Robot guide for the blind. Inventor Johann Boren- stein with a prototype Guidecane guidance robot. The 4-kilogram, two-wheeled robot is pushed by its user and has a thumb-operated joystick to control its direction. It emits high-frequency sound (ult- rasound). Sensors (circles on robot's front) detect any reflections from obstacles. Its computer uses the data from the sensors to calculate the best route every 50 milliseconds. The computer automat- ically steers the robot around the object and then resumes the original direction. The user feels the steering change as a direct physical force through the handle, making it easy to use. The Guidecane was developed at Michigan University, USA.