Producing items onto a screen simply by touching the air is a marvelous thing. One way to accomplish this involves four HC-SR04 ultrasonic sensor units that transmit data through an Arduino into a ...

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.

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 ...