2 layers100 × 100 mm Gas sensor, the printed circuit board in 3D

Gas sensor

Arduino compatible gas sensor

Size: 100 × 100 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 37
Nets: 34
Pads: 158
Tracks, vias: 389, 43
Pours: 2
Routed: Yes
KiCad: KiCad 5 (file 20171130)
Created: 4 Dec 2018
Updated: 31 May 2019

Overview

Gas sensor is an open-source printed circuit board by Hackuarium, from the Hackuarium/gas-sensor repository on GitHub. It is a 2-layer board of 100 × 100 mm with 37 parts on 34 nets, routed with 389 tracks and 43 vias.

It is built around the ATMEGA328P-AU, DHT22 and DS18B20, with the MQ-4 among its other parts. Its parts include 7 capacitors, 7 connectors, 6 resistors, 4 ICs and 3 diodes. It belongs with the sensors and measurement boards and the AVR (ATmega, ATtiny) boards of this library.

Main components

README

README.md

gas-sensor

The goal is to create a box allowing the determination of the gas composition of a bioreactor. The sensor that will be available are: CO2 (MH-Z19), H2 (MQ-8) and methane (MQ-4) as well as temperature (DS18B20) and humidity (DHT-22).

The board will be compatible with arduino Lilapad Pro using a dedicated PCB.

Need to compensate for humidity and temperature ???

https://forum.arduino.cc/index.php?topic=433045.0

Cloning the project

This project uses SUBMODULES

In order to clone use:

git clone --recurse-submodules https://github.com/hackuarium/gas-sensor

To update the submodules

git submodule update --recursive --remote

Sensors

name_pin	function	model		Arduino library
CH4	CH4	MQ-4
H2	H2	MQ-8
CO2	CO2	MH-Z19	3.3v (for RX / TX) + 5v!!!!	https://github.com/crisap94/MHZ19
TEMP	temperature	DS18B20
HUM	humidity	DHT-22		https://github.com/adafruit/DHT-sensor-library

Gaz sensor: http://www.china-total.com/Product/meter/gas-sensor/Gas-sensor.htm

Gaz sensor on sparkfun: https://www.sparkfun.com/products/8891 https://www.sparkfun.com/products/9404

Gaz sensor on mysensors: https://www.mysensors.org/build/gas

Drying the air / pumping Particulate or Coalescing Filters http://www.pneumaticplus.com/pneumaticplus-saf4000-series-particulate-air-filter-1-2-npt-with-bracket/ https://www.aliexpress.com/item/15L-M-12V-dc-electric-diaphragm-brush-small-air-compressor-pump/1790013118.html

Fans

https://www.pelonistechnologies.com/micro-fans

Pneumatic https://www.alibaba.com/product-detail/A102-China-sup

Pinout

n° Arduino	port	pin
A0	PC0	A0	H2
A1	PC1	A1	H2_ON
A2	PC2	A2	CO2_RX
A3	PC3	A3	CO2_TX
A4	PC4	SDA	Slave I2C
A5	PC5	SCL	Slave I2C
A6	ADC6	A6	CH4
A7	ADC7	A7	CH4_ON
0	PD0	RX	FTDI
1	PD1	TX	FTDI
2	PD2	D2	/
3	PD3	D3	PWM_MH-Z19	PWM
4	PD4	D4	TEMPERATURE
5	PD5	D5	HUMIDITY	PWM
6	PD6	D6	LCD RS	PWM
7	PD7	D7	/
8	PB0	D8	LCD E
9	PB1	D9	LCD LED	PWM
10	PB2	D10	LCD1	PWM
11	PB3	MOSI D11	LCD2	PWM
12	PB4	MISO D12	LCD3
13	PB5	SCK D13	LCD4

n.b: Two pins (PD2 and PD7) are free and could be used to add a fourth sensor.

Power supply

plug for 5V
MCP1703-33 for µC power supply

Schematic

Here is the schematic of the main components of the project:

ATMega328P:

Sensors:

Others (LCD, crystal and voltage regulator):

List of components

Type	Value	Quantity	Footprint
Resistor	1M	1	0805 Handsolder
Resistor	10k	2	0805 Handsolder
Resistor	4.7k	2	0805 Handsolder
Resistor	4.7	1	0805 Handsolder
Potentiometer		1	TRIM_3362R-1-222
Capacitor	10µF	2	0805 Handsolder
Capacitor	100nF	3	0805 Handsolder
Capacitor	18pF	2	0805 Handsolder
Diode Shottky		3	D_SOD-123
BSP75		2	SOT-223-3_TabPin3
Crystal	8Mhz	1	Crystal_SMD_5032 Handsolder
MCP-1703A		1	SOT-23
ATMega328P-AU		1	TQFP-32_7x7mm_P0.8mm
5V power source		1	BarrelJack_Horizontal
RJ12		1	RJ12_Amphenol_54601
LCD Screen		1	WC1602A
MHZ-19 (CO2)		1	footprints: MHZ-19
MQ-4 (CH4)		1	footprints: MQ-4
MQ-8 (H2)		1	footprints: MQ-8
DHT22 (Hum)		1	footprints: DHT-22_HOR
DS18B20 (Temp)		1	TO-92_Inline

Inspiration for PCB

https://github.com/Hackuarium/esp-12e/tree/master/kicad
- ICSP - TAG connect - take care of pin mapping !
- RJ12 - 6P6C
- FTDI232
- LCD: WC1602A

Get inspired from scale board

Category and platform

Sensors and measurement AVR (ATmega, ATtiny)

Project files

Show this board on your page

https://pcbkit.io/boards/Hackuarium/gas-sensor

The board's own page, for a message or a post.

Source

Repository: Hackuarium/gas-sensor
Board file: kicad/gas-sensor.kicad_pcb
Commit: 5f2dd29
Licence: Not stated

Parts

Qty	Value	Footprint	References
4	hole	MountingHole:MountingHole_3.2mm_M3	J3, J4, J5, J6
3	100nF	Capacitor_SMD:C_0805_2012Metric_Pad1.15x1.40mm_HandSolder	C4, C5, C6
3	D_Schottky	Diode_SMD:D_SOD-123	D1, D2, D3
2	10k	Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder	R3, R5
2	10u	Capacitor_SMD:C_0805_2012Metric_Pad1.15x1.40mm_HandSolder	C3, C7
2	18pF	Capacitor_SMD:C_0805_2012Metric_Pad1.15x1.40mm_HandSolder	C1, C2
2	BSP75	Package_TO_SOT_SMD:SOT-223-3_TabPin3	Q1, Q2
1	1M	Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder	R1
1	4,7	Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder	R2
1	4,7k	Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder	R6
1	4.7k	Resistor_SMD:R_0805_2012Metric_Pad1.15x1.40mm_HandSolder	R4
1	5V_Power_source	Connector_BarrelJack:BarrelJack_Horizontal	J7
1	8MHz	Crystal:Crystal_SMD_5032-2Pin_5.0x3.2mm_HandSoldering	Y1
1	ATmega328P-AU	Package_QFP:TQFP-32_7x7mm_P0.8mm	U2
1	Conn FT232RL	Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical	J1
1	DHT22	footprints:DHT22_HOR	U3
1	DS18B20	Package_TO_SOT_THT:TO-92_Inline	U1
1	ICSP	Connector:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical	SP1
1	LOGO	footprints:hackuarium	G1
1	MCP1703A-1202_SOT23	Package_TO_SOT_SMD:SOT-23	U4
1	MH-Z19	footprints:MH-Z19	GS3
1	MQ-4	footprints:MQ-4	GS1
1	MQ-8	footprints:MQ-8	GS2
1	RJ12	Connector_RJ:RJ12_Amphenol_54601	J2
1	R_POT	TRIM_3362R-1-222:TRIM_3362R-1-222	RV1
1	WC1602A	Display:WC1602A	DS1

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Questions

How big is the Gas sensor PCB?

It measures 100 × 100 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Gas sensor use?

37 parts, built around the ATMEGA328P-AU, DHT22, DS18B20 and MQ-4. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Gas sensor KiCad files?

From the Hackuarium/gas-sensor repository on GitHub, at the commit this page was made from: the board is kicad/gas-sensor.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Gas sensor design in my own project?

Its repository states no licence, so its author keeps all rights: ask Hackuarium before reusing the design.