0x0F: 8 ch Taguchi gas sensor array DIN100

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Background

Please see the e-nose project page for an elaborate description as well as practical examples.

Function

This PCB breaks out the connections to eight Taguchi type gas sensors and effectively forms an array of sensors; the sensor part of an electronic nose.

The board will accomodate both the more expensive 6-pin Figaro Engineering-type gas sensors as well as the cheaper 6-pin products from e.g. HW Sensor.

The optional two onboard four channel 8 bit analogue-to-digital converter have built-in OneWire communication, which allows the response of the eight Taguchi gas sensors to be read remotely over a very long wire. Four additonal digital temperature transmitters (DS18B20) allow for reliable monitoring of an addtional environmental parameter over the OneWire bus. The current consumption is roughly 160 mA per Taguchi gas sensor, so the entire board consumes around 1.300 mA @ 5 VDC or 6.5 W depending on the type of gas sensor. The DS2401 identifies the printed circuit board if other OneWire components with unique MAC addresses are not mounted. Sensitivity/baseline of each Taguchi gas sensor can be manipulated by adjusting the respective trimpotentiometers. Headers, 2×10, are available for expansion modules with external analogue-to-digital conversion as well as sensor heater element excitation.

An external Arduino Nano can be used together with the 0x11 design.

License terms
The 0x0F design is published under the Creative Commons Unported 3.0 License.  I do not profit from this design, neither should you. You are welcome to adapt, modify, and redistribute this design as long as the license terms are respected.

Physical size of PCB

Circular, 100 mm (diameter). Double-sided.

Rendering and photos

DipTrace 3D rendering, frontside with components (rev. 0)

DipTrace 3D rendering, backside  with components (rev. 0)

Photo of assembled PCB, backside (rev. 1)

Photo of assembled PCB, frontside (rev. 1)

Photo of assembled e-nose system (rev. 1)

 

Bill of materials

8 pcs. Taguchi gas sensor

8 pcs. Taguchi gas sensor sockets

8 pcs. trimpotentiometer, 50k, form factor 3296W

2 pcs. 2×10 male pin header (2.54 mm / 0.1″)

1 pcs. 2×8 male pin header (2.54 mm / 0.1″)

8 pcs. jumper (2.54 mm / 0.1″), locally sets VHx equal to VCC

1 pcs. resistor, 715R (current limiter for LED)

1 pcs. LED, 1206

 

optional (OneWire)

2 pcs. DS2450 four channel 8 bit analogue-to-digital converter

1 pcs. capacitor, 100 nF, form factor 1206 (SMD)

2 pcs. resistor 4k7, 1206 (pull-up for DQ)

4 pcs. DS18B20, digital temperature transmitter, TO-92

4 pcs. 1×2 male pin header (2.54 mm / 0.1″)

4 pcs. jumper (2.54 mm / 0.1″)

Estimated cost

Eight Taguchi gas sensors, two 2×4 connectors, and eight trimpotentiometers should not cost more than EUR 10,- depending on the type of sensors. The analogue-to-digital converter can be pricy, but it gives immense flexibilty, when monitoring remote locations.

Downloads

DipTrace v. 3.0.0.0 PCB design file: 0x0FRev1 Circular 8ch TGS – ratlined-public

Gerber files: 0x0Frev1

Sensor datasheet, HW Sensor: MQ-2

Sensor datasheet, HW Sensor: MQ-3

Sensor datasheet, HW Sensor: MQ-4

Sensor datasheet, HW Sensor: MQ-5

Sensor datasheet, HW Sensor: MQ-6

Sensor datasheet, HW Sensor: MQ-7

Sensor datasheet, HW Sensor: MQ-8

Sensor datasheet, HW Sensor: MQ-9

Sensor datasheet, HW Sensor: MQ131

Sensor datasheet, HW Sensor: MQ135

Sensor datasheet, HW Sensor: MQ136

Sensor datasheet, HW Sensor: MQ137

Sensor datasheet, HW Sensor: MQ138

Links

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