Dual-mode flexible sensor based on magnetic film for wearable smart finger sleeve

Flexible tactile sensors are an important branch of wearable devices and have received extensive attention in areas such as human–computer interaction and health detection. However, some existing flexible wearable devices have the limitation of single detection quantity, so it is particularly important to study a multi-mode flexible tactile sensor. We designed a dual-mode tactile sensor with high sensitivity and wide measurement range. The sensor consists of a magnetic film in the top layer, a silicone elastomer in the middle layer, and a tunneling magnetoresistive element in the bottom layer. The experimental results show that the haptic sensor is capable of measuring static forces in the range of 0.05–18 N, and the sensitivity of the sensor to static forces increases and then decreases as the applied force increases. The maximum sensitivity was 396.4 mV N⁻¹ in the range of 9–10 N. The tactile sensor was able to measure bending angle in the range of 1–60°. The bending angle sensitivity decreases as the applied bending angle increases, with a maximum sensitivity of 308.7 mV per 5° in the 0–5° range. The sensor has good dynamic performance, and after 1000 cyclic loading tests, the output voltage did not show any significant decrease, and the sensor response time and recovery time were 44 ms and 46 ms, respectively. This study lays a foundation for further research and development of various wearable devices and electronic skins.