Imported from GitHub: tikinson/kazhan · commit b7addf9 · license GPL-3.0

Description

custom 28-keys ergonomic mechanical keyboard powered by CH552T microcontroller

README

🦇Kazhan🦇

28 Keys. MX and Choc compatible keyboard with CH552T controller. This is the next logical step after my experimental keyboard ToadsTempest.

Idea

Kazhan (Кажан) is derived from the Ukrainian word meaning "bat". As a fan of ZilpZalp/Hummingbird projects i decided make something with same layout but more personalized. Same but different.

What this project is and what it is not

Goals:

• A pet project of a keyboard as an act of absolute self-expression.
• Flexibility and experiments over (and maybe in some case against) minimalistic design approach.
• Testing interesting "non - conventional" switches as extra keys.
• Testing things that i don't saw (yet?) in another keyboard PCB designs.

Non-goals:

• Creation of another variant of the Corne (I like Corne btw, that was my first love in this hobby).
• Design with a definite assembly variant.
• Go through the steps in the keyboard design that I have already tried.

Features

• Mirrored design of PCB to provide split and unibody functionality in one design.
• Alpsalpine limit switches (SW1, SW2 on schematics) as additional switches. I accidentaly understood, that MX keycap kinda fits on them (with 45 dergee rotation), so i would give them a try.
• Wired USB-C (USB 2.0) connection.
• Designed for usage with really affordable chip and F.A.K. firmware.
• Japanese (duplex) matrix of keys and diodes for them: first of all, it's way more easy to solder one dual diode instead of two regular, because you will never put this part with wrond polarity. And also because of type of key matrix, there is two types of dual diodes: with common anode and common cathode.

Layout

BOM

Opening local copy of ibom.html could save some times while soldering.

Reference	Value	Footprint	Qty	LCSC
C1, C2	100nF	Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder	2	C1525
D1, D4, D5, D8, D9, D11, D13, D15	BAS70-06-CAnode	Package_TO_SOT_SMD:SOT-23	8	C8651
D2, D3, D6, D7, D10, D12, D14, D16	BAS70-05-CCatode	Package_TO_SOT_SMD:SOT-23	8	C34489
D17	PMEG2010EA	Diode_SMD:D_0402_1005Metric_Pad0.77x0.64mm_HandSolder	1	C2837790
D18, D19	PWR LED	LED_SMD:LED_0402_1005Metric	2	C130724
F1	500mA	Fuse:Fuse_0402_1005Metric_Pad0.77x0.64mm_HandSolder	1	C210357
J3	USB_C_Receptacle_USB2.0	Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12	1	C2765186
R1, R6	10k	Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder	2	C25744
R2, R3	5.1k	Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder	2	C25905
R4, R5	1k	Resistor_SMD:R_0402_1005Metric	2	C11702
SW1, SW2	~	MyFootprintsCollection:SW-TH_SSCF110100	2	C470322
SW4, SW6	RESET	KEY-SMD_4P-L4.8-W4.8-P3.70-LS6.4-TL	2	C2888968
S1–S28	Keyswitch	SW_Hotswap_Kailh_Choc_MX_1.00u_One_Sided	28
U1, U4	USBLC6-2SC6	Package_TO_SOT_SMD:SOT-23-6	2	C2687116
U2, U3, U5	CH552T	-- mixed footprints --	3	C111367

Note: S1-S28 - is footprints for switches. You can choose between MX or Kailh Choc switches (or both if you like experiments) and solder hotswaps accordingly.