A Current Mode Interface for Dendrometry through an Additively Manufactured Sensor

Industrial sensor manufacturing through 3D printing is becoming increasingly frequent due to its flexibility, reduced time-to-market, and cost efficiency. Furthermore, sensor interfaces are mostly based on the voltage-mode approach, which affects their reliability compared to current-mode sensor interfaces. In this context, current-mode active blocks as second-generation voltage conveyors (VCIIs) and second-generation current conveyors (CCIIs) offer an effective solution by applying current-mode advantages directly to voltage signals. This preliminary work explores the possibility of using 3D-printed strain gauges as contact dendrometers, with a VCII-based current-mode sensor interface circuit. The sensor and circuit were simulated and tested by subjecting the strain gauge to predefined mechanical deformations and recording the output voltages. In particular, the interface DC characteristic and sensitivity are extracted, obtaining good agreement between simulation and measurements. The results indicate that the proposed interface achieves a sensitivity of about −24.5 mV/mm and a resolution of around 1 degree of curvature.