ABSTRACT
In this work, we have designed, implemented, and characterized an IoT-enabled optical platform that serves as a highly efficient colorimetric analyzer for disposable rapid diagnostic test kits. We have taken color images of the test chip using an external camera module connected to an IoT-enabled single-board mini-computer, which are then analyzed using an image processing algorithm. To prevent image burning and to reduce the impact of ambient lighting, we have proposed a unique light-diffusing model and have maintained a strategic distance within the white acrylic imaging enclosure of the platform. In order to ensure even and uniform distribution of light on the sample within the platform, we have carried out a study with the incorporation of a highly bright single LED, an LED array, and attaching a PDMS-made light diffuser on the LED array at varying light incident angles on custom-made single-channel test kits containing blood hematocrit. Finally, based on the optimized lighting conditions, we have successfully applied the proposed platform for the detection of blood hematocrit, β-hCG, and SARS-CoV-2 antigen, and were able to identify their different levels of concentration. Since the device is portable in size and cost-effective to implement, it can also be used for analyzing other biomarkers in resource-limited communities for point-of-care (POC) applications.