Rohan Sharma and Jeff Buente, at Cornell University, posted detailed notes on their haptic vision project:

The ultrasonic haptic vision system enables a person to navigate hallways and around large objects without sight, through the use of an ultrasonic rangefinder that haptically interfaces with the user via tiny vibrating motors mounted on the user’s head. The idea behind this project was to construct a sixth sensory system that interacts with the body in an intuitive and user friendly fashion and enables the user to navigate without vision.