Leonardo + USB Host Shield · Single PC
One PC. Your mouse connects through a Leonardo and USB Host Shield.
Knife.Baby and your game run on the same Windows PC. Your mouse connects to the USB Host Shield. Close your game before flashing firmware.
Have these ready.
- Arduino Leonardo
- Compatible USB Host Shield
- Micro-USB data cable
- Your gaming mouse
Assemble the hardware
With power disconnected, align the USB Host Shield’s headers with the Arduino Leonardo’s pins. Press the boards together evenly to form one stacked unit. Check that no pins are bent or offset.
Install Knife.Baby and flash the Leonardo
- Download Knife.Baby from Downloads, sign in and choose your game.
- In setup, choose Single PC → Arduino Leonardo + UHS.
- Connect the Leonardo’s micro-USB port to your PC using a data-capable cable.
- When Knife.Baby asks, press the board’s RESET button once.
- Keep the cable connected until the firmware has been written and checked.
Connect and test your mouse
Plug your gaming mouse into the USB Host Shield’s USB-A port. The Leonardo’s L light should turn on after the PC configures the board.
Move the mouse. If the cursor moves, the hardware connection is working.
Confirm the connection
Return to Knife.Baby. The board card in the sidebar should show Connected after the Leonardo responds. You can now configure your settings.
Let’s get you connected.
The Leonardo is not detected
Try another micro-USB cable. Some cables supply power but do not carry data. Try another USB port as well.
The mouse has no power or the cursor does not move
Check that the shield is seated correctly. Some shields require their 5V power jumper to be soldered. Check your shield’s documentation; have a repair shop handle soldering if needed. If the power jumper is already correct, check the shield and cable for faults.
My mouse is still not supported
Contact support or the Knife.Baby Discord with your exact mouse model, board, software version and setup mode.