Here is a cool project that involves building a smart walking stick with ultrasonic sensors to help visually impaired people detect obstacles in their way. Blind Assistance can measure obstacles from 2cm to 400cm. The vibration motor is activated when something is in the way.
Users can also have their details displayed on 4Duino’s display. You are going to need ultrasonic distance sensors, LEDs, a 5V power supply, and a few other parts in addition to a walking stick to put this together. 4D Systems has shared more info here.