Development of a Portable Water Turbidimeter Based on NIR Spectroscopy

Turbidity of water is a very important parameter in the aquaculture. An integrated portable optical detector was developed based Near Infrared Spectrum spectroscopy to measure turbidity of water body rapidly and accurately. And the integrated absorbance measuring approach was proposed in this paper. The detector used AT89S52 microcontroller as its control chip and consisted of the light emission unit, detection unit and control unit. Wherein, the light emission unit comprised two sets of 860 nm LED light source and the corresponding collimating lens; the detection unit comprised two photoelectric sensors; the control unit included the light source driving circuit, two-stage amplification circuit and A/D conversion circuit. The integrated detector was calibrated in laboratory and carried out field experiments. The experiment results showed that the water turbidity detector achieved a high accuracy, its calibration R 2 was 0.994 and validation R 2 was 0.999. With the resolution of 0.01 NTU and the error of ± 2 %, the turbidimeter reached the practical level. Copyright © 2014 IFSA Publishing, S. L.