Vibratese is a system of information transmission based on time and intensity modulated signals. The first Vibratese devices, developed by F. A. Geldard in 1957, were constructed of five

vibrating Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

modules attached to the interpreter's

chest The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

. Each vibrator was responsible for a different segment of the script, with the duration and intensity of the vibration corresponding to a particular symbol. Vibratese was initially developed as a potential avenue to transmit intelligence to military targets in compromising environments. While not touched upon in Geldard's first paper, its potential application for the

deaf Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...

and

visually impaired Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficul ...

was understood. Geldard identified three tactile dimensions that could be easily and quickly discerned by an interpreter: duration, intensity, and location.

Morse code Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code i ...

is an example of an auditory system which transmits information modulated by duration alone, and can be used in a tactile device. Geldard found that utilizing all of these dimensions, instead of just one, allowed for higher information transmission rates. Several device configurations were identified as possible, including a seven point arrangement, but five was deemed sufficient. Geldard determined that three durations of signal (100 ms, 300 ms, 500 ms), and three intensities of vibration per vibrator was a viable system, and allowed for 45 symbols to be encoded using the five vibrators. Individual symbols were spaced 50 ms apart with a 100 ms pause between words. This allowed for a theoretical maximum transmission rate of 67 words per minute, versus Morse code with about 30. To prevent ambiguity each vowel character was assigned to a separate vibrating module. To improve speed, numerals were assigned to the longest duration signals and the remaining letters were assigned according to frequency. Several of the symbol slots were assigned to common English words. Several issues were identified with the system. The amount of training time required was seen as excessive. It was stated that 30 lessons, equated as hours, was required to learn the system. Additionally, ambiguity along the short-time intensity axis was an issue. A solution offered was to add an additional time duration, while decreasing the intensity axis. Additionally, Geldard proposed a potential system using closely spaced vibrators which could transmit focal movements, like the tracing of a finger, on the subject. Such a system could be used like a Lorm alphabet.

References

External links

*http://www.cim.mcgill.ca/~haptic/pub/JP-CIM-TR-06.pdf *http://cobweb.ecn.purdue.edu/~hongtan/pubs/PhDThesis/tan.chap6.pdf {{list of writing systems Assistive technology Latin-script representations Telegraphy Writing systems introduced in 1957