Printed Soft Capacitive Sensor for Fingertip Contact Monitoring

This study presents a low-cost, highly customizable wearable capacitive sensor for measuring contact force and pressure, particularly those exerted by fingertips against objects. The sensor fabrication process leverages additive manufacturing technologies, including Fused Filament Fabrication (FFF) and Aerosol Jet Printing (AJP), enabling integration into gloves and garments. The experimental setup involved impedance measurements to characterize the sensor electrical behavior and mechanical testing to evaluate its response under cyclic loading and varying environmental conditions. The results demonstrate a consistent capacitive response to applied forces, with a sensitivity of about $2.07 \mathrm{pF} / \mathrm{N}$ and a resolution below 0.5 N. The sensors exhibited excellent repeatability and rapid recovery times of less than 10 seconds. Furthermore, temperature-dependent measurements revealed a capacitance variation of $-0.04 \mathrm{pF} /{ }^{\circ} \mathrm{C}$, which suggests the need for thermal compensation in applications with significant temperature fluctuations. These findings indicate that the proposed capacitive sensor is suitable for real-world applications, such as force measurement in industrial settings and wearable human-machine interfaces.