Directional Obstacle Warning Device Using Multiple Ultrasonic Transducers for People with Visual Disabilities

Though there are various electronic travel aids for people with visual disabilities, target users in some areas may not be able to afford one due to their high cost. This paper proposes a prototype of iSonar-2; a low-cost directional obstacle warning device using multiple ultrasonic transducers with a miniaturized, high performance. To avoid collision, four ultrasonic transducers with 40 kHz are used to detect obstacles within the range of the user's head and the ground, including stairs. iSonar-2 provides directional tactile feedback with six DC motors that vibrate in different position and frequencies, depending on the details of the obstacle's whereabouts and characteristics. The coverage area is 130 cm forward and 100 cm from each side. We evaluated the maximum scanning range and the performance of the system and found that iSonar-2 can reduce the average collision rate to 17.78%.