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RS485-Gassensor

Sarbf1·Gas-sens_Rs-485·PCB/RS485-Gassensor/RS485-Gassensor.kicad_pcb

RS485-Gassensor PCB layout, top view — open source STM32 board by Sarbf1

About the RS485-Gassensor PCB

RS485-Gassensor is an open source STM32 PCB design by Sarbf1, published on GitHub under the Apache-2.0 license. It is a 2-layer board measuring 92 × 46 mm, with 71 components from 33 distinct parts.

Its main chip is the STM32G031K8Tx, from the STM32 family. Other key parts include the MCP6002-xMS, OKI-78SR-5_1.5-W36-C, AP2127N-3.3, LT1785xS8 and SHT4x. By type, the board carries 30 resistors, 16 capacitors, 10 connectors, 8 ICs, 2 diodes and 1 switch.

It belongs with the sensors designs in this gallery.

From the project

a compact, cheap gas sensor with RS-485 connectivity

A STM32G031K8 is the logical unit. Is is cheap and readily available. The very most components use standart fooprints. Thus, they are easily exchangeble in case of a shortage. All parts are SMD, except for the Sensors, DCDC converter and Connectors. All PCB components can be sourced by Mouser, except for the Gas Sensor. For developement purposes (TAG v0.1) a gas sensor type MQ-X were used (MQ-7 and MQ-135) TAG v0.2 makes use of the nemoto sensor, that uses low current and is more gas specific. The I2C conection gives a possibility, to further extend with more sensors, such as the Sensirion…

RS485-Gassensor, from the project README
From the project README

Main components on the RS485-Gassensor

STM32G031K8TxMCP6002-xMSOKI-78SR-5_1.5-W36-CAP2127N-3.3LT1785xS8SHT4xAD8676

RS485-Gassensor bill of materials (BOM)

71 components, 33 distinct parts.

QtyPartRefs
1
STM32G031K8Tx
U1
2
MCP6002-xMS
U3, U6
1
OKI-78SR-5_1.5-W36-C
U4
1
AP2127N-3.3
U5
1
LT1785xS8
U7
1
SHT4x
U8
1
AD8676
U9
2
Screw_Terminal_01x08
J1, J3
1
Screw_Terminal_01x04
J2
2
Screw_Terminal_01x06
J4, J5
2
Conn_01x02_Pin
J6, J7
2
Conn_01x03
J8, J9
1
Conn_01x02
J10
4
R_Poti_1K
RV1, RV2, RV3, RV4
1
SW_DIP_x06
SW1
1
SM712_SOT23
D1
1
IR26-21C_L110_TR8
D2
1
CAP4.7uF
C1
1
CAP100nF
C2
1
CAP10uF
C3
Show 13 more
QtyPartRefs
2
470nF
C4, C8
1
CAP22uF
C5
4
CAP1uF
C6, C9, C10, C12
2
CAP100nF
C7, C16
4
CAP1uF
C11, C13, C14, C15
13
R10K
R1, R2, R3, R4, R5, R6, R7, R10 +5
2
10
R8, R26
5
1k
R9, R15, R17, R27, R28
2
R470
R11, R21
1
R100
R13
3
2.2k
R14, R16, R19
2
R1K
R18, R20
2
10KR
R22, R23

RS485-Gassensor design files

The KiCad project lives in the Sarbf1/Gas-sens_Rs-485 repository on GitHub; these links point at the commit this page was built from.

RS485-Gassensor: common questions

What microcontroller does the RS485-Gassensor use?

The RS485-Gassensor is built around the STM32G031K8Tx, from the STM32 family.

How big is the RS485-Gassensor PCB?

The RS485-Gassensor measures 92 × 46 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the RS485-Gassensor?

71 components, from 33 distinct parts. The full bill of materials is listed on this page.

Where can I download the RS485-Gassensor design files?

From the Sarbf1/Gas-sens_Rs-485 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the RS485-Gassensor design in my own project?

Yes, under the terms of its Apache-2.0 license, which Sarbf1 chose for the repository.

Can I test firmware for the RS485-Gassensor 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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