HardLabs

Uni-S3

OatMealXXII·Uni-S3

Uni-S3 PCB layout, top view — open source ESP32 board by OatMealXXII

About the Uni-S3 PCB

Uni-S3 is an open source ESP32 PCB design by OatMealXXII, published on GitHub under the MIT license. It is a 2-layer board measuring 100 × 100 mm, with 31 components from 27 distinct parts.

Its main chip is the ESP32-S3-WROOM-1, from the ESP32 family. Other key parts include the AMS1117-3.3 and MT3608. By type, the board carries 11 connectors, 5 diodes, 5 resistors, 4 capacitors, 3 ICs and 1 fuse.

It belongs with the iot & wireless and power & battery designs in this gallery.

From the project

A highly flexible ESP32-S3 universal controller board featuring robust power management (5V Boost & 3.3V LDO) and Type-C interface, designed for maker projects.

It provides a solid foundation—a reliable power system and plenty of accessible I/O ports via JST connectors—allowing you to connect external sensors, audio modules, or peripherals exactly how your project needs them.

I designed this V1.0 board using KiCad to learn about PCB layout, DRC routing, and power delivery. It's fully open-source—feel free to use it, modify it, or give me feedback!

Uni-S3, from the project README
From the project README

Main components on the Uni-S3

ESP32-S3-WROOM-1AMS1117-3.3MT3608

Uni-S3 bill of materials (BOM)

31 components, 27 distinct parts.

QtyPartRefs
1
ESP32-S3-WROOM-1
U1
1
AMS1117-3.3
U2
1
MT3608
U3
1
USB_C_Receptacle_USB2.0_16P
J1
1
JST 1
J2
1
JST2
J3
1
JST3
J4
1
JST4
J5
1
UART_MAIN
J6
1
UART_AUX
J7
1
GPIO_EX1
J8
1
GPIO_EX2
J9
1
DC_In
J10
1
Battery
J11
1
Polyfuse
F1
1
SW_SPDT
SW1
1
D_TVS
D1
2
D_Schottky
D2, D3
1
1N5819WS
D4
1
D_Schottky
D5
Show 7 more
QtyPartRefs
1
22uH
L1
2
10uF
C1, C2
2
22uF
C3, C4
2
5.1k
R1, R2
1
10k
R3
1
150k
R4
1
20k
R5

Uni-S3 design files

The KiCad project lives in the OatMealXXII/Uni-S3 repository on GitHub; these links point at the commit this page was built from.

Uni-S3: common questions

What microcontroller does the Uni-S3 use?

The Uni-S3 is built around the ESP32-S3-WROOM-1, from the ESP32 family.

How big is the Uni-S3 PCB?

The Uni-S3 measures 100 × 100 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Uni-S3?

31 components, from 27 distinct parts. The full bill of materials is listed on this page.

Where can I download the Uni-S3 design files?

From the OatMealXXII/Uni-S3 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Uni-S3 design in my own project?

Yes, under the terms of its MIT license, which OatMealXXII chose for the repository.

Can I test firmware for the Uni-S3 without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.

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