Design of a Water Salinity Difference Detector for Monitoring Instantaneous Salinity Changes in Aquaculture

摘要

A water salinity difference detector is proposed herein for monitoring instantaneous salinity changes in aquaculture. The detector comprises a water salinity difference sensor and a proposed water salinity difference sensor transducer. The proposed sensor transducer can linearly convert the water salinity difference into a frequency output. Moreover, a technique for automatically changing the sensitivity of the proposed sensor transducer is presented. By using this functionality, the instantaneous salinity changes can be detected with high sensitivity when aquatic organisms are in water with high salinity difference. The performance of the proposed water salinity difference detector was verified through measurements. The measured input current range of the proposed sensor transducer was 12.5- $60mu ext{A}$ , and the sensitivities of 1.6, 2.38, 3.17, and 4.05 kHz/ $mu ext{A}$ were automatically adjusted. The water salinity difference ranged from 7.5 to 35 parts per thousand, and the sensitivities of 2.492, 2.72, and 3.56 kHz/parts per thousand were also successfully guaranteed. The maximum linear error measured was 0.47%, and the chip area was $1.49imes1.49$ mm(2). Finally, a case for monitoring instantaneous salinity changes in aquaculture was developed through experimentation. The results of this study revealed that the proposed chip is suitable for detecting water salinity difference.