VirtusDev - Virtual Input Device Emulator (Rust Edition)

A comprehensive virtual input device emulator with modern GUI that emulates USB devices including barcode scanners, bill validators, and coin acceptors as HID keyboard devices on Linux.

Features

• 🎨 Native GNOME interface using GTK4
• ⚡ 115200 baud barcode scanner emulation
• 💰 Bill and coin emulator with serial bridge support
• 📊 Real-time scan history with duration tracking
• 🖥️ Native GUI with system theme support
• 🔒 Safe Rust implementation with proper error handling

Quick Start

All dependencies (Rust, system libraries) are already installed!

Just run:

./run.sh

This will:

1. Build the project (if not already built)
2. Launch the GUI with sudo (required for /dev/uinput access)

Manual build:

./build.sh
sudo ./target/release/virtusdev

3. Use the GUI

1. Enter a barcode in the input field
2. Click SCAN or press Enter
3. The barcode will be sent as keyboard input to the focused application
4. View scan history with timing information

Device Information

The GUI displays:

• Device Name: Virtual Keyboard 115200
• Event Path: /dev/input/eventX (auto-detected)
• Baudrate: 115200 bps
• Vendor ID: 0x1234
• Product ID: 0x5678
• Status: Running / Scanning indicator
• Recent Scans: Last 10 scans with duration

Permissions

Option 1: Run with sudo (Quick)

sudo ./target/release/virtusdev

Option 2: Add user to input group (Permanent)

# Add your user to the input group
sudo usermod -a -G input $USER

# Create udev rule
echo 'KERNEL=="uinput", MODE="0660", GROUP="input"' | sudo tee /etc/udev/rules.d/99-uinput.rules

# Reload udev rules
sudo udevadm control --reload-rules
sudo udevadm trigger

# Log out and back in for group changes to take effect

How It Works

1. Creates a virtual input device via Linux uinput kernel module
2. Registers as a USB HID keyboard (/dev/input/eventX)
3. Sends keyboard events for each character in the barcode
4. Automatically appends Enter key after each scan
5. Timing matches 115200 baud rate behavior

Bill & Coin Emulator

The emulator provides comprehensive support for vending machine and payment system testing through the eSSP (Encrypted Serial Protocol):

Features

Note Validator (NV200)

• Simulates an ICT NV200 bill validator
• Supports BRL currency (Brazilian Real)
• 7 denominations: R$2, R$5, R$10, R$20, R$50, R$100, R$200
• Protocol 6 eSSP compliance
• Configurable balances for testing

Coin Acceptor (Smart Hopper)

• Simulates coin acceptance and payout
• USD currency support
• 6 denominations: 1¢, 5¢, 10¢, 25¢, 50¢, $1.00
• Full payout simulation with event tracking

Serial Bridge (PTY)

• Virtual serial port (PTY) for device communication
• Auto-creates /dev/pts/X for payment system integration
• Transparent eSSP protocol handling
• Real-time transaction logging

Usage

# Run the bill emulator with serial bridge
./target/release/bill_emulator

# The emulator will display:
# ✓ Virtual serial port created: /dev/pts/X
# Configure payment system to use: /dev/pts/X

Supported eSSP Commands

• SYNC - Device synchronization
• SETUP_REQUEST - Device information query
• POLL - Event polling and status
• ENABLE / DISABLE - Device control
• SET_INHIBITS - Denomination masking
• GET_ALL_LEVELS - Current inventory
• PAYOUT - Coin dispensing simulation
• REJECT - Note rejection
• SET_ROUTE - Stacking/routing control

Event Codes

• RESET (0xF1) - Device reset
• READ (0xEF) - Note detected
• CREDIT (0xEE) - Note accepted
• STACKING (0xCC) - Note being stacked
• STACKED (0xEB) - Note stacked
• DISPENSING (0xDA) - Coin dispensing
• DISPENSED (0xD2) - Coin dispensed
• COINS_VALUE_ADDED (0xBF) - Coin credit received

Architecture

src/
├── main.rs             # GUI application (GTK4)
├── device.rs           # VirtualKeyboard, keymap, event emission
├── bill_emulator.rs    # Device state & eSSP command handling
├── essp_protocol.rs    # eSSP packet encoding/decoding with CRC-16
├── serial_bridge.rs    # PTY serial port & device communication
└── bin/
    ├── bill_emulator   # Standalone bill/coin emulator
    └── crc_check       # CRC validation utility

Key Components:

• VirtualKeyboard: Wraps evdev::uinput::VirtualDevice
• Arc<Mutex<>>: Thread-safe device access for async scans
• glib::spawn_future: Non-blocking scan execution with GTK4
• DeviceState: Bill validator and coin device emulation
• EsspPacket: Protocol-compliant packet serialization with CRC-16
• SerialBridge: PTY-based serial communication

Supported Characters

• Alphanumeric: a-z, A-Z, 0-9
• Special: space, enter, tab, -_=+[]{};:'"<>,./?|\~`
• Automatic shift: Uppercase and shifted symbols

Testing

Barcode Scanner (GUI)

# Terminal 1: Start a text editor
nano test.txt

# Terminal 2: Run virtusdev and enter barcodes in the GUI
sudo ./target/release/virtusdev

Monitor Keyboard Events

# Find the event device
cat /proc/bus/input/devices | grep -A 5 "Virtual Keyboard 115200"

# Monitor events (requires sudo)
sudo evtest /dev/input/eventX

Bill & Coin Emulator Testing

# Terminal 1: Start the emulator
./target/release/bill_emulator

# Terminal 2: Connect using a payment system or test client
# Using socat for testing:
socat - /dev/pts/X

# Send raw eSSP commands and monitor responses
# Check /tmp/emu_cmd.log for transaction logs
tail -f /tmp/emu_cmd.log

Protocol Validation

# Verify CRC calculations
./target/release/crc_check

Legacy C Version

The original C implementation is preserved in legacy/ directory for reference.

Troubleshooting

"Permission denied: /dev/uinput"

Run with sudo or follow the permanent permissions setup above.

Device not appearing

# Check if uinput module is loaded
lsmod | grep uinput

# Load if missing
sudo modprobe uinput

Build errors

Ensure all system dependencies are installed:

sudo apt-get install -y pkg-config build-essential libgtk-4-dev

Created By

jvwaldrich0

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Technical Specifications

• Baudrate: 115200 bps
• Interface: USB HID (emulated via uinput)
• Character timing: ~87 μs per character
• Protocol: Keyboard wedge (HID keyboard)
• GUI Framework: GTK4 (gtk4-rs 0.9)
• Language: Rust (edition 2021)