The Tacit Project is a hand-mounted, haptic-feedback device that assists the visually impaired. Developed by Steve Hoefer's Grathio Labs, the device has ultrasonic sensors that sit above the knuckles (of either hand) and sense the distance of objects from 1 inch to 10 feet away. Once the distance is read by the microcontroller, it sends a signal to the servomonitor, which uses cushioned extensions to add pressure to the wrist — the closer the object, the more pressure that's applied.
Hoefer isn’t keeping this device to himself. The necessary parts, instructions and code have been posted on his website for anyone wanting to make this DIY project. As complicated as it may seem, only a basic knowledge of circuitry and software is needed to make the internal part of the sonar device. The most complex part is sewing the neoprene wrist strap.
There's only one stipulation to building a device of your own: The circuit and software are under a Creative Commons BY-NC-SA license. Hoefer boils it down to this, "Make it, learn from it, teach it, improve it, modify it. Just share what you do, give credit and don’t sell any without contacting me first."
Credit: Steve Hoefer/Grathio Labs