A bluetooth dongle that's small, uses USB C and is compatible with any ZMK keyboard: that's the Halcyon wireless USB C dongle.

This dongle is useful for two reasons: when your device doesn't already have bluetooth on its own, this dongle will enable you to use your ZMK keyboard wirelessly. And two, the main reason most will want this: using a dongle drastically reduces the power draw of the main half of your wireless keyboard.

Without a dongle, the main half will keep two connections open. One to the peripheral half, and another to the host device. This means that the main half will be able to be asleep considerably less than the peripheral half, which reflects on the battery life. Using a dongle, both halves connect directly to the dongle and will not need a connection between the two halves. Removing this second connection can save up to as much as 95% of battery consumption on the main half, so your battery can last up to twenty times longer!

We highly recommend using a dongle when powering your keyboard with the Coin Cell power board, as the coin cells are non-rechargeable. We estimate your coin cell will last between 6 to 9 months of use with the dongle, while the main half would last roughly two weeks without a dongle.

When using a LiPo power board, using a dongle can still be useful as you'll have to charge your keyboard far less frequently. Charging your LiPo is easy to do though, so the dongle will be more of a luxury there.

Features

• Uses a nRF52840 module for its wireless connection, featuring an ARM Cortex-M4 processor, 1MB of embedded flash memory and 256 kB of RAM.
• Powered by ZMK Firmware.
  • Halcyon keyboards are compatible: either through downloadable firmware files which you can customise with ZMK Studio, or by compiling it yourself through a provided sample repository.
  • Other ZMK-powered keyboards are compatible too, by following our comprehensive setup guide.
• Easily flashable: double-tap the button and the dongle will present itself as an attached drive. Simply drag a new firmware file to it and you're done!
• Comes with a matte black 3D printed case in PLA.
• It's as small as we could manage to make it! It easily fits on most laptops, phones and tablets with a USB C port. It'll even fit on the thinnest of laptops, such as the MacBook Air, without touching the desk, and without impairing the ports next to it.
• The module used is certified for use worldwide, including CE-certification. It has been tested to meet and/or exceed regulations, and so will work reliably without interfering with other devices.

In the package

• One bluetooth dongle with assembled case, consisting of a case body and a case lid.

Open source

Want to personalise your dongle? You can! The case files are available to download on Github.

Remarks

We recommend to not disassemble the case, the lid might get loose and not close as tightly anymore. We included some photos of the PCB on this page to hopefully satisfy your curiosity ;)