Toward industrial revolution 4.0: Development, validation, and application of 3D-printed IoT-based water quality monitoring system

Recent technological advances and developments have evolved the application of the Internet of Things (IoT), low-cost sensors, and three-dimensional (3D) printing for near-real-time water quality monitoring; however, these technologies have not yet been widely implemented in field operations. In this study, a solar-powered 3Dprinted IoT-based water quality monitoring system (WQMS) that measures turbidity and water level every 2 h was developed and utilized in a palm oil plantation on Carey Island, Malaysia, for two months (November 28, 2019-January 21, 2020). The WQMS consists of four modules: energy, time, monitoring, and communication. The electrical consumption values of the WQMS in the standby, operating, and data transmission modes were calculated to determine the optimal monitoring frequency. The monitored data were uploaded to Ambient (an open cloud platform) for visualization and anomaly detection. The turbidity and ultrasonic water level sensors were calibrated and validated, and high linearities (R2 > 0.97) were obtained between the signal received and the actual measurements. The turbidity sensor provided an accurate measurement of turbidity within a range of 10-1000 FNU, whereas the optimum measurement range of the water level sensor was determined to be 2-400 cm. From the field study results, it can be observed that the contact-type sensor (for turbidity) requires monthly maintenance to prevent the deposition of mud/silt and biofouling problems, whereas the non-contact sensor (for water level) can consistently provide accurate measurements throughout a period of at least two months. The proposed WQMS implemented demonstrates the effective integration of IoT with 3D printing, microcomputers, and low-cost sensors, paving a new path for the development of cost-effective and reliable systems for water quality monitoring.