An Arduino Leonardo runs the show, ... a HC-SR04 ultrasonic sensor, and a 1602 serial LCD. Once the gadget has been mounted in the proper position and activated, ...

When you power the Ultrasonic Experiment board up in range finder mode, the LCD will read out the distance between the sensor and the object that it is lined up with in centimetres.

This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 Ultrasonic ranging module,used here for non-contact object detection purpose. The HC-SR04 module includes ultrasonic ...

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.