Perancangan dan Pembuatan Alat Pendeteksi Mikroplastik Berbasis IoT Menggunakan Sensor Optik Photodioda BPW34

Abstract

Microplastics are plastic particles smaller than 5 mm that have become one of the main pollutants in water bodies. The Deli River in Medan City is one of the areas affected due to high domestic waste and poor waste management. This study aims to design a microplastic detection tool based on the Internet of Things (IoT) using a BPW34 photodiode sensor. The system works by measuring the infrared light reflectance from plastic particles in the water, then transmitting the data in real-time to the ThingSpeak platform. This tool consists of the BPW34 sensor, which is sensitive to the 320–1100 nm spectrum, combined with a halogen lamp, an IR720 filter, an LM358 amplifier, and an ESP32 microcontroller. The sensor calibration showed an average error of only 0.94%. Testing was conducted at three points on the Deli River (upstream, middle, downstream) at four different times over three days. The highest reflectance was recorded at the downstream point, with a peak reflectance of 87.1% at an intensity of 6976 Lux during hot weather, and the lowest at the upstream point with 9.5% at 765 Lux during light rain. This tool has proven effective in detecting microplastics in the field, with easy real-time data monitoring through IoT. This system offers a practical, affordable, and potential solution for sustainable water quality monitoring, especially in areas with limited laboratory facilities.