deenewcum/pi400kb

Raw HID keyboard forwarder to turn the Pi 400 into a USB keyboard

Raspberry Pi 400 as a USB HID Keyboard & Mouse

Hook your Pi 400 up to your PC somehow, using a USB Type-C cable into the power port. Anker make good ones- I used a 3m white one for my tests.

Our USB-C to USB-A is great if you're using a USB-A port (but make sure it's a high power one): https://shop.pimoroni.com/products/usb-c-to-usb-a-cable-1m-black

A Raspberry Pi Mouse is also supported if plugged in, eg: https://shop.pimoroni.com/products/raspberry-pi-mouse?variant=29390982119507

This project started out life as a gist - https://gist.github.com/Gadgetoid/5a8ceb714de8e630059d30612503653f

Thank you to all the people who dropped by with kind words, suggestions and improvements.

• Quickstart (Ish)
  • Mouse Support
• Building & Contributing
  • Building
  • Custom Mouse/Keyboard Devices

Quickstart (Ish)

Add dtoverlay=dwc2 to /boot/config.txt

Reboot!

sudo modprobe libcomposite

wget https://github.com/Gadgetoid/pi400kb/blob/main/pi400kb?raw=true

chmod +x pi400kb

sudo ./pi400kb

✨ YOUR PI 400 IS NOW A FREAKING KEYBOARD & MOUSE FOR YOUR PC WHAAAAT!? ✨

Your keyboard input will be detached from your Pi while it's forwarded to your host computer.

Press Ctrl + Raspberry to grab/release your keyboard and mouse, switching between local use and USB.

Press Ctrl + Shift + Raspberry (on the grabbed keyboard) to exit.

Mouse Support

Pi 400 KB supports the official Raspberry Pi Mouse VID:PID = 093a:2510 by default, but other mice should work.

Autostart

sudo cp pi400kb /usr/sbin/pi400kb
sudo systemctl edit --force --full pi400kb.service

Add the contents of the pi400kb.service file.

Start the service and check its status:

sudo systemctl start pi400kb.service
sudo systemctl status pi400kb.service

Enable start on boot if it's okay:

sudo systemctl enable pi400kb.service

Building & Contributing

Building

sudo apt install libconfig-dev
git clone https://github.com/Gadgetoid/pi400kb
cd pi400kb
git submodule update --init
mkdir build
cd build
cmake ..
make

Custom Mouse/Keyboard Devices

CMake accepts the following build arguments to customise the VID/PID and device path for the mouse/keyboard:

• KEYBOARD_VID - Keyboard Vendor ID, default: 0x04d9
• KEYBOARD_PID - Keyboard Product ID, default: 0x0007
• KEYBOARD_DEV - Keyboard device path, default: /dev/input/by-id/usb-_Raspberry_Pi_Internal_Keyboard-event-kbd
• MOUSE_VID - Mouse Vendor ID, default: 0x093a
• MOUSE_PID - Mouse Product ID, default: 0x2510
• MOUSE_DEV - Mouse device path, default: /dev/input/by-id/usb-PixArt_USB_Optical_Mouse-event-mouse

Supply these arguments when configuring with CMake, eg:

cmake .. -DMOUSE_DEV="/dev/input/by-id/usb-EndGameGear_XM1_Gaming_Mouse_0000000000000000-event-mouse" -DMOUSE_VID=0x3367 -DMOUSE_PID=0x1903

pi400kb's Issues

don't hard-code the keyboard mapping

Per discussion here, there are international versions of the Raspberry Pi 400 (and other keyboards), and the scancode mapping is already available under Linux: Gadgetoid#26

bug when pressing and releasing keys in the right order

If you, for instance, press keys in this order:

1. press and hold Ctrl
2. press and hold A
3. press and hold Raspberry
4. release A

Then this code will interpret this as "toggle capture on/off", even though the user has just released something. Is this the right thing to do, or should we track "keys that have just been pressed" vs "keys that have just been released"?