Flouda Vault

8 min read

Using Android Tablet as External Screen for Linux

Transform your Android tablet into a wireless external monitor for your Linux desktop using VNC technology. This guide provides a complete automated setup solution that creates a virtual display, establishes secure connections, and maintains stable performance for extended productivity sessions.

Overview

This solution creates a headless virtual display on your Linux system and streams it to your Android tablet via VNC over USB connection with port forwarding. The setup is optimized for Hyprland window manager and includes automated device monitoring, connection management, and cleanup procedures.

Key Features

  • Automated Setup: Single script handles all configuration steps
  • Live Device Monitoring: Real-time ADB device status with automatic reconnection
  • Stable Connection: USB-based connection with port forwarding for reliability
  • Clean Teardown: Automatic cleanup on exit with proper resource management
  • Optimized Performance: Configured for high-resolution tablets with appropriate scaling

System Requirements

Linux System:

Android Device:

  • USB debugging enabled in Developer Options
  • VNC viewer application (RealVNC, VNC Viewer, or similar)
  • USB cable for initial setup

Quick Start

1. Download and Setup

The automated setup script is available in the vault utilities:

# Download the script
curl -O https://vault.flouda.io/scripts/android-screen
 
# Make it executable
chmod +x android-screen
 
# Run the setup
./android-screen

2. Enable Android USB Debugging

  1. Open Settings on your Android device
  2. Navigate to About phone/tablet
  3. Tap Build number 7 times to enable Developer Options
  4. Go back to Settings → Developer Options
  5. Enable USB Debugging
  6. Connect your tablet via USB

3. Authorize Connection

When you first connect, your Android device will prompt to authorize the computer:

  • Check “Always allow from this computer”
  • Tap “OK” to authorize

4. Connect VNC Client

Once the script completes setup:

  1. Open your VNC client app on the tablet
  2. Connect to localhost:5900
  3. The virtual desktop will appear on your tablet

Script Configuration

Default Settings

The script comes pre-configured for Samsung Galaxy Tab S8 Ultra but can be customized:

monitor_resolution="2960x1848@120"  # Display resolution and refresh rate
monitor_scale="1.6"                 # UI scaling factor

Customization for Different Devices

For smaller tablets (10-11 inch):

monitor_resolution="1920x1200@60"
monitor_scale="1.2"

For larger tablets (12+ inch):

monitor_resolution="2880x1800@90"
monitor_scale="1.4"

For standard tablets:

monitor_resolution="1920x1080@60"
monitor_scale="1.0"

How It Works

1. Virtual Display Creation

The script creates a headless virtual monitor using Hyprland’s output management:

# Create virtual display
hyprctl output create headless Virtual-1
 
# Configure resolution and positioning
hyprctl keyword monitor Virtual-1,${monitor_resolution},auto-left,${monitor_scale}

2. VNC Server Setup

wayvnc streams the virtual display content:

  • Binds to localhost:5900 for security
  • Captures only the virtual display (Virtual-1)
  • Optimized for low latency over USB connection

3. USB Port Forwarding

ADB establishes secure tunneling:

# Forward tablet port 5900 to host port 5900
adb reverse tcp:5900 tcp:5900

This allows the tablet to connect to localhost:5900 and reach the host VNC server.

4. Connection Monitoring

The script continuously monitors:

  • ADB device connection status
  • USB debugging authorization
  • Port forwarding health
  • Automatic reconnection on temporary disconnects

Troubleshooting

Common Issues and Solutions

Device Not Detected:

  • Ensure USB debugging is enabled
  • Try different USB cable or port
  • Check that device appears in adb devices
  • Restart ADB server: adb kill-server && adb start-server

Authorization Denied:

  • Device will show authorization prompt on first connection
  • Check “Always allow from this computer”
  • If prompt doesn’t appear, revoke authorizations in Developer Options

VNC Connection Failed:

  • Verify port forwarding: adb reverse --list
  • Check VNC server is running: ps aux | grep wayvnc
  • Test local connection: nc -zv localhost 5900

Poor Performance:

  • Reduce resolution in script configuration
  • Lower refresh rate (e.g., 60Hz instead of 120Hz)
  • Adjust scaling factor for better performance
  • Use USB 3.0 connection for better bandwidth

Display Not Appearing:

  • Check virtual monitor creation: hyprctl monitors
  • Verify monitor configuration is applied
  • Try recreating virtual display manually

Advanced Troubleshooting

Debug ADB Connection:

# Check device status
adb devices -l
 
# View ADB logs
adb logcat | grep -i vnc
 
# Test port forwarding
adb reverse --list

Monitor VNC Performance:

# Check VNC server logs
journalctl -f -u wayvnc
 
# Monitor network traffic
ss -tulpn | grep 5900
 
# Check CPU usage
top -p $(pgrep wayvnc)

Recovery Procedures

Manual Cleanup: If the script exits unexpectedly, clean up manually:

# Kill VNC server
pkill wayvnc
 
# Remove virtual display
hyprctl output remove Virtual-1
 
# Clear port forwarding
adb reverse --remove tcp:5900
 
# Restart ADB
adb kill-server

Reset Android USB Settings:

  1. Settings → Developer Options
  2. Revoke USB debugging authorizations
  3. Turn off USB debugging
  4. Turn on USB debugging
  5. Reconnect and reauthorize

Window Management

Moving Windows to Tablet

Using Hyprland Commands:

# Move active window to virtual display
hyprctl dispatch movetoworkspace Virtual-1
 
# Move specific application
hyprctl dispatch movetoworkspace Virtual-1,title:Firefox

Keyboard Shortcuts: Add to your Hyprland config:

bind = $mainMod SHIFT, T, movetoworkspace, Virtual-1
bind = $mainMod, T, focusmonitor, Virtual-1

Workspace Configuration

Configure dedicated workspaces for the tablet:

workspace = Virtual-1, 1
workspace = Virtual-1, 2
workspace = Virtual-1, 3

Performance Optimization

Network Optimization

USB Connection Benefits:

  • Stable bandwidth compared to WiFi
  • Lower latency for real-time interaction
  • No network congestion issues
  • Reliable for extended work sessions

VNC Optimization:

  • Use efficient encoding (ZRLE or Tight)
  • Adjust compression levels in VNC client
  • Disable unnecessary visual effects

Hardware Considerations

Tablet Requirements:

  • Minimum 8GB RAM for smooth performance
  • Modern processor (Snapdragon 865+ or equivalent)
  • USB-C connection for best bandwidth
  • Large screen (10+ inches) for productivity

Host System:

  • Sufficient GPU memory for additional display
  • USB 3.0+ ports for optimal data transfer
  • Modern CPU for VNC encoding performance

Security Considerations

Connection Security

Local Network Only:

  • VNC server binds only to localhost (127.0.0.1)
  • No external network exposure
  • Traffic encrypted through USB connection

ADB Security:

  • USB debugging authorization required
  • Device-specific RSA key authentication
  • Revocable access through developer settings

Best Practices

  • Disable USB debugging when not needed
  • Use screen lock on Android device
  • Regularly revoke old device authorizations
  • Monitor for unauthorized ADB connections

Integration Examples

Development Workflow

Code Editor on Tablet:

# Open VS Code on virtual display
code --new-window &
hyprctl dispatch movetoworkspace Virtual-1

Terminal Sessions

For comprehensive terminal management during your tablet workflow, leverage the tmux terminal multiplexer with custom keybindings:

# Dedicated terminal for tablet
alacritty --class tablet-term &
hyprctl dispatch movetoworkspace Virtual-1

Productivity Setup

Reference Material Display:

  • Documentation on tablet screen
  • Main work on primary monitor
  • Easy reference without window switching

Communication Tools:

  • Slack/Discord on tablet
  • Email client for monitoring
  • Calendar view for scheduling

Alternative VNC Clients

RealVNC Viewer (Free):

  • Excellent performance and features
  • Good touch gesture support
  • Reliable connection handling

VNC Viewer (Open Source):

  • Lightweight and fast
  • Customizable interface
  • Good for basic usage

bVNC (Free):

  • Feature-rich with many options
  • Good for advanced users
  • Extensive configuration options

Client Configuration Tips

Touch Optimization:

  • Enable direct touch mode
  • Configure gesture mappings
  • Adjust pointer sensitivity

Display Settings:

  • Match tablet resolution to virtual display
  • Enable hardware acceleration
  • Optimize color depth for performance

References and Resources

Official Documentation

  • scrcpy - Alternative Android screen sharing
  • x11vnc - X11 VNC server alternative
  • TigerVNC - High-performance VNC implementation

Community Resources

Questions Answered in This Document

Q: Can I use any Android tablet as an external screen for Linux? A: Yes, any Android tablet with USB debugging capability can work. You’ll need to adjust the resolution and scaling settings in the script to match your specific tablet’s specifications.

Q: Do I need root access on my Android device? A: No, root access is not required. You only need to enable USB debugging in Developer Options, which is available on all Android devices.

Q: Is the connection secure when using VNC over USB? A: Yes, the VNC server only binds to localhost (127.0.0.1) and traffic goes through USB connection with ADB port forwarding, providing a secure local connection without network exposure.

Q: Can I use this setup wirelessly instead of USB? A: While the script is designed for USB connections for stability, you can modify it to use wireless ADB connections. However, USB provides better performance and reliability for extended use.

Q: What happens if the USB connection is temporarily disconnected? A: The script includes live monitoring that detects disconnections and automatically restores port forwarding when the device reconnects, minimizing disruption to your workflow.

Q: Will this work with window managers other than Hyprland? A: The virtual display creation is Hyprland-specific. For other window managers, you would need to modify the script to use xrandr or other display management tools appropriate for your system.

Q: How much bandwidth does the VNC connection require? A: Bandwidth usage depends on screen content and activity. Static content uses minimal bandwidth, while video or frequent screen updates may require 10-50 Mbps. USB 3.0 connections provide sufficient bandwidth for smooth operation.

Q: Can I run multiple tablets as separate screens simultaneously? A: Yes, you can modify the script to create multiple virtual displays and set up separate VNC servers on different ports, allowing multiple tablets to function as independent screens.

Q: What’s the input lag like for interactive applications? A: With USB connection and proper configuration, input lag is typically 50-100ms, making it suitable for productivity tasks but less ideal for gaming or real-time applications requiring immediate response.

Q: Can I customize the virtual display position relative to my main monitor? A: Yes, modify the monitor configuration in the script. Options include auto-left, auto-right, auto-up, auto-down, or specific coordinates like 1920x0 to position the virtual display precisely.

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