HardLabs

Sim multiplexer

0x178F·sim-multiplexer·hardware/X512_A_R1.0.kicad_pcb

Sim multiplexer PCB layout, top view — open source STM32 board by 0x178F
Simulate this board

About the Sim multiplexer PCB

Sim multiplexer is an open source STM32 PCB design by 0x178F, published on GitHub under the Apache-2.0 license. It is a 4-layer board measuring 436 × 70 mm, with 150 components from 30 distinct parts.

Its main chip is the STM32F103C8T6, from the STM32 family. Other key parts include the 74HC4051PW,118, SIM800C, LM2596 and MAX485E. By type, the board carries 56 capacitors, 35 connectors, 31 resistors, 20 ICs, 3 LEDs and 3 diodes.

It belongs with the dev boards & breakouts designs in this gallery.

From the project

Prototype board that switches one GSM modem across 32 SIM slots. STM32 slave, ESP32 master over RS-485, REST API and web dashboard over Ethernet.

This project connects one GSM modem to 32 SIM card slots. Analog multiplexers do the switching. An ESP32 board controls it over RS-485 and runs a web page and a REST API over Ethernet.

Project status: prototype, R1.0. This is not a product. It is not for sale. It has no type approval. The circuit ran on a breadboard and it worked, but nobody has ever made the board in hardware/. So anything that depends on the board layout is not tested.

Sim multiplexer, from the project README
From the project README

Main components on the Sim multiplexer

74HC4051PW,118SIM800CSTM32F103C8T6LM2596MAX485E

Sim multiplexer bill of materials (BOM)

150 components, 30 distinct parts — part numbers from the project's BOM.

QtyPartRefs
16
74HC4051PW,118
74HC4051PW
Nexperia
U1, U2, U3, U4, U5, U6, U7, U8 +8
1
SIM800C
U17
1
STM32F103C8T6
U18
1
LM2596
U19
1
MAX485E
U20
1
BC817-40
Q1
32
L-KLS1-SIM-030-6P-1-R
SIM_6P
KLS Electronic
J1, J2, J3, J4, J5, J6, J7, J8 +24
2
1757242
MSTBA_2P
Phoenix Contact
J33, J35
1
132134
SMA
Amphenol
J34
1
OPEN
JP1
1
RED
LD1
1
GREEN
LD2
1
HL-AF-5060H248BS36FU76GC-S1
HLAF5060H248BS36FU76GCS1
HONGLITRONIC
LD3
1
M7-DC
M7
DC CORP.
D1
2
MBRA340T3G
MBRA340
ONS
D2, D3
32
22NF/25V
22nF/25V
C1, C2, C3, C4, C5, C6, C7, C8 +24
16
100nF/25V
C33, C34, C35, C36, C37, C38, C39, C40 +8
1
100UF/16V
100uF/16V
C49
1
2200UF/16V
2200uF/16V
C50
1
1UF/16V
1uF/16V
C51
Show 10 more
QtyPartRefs
2
100NF/25V
100nF/25V
C54, C55
2
10UF/16V
10uF/16V
C57, C59
1
100NF/50V
100nF/50V
C58
3
1k
R1, R3, R22
4
470R
R2, R12, R26, R31
12
10k
R7, R8, R9, R27, R28, R29, R30, R32 +4
2
100R
R11, R13
6
10K
10k
R14, R18, R20, R21, R23, R24
3
51R
R15, R16, R17
1
120R
R25

Sim multiplexer design files

The KiCad project lives in the 0x178F/sim-multiplexer repository on GitHub; these links point at the commit this page was built from.

Sim multiplexer: common questions

What microcontroller does the Sim multiplexer use?

The Sim multiplexer is built around the STM32F103C8T6, from the STM32 family.

How big is the Sim multiplexer PCB?

The Sim multiplexer measures 436 × 70 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Sim multiplexer?

150 components, from 30 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 Sim multiplexer design files?

From the 0x178F/sim-multiplexer 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 Sim multiplexer design in my own project?

Yes, under the terms of its Apache-2.0 license, which 0x178F chose for the repository.

Can I test firmware for the Sim multiplexer 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.

Similar boards