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Bonsai C

customMK·Bonsai-C·C3/Bonsai_C.kicad_pcb

Bonsai C PCB layout, top view — open source STM32 board by customMK

About the Bonsai C PCB

Bonsai C is an open source STM32 PCB design by customMK, published on GitHub under the CERN-OHL-P-2.0 license. It is a 4-layer board measuring 17.8 × 51.6 mm, with 37 components from 27 distinct parts.

Its main chip is the C81523, from the STM32 family. Other key parts include the C370742, C274624 and C78541. By type, the board carries 11 capacitors, 7 connectors, 6 resistors, 4 ICs, 3 diodes and 1 transistor.

It belongs with the keyboards designs in this gallery.

From the project

An open-source ARM-based microcontroller board

- Images - Background - Comparison to Proton C - Build information - License

Bonsai C3 fabricated by JLCPCB (disregard the extra width, 20mm minimum width used to be JLCPCB requirement)

Bonsai C3 is a general-purpose ARM-based microcontroller board. It was designed to help with the protoype and development of mechanical keyboards, but is versatile enough to be used in a variety of other applications. Mechanical keyboards can use Bonsai C3 as a "plug in" microcontroller board to their own designs sans-microcontroller, or they can incorporate the Bonsai C schmatic and layout directly into a…

Bonsai C, from the project README
From the project README

Main components on the Bonsai C

C370742C274624C81523C78541

Bonsai C bill of materials (BOM)

37 components, 27 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
C370742
AAP2967-33VIR1
U1
1
C274624
NUF2221W1T2G
U2
1
C81523
STM32F303CCT6
U3
1
C78541
SN74LV1T34DCKR
U4
1
C152542
MUN5311DW1T1G
Q1
1
C115962
SMD-CRYSTAL-8MHZ-20PF-10PPM_2P-5.0X3.2MM_
Y1
1
HEADER-VERT_3P-2.54_
J1
1
HEADER-VERT_1P-2.54_
J2
1
C165948
TYPE-C-31-M12_13
J3
2
HEADER-VERT_12P-2.54_
J4, J5
2
HEADER-VERT_6P-2.54_
J6, J7
1
C201047
Buzzer_Mallory
BZ1
1
C66452
SMD-PPTC-500MA_0805_
F1
1
C231329
SMD-SWITCH-TACTILE-SPST-NO_2P-2.5MMx3.0MM_
K1
1
C8598
B5819W
D1
1
C68948
1N4148
D2
1
C74342
SMD-LED-WHITE_0402_
D3
1
C668229
fb_0402_26ohm
FB1
5
C1525
cap_100nF_16v_0402
C1, C2, C3, C4, C7
1
C1779
cap_4.7uF_25v_0805
C6
Show 7 more
QtyPartRefs
2
C1554
cap_20pF_50v_0402
C8, C9
2
C52923
cap_1uF_10v_0402
C10, C11
1
C19702
cap_10uF_6v_0402
C12
1
C25741
r_100k_0402_1p
R1
2
C25905
r_5.1k_0402_1p
R2, R3
1
C25133
r_75_0402_1p
R4
2
r_0_0402_nopop
R5, R6

Bonsai C design files

The KiCad project lives in the customMK/Bonsai-C repository on GitHub; these links point at the commit this page was built from.

Bonsai C: common questions

What microcontroller does the Bonsai C use?

The Bonsai C is built around the C81523, from the STM32 family.

How big is the Bonsai C PCB?

The Bonsai C measures 17.8 × 51.6 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Bonsai C?

37 components, from 27 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 Bonsai C design files?

From the customMK/Bonsai-C repository on GitHub, which has the KiCad layout and the BOM; the links under Design files point to each one.

Can I use the Bonsai C design in my own project?

Yes, under the terms of its CERN-OHL-P-2.0 license, which customMK chose for the repository.

Can I test firmware for the Bonsai C 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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