A dynamic ultrasonic ranging system as a mobility aid for the blind

A microprocessor-based ultrasonic ranging system, configured around a PVC tube resembling the form of a long cane, has been designed. The system, intended to serve as a mobility aid for the blind, consists of four ultrasonic sensors integrated into the cane, and a microcontroller. It is able to provide real-time information on the distance and height of over-hanging obstacles within 5 meters along the travel path ahead of the user. Laboratory experiments under various cane motion patterns have shown that at 5 meters, the maximum relative error of the measurement is below 14%. This drops to less than 5%, when the measurement range is within 3 meters. Upon miniaturization, the system can be integrated into a conventional long cane for practical daily use by the blind.