Optical Sensor Based on Redox-Active Tetrazolium / Pluronic Nanoparticles - Device Design

The project contains the HW, FW and SW needed to build and operate the LED/photodiode colorimetric optical devices for real time detection of NO₂, through the color-responsive nanocomposite membrane, presented in the work “Oxidant Optical Sensor Based on Redox-Active Tetrazolium / Pluronic Nanoparticles Embedded in PDMS Membranes”, by Esteban Araya-Hermosilla, Rodrigo Araya-Hermosilla, Francesco Visentin, Francesco Picchioni, Andrea Pucci and Virgilio Mattoli, published on MDPI Chemosensors, 10(6): 213 (2022) [DOI: 10.3390/chemosensors10060213]. All material is available as open source. This is part of Supporting Information of the aforementioned paper.

The overall system assembly is schematized in “System Overview.pdf” file.

The electronic conditioning of the photodiode and the interface with a PC through USB connection is done by using a low-cost system-on- chip microcontroller board, PSoC CY8CKIT-059 for Cypress. Photodiode is directly connected to the board; additional electronic components are not needed.

Firmware for programming the board has been developed with PSoC Creator 4.3 (Cypress), and can be found in in file “ColorPhotometerFW.zip”. The board has a firmware programmer included, directly using the USB connection.

The software for device interface has been developed in Visual Basic .NET (Visual Studio 2017) and can be found in file “ColorPhotometer.zip”.

The STL files of the enclosing case for 3D printing are in the file “CaseColorPhotometer.zip”.

To complete the integration, 3 optical components (lens, mirror and beam splitter) are required, as described in the main text and in “System Overview.pdf” file. In the original design, the LED and the Photodiodes are supported by small pieces of PCB board (7 x 7 x 1.6 mm³) for easiness of housing in the case and wiring.