What a great, creative project for kids of all ages and a prototype for something that could be very useful. This project uses the LittleBits interlocking electronics kit, but it would be easily recreated using standard Arduino parts. It looks like even the code could be re-used, too. I have an ultrasonic sensor I picked up cheap and some other parts from an Arduino Start Kit. I think I might put this together just for the shear fun of it! See links for parts below.
This device can detect the obstacles on your way using echolocation method just like bats do. It's like you have your own bat-friend who can accompany you wherever you go and tell you if there is something on your way that you cannot see.
It is a useful tool for blind people and for people working in the conditions of very low or no visibility. Of course, it can also be used for playing fun games.
The voice alert will turn on once you appear within a dangerous distance from the obstacle ahead.
It is based on the Arduino Bit. It drives the ultrasonic sensor and keeps measuring the distance from the objects ahead. The buzz alert indicates that the distance from the object is within 50 cm.
Parts that can be used to recreate this project