This ultrasonic radar project is from [mircemk] who uses a small ultrasonic distance sensor attached to a rotating platform.

Posted in classic hacks, Toy Hacks Tagged cardboard, Cardboard model, ultrasonic distance sensor ← How To Cram 945 LEDs Into A Teeny Tiny Vegas-Style Sphere ...

A low-cost (~$100), do-it-yourself (DIY) ultrasonic water level sensor/datalogger has been designed, constructed, and tested for use in education, citizen/community science, and research settings. The ...

An ultrasonic sensor emits sound waves to measure the distance of potentially hazardous objects. The cane can then vibrate to alert its user. (Nick Boisvert/CBC) ...