Obstacle detection and location using acoustic technology in time domain for visually impaired

An obstacle detector using ultrasonic phased array with the principle of beam steering by time of flight method is proposed. To detect and locate linear ultrasonic phased array it is designed using ultrasonic piezo-sensors. The motivation was to design/evolve an economical system/gadget, which is capable of detecting, ranging and determining bearing/relative angular position of an obstacle. With this aim, an ultrasonic phased array system was designed and developed. The designed linear array detects and locates objects with range resolution of 2.5 cm and bearing resolution of 4.23 degree. The problem of grating lobes in the transmitter array are minimised by adjusting the interelement spacing of the receiver array. This helps in proper reception of the echo signal and hence accurate distal and angular information about the object. The designed system is economically reliable, measurements are performed in time domain reducing complex computation and giving enough and accurate information to a visually impaired person to travel. This paper presents the design details, results of the experiments that were conducted to confirm the capability to transmit and receive in the desired direction and estimate the distance of the target.