SMARTPHONE BASED OPTICAL SENSOR FOR ENVIRONMENTAL APPLICATION

Abstract

In the recent years there has been a huge development on the detection devices using smartphone that are reliable, easy-to-use, and low cost. In this work, a smartphone based optical sensor is constructed by implementing an external light source, a collimating
lens, a diffraction grating, and a CMOS chip of a smartphone as a detector. The construction allows the device to function with an optical bandwidth of 300 nm (from 400 to 700 nm) and its resolution of 0.26 nm/pixel. It can be used both for measuring the absorption, transmission emission spectrum. As a proof of concept, the optical sensor using smartphone is then applied to investigate concentration of methylene blue (MB), a reactive dye in wastewater from textile industry. Despite of its cost-effectiveness, the sensor exhibits reliable results, which can be considerably comparable with that of laboratory instrument.