By attaching an ultrasonic sensor to the top of the white cane used by the blind to detect obstacles, Indian engineer Rohan Paul has reduced upper body collisions by 90% among 200 people who tested the device. More than 10,000 Indians now use the smart cane, which costs $50. "People have been trying to put sensors on canes for a very long time, but there was still an unmet need for a low-cost, effective, usable device," Paul, now a postdoctoral fellow at MIT, said. More (sub. req.)