FingerWhisper Prototype uses human hand as part of the receiver

FingerWhisper Prototype uses human hand as part of the receiver


Yokosuka City, Japan — The FingerWhisper currently being developed at the NTT DoCoMo Yokosuka R&D center, in its quest for future communications possibilities, is a new kind of wearable telephone handset that utilizes the human hand as part of the receiver.

Worn on the wrist, this watch-like terminal converts voice to vibration through an actuator and channels this vibration through the bones to the tip of the index finger. By inserting this finger into the ear canal, the vibration can be heard as voice. We call this process the bone conduction receiving mechanism.

Since the microphone is located on the inner side of the wrist, the posture of the user’s hand, when using the terminal, is the same as when using a cellular phone.

Limits to miniaturizing existing interfaces

Efforts toward developing the FingerWhisper began back in 1996. This line of research sprang to life when the limits of mobile phone miniaturization was reached after 20 years of drastic receiver shrinkage. In fact, the distance between the speaker and microphone is now shorter than the actual distance between the ear and mouth. Miniaturization beyond this point may reduce usability.

The FingerWhisper concept was born when researchers began questioning whether it was feasible to use bone conduction to replace a part of the receiver with the human hand.

FingerWhisper also presents an elegant solution to another dilemma: the number keys on mobile phones have reached the smallest dimensions practical for fingertip use. The FingerWhisper eliminates the need for buttons altogether by using an accelerometer to detect the tapping action of fingers. Combinations of the finger tapping sequence serve as Morse code-like commands such as “talk” or “hang up”. Through a 5-stroke tapping sequence, approximately 30 commands can be issued.

Toward an easy-to-use mobile interface for everyone

FingerWhisper, using the bone conduction receiving mechanism, delivers the received voice clearly even in noisy environments and allows the user to speak in a lower volume of voice when compared with ordinary handsets. Its watch-like design makes it easy to wear and frees the user’s hands when not in use. Furthermore, the advantages of a natural looking pose cannot be overly stressed.

Earphone-microphones may be popular in the United States, but they never caught on in Japan. This is probably because people are reluctant to be seen as talking to themselves. Although no terminal is held, FingerWhisper usage conveys the impression of talking on a mobile phone, and alleviates any sense of discomfort. FingerWhisper’s watch-like shape makes it easy-to-wear and the mobile phone-like hand posture enables natural operation. Thus, FingerWhisper potentially points the way to a world full of wearable interfaces.

“Fulltime – wear” interfaces for realizing ubiquitous era

The FingerWhisper as an interface for 24-hour use is an exciting prospect for the coming ubiquitous era.

Currently, the concept of ubiquity lends itself to placing interfaces in the surrounding environment. The wearable terminal offers an alternative solution, with people carrying the interfaces and sensors themselves. Both approaches have the same objective: a world in which information is accessible anywhere, anytime.

According to the prevailing concept of wearable computers, people would one day wear miniaturized CPUs. But now that continuous mobile connections have become available, this concept is obsolete. One need only wear interfaces and connect via mobile network to CPUs far away.

From our standpoint, FingerWhisper is one of the new paradigms in ubiquitous computing.

FUKUMOTO, Masaaki and TONOMURA, Yoshinobu
“Whisper: A Wristwatch Style Wearable Handset”,
CHI99 Conference Proceedings, pp112-119, Pittsburgh, May 1999.