Zephyr ble hid usb translator

This is a project intended to use a bluetooth keyboard as a dongle. This allows you to use the keyboard in BIOS and can offer more stability than standard bluetooth connection.

Installing in a board

Similar to ZMK, download the latest build of the supported board in github actions. For boards that don't use uf2 bootloader, check Flash with nrfutil.

How to pair

Once you plug the dongle, it will wait for a keyboard that wants to connect to bluetooth. You should put your keyboard in bluetooth pairing mode. On a ZMK board, you can do that by selecting the profile you want to use for the dongle and pressing the key assigned to &bt BT_CLR.

How to unpair

If you are using a board that supports reset button, simply plug the dongle leaving the button pressed. The board will blink 3 times indicating it is has reseted all the pairing keys it had. You can pair with any keyboard again.

Boards that don't support the reset button should be flashed with the shield settings_reset and then flashed again with the dongle shield.

Supported boards

Currently the projectg is auto building for using uf2 for:

• xiao ble
• nordic nrf52840 dongle
• nrf52840 mdk dongle
• nice_nano_v2

Shields

Boards that offer a programable button, such as nordic nrf52840 dongle, can be built using reset_dongle shield. The ones don't support that can use the normal dongle shield.

• dongle: The simple dongle implementation.
• settings_reset: Clears the dongle pairing keys if you need to pair to another.
• reset_button: Is the dongle implementation with support to unpair without flashing, by pressing a button while plugging in.

Build locally

Requirements:

• west

Init the repo with west:

west init -l .
west update

Building a board

You can build any of the supported boards by zephyr or the ones offered in this repo

west build -p -s ./app -b nrf52840_mdk_dongle  -- -DSHIELD=dongle

Copy the build/zephyr/zephyr.uf2 file to the board.

If you need to reset the dongle you can build the settings_reset shield

west build -p -s ./app -b nrf52840_mdk_dongle  -- -DSHIELD=settings_reset

Flashing with nrfutil

Boards such as nrf52840dongle_nrf52840 require you to flash using nrfutil tool. Download the hex file from github actions.

Using the hex file, use the nrfutil to flash it. Once it is in the step to flash, you should press the reset button on the board.

nrfutil pkg generate --hw-version 52 --sd-req=0x00 \
        --application build/zephyr/zephyr.hex \
        --application-version 1 dongle.zip && \
nrfutil dfu usb-serial -pkg dongle.zip -p /dev/ttyACM0