The sensor shown here is essentially two plates mounted side-by-side, attached to an Arduino Nano using the Capacitor library which uses just two pins, one digital and one analog.

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 ...

This paper shredder bin monitor is an easy Arduino project for beginners to get into. It uses an ultrasonic sensor, which is placed inside the bin, to detect the trash level.