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.

That’s right, these parking sensors are powered by an Arduino board, and the only extra components that were used in the project are a HC SR04 ultrasonic sensor, an active buzzer, and jumper wires.

A low-cost (~$100), do-it-yourself (DIY) ultrasonic water level sensor/datalogger has been designed, constructed, and tested for use in education, citizen/community science, and research settings. The ...

For the physical feedback, Denver has made some vibrating boxes that you put in your pockets. An Arduino polls the ultrasonic sensors and provides feedback via the boxes. This completely frees up the ...