Med. & Biol. Eng. & Comput., 1979, 17, 489-491

Fingercom-an electronic communicatorfor the disabled Z. F. J o u b e r t Training and Information Division, National Electrical Engineering Research Institute, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, South Africa

Abstract--A description is given of a new type of character input tablet consisting of a 16-segment layout of sensitive pads that are activated by a finger in a normal writing action. A character is built up segment by segment in an electronic display that acts as a monitor, and is then transferred to a multicharacter display for visual communication. By incorporating a dot-matrix printer, the unit becomes an electronic typewriter that converts "writing" motionsin to print. The finger communicator could be modified and used as a writing exerciser and trainer by preschool children and in rehabilitation centres. Although the new input technique is slower compared with direct selecting keyboards, it has certain advantages over keyboards and encoding or scanning mechanisms which makes it especially suitable for certain types of physically handicapped persons. K e y w o r d s - - A i d s for the disabled, Communication aids, Electronic communicators, Electronic typewriter, Input mechanism, Segmented keyboard

1 Keyboard mechanisms for the disabled CERTAIN disabled persons are capable of gross movement only and are therefore unable to use a pen or operate an ordinary typewriter. They often have no alternative means of communication other than elaborate and bulky scanning or encoding mechanisms by means of which characters or words have to be manually selected before being displayed on electronic readout units or printed on modified typewriters when printed copies of their communications are required.

the conductive pads were connected to the input of m.o.s, inverters. The segments are activated by earthing the input. This is done by connecting the body of the person to the earth connection of the instrument and by touching the metal pad with a fingertip.

R]E3EFGHI IKL MNOPgR 5 TUYNXEZ

/\///

2 New type of constructive input tablet ///\/ /// \/ A new type of input tablet has been developed for use by those disabled persons who can trace the ~6 form of large characters with their fingers. The input unit is constructed in the form of a large 16-segment pattern, as used in certain electronic displays (see Fig. 1). Each segment o f the pattern consists of a sensitive pad that is activated by a finger tracing the form of ~he desired character in a normal writing motion. This activation causes the respective segments to be displayed one by one on an electronic readout (monitoring unit) until the required letter or figure has been completed. If the character that appears on the monitor is not correct, it can be erased by activating an 'erase' control pad; otherwise it is transferred to a multicharacter display (the 'message' unit) or a printer by activating a 'transfer' pad. Various techniques can be used for the construction of the sensitive segment pattern. In the first prototype a printed-circuit board was used and

122

Fig. I Received 2nd December 1978

EETBqE

h c de s , J kZ nTn o F ZZr u v VTrY z Letters (both upper and lower case) and figures formed by using a 16-segment pattern

0140-0118/79/040489 -F 03 $01.50/0 9 IFMBE: 1979

Medical & Biological Engineering & Computing

July 1979

489

A thick stencil with smooth slots and curves is used as a finger guide to help the disabled or blind person trace the form of the letters and figures necessary to convey the message. A modified tablet is being constructed with monitor lamps built into the segments. As each segment is activated, its monitor lamp will start glowing, thus allowing persons who have to concentrate intensely on their finger movements to focus on one workface only. As soon as the character that has been generated in the tablet is transferred to the visual communicator, or message unit, the segment lamps are restored for the next activation. 3 Classification of the fingerwriting tablet According to VANDERHEIDEN(1974, 1978) existing character-generating mechanisms are based on either scanning, encoding, direct selection or a combination of the three techniques. The new tablet (referred to as the Fingercross tablet) is the only mechanism known to the author to employ a constructive mode to initiate electric signals for the operation of alphanumeric displays and printers. The Fingercross approach can be considered a variation to the encoding technique, where the code that is used is defined in terms of geometric units, namely, line segments. However, it is more appropriate to class this approach as a new 'constructive' technique of generating communication signals.

4 Use of the tablet in a finger communicator (the Fingercom) The Fingercross tablet forms the basic element of a finger communication unit (the Fingercom), which consists of a Fingercross tablet, a monitor and a message unit (see Fig. 2). The error-correcting feature, introduced into the unit by the use of the monitor and the control action before the characters are transferred to the message unit, is an important advantage in communicators for handicapped persons who tend to make mistakes because of their physical disabilities. The message unit of the first prototype consists of a multicharacter 1.c.d. unit displaying easily-readable 16-segment characters, approximately 18 mm high. The last character position is used as a monitol and is cleared when the 'erase' control segment is activated. When the 'transfer' control segment is activated, all the characters in the message unit are moved to the left (see Fig. 3). The Fingercross tablet can be manufactured in any convenient size, and can be used remotely from the rest of the equipment; e.g. it can be mounted in the position most convenient to the disabled persons. The physically handicapped person often suffers from uncontrolled upper-arm movements that affect his finger movements. To overcome this problem, the upper arm is bound to the body to restrict 490

movement. A convenient position in which to mount the Fingercross tablet in such cases is on the stomach. One of the interesting features of the 16-segment Fingercom is its ability to display, in addition to the alphanumeric characters, various other symbols that can be used to represent words, e.g. the socalled Bliss symbols (BLIss, 1966). A modified version of the Fingercom with a built-in dot-matrix printer is being constructed.

5 Comparison with other input mechanisms The Fingercross technique uses a natural writing motion of a known pattern, whereas in the direct selecting mechanisms the positions of randomly arranged keys, i.e. a difficult pattern, must be learned, which requires fine finger control and an ability to operate the individual keys. In the case of the encoding technique, a difficult code must be learned before communication can be established. A special feedback technique is used with the Fingercioss tablet to confilm the correctness of the character generated before it is transferred to the actual communicator. A similar control action could be used to check the contents of the 'message unit' before transferring it to a printer, thus reducing the frequency of 'typing errors' and other mistakes. No similar feature is used with other input mechanisms.

11lb 1-151EIEIr'II I 131II5PILIIqlXI

A

r .......... q I\1/I T ~ electronics L_-. ', I i/i\l monitor .

L- .

.

.

.

erase

.

.

.

.

.

.

.

.

.

-1

store

delete

active areas

Fig. 2 Schematic of the finger communicator (Fingercorn) also showing the segmented layout of the Fingercross input tablet with additional control segments

Medical & Biological Engineering & C o m p u t i n g

J u l y 1979

By integrating the visual monitor with the actual workface of the input tablet, the attention is largely concentrated on one workplane. In the direct selection mechanisms the attention has to be divided between a keyboard and the print or display. In the encoding mechanism a third dimension needs attention, namely, the code. In the case of the Fingercross the feedback also consists of a large format, while, in the others, small print or displayed characters are normally used.

some form of automatic reward signal emitted every time a correct symbol was generated in a second display. The Fingercom could also be used in rehabilitation centres by persons in need of writing exercises to acquire or regain fine finger control before returning to ordinary writing or proceeding to the use of direct selection keyboards. 6.3 Suitability for nonhandicapped persons The Fingercross tablet is plimarily intended for use by those handicapped persons capable of gross motor resFonses, but not of the hand movements and finger dexterity necessary for ordinary writing or typing. However, the advantage of a large character variety and the inherent error correction features could also be of an advantage to the nonhandicapped person. A modified tablet adapted to the standard 5• 7 dot-matrix format has been designed to further expand the range of characters and symbols that can be used with dot-matrix displays and printers. 7

Fig. 3 First prototype of the Fingercom

A greater variety of characters and signs is possible with the Fingercross technique, without the need for additional control keys and a new 'typing head', as would be required in the standard cquipment supplied with other mechanisms. However, the Fingercross technique is noimally much slower to use than the direct selecting units, although it does not require the same degree of fine finger control of the latter.

Use of Fingercross technique encouraged

It was decided not to apply for a patent but rather to encourage the use of this technique as much as possible for the benefit of the disabled. Various applications for input devices based on the Fingercross principle have been formulated and a development programme is being prepared in co-operation with the engineering departments of local universities. A few applications for nonhandicapped persons are also being pursued.

6 Variations of Fingercom units 6.1 Portable unit with extension facilities A small portable version of the basic Fingercom unit with limited display facilities, e.g. 8 characters, is envisaged, to be used for basic communication requirements only. Facilities could be provided to link the unit to various other output devices at home, in the classroom or at work, such as television sets for a large display, printers for hard copy, cassette recorders to store a large volume of character information and modems for communication with computers and computerised equipment over telephone lines.

References

6.2 Writing exercisers One of the main features of the Fingercross technique is its use of a writing motion. A modified version of the Fingercom is being prepared to be used by preschool children learning to write. All the elementary writing motions would be practised against examples set up on one display unit, with

VANDERHEIDEN, G. C. and HARRIS--VANDERHEIDEN, D.

Medical & Biological Engineering & Computing

BLISS, C. K. (1966) Semantography (Blissymbolics), Coogee Sydney: Semantography-Blissymbolics Publications. HOLLIS, J. H., CARr~IE8,J. K. and SPRADLIN,J. E. (1976) An approach to remediation of communication and learning deficiencies. In LLOYD,L. L. (Ed.) Communication assessment and intervention strategies, University Park Press, 276, 277. JOUBERT,Z. F. (1978) Electronic aids for the handicapped (in Afrikaans). Proceedings of the National Congress of the South African Association of Occupational Therapists, The Occupational Therapist and Communications, 12-23 August, 137-155. (1974) Communication, techniques and aids for the non-vocal severely handicapped. In Communication assessment and intervention strategies, Baltimore, University Park Press, 607-652. VANDERHEIDEN, G. C. (Ed.) (1978) Non-vocal communication resource book, Baltimorei University Park Press, II. July 1979

491

Fingercom--an electronic communicator for the disabled.

Med. & Biol. Eng. & Comput., 1979, 17, 489-491 Fingercom-an electronic communicatorfor the disabled Z. F. J o u b e r t Training and Information Divi...
NAN Sizes 0 Downloads 0 Views