Development of an IoT-Enabled Automated Marine Sand Washing Machine with Conductivity Measurement

This paper presents an automated marine sand washing system based on the conductivity measurement performed at various mix ratio of marine sand and harvested rain water. The amount of the chloride ion removed in marine sand will be reflected as a decrease in conductivity measurement. The proposed automated system will perform sand washing to reduce the amount of chloride ion in marine sand based on the conductivity measurement, which helps worker to monitor and deliver sand that meets the industry standards for construction purpose. Meanwhile, Volhard's chemical testing method was used to verify the amount of chloride ion in the sample sand compared with the conductivity measurement. Based on the experimental results, two linear regression models from different conductivity probes were proposed to predict chloride content in the sand. The programmable logic controller (PLC) was adopted to implement control logic of the automation process of the machine including watering, mixing, dewatering, and sand discharge. Furthermore, Internet of Things (IoT) was used to monitor the data received from various sensors and enable the user to remotely control the system. The results show that the proposed automated system is able to perform marine sand washing and the linear regression model can help in the estimating the required conductivity to meet the required standard of the chloride concentration in sand for construction purpose.