To create an affordable obstacle detection system for blind people, he began
  by simply asking them what they needed
From: MIT Technology Review - 09/2015 - page 40

Ultrasonic sensors detect obstacles. The device vibrates in patterns that
indicate the distance to obstacles. The full system includes a foldable cane
for easy storage. It can also be mounted on a traditional cane.

Read the entire article at:
http://www.technologyreview.com/lists/innovators-under-35/2015/inventor/rohan-paul

Links:
Rohan Paul
http://www.robots.ox.ac.uk/~mobile/wikisite/pmwiki/pmwiki.php?n=People.RP

Assistech India
http://assistech.iitd.ernet.in

SmartCane Device
http://smartcane.saksham.org