Serpentine Shape Memory Alloy-Based Skin-Attachable Haptic Interface for Multimodal Tactile Feedback in Wearable Systems

• • The device generates stable tactile forces of 0.5–0.85 N, surpassing the finger's 0.1 N threshold, ensuring perceptible feedback for VR and assistive applications. • • Response time is ≤0.5 s, enabling real-time haptic interaction critical for immersive VR and navigation systems. • • Durability tests show >95% displacement retention after 100 cycles at conventional frequency, with reversible high-frequency decay, indicating mechanical robustness for repeated use. • • Safety is maintained by limiting driving current to 0.8 A and single-drive duration to 0.1 s, keeping skin contact temperature below 36°C, eliminating burn risk during SMA actuation.