A team of technologists in India developed a high-tech walking canes that use ultrasound to let blind people know about their surroundings.
"On the streets the sidewalks are cluttered with street vendors, animals, streetlights and other obstacles which make them uncomfortable even for sighted people," explains Prof Meenakshi Balakrishnan, a computer engineer at the Indian Institute of Technology in New Delhi.
Balakrishnan heads the team behind the "Smartcane," a new device using ultrasound to guide the visually impaired by building upon the widely used white cane.
"A white cane is an excellent device, providing a lot of information to users," he says. "But it is poor at detecting obstacles that are above waist height and do not have a touch-point on the ground, such as a tree branches sticking out into your path."
The team at Smartcane took on this challenge by copying the skills of animals such as bats, which emit sonar calls into their surroundings and use the echoes bouncing back from nearby objects to divert around them.
The smart technology version instead sends out ultrasound waves via a device attached to a standard white cane; it detects them on their return, and uses vibrations to inform users of any obstacles in their way.
The real benefit comes from the ultrasound scanning a 45 degree span above the knee, providing information a regular cane simply can't provide.
As people move the cane from left to right when they walk, vibrations detected on one side mean they should move towards the other.
The goal for Balakrishnan and his team, however, had been a low-cost technology to provide independence to the 15 million people estimated to be blind in India.