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 ...

Thankfully, there's an Arduino project to help you out with that — this gesture-controlled system for VLC. It features two ultrasonic sensors mounted on your computer's display monitor (much ...

The code includes two Arduino libraries: one for the servo and another for the ultrasonic sensors. The main code is a simple 14-line piece with a simple if-else statement you can readily modify.

Instead, it relies on an ultrasonic distance sensor to detect a hand (or foot) waved in front of the door. An Arduino Leonardo runs the show, sounding a buzzer when the ultrasonic sensor is triggered.