HardLabs

Numpad

npwhl·numpad-pcb

Numpad PCB layout, top view — open source AVR/Arduino board by npwhl

About the Numpad PCB

Numpad is an open source AVR/Arduino PCB design by npwhl, published on GitHub. It is a 2-layer board measuring 76.2 × 118.8 mm, with 63 components from 37 distinct parts.

Its main chip is the ATmega32U4-A, from the AVR/Arduino family. By type, the board carries 22 switches, 22 diodes, 7 capacitors, 6 resistors, 1 IC and 1 crystal.

It belongs with the keyboards designs in this gallery.

From the project

A PCB for a 6x4 numpad with a row for four customizable macros.

TBA: an image of the final PCB in person! :-) TBA: link to firmware repository

A schematic of the matrix of switch connections.

The 3D modeling software Blender has many shortcuts that are only accessable using numpad shortcuts. Although these features are also accessable on Blender's UI, these shortcuts greatly accelerate the modeling process. However, my partner's keyboard is 65% and lacks a numpad. I wanted to design him a numpad that could solve this problem while using the keycaps and Alps switches he currently had. I also wanted to design the numpad with USB-C conectivity and a 4-key…

Numpad, from the project README
From the project README

Main components on the Numpad

ATmega32U4-A

Numpad bill of materials (BOM)

63 components, 37 distinct parts.

QtyPartRefs
1
ATmega32U4-A
U1
1
Crystal_GND24_Small
Y1
1
AVR-ISP-6
J1
1
Polyfuse_Small
F1
1
SW_Push
SW1
1
ESC
SW2
1
TAB
SW3
1
BACKSPACE
SW4
1
FN
SW5
1
NUM_LOCK
SW6
1
/
SW7
1
*
SW8
1
-
SW9
1
7/home
SW10
1
4/left
SW11
1
8/up
SW12
1
5
SW13
1
9/pgup
SW14
1
6/right
SW15
1
+
SW16
Show 17 more
QtyPartRefs
1
1/end
SW18
1
0/insert
SW19
1
2/down
SW20
1
3/pgdn
SW22
1
./delete
SW23
1
ENTER
SW24
1
HRO-TYPE-C-31-M-12
USB1
1
PRTR5V0U2X
D1
21
D
D2, D3, D4, D5, D6, D7, D8, D9 +13
1
60@100MHz
FB1
1
1uF
C1
3
0.1uF
C2, C3, C4
1
10uF
C5
2
22pF
C6, C7
2
10k
R1, R4
2
22
R2, R3
2
5.1k
R5, R6

Numpad design files

The KiCad project lives in the npwhl/numpad-pcb repository on GitHub; these links point at the commit this page was built from.

Numpad: common questions

What microcontroller does the Numpad use?

The Numpad is built around the ATmega32U4-A, from the AVR/Arduino family.

How big is the Numpad PCB?

The Numpad measures 76.2 × 118.8 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Numpad?

63 components, from 37 distinct parts. The full bill of materials is listed on this page.

Where can I download the Numpad design files?

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

Can I use the Numpad design in my own project?

The repository has no license, so all rights stay with npwhl. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the Numpad 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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