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.

John Boxall, author of the new book Arduino Workshop, shares a few of the projects from his book on how to get started with the microcontroller. (Click the links to see PDFs of the complete ...

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 ...