A Self-Adaptive and Wide-Range Conductivity Measurement Method Based on Planar Interdigital Electrode Array

• Published in: IEEE access Vol. 7; pp. 173157 - 173165
• Main Authors: Wang, Xiaolei, Wang, Yuhao, Leung, Henry, Mukhopadhyay, Subhas Chandra, Chen, Shaoping, Cui, Yongqiang
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive algorithms; Circuit boards; Conductivity; Conductivity measurement; Electrodes; environmental monitoring; Measurement methods; Optimization; Parameters; Performance measurement; Printed circuits; Production costs; Resistance; Sensitivity; Sensor arrays; water pollution; Water quality
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2019.2956568

Conductivity is a crucial parameter in water quality detection, which can roughly represent overall concentration of various inorganic ions. However, traditional conductivity sensors can only afford high performance measurement in a relatively low range while the concentration may vary much more in realworld water environment. This paper proposes a high-precision and wide-range measurement method based on a novel planar interdigital electrode sensor array and a self-adaptive algorithm. The array is composed of 3 pairs of planar electrodes with various cell constants aiming at different subdivided conductivity sections. The follow-up circuit and the self-adaptive algorithm keep the optimal electrode pair dominates the output of the array. Numerical simulations were utilized to optimize sensor parameters before fabrication. PCB manufacturing technique was used which guaranteed a relatively low manufacturing cost and stable performance. Experiments were conducted to verify the sensing performance and results showed that the array can maintain precise measurement from 0.5μs/cm to 500ms/cm.