Wearable Tactile Interfaces Using SMA Wires

This paper describes the use of SMA (Shape Memory Alloys) wires to develop wearable tactile interfaces. In this early work, the wearable interface consists of a nylon glove with thin SMA wires stitched on it. The SMA wires provide a tunable pressure sensation when they are electrically actuated appropriately. Each wire is anchored to the fingernail-shaped support via screw clamps to ensure both the electrical continuity of the connections and to efficiently transmit the contraction force on the fingertip. A suitable actuation system of SMA wires has been designed and implemented on an Arduino Uno microcontroller to prevent their overheating. The knowledge of SMA wires mechanical, thermal and electrical properties allowed the implementation of a proper actuation strategy. The interface was characterized in terms of response time and force felt on the fingertip. Ten subjects have positively evaluated the interface in terms of wearability, comfort and tactile sensations. This work paves the way for the development of highly wearable tactile interfaces to be integrated in Virtual Reality (VR) and Augmented Reality (AR) environments.