HardLabs

KB79

jonathan512·KB79·hardware/kicad files/keyboard_pcb.kicad_pcb

KB79 PCB layout, top view — open source AVR/Arduino board by jonathan512

About the KB79 PCB

KB79 is an open source AVR/Arduino PCB design by jonathan512, published on GitHub under the GPL-3.0 license. It is a 2-layer board measuring 308 × 153 mm, with 181 components from 23 distinct parts.

Its main chip is the ATMEGA32A-PU, from the AVR/Arduino family. By type, the board carries 82 diodes, 81 switches, 7 resistors, 5 capacitors, 2 connectors and 1 IC.

It belongs with the keyboards designs in this gallery.

From the project

Custom 79-key mechanical keyboard designed in KiCad, featuring an ATmega32A, USB-C, and QMK firmware.

Custom 79-key mechanical keyboard | Jonathan Li

KB79 is a custom 75% mechanical keyboard designed around an ATmega32A microcontroller. The project covers the complete hardware development process, including schematic design, PCB layout, component sourcing, fabrication, assembly, firmware integration, and testing.

The finished keyboard features USB-C connectivity, a rotary encoder for media controls, and a hybrid switch footprint designed for both Kailh Choc V2 low-profile and MX-style switches.

KB79, from the project README
From the project README

Main components on the KB79

ATMEGA32A-PU

KB79 bill of materials (BOM)

181 components, 23 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ATMEGA32A-PU
ATmega32A-P
U1
1
Crystal
Y1
1
AVR-ISP-6
J1
1
USB4085-GF-A
USB4085-GF-A_C7095263
GCT
J2
1
~
*D80
1
500mA
F1
67
~
S0, S1, S2, S3, S4, S5, S6, S7 +59
1
~
S26
4
~
S28, S41, S75, S76
2
~
S43, S68
2
~
S55, S57
3
~
S71, S72, S73
1
~
S74
1
RotaryEncoder_Switch
SW1
80
~
D0, D1, D2, D3, D4, D5, D6, D7 +72
2
3.6V
D87, D88
2
0.1u
C1, C2
1
4.7u
C3
2
22pF
C4, C5
1
10k
R1
Show 3 more
QtyPartRefs
2
5.1k
R2, R3
2
75
R4, R5
2
1.5k
R6, R7

KB79 design files

The KiCad project lives in the jonathan512/KB79 repository on GitHub; these links point at the commit this page was built from.

KB79: common questions

What microcontroller does the KB79 use?

The KB79 is built around the ATMEGA32A-PU, from the AVR/Arduino family.

How big is the KB79 PCB?

The KB79 measures 308 × 153 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the KB79?

181 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 KB79 design files?

From the jonathan512/KB79 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 KB79 design in my own project?

Yes, under the terms of its GPL-3.0 license, which jonathan512 chose for the repository.

Can I test firmware for the KB79 without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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