The Elektor Speaking Sonar Stick (May & June 2016 edition) based on RPi
In good experimental fashion, this project is a valuable study into what can be achieved with ‘commodity embedded technology’ like a Raspberry Pi. This ultrasonic distance measuring “robot” will greet you, measure distances to objects continuously and read the values out loud. It can also be programmed to activate alarms when the measured distance crosses a user-programmed limit. Got a pair of U/S distance sensors and an RPi ready? Then go.