Polynomial regression of multiple sensing variables for high-performance smartphone colorimeter

A robust and adaptive smartphone-based colorimetric sensing platform is reported. It utilizes multiple regression analysis to address nonlinear concurrent variations of variables. The instrument can perform measurement with improved accuracy over a wide range where both color intensity information signal varies independently often simultaneously. the smartphone in-built flash LED ( λ = 400–700 nm) illuminate test sample phone’s CMOS camera as detector, collecting digitizing reflected light from that sample. 3D printing technology used fabricate specially designed optical enclosure performs diffuser, neutral density filter, reflector ensure constant uniform illumination platform. Thus, an ultra-low-cost (< 3 USD) portable diagnostic system becomes feasible along easy-to-use customized android app adaptable for multi-analyte assays. performance validated by: (a) monitoring concentration laser dye, (b) measuring pH drinking water, (c) quantifying chlorine shrimp ponds.