VirtualFunGo

VirtualFunGo is a bridge service written in Go that connects the virtual_fan Linux kernel driver with external fan control hardware, such as a Raspberry Pi Pico, via USB.

It acts as the missing link between:

• Linux virtual fan values (hwmon)
• User-space control logic
• Real, external fan speed controllers

This project is designed to be used together with
👉 virtual_fun_kernel
https://github.com/tokyohost/virtual_fun_kernel

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✨ Features

• ✅ Written in Go, lightweight and efficient
• ✅ Reads fan speed values from Linux hwmon
• ✅ Communicates with Raspberry Pi Pico over USB (CDC / serial)
• ✅ Translates virtual fan values into real hardware control signals
• ✅ Suitable for:
  • Mini PCs
  • NAS devices
  • Industrial / embedded systems
  • Motherboards without fan control support

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🧩 Architecture Overview

+----------------------+
|   Linux Kernel       |
|  virtual_fan module  |
+----------+-----------+
           |
           | hwmon (/sys)
           v
+----------------------+
|     VirtualFunGo     |
|  (Go bridge service) |
+----------+-----------+
           |
           | USB / Serial
           v
+----------------------+
| Raspberry Pi Pico    |
| Fan control firmware |
+----------+-----------+
           |
           v
+----------------------+
| Physical Fan (PWM)   |
+----------------------+

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🧠 How It Works

1. virtual_fun_kernel exposes a virtual fan device via hwmon
2. VirtualFunGo:
   • Monitors fan speed / target values from /sys/class/hwmon
   • Applies custom logic (mapping, scaling, limits)
3. Fan speed values are sent over USB serial
4. Raspberry Pi Pico:
   • Receives commands
   • Generates PWM signals
   • Controls real fan hardware

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📦 Requirements

Linux Side

• Linux with virtual_fun_kernel installed
• Go ≥ 1.24
• USB access permission (may require udev rules)

Hardware Side

• Raspberry Pi Pico (2040)
• Pico firmware supporting USB CDC
• External fan (5V / 12V, PWM supported)

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🚀 Installation

curl -fsSL https://raw.githubusercontent.com/tokyohost/virtualFunGo/master/install.sh

🧪 Example Use Cases

• Software fan curve on unsupported hardware
• Quiet NAS fan control
• External smart fan controller
• Temperature-based fan automation

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📜 License

MIT License

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🤝 Related Projects

• virtual_fun_kernel
  https://github.com/tokyohost/virtual_fun_kernel
• Pi Pico Fan microPython code https://github.com/tokyohost/virtual_funPico

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🙌 Contributing

Issues and pull requests are welcome.

If you are using this project in production or embedded systems, feedback is highly appreciated.