GuideTouch: An Obstacle Avoidance Device for Visually Impaired

TL;DR

GuideTouch presents a compact wearable obstacle-avoidance device for visually impaired users that fuses two vertically arranged ToF sensors with a four-point vibrotactile feedback system to convey obstacle direction. The architecture combines a centrifugal self-cleaning optical cover, ToF-based depth sensing, and an ESP32-driven processing pipeline to deliver rapid, zone-based haptic cues, supplemented by an audible alarm if the device is displaced. Evaluation shows high recognition accuracy for simple directional cues (≈93%) in preliminary studies with visually impaired and blind participants, while more complex patterns reduce accuracy and reveal individual wearability factors. The work demonstrates a practical, low-cost approach to enhancing safety and autonomy in independent navigation, with planned enhancements in sensing resolution, training, and dynamic real-world validation.

Abstract

Safe navigation for the visually impaired individuals remains a critical challenge, especially concerning head-level obstacles, which traditional mobility aids often fail to detect. We introduce GuideTouch, a compact, affordable, standalone wearable device designed for autonomous obstacle avoidance. The system integrates two vertically aligned Time-of-Flight (ToF) sensors, enabling three-dimensional environmental perception, and four vibrotactile actuators that provide directional haptic feedback. Proximity and direction information is communicated via an intuitive 4-point vibrotactile feedback system located across the user's shoulders and upper chest. For real-world robustness, the device includes a unique centrifugal self-cleaning optical cover mechanism and a sound alarm system for location if the device is dropped. We evaluated the haptic perception accuracy across 22 participants (17 male and 5 female, aged 21-48, mean 25.7, sd 6.1). Statistical analysis confirmed a significant difference between the perception accuracy of different patterns. The system demonstrated high recognition accuracy, achieving an average of 92.9% for single and double motor (primary directional) patterns. Furthermore, preliminary experiments with 14 visually impaired users validated this interface, showing a recognition accuracy of 93.75% for primary directional cues. The results demonstrate that GuideTouch enables intuitive spatial perception and could significantly improve the safety, confidence, and autonomy of users with visual impairments during independent navigation.

Figures (3)

• Figure 1: Custom ToF sensor module. (a) PCB layout design, (b) Assembled board with dual VL53L5CX sensors mounted behind the optical lens.
• Figure 2: System operational workflow.
• Figure 3: Sensor data visialization methods. (a) 3D point cloud of obstacle geometry. (b) 2D heat map of distance measurements.