Acoustic levitation can be used to make small objects float in midair, which is a neat trick that seems to magically defy the laws of physics. In reality, of course, it’s physics that make acoustic levitation possible. Sound waves are projected in a vertical cone to create a field. Then anything small and light enough that is placed in that field will be suspended in place and levitate. In their newest YouTube video, ET Discover shows how they built a wearable acoustic levitation device that can be used to suspend objects between their fingertips.
ET Discover built this wearable acoustic levitation device for a student project, and was kind enough to create a build video and upload their code and schematics. In principle, it works the same as any other acoustic levitation device. Transducers are placed facing each other along the same vertical axis. They produce a sound wave at a specific frequency, and that causes pockets of high and low air pressure at the points where the waves are at their closest and furthest points. By using the proper frequency — 40KHz in this case — multiple levitation zones are created at equidistant locations where small objects can float.
For this build, ET Discover uses the transducers from an ultrasonic distance sensor. Normally one of those transducers is used as a receiver, but it works as a transmitter in a pinch. That’s controlled by an Arduino-compatible ATmega328P microcontroller, and the voltage is boosted by an L293D IC (integrated circuit) that is normally used for driving motors. Those, along with the necessary discrete components, are soldered onto a custom PCB fabricated by JLCPCB. This device works with the transducers mounted onto a base, but can also be used by simply putting the transducers between your fingers.