"Leptos" stands for "flat" in greek, added with the suffix is, it forms the word "Leptosis", signifying the most flat. This represents my long lasting desire for an real flat keyboard that is portable and light. The name is also quite similar to the latin word "levitatio", signifying levitation and thus light.

Features

• Ultra long battery life (~4 months for central and 1 year for peripheral)

• Ultra thin (7.5mm)

• Compact (13.2x9.2cm)

• Custom battery management and optimization

• Embedded nrf52 mcu

• ZMK bluetooth

Fabrication

You can either use PCBA to fabricate the PCB, or reflow it yourself. I highly discurrage you to reflow the yourself if you haven't reflowed a aQFN package before - it's a nightmare to get right.

The PCB files are in the hardware directory, you need to buy one pcb for the right and the left. There is also a V-Cut panneled version in hardware/panel. It uses a 1.2mm PCB with a JLC04121H-7628 stackup.

The case is in the CAD directory. Print out all .step files.

The software is in the firmware. Leptosis uses ZMK, allowing ultra long battery life.

After fabrication, solder on some jumpers onto the 4 test pads, and connect it to a JTAG connector (I'm using the ST-LINK). Download the bootloader from the newest action here and unzip it.

For stlink, install openocd and run the following commands:

openocd -f /usr/share/openocd/scripts/interface/stlink.cfg -f /usr/share/openocd/scripts/target/nrf52.cfg -c 'program <path_to_bootloader>.hex verify reset; shutdown;'

For other JTAG connectors, please refer to your own documentation.

Now plug in a USB-C cable, and you should see a mass storage device called LEPTOSIS.

Download the ZMK config from this repo: https://github.com/cheyao/zmk-config/actions, drag the utf file to the mass storage device and you are done!

Open Source

This project is licensed under the hardware CC0 equivalent: the Solderpad license!

Misc

Liked this project? Drop a star on github and check out my other Icepi Zero project!