Sonar is a great sensor to add to any small-scale robot project. And for a couple bucks, the ubiquitous HC-SR04 modules make it easy to do. If you’ve ever used these simple sonar units, ...

While a well-known use of this is sonar, ultrasonic sensors can also be put to use to make a radar-like system. This ultrasonic radar project is from [mircemk] who uses a small ultrasonic distance ...