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Cirrus40

schuay·cirrus40·pcb/pcb.kicad_pcb

Cirrus40 PCB layout, top view — open source board by schuay
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About the Cirrus40 PCB

Cirrus40 is an open source PCB design by schuay, published on GitHub under the CC-BY-4.0 license. It is a 2-layer board measuring 133.2 × 91.7 mm, with 53 components from 11 distinct parts.

Other key parts include the SRV05-4 and ProMicro. By type, the board carries 21 diodes, 18 relays, 4 inductors, 3 ICs, 2 switches and 1 connector.

It belongs with the keyboards designs in this gallery.

From the project

A 40% split mechanical keyboard with a focus on usable rotary encoders

The Cirrus40 is a 40% split mechanical keyboard, with an ortholinear layout and a focus on usable rotary encoders.

- A 3x thumb cluster where each key is equally usable and comfortable to reach. - Rotary encoders under the palms are nicely reachable without moving hands from the homerow position. One-handed use together with homerow modifiers (think: switching tabs, workspaces; word-by-word navigation, selection, and deletion). Hardware debouncing for the perfect input signal; no more missed transitions. - A full 3d printed case protects the internals. - An optional 3d printed 30deg tenting…

Cirrus40, from the project README
From the project README

Main components on the Cirrus40

SRV05-4ProMicro

Cirrus40 bill of materials (BOM)

53 components, 11 distinct parts — part numbers from the project's BOM.

QtyPartRefs
2
SRV05-4
U1, U2
1
ProMicro
U3
1
USB_C_Receptacle_USB2.0_16P
J1
1
8kOhm
8.2kΩ
1
10kOhm
10kΩ
1
470nF
100nF
1
RotaryEncoder_Switch_MP
ENC1
18
SW_Push
K1, K2, K3, K4, K5, K6, K7, K8 +10
2
MSK12C02
S1, S2
21
DIODE
D1, D2, D3, D4, D5, D6, D7, D8 +13
4
Ferrite Bead
FB1, FB2, FB3, FB4

Cirrus40 design files

The KiCad project lives in the schuay/cirrus40 repository on GitHub; these links point at the commit this page was built from.

Cirrus40: common questions

How big is the Cirrus40 PCB?

The Cirrus40 measures 133.2 × 91.7 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Cirrus40?

53 components, from 11 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 Cirrus40 design files?

From the schuay/cirrus40 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 Cirrus40 design in my own project?

Yes, under the terms of its CC-BY-4.0 license, which schuay chose for the repository.

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