Kobold
About the Kobold PCB
Kobold is an open source STM32 PCB design by tzarc, published on GitHub under the CERN-OHL-S-2.0 license. It is a 4-layer board measuring 76 × 75.1 mm, with 94 components from 23 distinct parts.
Its main chip is the STM32G431CBU6, from the STM32 family. Other key parts include the SN74LVC1G14DRL, AP2552FDC-7, XC6206PXXXMR, INA180A4 and H5VU25U. By type, the board carries 27 capacitors, 19 switches, 18 diodes, 16 ICs, 13 resistors and 1 connector.
It belongs with the keyboards designs in this gallery.
From the project
@tzarc's custom keyboard designs.
4x4 macropad running QMK, in the same form factor as a bm16s. Non-standard Choc key spacing.
STM32G431, North-facing RGB, SPI NOR Flash, voltage and current measurement, direct pin matrix, reset to bootloader by holding top 4 keys.
Main components on the Kobold
Kobold bill of materials (BOM)
94 components, 23 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 7 | SN74LVC1G14DRL | SOT-553-5_L1.6-W1.2-P0.50-LS1.6-BL | U1, U2, U9, U11, U13, U15, U16 |
| 1 | AP2552FDC-7 | WDFN-6_L2.0-W2.0-P0.65-BL-EP-1 | U3 |
| 1 | XC6206PXXXMR XC6206PxxxMR | SOT-23-3 | U4 |
| 1 | INA180A4 | SOT-23-5_L3.0-W1.7-P0.95-LS2.8-BR | U5 |
| 1 | H5VU25U | DFN2510-10_L2.5-W1.0-P0.50-BL | U6 |
| 1 | STM32G431CBU6 | QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm | U7 |
| 1 | W25Q128JVSIQ | SOIC-8_5.3x5.3mm_P1.27mm | U8 |
| 3 | SN74AHC1G08DRL | SOT-553-5_L1.6-W1.2-P0.50-LS1.6-BL | U10, U12, U14 |
| 1 | TYPE-C-31-M-12 | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
| 16 | Push | SW_choc_v1_HS_CPG135001S30_1u | SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8 +8 |
| 1 | BOOT0 | SW-SMD_4P-L3.0-W2.6-P1.80-LS3.4-TL | SW17 |
| 1 | BOOT0 DFU | SW-SMD_4P-L3.0-W2.6-P1.80-LS3.4-TL | SW18 |
| 1 | BOOT0 nRST | SW-SMD_4P-L3.0-W2.6-P1.80-LS3.4-TL | SW19 |
| 8 | C5149201 RGB | LED_choc_6028R | D1, D2, D3, D4, D9, D10, D11, D12 |
| 8 | C5149201 RGB | LED_choc_6028R-ROT | D5, D6, D7, D8, D13, D14, D15, D16 |
| 1 | H5VL10B | D_SOD-882 | D17 |
| 1 | 1N4148 | D_SOD-323 | D18 |
| 21 | 100N 100n | C_0402_1005Metric | C1, C2, C3, C10, C11, C12, C13, C14 +13 |
| 6 | 4.7U 4.7u | C_0402_1005Metric | C4, C5, C6, C7, C8, C9 |
| 6 | 10K 10k | R_0402_1005Metric | R1, R6, R7, R8, R11, R12 |
Show 3 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 4 | 75K 75k | R_0603_1608Metric | R2, R4, R5, R9 |
| 1 | 0.05R | R_1206_3216Metric | R3 |
| 2 | 1k | R_0402_1005Metric | R10, R13 |
Kobold design files
The KiCad project lives in the tzarc/keyboards repository on GitHub; these links point at the commit this page was built from.
Kobold: common questions
What microcontroller does the Kobold use?
The Kobold is built around the STM32G431CBU6, from the STM32 family.
How big is the Kobold PCB?
The Kobold measures 76 × 75.1 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Kobold?
94 components, from 23 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Kobold design files?
From the tzarc/keyboards repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Kobold design in my own project?
Yes, under the terms of its CERN-OHL-S-2.0 license, which tzarc chose for the repository.
Can I test firmware for the Kobold without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug STM32 firmware against it before you order a PCB.
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