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 ...

[mircemk] shows how to create a simple non-contact proximity sensor using little more than an Arduino Nano board, and a convenient software library intended to measure the value of capacitors. The … ...

His first video deals with using with ultrasonic sensors. He found an interesting white paper that described measuring airflow with a single-path acoustic transit time flow meter.