Tacit: Wrist-Mounted Sonar for the Visually Impaired
From: EE-News - 08/31/2011
By: Darren Quick

We've seen a number of devices—such as the UltraCane and EYE 21 system—that
combine sonar and haptic or audio feedback to let the visually impaired "see"
their surroundings through the senses of touch or hearing. Tacit is a similar
device that also uses sonar to measure the distance to objects and provide
users with a 'view" of their surroundings through haptic feedback. But unlike
previous devices we've looked at, Tacit is mounted on the wrist so it doesn't
impair a user's hearing or interfere with the use of other assistance devices
such as canes. 

The prototype Tacit device developed by Steve Hoefer at Grathio Labs consists
of four ultrasonic range finding sensors connected to a microcontroller that
calculates the distance to objects by reading how long it takes for the
ultrasonic pulses to return to the device. The distances are then translated
into force feedback on the back of the user's wrist through servo motors,
with the force of the pressure indicating how near or far the detected
objects are. By waving their arm around an area, the wearer is able to get
the lay of the land and navigate complex environments. 

Read the entire article at:
http://www.gizmag.com/tacit-wrist-mounted-sonar/19580/

Links:
Tacit Project
http://grathio.com/2011/08/meet-the-tacit-project-its-sonar-for-the-blind/

How Trying to Make a Videogame Created Sonar for the Blind
http://grathio.com/

Grathio Labs
http://grathio.com/about/