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CFWatch

Dragon863·CFWatch·PCB/Watch.kicad_pcb

CFWatch PCB layout, top view — open source Microchip SAM board by Dragon863
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About the CFWatch PCB

CFWatch is an open source Microchip SAM PCB design by Dragon863, published on GitHub. It is a 2-layer board measuring 37 × 39.8 mm, with 47 components from 25 distinct parts.

Its main chip is the ATSAMD21E18A-A, from the Microchip SAM family. Other key parts include the MCP73831-2-OT and TPS63900. By type, the board carries 18 resistors, 6 capacitors, 4 transistors, 3 ICs, 3 switches and 3 diodes.

It belongs with the wearables designs in this gallery.

From the project

A watch I built from scratch, inspired by cassette futurism

CFWatch is a project that I've been wanting to build for years now. I've always dreamed of building a watch, but was never quite sure where to start - sure, the pinetime and other hackable watches were really cool, but they never quite felt "personal" or quite reflective of the stuff I enjoy. Eventually I decided I'd just build my own, but I didn't really have the knowledge or skills to do so until very recently, so when highway came along I decided it was finally time! The "CF" in "CFWatch" came from r/cassettefuturism, a huge source of design inspiration for this

CFWatch, from the project README
From the project README

Main components on the CFWatch

MCP73831-2-OTTPS63900ATSAMD21E18A-A

CFWatch bill of materials (BOM)

47 components, 25 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
MCP73831-2-OT
U1
1
TPS63900
U2
1
ATSAMD21E18A-A
U7
4
2N3906
Q1, Q2, Q3, Q4
1
32768HZ
32768Hz
Y2
1
USB_C_RECEPTACLE_USB2.0_14P
USB_C_Receptacle_USB2.0_14P
J1
1
Battery_Cell
BT1
1
10uF
C_IN1
1
22uF
C_OUT1
4
KCSA02-105
Dig1, Dig2, Dig3, Dig4
3
SW_Push
SW1, SW3, SW4
2
C191023
D
D1, D2
1
LED
D3
1
2.2UH
2.2uH
L1
2
1UF
1uF
C1, C5
1
1UF
1u
C7
1
4.7U
4.7u
C8
2
CL21C100JBANNNC
10pF
C9, C10
1
27K
27k
R1
2
5.1K
5.1k
R2, R3
Show 5 more
QtyPartRefs
1
220
R4
1
10K
10k
R5
8
150
R6, R7, R8, R9, R13, R14, R15, R16
4
390
R17, R18, R19, R20
1
36.5K
36.5k
R21

CFWatch design files

The KiCad project lives in the Dragon863/CFWatch repository on GitHub; these links point at the commit this page was built from.

CFWatch: common questions

What microcontroller does the CFWatch use?

The CFWatch is built around the ATSAMD21E18A-A, from the Microchip SAM family.

How big is the CFWatch PCB?

The CFWatch measures 37 × 39.8 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the CFWatch?

47 components, from 25 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 CFWatch design files?

From the Dragon863/CFWatch 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 CFWatch design in my own project?

The repository has no license, so all rights stay with Dragon863. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the CFWatch without the hardware?

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

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