Design and realisation of a turbidimeter using TSL250 photodetector and Arduino microcontroller

In this research it has been developed a turbidimeter using TSL250 photodetector and 650 nm laser light source. The method used was based on nephelometric principle with the photodetector positioned at 90
^o
angle against the incident light from the laser source. Light intensity changes due to particles in the liquid were converted into voltage, and an Arduino microcontroller was then used to convert the measured voltage into the standart turbidity measurement unit (NTU) and displayed the results on an LCD. The system has been tested against a commercial turbidimeter, and the results showed an average accuracy of 98.7%, and good precision over 25 series of measurement and 5 day measurement cycle. The ideal measurement range of the developed system was from 10 - 150 NTU, with the smallest measurable value (resolution) of 0.17 NTU. The turbidimeter was expected to be applied in an online water quality monitoring system.