Design of online data measurement and automatic sampling system for continuous water quality monitoring

In this research, it has been designed a continuous water quality monitoring system consisting of sensors for measuring Dissolved Oxygen (DO) and pH, data acquisition based on a PCDuino microcontroller, a sample collection unit, and PC based graphical display. The main part of the system is the PCDuino microcontroller, that has a function of controlling the data transmission and the operation of the automatic sampling unit based on comparison of the measured parameter values against certain threshold. The automatic sampling unit was constructed from PVC holder, a 12V motor stepper, a 12V DC pump, and 8 glass tube sample storages. Experimental results showed that when the measured DO value dropped below 5 mg/l, or the pH values below 4 or above 9, the sample collection unit worked by filling up 20 ml sample in just under 650 ms. All the measured data can be displayed on a PC for further analysis. This prototype system is expected to find wide applications in the field of environmental and aquaculture monitoring.