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Otago Daily Times Article "Sonic tool a boost"
By Blair Mayston
Life has become a lot easier for John Barnes in the past two and a-half weeks. The legally-blind Dunedin man has bought a sonar device which attaches to the top of his white cane, warning him through tones transmitted through a set of headphones whether the path ahead is clear.
That has made a huge difference to Mr Barnes (52), who somewhat ruefully acknowledged he had become "intimately acquainted" with many of the power poles on the streets of Dunedin during the past few years.
"With a white cane you can see as far as the cane is long, but with this you can see up to 16ft [4.9m]," he said.
The New Zealand-made K-Sonar device sends out ultrasonic waves, and when they bounce off objects in their path they are translated into sounds, which the user listens to through a set of headphones.
The tones also let users know how far away objects ahead of them are. "So [for example] I can tell there's a clear pathway on a footpath when I don't hear any noise," Mr Barnes said.
Different objects with different textures produced different sounds. "You can tell, with practice, what the object is," he said.
The headphones through which the signals were transmitted were designed to allow outside noises, such as traffic, to be heard, too, he said. That was important, because, unlike a guide dog, the sonar device did not pick up the edge of roads, he said. The K-Sonar website said scientists recognised from the late 1950s the potential of sonar to help the blind, and although some devices such as a sonic torch and sonic glasses had been produced, they had, until recently, proved too expensive for widespread use.
