The set-up process is very simple, and best understood by referring the wiring diagram. If everything goes right,you should see the burning eye of the red LED when there is no object in the safe-zone ...

Inside [Klaus]’ device is an Arduino Uno, an HC-SR04 ultrasonic distance sensor, ... He’d have got 3-4 sensors and a little LED/beep display to be placed on his dash. Report comment.

The treat in question is detected by an SR-04 ultrasonic distance sensor connected to an Arduino Nano. All in all this was a highly successful build as far as neighborhood entertainment value goes.