Ishin-Den-Shin: Transmitting Sound Through Touch
Yuri Suzuki (Disney Research Pittsburgh)
Olivier Bau (Disney Research Pittsburgh)
Ivan Poupyrev (Disney Research Pittsburgh)
Matt Glisson (Disney Research Pittsburgh)
Alexander Rothera (Disney Research Pittsburgh)
In this project we explore the use of the human body as sound transmission medium. Called “Ishin-Den-Shin,” a Japanese expression for communicating through an unspoken mutual understanding, the technology turns an audio message into an inaudible signal that is relayed by the human body. When the communicator’s finger slightly rubs an object, this physical interaction creates an ad-hoc speaker that makes it possible to hear the recorded sounds.
A special case of Ishin-Den-Shin is when the communicator touches another person’s ear. In this case, a modulated electrostatic field creates a very small vibration of the ear lobe; the finger and the other person’s ear, together, form a speaker which makes the signal audible only for the person touched.
The Ishin-Den-Shin system includes a handheld microphone connected to a computer. When someone speaks into the microphone, the computer turns the sound into a looped recording. The recording is then converted into a high-voltage, low-current inaudible signal that flows into a thin wire connected to the interior of the microphone. This looped, inaudible signal creates a modulated electrostatic field and produces a very small vibration as the finger touches an object, forming a speaker.
The Ishin-Den-Shin technology thus can turn everyday artifacts into interactive sound devices without the need to instrument them with any special technological apparatus. It can be used to explore new approaches for inter-personal communication and can be used to transmit sound from person to person via any sort of physical contact.
A Shure 55 microphone is connected to a computer’s sound card. The microphone is recording as soon as person voice is detected. The computer creates a loop with the recording which is then sent back to an amplification driver. This amplification driver converts the recorded sound signal into a high voltage, low current inaudible signal that is connected to the conductive metallic casing of the microphone. 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 filed around the visitors’ skin. When touching another person’s ear, this modulated electrostatic field creates a very small vibration of the ear lobe. As a result, both the finger and the ear together form a speaker which makes the signal audible for the person touched. The inaudible signal can be transmitted from body to body, using any sort of physical contact. The same principle also works with inanimate objects as explained below.