This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 Ultrasonic ranging module ... cm from the HC-SR04 module), and an ear-splitting beep from the piezo-buzzer otherwise.

In this version, you'll be using a keypad instead of a simple push button to deactivate the alarm. After the buzzer ... Arduino libraries: one for the servo and another for the ultrasonic sensors.

This one is an unusual smart home project, potentially - how to monitor a fish tank’s health with an AI-enabled ultrasonic sensor system. The detailed project is highlighted on Hackser.io and features ...