An intelligent turbidity and temperature sensing unit for water quality assessment

This paper reports the development of an intelligent turbidity and temperature-sensing unit for water quality assessment. The intelligent unit is based on an original turbidity sensor, which includes three IR light sources and a single IR detector, and on a thermistor-based temperature sensor. The system is designed around a PIC16F877 microcontroller that performs tasks such as sensor control, data acquisition, data processing and communications. The proposed turbidity sensor allows a reduction in the effects of detector-to-defector variability, light source intensity variations and water absorbance. For sensor data processing, different solutions, including neural processing, are considered and discussed. Elements of the sensing unit calibration, autocalibration, testing and RS232 communication between the microcontroller and a PC are also presented.