Obstacle detection by multiple ultrasonic sensing for visually impaired users

World Health Organization estimates that, in 2010, there were about 285 million people in the world with disabling eyesight loss 246 millions were visually impaired (VI) and 39 millions were totally blind. In Italy, the number of VI subjects is estimated in 530,000, of whom about 50,000 are blind. For such users, hits with obstacles during mobility tasks are reason of major concerns. The white cane is the primary device used by the majority of blind or VI users to explore and possibly avoid obstacles, but it can monitor only the ground (<1 m) and it does not provide information on leg-trunk-head. In this paper, authors propose a novel stand-alone Electronic Travel Aid (ETA) device for obstacle detection based on four ultrasonic transducers and a microcontroller. Portability, simplicity, reduced dimensions and cost are among the pros of the proposed system, which can detect and localize (angular position and distance from the user) obstacles eventually present in the whole volume in front of him.