Cane Mounted Knee-Above Obstacle Detection and Warning System for the Visually Impaired

There are numerous constraints that visually challenged people face in independent mobility and navigation. They primarily use the white cane as a mobility aid allowing them to detect close by obstacles on the ground. The detection of objects above knee height is almost impossible and is a major hindrance for them. In this work, we have reported the design and implementation of a detachable unit which acts to augment the functionality of the existing white cane, to allow knee-above obstacle detection. This unit consists of an ultrasonic ranger and a vibrator controlled by an eight bit microcontroller to offer an increased detection range of three meters. The distance information is conveyed to the user through non-interfering multi-frequency vibratory stimuli, the frequency of vibration indicating the proximity of obstacles. This unit is also capable of detecting fast moving obstacles. Considerable effort has gone into the electromechanical design of this unit conveying the vibrations effectively and ensuring that it is easily attachable on the existing white cane without sighted assistance. A crucial design optimization goal was cost — the unit has been developed as a “low cost” device which is affordable by the poor in developing countries.