$65 these days likely can’t get you a very sophisticated medical device, but with an Arduino microcontroller, a bit of programming and soldering experience, and a lot of patience, you can build your own device capable of using sonar to assist the blind.
Project Tacit is the newest creation from inventor Steve Hoefer and his company, Grathio Labs. It consists of a device worn on the hand like a glove, known as the gauntlet. Ultrasonic sensors on the back on the hand emit sonar waves. The Arduino microcontroller measures the amount of time it takes for the ultrasonic waves to return and causes servo motors to rotate and place varying amounts of pressure on the back of the hand. When objects are far away, the user feels little to no pressure on their hand; the closer the object, the firmer the pressure on the hand.
According to Grathio Labs, Project Tacit can sense objects from about 1 inch to 10 feet. Its response time is fractions of a second, which makes the unit practical for the visually impaired. Best of all, Grathio Labs has provided instructions on how to build your own Project Tacit gauntlet!
From Grathio Labs: Meet The Tacit Project. It’s Sonar For The Blind
(hat tip: Engadget)