Inside [Klaus]’ device is an Arduino Uno, an HC-SR04 ultrasonic distance sensor, ... He’d have got 3-4 sensors and a little LED/beep display to be placed on his dash. Report comment. Reply.

The sensor package comprises an ultrasonic distance sensor, a microcontroller running Arduino firmware, a micro-SD card for datalogging, a real-time clock for timekeeping and sleep functions, and an ...

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.