Keyboard Input Blocker

A graphical application for Linux that toggles keyboard input blocking with a single button. Perfect if your toddler likes to press a lot of buttons during video calls.

Features

• Simple one-button toggle interface built with PyQt6
• Disables/enables all keyboard input at the system level
• Status indicator showing current state
• Works on Wayland and X11

Requirements

• Python 3.7+
• PyQt6
• evdev (Linux kernel input device library)

Installation

1. Install dependencies

On Ubuntu/Debian:

sudo apt-get install python3 python3-pip libevdev-dev
pip install -r requirements.txt

On Fedora:

sudo dnf install python3 python3-pip libevdev-devel
pip install -r requirements.txt

On Arch:

sudo pacman -S python3 libevdev python-pyqt6 python-evdev

2. Run the application

The application requires elevated privileges to access input devices:

sudo -E python3 kb-block.py

Or make it executable:

chmod +x kb-block.py
sudo -E ./kb-block.py

Usage

1. Launch the application with sudo -E
2. Click "Block Keyboard" to disable all keyboard input
   • The button turns red and shows "Unblock Keyboard"
   • Status shows "Keyboard BLOCKED ⚠"
3. Click "Unblock Keyboard" to re-enable keyboard input
   • The button returns to normal
   • Status shows "Keyboard enabled ✓"

Note: When keyboard is blocked, you'll need to use:

• Mouse to unblock via the button
• External input devices (if available)
• Or kill the process from another terminal: sudo killall -9 python3 (or the specific PID)

How it Works

The application uses the evdev library to grab input devices at the kernel level:

• grab() - Prevents the keyboard from sending any events
• ungrab() - Restores keyboard input

This works with both X11 and Wayland display servers.

Permissions Note

The application requires sudo because it needs to directly access /dev/input/event* devices.

If you want to run without sudo, you can add your user to the input group:

sudo usermod -a -G input $USER
# Log out and back in for the change to take effect

However, this is less secure as it grants all users in the input group broad input device access.

Troubleshooting

No keyboard device found

• Ensure you're running with sudo -E
• Check that keyboard input devices exist: ls -la /dev/input/event*

Permission denied"

• Run with sudo -E
• Or add your user to the input group (see Permissions Note above)

Keyboard still responds

• Multiple keyboard devices may exist; the app grabs the primary one
• Try unblocking and re-blocking

License

This project is licensed under the Zlib license (see LICENSE file for more information).