Validation and Optimization of a Low-Cost Sensor for the Measurement of the Radial Displacements of a Cylindrical Conductive Target

Accurate measurement of the radial displacement of cylindrical conductive targets is essential for various industrial and scientific applications. This study presents the design and development of a low-cost, inductive-based sensor system and a dual-Axis calibration test bench for its validation. The sensor consists of three flexible printed circuit (FPC) coils configured as eddy-current sensors, designed to optimize sensitivity and improve measurement accuracy. A dedicated test bench has been developed to provide precise reference positioning along two orthogonal axes, incorporating compensation for misalignment errors and Monte Carlo-based uncertainty estimation. The test bench achieves a positioning uncertainty of 3.2 \mu \mathrm{~m}(\mathrm{P}=95 \%), confirming its suitability for high-precision calibration. Additionally, the measurement system is designed to enable high-speed Ethernet communication through a FreeRTOS-based architecture with an integrated TCP/IP stack, supporting future IoT applications to real-Time monitoring and predictive maintenance. Future work will focus on completing the sensor validation and integrating it into networked industrial environments