Buy arduino, buy sound shield, buy distance sensor shield, plug into each other, burn example code, stuff components inside box. Not only is this not a hack but he might as well have just bought a ...

This ultrasonic radar project is from [mircemk] who uses a small ultrasonic distance sensor attached to a rotating platform. A motor rotates it around a 180-degree field-of-view and an Arduino ...

In this mode, you can interface the HC-SR04 ultrasonic ping sensor with a servo motor and the main board (Only some reward tiers include the extra servo motor PCB and servo motor kit).