HapToes: Vibrotactile Numeric Information Delivery via Tactile Toe Display

Tactile rendering of numeric information via a single actuator has been considered for such purposes as fitness progress tracking. However, multi-actuator designs, leveraging spatial mapping, may offer superior performance. Motivated to explore this approach without requiring hardware on the fingers or wrist, we designed HapToes, a novel ten-digit spatial mapping of numeric information to the toes, which overcomes inter-toe discrimination ambiguity. Compared to ActiVibe, a single-actuator wrist-based numeric rendering technique, under similar distraction conditions, HapToes demonstrates equivalent performance for single-value identification, and improved accuracy, response time, and cognitive load when conveying three values sequentially in a single message.