le_chiff_ble

What is this?

This is a drop-in replacement PCB for tominabox1's Le Chiffre keyboard, one of my all time favourite boards. I redesigned the existing PCB from top up and added bluetooth. Please be so kind and check out the original repo and leave a star. This is where you can also find case files for this PCB.

Some of the footprints are not taken from the standard kicad libraries, huge thanks to foostan for making the awesome "kbd" library and to ai03 for their super nice footprint libraries, the minew symbol and footprints are by oreore.

All graphics on my PCB are hand drawn and belong to no-one but me.

There are two PCBs in this repo one

• with hotswap, no silkscreen, see kicad/le_chiff_ble_hotswap
• without hotswap, with silkscreen, see kicad/le_chiff_ble

I do not take any responsibility for what you do with the files supplied here in any way. Neither do I guarantee they're working for whatever purpose you intend ot use them.

State of the project

implemented

• charging circuit is working
• MCU connects via bluetooth and USB
• all features have been tested and are working, including OLED and Encoder
• a working zmk firmware can be found here.

open tasks

• the widgets in zmk for the OLED are still very basic, I'd like to do something to make them look better, this will be added after I finished and uploaded the firmware

How can I obtain one

• Gerbers are supplied, be free to order them from the PCB manufacturer you prefer.

you will need parts:

1. Resistors, footprint is 0805:

• 1x 2M
• 1x 1M
• 1x 806k
• 1x 100k
• 2x 5.1k
• 1x 1.8k
• 3x 1k
• 2x 100
• 1x 2.1

2. Capacitors, footprint is 0805

• 4x 10uF
• 2x 1uF
• 2x 0.1uF
• 1x 1nF

3. Diodes

• 35x SOD123 for the switches and encoder
• 1x Schottky, SOD323, should be low voltage drop
• either 2x in switch LEDs or 2x 0805 SMD LEDs for the charging indicator

4. 1x PMOS, A03401A
5. 1x battery management chip, TP4056, footprint is SOP-8-PP
6. 1x LDO, XC6206PxxMR
7. 1x usblc6, footprint is sot-23-6
8. 1x 500mA Fuse, footprint is 1206/ 3216Metric
9. 1x battery protection IC DW01A, footprint is sot-23-6
10. 1x two nmos with gates connects FS8205, footprint is sot-23-6
11. 1x Minew MS88SF2, be careful to choose the version with nrF52840, there's also another version with the same name which won't work
12. 1x USB type c port, 12 pin
13. 1x MSK-12C02 smd toggle switch
14. 1x SW SPST TL3342 push switch for reset
15. 34-35 MX/alps/choc switches depending on whether you use the encoder or not
16. Battery connector with 1.25mm pitch, choose whichever you're fine with
17. optional: 1x Encoder, 1x 128x32 OLED

How do I build one?

• solder all components
• flash bootloader (I liked this one a lot, it's fairly easy to modify to your needs, e.g. the name the board will appear with in bootloader mode)
• plug into PC and test whether everything is working, flash Firmware
• the firmware can be forked from here, just adjust the .keymap file, push, let GitHub Actions build it for you, download, done
• plug in battery, plug in PC again to unlock DW01A (this needs to be done everytime you physically disconnect the PCB from the battery)
• be careful to adjust resistor value of the tp4056 when you take different battery sizes, I chose 1Ah which works fine with the specified resistor values
• verify charging and bluetooth works
• continue building as if this was a "normal" chiffre