Design of a miniature sensing module for pressure mapping in functionality hydrogel using programmable system-on-chip.

Flexible tactile sensors show great promise in mimicking human skin to achieve tactile perception. However, their practical implementation still faces key technical challenges, including device miniaturization, high-sensitivity detection, and suppression of signal crosstalk. In this work, we propose a micro multi-channel pressure collection and monitoring system for functional hydrogels, which integrates a sensor electrode array with a downsized multi-channel acquisition module for efficient pressure sensing. The hydrogel material was combined with the electrode array to form the sensing units. To address the influence of different array structures on the integrity of the hydrogel, an independent array design is adopted to reduce interference from redundant conductive pathways. The array is downscaled to a 4 × 4 structure with a size of 1.8 cm × 1.8 cm. The system employs a conversion circuit to provide alternating current excitation, which helps mitigate electrochemical corrosion caused by redox reactions between the hydrogel and metal electrodes. The system consists of a programmable system-on-chip (PSoC) and a multiplexer, enabling multi-pixel tactile array measurement while minimizing the use of additional components. The acquisition circuit is compact, with dimensions of only 2.3 cm × 3.0 cm. The array characteristics were validated by testing individual pixel elements, and experiments such as pressing concave and convex letter patterns as well as vascular structure detection were conducted, with vascular structures successfully displayed on the interface. This system enables real-time tactile measurement through touch, demonstrating significant potential in applications such as human-machine interaction and electronic skin.