It is a classic scene in many movies and television, where to share a secret someone puts their mouth very near another's ear and whispers. Researchers at Disney Research though have a new way to secretly communicate by touching someone's earlobe.
Ishin-Den-Shin is a Japanese concept of communication through understanding instead of words, and is the name of this new technology. It utilizes a Shure microphone with a metal body, which the secret is whispered into. The sound is then processed by a computer to make it a high-amplitude, low-power signal, which is sent along a thin wire that wraps around the microphone. As the surface of our skin is conductive, the signal travels over the secret-holder's body, creating an electrostatic field. When that person touches the earlobe of another, fluctuations in the signal and field cause the earlobe and finger to act like a speaker, vibrating back and forth, recreating the sound. This sound can only be heard by the second person.
While this technology is a bit too obvious for sharing secrets, it could see use for turning almost any object into a sound device.
Source: Disney Research