With the price of guide dogs running into the tens of thousands of dollars, the white cane is still the most commonly used aid for the visually impaired. That venerable tool is the focus of research by Johann Borenstein and Iwan Ulrich, mechanical engineers at the University of Michigan. They have developed a cane that uses sonar to steer the cane’s user around obstacles.
The sonar cane looks a bit like a traditional white cane but has a semicircular black box on two wheels attached to its bottom end. As a person pushes the cane along, it transmits ultrasonic pulses that bounce off obstacles up to six feet ahead and reflect back to sensors at the base of the cane. The cane then automatically turns its wheels to steer around the obstacle. The person feels the movement and follows along, also sidestepping the object. It’s so intuitive to follow that ...
