This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 ... If everything goes right,you should see the burning eye of the red LED when there is no object in the safe-zone ...

Inside the light is an Arduino Nano, which reads from the ultrasonic sensor mounted underneath the enclosure and lights up the appropriate LED depending on the car’s distance.

In the real world, missile systems use advanced radars, infrared sensors, and other hardware to track and prosecute their targets. [Raspduino Uno] on YouTube has instead used ultrasound for targeti… ...