Research and design of a portable electrolyte conductivity meter based on eddy current effect

A non-contact portable electrolyte solution conductivity detection method based on the eddy current effect is proposed to overcome the issues of electrode polarization and susceptibility to contamination inherent in traditional contact measurement methods for electrolyte solution conductivity. Initially, the analysis focuses on the PCB planar coil to investigate the impact of geometric parameters such as coil line width, spacing, and number of turns on detection sensitivity, aiming to determine the optimal parameter combination. Subsequently, the hardware system integrates the LDC1001 inductance-digital converter and MCU architecture with a built-in digital communication interface and display module. This setup enables conductivity measurement and data visualization within the 1-10 S/m range. The system calculates the electrolyte solution conductivity by monitoring changes in coil inductance and parallel resistance. Experiments are conducted using solutions of varying conductivity. The results confirm the feasibility of determining electrolyte solution conductivity based on variations in coil inductance and resistance. Through temperature characteristic and anti-interference experiments, the system's stability, effective temperature compensation function, and robustness against interference are demonstrated. The relative error in measurements is found to be less than 2.3 %, with a temperature compensation error below 1 %. The entire system design is realized through PCB design. In comparison with conventional electrode conductivity meters, this method enables non-contact measurements, eliminating issues related to electrode polarization and contamination. Additional benefits include flexible design, real-time display of measurement results, and portability.