KeyChatter

KeyChatter is a lightweight C++ utility that filters out mecanical keyboard chatter on Linux.

---

Build Instructions

Dependencies

• A C++ compiler (e.g. g++)
• libevdev development headers
• Linux kernel support for uinput

On Debian/Ubuntu:

sudo apt install g++ libevdev-dev

Build

g++ -std=c++17 -o keychatter main.cpp $(pkg-config --cflags --libs libevdev)

---

Finding Your Keyboard Device

ls -l /dev/input/by-id/

Example:

ls -l /dev/input/by-id/
total 0
lrwxrwxrwx 1 root root 10 Jun 13 17:25 usb-Razer_Razer_BlackWidow_V4-event-if01 -> ../event17
lrwxrwxrwx 1 root root 10 Jun 13 17:25 usb-Razer_Razer_BlackWidow_V4-event-kbd -> ../event15
lrwxrwxrwx 1 root root 10 Jun 13 17:25 usb-Razer_Razer_BlackWidow_V4-if01-event-kbd -> ../event16
lrwxrwxrwx 1 root root 10 Jun 13 17:25 usb-Razer_Razer_BlackWidow_V4-if02-event-mouse -> ../event27
lrwxrwxrwx 1 root root  9 Jun 13 17:25 usb-Razer_Razer_BlackWidow_V4-if02-mouse -> ../mouse4

In my case the correct one is usb-Razer_Razer_BlackWidow_V4-event-kbd

Usage

When started manually it may spam the last used key (enter most likley) untill you press any key. As the kernel is slightly confused

sudo ./keychatter /dev/input/by-id/usb-Razer_Razer_BlackWidow_V4-event-kbd [threshold_ms]

• /dev/input/by-id/usb-Razer_Razer_BlackWidow_V4-event-kbd: Path to your keyboard
• threshold_ms (optional): Milliseconds to treat as chatter (default: 55)

---

Install as a systemd Service

To run KeyChatter automatically at startup:

1. Copy the binary

sudo cp keychatter /usr/local/bin/

2. Create a systemd service file

# /etc/systemd/system/keychatter.service
[Unit]
Description=KeyChatter - Keyboard Debounce Filter
After=network.target

[Service]
ExecStart=/usr/local/bin/keychatter /dev/input/by-id/usb-Razer_Razer_BlackWidow_V4-event-kbd
Restart=on-failure
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

Replace /dev/input/by-id/usb-Razer_Razer_BlackWidow_V4-event-kbd with your actual keyboard device.

3. Enable and start the service

sudo systemctl daemon-reexec
sudo systemctl enable --now keychatter.service

To view logs

sudo journalctl -u keychatter.service -f

---

License

MIT License — use responsibly. Contributions and suggestions welcome!