0x0D: 32 ch Taguchi array heater switcher




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


This PCB allows each heater voltage VH for a 32 ch Taguchi gas sensor array to be controlled individually. Heaters can either be turned on and off via jumpers or be controlled over the I2C bus via the MCP23017 GPIO port expander.

License terms
The 0x0D 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

100 mm (width) by 50 mm (height). Double-sided.

Rendering and photos

DipTrace 3D rendering, frontside without components


DipTrace 3D rendering, frontside with components


Photo of the assembled PCB


Bill of materials

2 pcs. MCP23017 port expander, SOIC-28 (300 mil)

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

4 pcs. ULN2803LW eight channel Darlington array (SMD)

4 pcs. I2C pullup resistor, 3K9 , form factor 1206

2 pcs. 3×3 pin header (3 rows each 3 pins) male header, 2.54 mm pitch

6  pcs. jumper, 2.54 mm pitch

1 pcs. 80-pin (2 rows each 40 pins) 2.00 mm pitch male header, angled 90°

1 pcs. DS2401Z

Estimated cost

Four ULN2803LW, two MCP23017, headers, and jumpers should not cost more than EUR 15,- (32 ch).


Schematic PDF: 0x0Drev1_schematic

DipTrace v. 3 schematic file: 0x0Drev1_schematic

DipTrace v. 3 PCB design file: 0x0D-ratlined-public

Gerber files: 0x0Drev1


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