5 open source boards using the U1
Real designs built with the U1, from public GitHub projects: a quick way to see how others power, decouple and connect it. Each board comes with its KiCad files, full parts list and a render — and you can simulate its firmware on HardLabs.
RP2040/RP2350GPSDO
pwengel
97.4 × 75.4 mm115 parts2LNo license2- schematic only · 11 partsAVR/Arduino
VArm6
VJPatz
11 partsMIT2 
LR P3A
Lightiam
167 × 111.2 mm44 parts16LBSD-3-Clause0
RP2040/RP2350GPSDO DIP
126.1 × 87.1 mm86 parts2LNo license2
Edge io ring evt0
gunnchOS3k
28 × 10 mm14 parts2LMIT0
The U1 in open source designs
The gallery holds 5 open source boards using the U1 from 4 GitHub repositories; a typical one measures about 111.8 × 81.3 mm and carries around 44 components.
75% are two-layer designs, the rest use four layers or more, and 60% carry an open source license.
The most starred is GPSDO by pwengel.
Microcontrollers on boards using the U1
What boards using the U1 are built for
U1: common questions
Where can I find a U1 reference design?
Each of the 5 boards on this page is a real design using the U1. Open one to see how it is wired up, with the full BOM, a render of the layout and links to its KiCad files.
What parts are used alongside the U1?
The U2, U3, U4, U5 and U6 appear in the most repositories here.
Which microcontrollers do boards using the U1 use?
Most are built on RP2040/RP2350 (2) and AVR/Arduino (1).
How big is a typical board using the U1?
The median is 111.8 × 81.3 mm, and 75% are two-layer designs.
What is the most popular open source board using the U1?
By GitHub stars, GPSDO by pwengel, with 2 stars.
Can I simulate one of these boards using the U1 before building it?
Yes. HardLabs turns a board's netlist and BOM into a working simulation, so you can boot and test firmware against it with no hardware on your desk.