Ext by floookay: open-source KiCad PCB and BOM

Overview

Ext is an open-source printed circuit board by floookay, from the floookay/olice repository on GitHub. It is a 2-layer board of 82.4 × 74.6 mm with 44 parts on 24 nets, routed with 247 tracks and 20 vias.

It is built around the 1N4148WT. Its parts include 16 diodes and 1 connector. It belongs with the keyboards and input boards of this library.

Main components

1

1N4148WT
SOD-523-55℃~+150℃ 1.25V@150mA 100V 150mA 150mW 1uA@75V 2A 4ns Independent SOD-523 Switching Diodes ROHShongjiachengSwitching Diodes

README

README.md

olice

The olice is 40% alice-like ortho keyboard. It features two board extension modules that can be magnetically attached on the sides.

basic pogo extended

additional pictures

oled numpad bottom ble

layout

https://www.keyboard-layout-editor.com/#/gists/c1cd375404f84e521f4a214a25ba4b32

Keycap compatibility is best with uniform profiles or keycaps that use the same profile on the home row as on the bottom row. R2 1.25u keycaps are otherwise rather unusual.

pcb

The keyboard is powered by a 0xCB Helios and the pogo pin connectors extend the matrix to the extension modules.

naked pcb

additional pictures

bottom top pogo oled

(don't mind the bodge wires on the oled header, I had the footprint flipped on v1.0, it's fixed now)

case

The case is 3d printed with an acrylic top layer. The board is kinda sandwich mounted via the extension connection holes on each side and has no other mounting points. I used a sheet of rubber to minimize flex. The extensions have additional mounting posts so the board doesn't fall out.

Your 3d printer needs at least a bed size of 250x210 and I printed mine with 100% infill and 0.2mm layer height.

firmware

The keyboard can be powered by QMK or ZMK:

QMK: https://github.com/floookay/qmk_firmware/tree/olice
VIAL via QMK: see olice_vial.uf2 and vial.json
ZMK: see olice-nice_nano-zmk.uf2 and shield config

assembly

additional pictures

printing case feet bottom

also see additional pcb pictures

main

Start with flashing the firmware to the Helios.
Then solder the main board, I'd start with soldering the diodes and hot swap sockets, then continue with soldering the controller (don't use a header, solder it directly to the pcb).
Then put the pogo pin connectors into the top side and solder them from the bottom (like the sockets and diodes), make sure they are flush with the border of the pcb.
Solder the OLED header on the same side. I recommend the hot swap header so you can easily remove the plate without having to remove all switches first.
Insert some leftover wire into the oled pin header socket and solder them to the oled display. Make sure that you're not soldering it to the hot swap header, don't apply too much solder.
Click the switches into the plate and install them onto the pcb. Plug the pcb into your PC and test every key
Melt the 10 heat set inserts into the case
Cut the thin sheet of rubber to the correct size of the front case piece and put it there
Slide the pcb into both case pieces and secure it via the 6 screws on the back
Put the acrylic cover on and screw it in
Put some glue in the magnet pockets and secure the disc magnets

extension 4u

Select on which side you want to use the extension and mark it. This is the top side, the only thing that is later going onto this side is the pogo pin connector.
Flip the pcb and solder the hot swap sockets and diodes. The diode placement is a bit tricky, I'd start with soldering the inner pads, then securing the diode, then moving to the next diode.
Then put the pogo connector into the top side and solder it from the bottom side (like the sockets and diodes), make sure they are flush with the border of the pcb.
Install all but one heat set inserts into the two case pieces. The split-in-half heat set insert hole is going in later
Click the switches into the plate and install them onto the pcb
Slide and wiggle the pcb into both case pieces with the pcb posts and and secure it via the screws on the back
Install the split-in-half heat set insert in the now closed hole
Put the acrylic cover on and screw it in
Put some glue in the magnet pockets and secure the disc magnets. Make sure that the orientation of the disc magnets matches the orientation of the disc magnets on the main case.

extension 2u

Select on which side you want to use the extension and mark it. This is the top side, the only thing that is later going onto this side is the pogo pin connector.
Break off the additional columns and file the excess pcb flat if neccessary.
Continue with step 2. from extension 4u

BLE version

bom (additional)

3.7V battery, e.g. 18x32x4mm
2.54mm 2 way on/off SMD DIP switch
nice!nano v2.0 instead of 0xCB Helios

The oled module is not supported and because of the limited pins on the controller only 2u extensions are supported. Please note the following differences during assembly:

Close both jumper pads if you want to use a 2u extension. This makes the pins that were previously used by the oled display usable as matrix rows.
The nice!nano doesn't have castellated holes so I'd recommend using some leftover wire pieces and soldering it from both sides shortly to ensure a good connection.
Solder the on/off switch and turn it off
Solder the battery to the 2-pin header area, the square hole is b-

additional pictures

testing pcb switch battery

Parts

44

Qty	Value	Footprint	References
22	MX_SW_HS	olice:SW_MX_HS_S_CPG151101S11_1u_reversible	MX1, MX2, MX3, MX10, MX11, MX12, MX13, MX14, MX15, MX16, MX17, MX18, MX19, MX20, MX21, MX22 +6
16	1N4148WT	olice:D_SOD-123FV	D1, D2, D3, D4, D7, D8, D9, D10, D13, D14, D15, D16, D19, D20, D21, D22
2	LOGO	LOGO	G*, G*
1
1	Conn_01x08	olice:pogo_header_1x08_P2.54mm_Horizontal	J2

The 42 most common of 44 parts.

Questions

How big is the Ext PCB?

It measures 82.4 × 74.6 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Ext use?

44 parts, built around the 1N4148WT. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Ext KiCad files?

From the floookay/olice repository on GitHub, at the commit this page was made from: the board is pcb/ext/ext.kicad_pcb and its schematic pcb/ext/ext.kicad_sch. PCBKit opens the board in the browser, with nothing to install.