardware Support

• Networking: Ethernet shield support with web server and Telnet
• Storage: SD card support with logging and script execution
• Display: I2C LCD (16x2) support
• Watchdog Timer: System stability protection

Built-in Shell Commands

• help - Display available commands
• tasks - List all tasks with status
• mem - Show free memory and system stats
• led <0|1> - Control built-in LED
• adc <pin> - Read analog pin value
• net - Network status
• telnet - Telnet server status
• lcd [text] - LCD control/display text
• sd - SD card status and file listing
• run <file> - Execute script from SD card
• suspend <id> - Suspend a task
• resume <id> - Resume a task
• power <0|1> - Toggle power saving mode

📋 Requirements

Hardware

• Arduino Uno/Mega or compatible board
• (Optional) Ethernet Shield (W5100/W5500)
• (Optional) SD Card module
• (Optional) I2C LCD Display (16x2)

Software

• Arduino IDE 1.8.x or newer
• Required Libraries:
  • Ethernet (for networking features)
  • SD (for SD card support)
  • LiquidCrystal_I2C (for LCD support)

🔧 Installation

1. Clone this repository:

git clone https://github.com/JustVugg/NimbusOS.git

2. Install required libraries through Arduino Library Manager:

   • Ethernet
   • SD
   • LiquidCrystal I2C

3. Open NimbusOS.ino in Arduino IDE

4. Configure features in the code (optional):

// Enable/disable features as needed
#define ENABLE_WATCHDOG
#define ENABLE_SUSPEND_RESUME
#define ENABLE_MESSAGING
#define ENABLE_NETWORKING
#define ENABLE_SD_CARD
#define ENABLE_LCD
#define ENABLE_TELNET
#define ENABLE_SCRIPT_ENGINE

5. Upload to your Arduino board

💻 Usage Example

// Task function example
void blinkTask() {
    static bool ledState = false;
    digitalWrite(LED_BUILTIN, ledState);
    ledState = !ledState;
    os.sleep(500); // Sleep for 500ms
}

void sensorTask() {
    int value = analogRead(A0);
    Serial.print("Sensor: ");
    Serial.println(value);
    
    // Send message to another task
    uint8_t data = value >> 2; // Scale to 8-bit
    os.sendMessage(2, 1, &data, 1);
}

void setup() {
    Serial.begin(115200);
    
    // Add tasks (function, period_ms, priority)
    os.add(blinkTask, 0, PRIORITY_NORMAL);
    os.add(sensorTask, 1000, PRIORITY_HIGH);
    
    // Run the OS
    os.run(); // Never returns
}

🌐 Network Features

Web Server (Port 80)

Access the built-in web interface:

• http://192.168.1.100/ - Main page
• http://192.168.1.100/status - JSON system status
• http://192.168.1.100/led/on - Turn LED on
• http://192.168.1.100/led/off - Turn LED off
• http://192.168.1.100/tasks - Task list

Telnet Server (Port 23)

Connect via telnet for remote shell access:

telnet 192.168.1.100
# Login: admin
# Password: nimbus

📝 Script Engine

Create automation scripts on SD card:

# example.txt
led 1
adc 0
tasks
led 0

Run with: run example.txt

🏗️ Architecture

NimbusOS uses a cooperative multitasking approach with priority-based scheduling:

1. Task Scheduler: Round-robin with priority selection
2. Timer-based Ticks: 100Hz system tick via Timer1
3. Memory Protection: Stack overflow detection via watchdog
4. Resource Sharing: SPI manager for SD/Ethernet multiplexing

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the project
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Inspired by FreeRTOS and other embedded RTOS systems
• Built for the Arduino community
• Special thanks to all contributors

📞 Contact

justvugg - @justvugg

Project Link: https://github.com/JustVugg/NimbusOS

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