Disney Research's Finger-to-Ear Sound Transmission

By Norman Chan

Hear a friend's whispers with a touch to the ear.

Before an attraction ever gets built and installed into a Disney theme park, Disney Imagineers have to invent new ways to amaze a generation of visitors that have grown up with cutting-edge technology like smartphones and tablets. That's why Disney has its own dedicated research division to experiment with robotics, computer graphics, computer-human interaction, and even material science to empower their Imagineers. Many of these research areas explore new ways of manipulating our senses, such as adding touch responses to everyday object or delivering haptic feedback using air cannons. However, a newly revealed research project exploits our perception of sound.

Ishin-den-shin, a name derived from the Japanese idiom for telepathy, is a project that allows participants to communicate by touching each other's ears. The system consists of a normal microphone which records sounds, but has electronics built in to process those sounds into an inaudible signal. The user holding the microphone can then transmit that sound by touching another person's ear, who will hear the recorded sound as a whisper.

Sounds like magic, but it's just science. Here's how Disney Research explains how Ishin-den-shin works:

"The microphone is recording as soon as a sounds of amplitude higher than a set threshold is sensed. The computer then create a loop with the recording, that is sent back to an amplification driver. This amplification driver converts the recorded sound signal into a high voltage, low current (<300 Vpp, <50 uA) inaudible signal. The output of the amplification hardware is connected to the conductive metallic casing of the microphone via a very thin, almost invisible wire wrapped around the microphone audio cable. When holding the microphone, the visitor comes in contact with the inaudible, high voltage, low power version of the recorded sound. This creates a modulated electrostatic field around the visitors’ skin. When touching another person’s ear, this modulated electrostatic field creates a very small vibration of the ear lobe."

The trick lies in the high-voltage, low current signal that's transmitted from the conductive wire around the microphone through the transmitter's body. The resulting electrostatic field creates a very small vibration that extends to the fingers. It's the same principle by which those thin panel electrostatic speakers work without using traditional electromagnet drivers. Theoretically, that also means that the sound can be transmitted with other parts of the body and not just a finger. But toe-to-ear audio transmission just doesn't sound as appealing.

Watch a video demo of Disney Research's Ishin-Den-Shin below.