Analisis Pengaruh Suhu terhadap Kinerja Sensor Optik pada Alat Pendeteksi Mikroplastik Berbasis IoT: Studi pada Sungai Deli Medan

Abstract

Water temperature plays a crucial role in influencing the physical properties of microplastics in aquatic ecosystems. This research investigates how temperature fluctuations affect the response of optical sensors in an Internet of Things (IoT)-driven microplastic detection system deployed in the Deli River, Medan. The system integrates a DS18B20 digital temperature sensor with an optical photodiode sensor, both managed by an ESP32 microcontroller. The data collected is sent and displayed in real-time through the ThingSpeak platform. The data gathering process took place at three different locations along the river: upstream, midstream, and downstream. Parameters such as water temperature and microplastic reflectance were measured under varying weather conditions and times of day. Calibration tests showed that the DS18B20 sensor delivered precise measurements, with an error margin ranging from 0.05% to 0.088% within a temperature range of 10°C to 40°C. Observations revealed a pattern where an increase in water temperature correlated with a rise in microplastic reflectance. For example, at the upstream location, reflectance rose from 10.38% to 16.4% as the temperature increased from 26.3°C to 28.4°C. A similar pattern was observed at the midstream and downstream sites. This temperature increase is believed to speed up the degradation of microplastics and alter the refractive index of water, thereby boosting the light intensity reflected and detected by the sensor. Correlation analysis yielded a significance value (Sig. 2-tailed) of 0.024, which is below the 0.05 threshold, indicating a statistically significant relationship between temperature and reflectance. The Pearson correlation coefficient of 0.375 suggests a weak positive relationship between these two factors. These results highlight the critical role of temperature in the development of optical sensor-based microplastic detection systems.