Topre - joric/jorne GitHub Wiki

Corne EC Revival

New! There's an open-source Corne version made in KiCad:

corne_hold

Topre Helix

New! There's an opensource Topre PCB for Helix, https://github.com/ginjake/ec_helix_build that kind of works (need straight plate and more attachment points). Supports Realforce, NIZ, HHKB switches. Has full building manual (in Japanese).

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Corne ECWL

Topre-based Сrkbd clone entirely made by sekigon-gonnoc (NOT foostan). (ECWL = Electro Capacitive + WireLess)

See https://www.reddit.com/r/MechanicalKeyboards/comments/lfomvh/my_first_electro_capacitive_keyboard

Here's the list:

You can find the firmware here: https://github.com/sekigon-gonnoc/qmk_firmware/tree/dev/crkbd_ecwl

Switches

See https://aficionerds.com/en/blog/20210205_crkbd_ec/

I would recommend the NIZ. The BTO switches have a large gap between the switch cover and the stem, making them very difficult to type, much more so than the switches on Gatetron’s cheapest model.

NIZ BTO

Springs

A lot of issues with parts, you can buy NIZ switches here but no springs

Japanese shops apparently sells complete switches:

Author of Conundrum (November 2018, see https://geekhack.org/index.php?topic=97975.0):

First of all, the springs - springs used in such designs aren't readily available, so they had to be designed and manufactured for this specific use case. I have already received some prototypes from the factory and - while they were a bit too stiff, something I have addressed in the 2nd revision - they did work correctly with "major brand's" electro-capacitive keyboard PCB. 2nd prototype batch is on the way.

Build guide

Schematic

There's documentation in PDF that's pretty detailed you can build the keyboard pretty easily:

I uploaded files here so you don't need to create an account:

Sensing scheme is very similar to HHKB, not sure why use dedicated multiplexer though.

Components are 74HC4051 multiplexer and LTC6255 operational amplifier, that's, basically, it. Analog mulitiplexer seems unnecessary but it works as a final amplifier and evens out varying analog inputs from columns to a digital level.

schematic

There's no kicad source but there is schematic and high-res drawings of the PCB so you can replicate it in like 15 minutes.

Firmware

Controller is either a regular Pro Micro (!) or BLE Micro Pro. Firmware is open source and available here:

Donors

NIZ 108 (NIZ x108 White) seems like a perfect candidate ($159 + $10 shipping, 108 switches, 45g is preferable):

References