HardLabs

Opensolder

howie-j·opensolder·hardware/kicad/opensolder.kicad_pcb

Opensolder PCB layout, top view — open source STM32 board by howie-j
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About the Opensolder PCB

Opensolder is an open source STM32 PCB design by howie-j, published on GitHub under the GPL-3.0 license. It is a 2-layer board measuring 100 × 44 mm, with 63 components from 31 distinct parts.

Its main chip is the STM32F072CBTx, from the STM32 family. Other key parts include the VOS628A, L78L24_SOT89, Si8751, AP2111H-3.3 and MAX4238ASA. By type, the board carries 21 capacitors, 20 resistors, 8 ICs, 5 connectors, 3 diodes and 2 transistors.

It belongs with the displays & leds designs in this gallery.

From the project

Fully open source JBC T245-compatible soldering station

The unisolder project is very impressive, but way to complex and "universal" for my needs. Marco Reps built a cool C470 station that i liked the simplicity of, and this project is highly inspired by that.

The schematic is divided into three sheets: AC, Analog and MCU.

Zero cross detection is done with an AC optocoupler, and the current is limited by three 10k resistors (to reduce BOM items). This solution triggers the ZeroCross about 90uS prematurely, and that is compensated for in firmware.

Opensolder, from the project README
From the project README

Main components on the Opensolder

VOS628AL78L24_SOT89Si8751AP2111H-3.3MAX4238ASAOLEDSTM32F072CBTxPCT2075GV

Opensolder bill of materials (BOM)

63 components, 31 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
VOS628A
U1
1
L78L24_SOT89
U2
1
Si8751
U3
1
AP2111H-3.3
U4
1
MAX4238ASA
U5
1
OLED
U6
1
STM32F072CBTx
U7
1
PCT2075GV
U8
2
KIA50N06BD
Q1, Q2
1
Crystal_8MHz
Y1
1
AC_Input
J1
1
Hirose RPC1-12RB-6P(71)
J2
1
SWD
J3
1
UART
J4
1
Reset_Switch
J5
1
Fast 12A
F1
1
PDSE1-S24-S5-S
PS1
1
PEC11R-RotEnc
SW2
1
MB6S-TP
D1
2
S1M
D2, D3
Show 11 more
QtyPartRefs
1
47u
C1
5
1u
C2, C3, C4, C6, C11
10
100n
C5, C8, C12, C13, C14, C15, C16, C17 +2
3
10n
C7, C20, C21
2
20p
C9, C10
10
10k
R1, R2, R3, R4, R5, R9, R11, R13 +2
1
22k
R6
1
100
R7
1
390
R8
5
100k
R10, R12, R14, R16, R18
2
3k3
R19, R20

Opensolder design files

The KiCad project lives in the howie-j/opensolder repository on GitHub; these links point at the commit this page was built from.

Opensolder: common questions

What microcontroller does the Opensolder use?

The Opensolder is built around the STM32F072CBTx, from the STM32 family.

How big is the Opensolder PCB?

The Opensolder measures 100 × 44 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Opensolder?

63 components, from 31 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 Opensolder design files?

From the howie-j/opensolder 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 Opensolder design in my own project?

Yes, under the terms of its GPL-3.0 license, which howie-j chose for the repository.

Can I test firmware for the Opensolder without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug STM32 firmware against it before you order a PCB.

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