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 ...

Suitable for beginners and experts alike, this kit comes with over 250 components including a development board that’s compatible with Arduino Uno, 1602 I2C LCD, motors and ultrasonic modules.

Runner and Arduino enthusiast Nikodem Bartnik has created a DIY 100m sprint timer which is placed at the finish line and signals the start of timing via an audible bleep from its integrated speaker.