HardLabs

Choccy47

leenknegt-eu·choccy47·choccy47/choccy47.kicad_pcb

Choccy47 PCB layout, top view — open source STM32 board by leenknegt-eu

About the Choccy47 PCB

Choccy47 is an open source STM32 PCB design by leenknegt-eu, published on GitHub under the Custom license license. It is a 2-layer board measuring 227 × 75.4 mm, with 115 components from 15 distinct parts.

Its main chip is the STM32F072CBTx, from the STM32 family. Other key parts include the MCP1703Ax-330xxDB. By type, the board carries 48 switches, 47 diodes, 10 capacitors, 5 resistors, 2 ICs and 1 connector.

It belongs with the keyboards designs in this gallery.

From the project

47 key planck-style layout layer switching mechanical keyboard for use with Gateron KS-33 low profile switches

The choccy47 is a layer switching keyboard based on the popular Planck, using the same basic layout as the Planck. This keyboard is compatible with Gateron KS-33 low profile mechanical switches, being named after the chocolate coloured KS-33 variant. An Atmega32u4 microcontroller is used to run the QMK firmware for the board. The mounting holes, PCB size, and connector location are the same as the Planck and other similar 40% keyboards, therefore this PCB should be compatible with most 40% cases.

Main components on the Choccy47

MCP1703Ax-330xxDBSTM32F072CBTx

Choccy47 bill of materials (BOM)

115 components, 15 distinct parts.

QtyPartRefs
1
MCP1703Ax-330xxDB
U1
1
STM32F072CBTx
U2
1
USB_C_Plug_USB2.0
P1
1
Polyfuse ~250mA
F1
1
ECMF02-4CMX8
USBLC6
FL1
47
Keyswitch
S1, S2, S3, S4, S5, S6, S7, S8 +39
1
SW_Push
SW1
47
Diode
D1, D2, D3, D4, D5, D6, D7, D8 +39
3
1u
C1, C2, C4
1
10n
C3
4
100n
C5, C7, C8, C9
2
4.7u
C6, C10
2
22
R1, R2
1
10k
R3
2
5.1k
R5, R6

Choccy47 design files

The KiCad project lives in the leenknegt-eu/choccy47 repository on GitHub; these links point at the commit this page was built from.

Choccy47: common questions

What microcontroller does the Choccy47 use?

The Choccy47 is built around the STM32F072CBTx, from the STM32 family.

How big is the Choccy47 PCB?

The Choccy47 measures 227 × 75.4 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Choccy47?

115 components, from 15 distinct parts. The full bill of materials is listed on this page.

Where can I download the Choccy47 design files?

From the leenknegt-eu/choccy47 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Choccy47 design in my own project?

It is published under Custom license, which limits how it may be reused; read the license before building on it.

Can I test firmware for the Choccy47 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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