An affordable, 44-key low-profile split mechanical keyboard using kailh choc switches with (optional) hot-swap and pure Rust firmware.
Inspired by:
- crkbd - overall keyboard shape, case mounting
- lily58 - additional thumb button
- keyseebee - firmware, switches
- Portability
- Very low profile - contributes towards portability, minimum hand strain
- Affordable - no fancy and expensive parts, minimum 'extra' features
- Easy to build - all of the components are hand-solderable
- Easily sourceable components
- Simple schematic and PCB
- Simple and user-friendly firmware (written in Rust)
- 3D printable case+plate - designed for painless printing even on non-professional printers
- Optional hot-swap sockets - hot-swap is useful, but not everyone needs it
- USB-C sockets - the new standard; one less reason to keep legacy cables around
- No backlighting - less distracting keyboard, simpler design and firmware, easier to build
- No ESD/overvoltage/etc protection - much more affordable, very rarely needed when the keyboard is used under normal conditions
- No reversible PCB - heavily complicates PCB design and the building process; doesn't make manufacturing PCBs cheaper in most cases
- TRRS sockets at the top - doesn't require angled jacks, and the cable doesn't get in the way
- +3V3, GND and a single GPIO pin breakout (for one-wire RGB LEDs or other custom features)
- Test pads for debugging
- The firmware is located in the vgbd44-firmware repository. Head there for instructions on flashing and other firmware-related resources.
- Case options and other notes on cases: CASES.md
- Layout info and printable layout diagrams: LAYOUT.md
The parts list is also available here in spreadsheet form.
This table is a parts list for a full keyboard, with estimate, rounded up prices in EUR.
| Item | Remarks | Qty | Price (for exact qty) |
|---|---|---|---|
| left PCB, right PCB | 1, 1 | 18.00 | |
| 1N4148 diodes | MINIMELF package (or footprint-compatible) | 44 | 0.50 |
| 100nF capacitor | 0603 package | 6 | 0.05 |
| 10nF capacitor | 0603 package | 2 | 0.01 |
| 1uF capacitor | 0603 package | 4 | 0.02 |
| 4.7uF capacitor | 0603 package | 4 | 0.02 |
| 10k resistor | 0603 package | 2 | 0.01 |
| 5.1k resistor | 0603 package | 4 | 0.02 |
| MIC5504-3.3 or compatible | SOT23-5 package | 2 | 0.24 |
| 6mm OFF-(ON) SMD button | for example PTS645SH50SMTR92 | 2 | 0.40 |
| PJ320A 3.5mm jack socket | easy to get on aliexpress | 2 | 0.30 |
| 217B-AG01 USB-C socket | 2 | 4.00 | |
| STM32F042K6T6 or compatible | see notes in firmware | 2 | 6.00 |
| Mechanical parts | |||
| 4mm M2 screws | for example M2X4/D7985-A2 | 20 | 0.22 |
| 5mm M2 standoffs | for example TFF-M2X5/DR111 | 10 | 2.00 |
Which equals about 13.80 EUR for a single keyboard (both halves). For a full keyboard one would also (obviously) need switches and keycaps, which can and usually are the most expensive part of a keyboard.
Other optional and/or extra parts are:
- Kailh choc hotswap sockets (one per key)
- USB-C cable (1)
- TRRS cable (1)
