While it’s not radar, subbing in ultrasonic sensors is how [Dzl] built this ... With this assembly stuck on a stepper motor to swivel it back and forth, [Dzl] was able to get pretty good ...

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 ...