For blind people, a guide dog is useful when crossing a noisy and busy street, and a cane is helpful in tapping out dangerous objects scattered around. However, not everyone is willing to look after a seeing-eye dog and canes have their limitations.
For those who are looking for something more efficient, Steve Hoefer designed and constructed the Tacit, a wrist-mounted device that uses sonar to measure the user’s distance to objects. Through haptic feedback, it provides the visually impaired with a view of his surroundings.
Since the device is mounted at the back of the user’s hand, it will not interfere with his sense of touch, or with other devices that use audio feedback. Hoefer designed a similar product that was worn in the head, but he decided that a vibrating head gear could drive someone crazy.
An earlier version of the wrist-mount was designed after a medical wrist support, but Hoefer explains that it required a separate design for left-handed users. The latest version of the Tacit attaches by a velcro strap around the user’s wrist and a loop over his middle finger, so it can be worn on either left or right hand.
The Tacit uses ultrasonic sensors, Arduino Mini Pro 5v, hobby servomotors and a battery. The parts of the device retail for only $65, as Hoefer says that he doesn’t “see the point of an accessibility device that has an inaccessible price tag.”