One Finger Mk.II

Sinclair User

CLUB HELPS HANDICAPPED TAKE ADVANTAGE OF ZX-81 A competition to see how micros could help the disabled resulted in an idea which was developed into the one-fingered typewriter. At a time when a competition was being run on the application of microcomputers to the problems of disability, a suggestion was made at Ashley House, a Shaftesbury Society home for the care of severely handicapped men at Bognor Regis, that a little black box used for chess could be doing something useful. How about making it work as an intelligent interface between someone's disability and something a person really wanted to do? It seemed a good idea and was identified as an area which looked promising. A resident of 25 years, balanced and intelligent but permanently confined to a bed or a chair since the age of three, has a disability which means he can just about move one finger over a four-position microswitch touchplate by which he controls his electrically-propelled bedchair. The problem was that he wanted desperately to be able to write his own letters, and perhaps even his life story. So began the quest for the one-fingered typewriter. There was sufficient respect for the ZX-81 to believe it was capable of doing the job but attempting to develop a program for it seemed difficult. After two attempts to obtain help the project was shelved for a time. Then at the Regis Amateur Micro Society when ideas were requested for a club community project it seemed like something those earnest enthusiasts could do. Many club members contributed ideas and suggestions and Paul Chase, a bright young Bognorian, leapt at the chance and began to produce programs of ever-increasing application and sophistication. He had seen that if the problem could be solved it was applicable to any disabled person who could move a finger or a toe or an elbow or a head sufficiently to operate a four-position sensor that they would be able to type. It was a fascinating and exciting idea and the cost of the equipment was falling by the month. He produced not only a one-fingered typewriter program but carried through to add a current-line edit facility which resulted in virtually a one-fingered word processor. The description of the one-fingered typewriter will necessarily be brief and incomplete, since new ideas are being conceived fast. Also there are many improvements which can be made when time and money are available. The Mark 1 equipment consists conventionally of a TV set used as a monitor, a ZX-81 with 16K RAM, a Sinclair printer and a tape recorder. Additionally there are five wires soldered inside the ZX.81 to provide the four control signals required. Those wires are connected via a plug and lead to a four-position microswitch touchplate closely matching the device already used for chair control, but other control devices could be fitted for Others with different disabilities. The clever portion goes into the program. On loading, the first few lines appear automatically at the top of the screen as the text control system. It looks like this: To explain, there is a central cursor in line three which can be moved left and right and up and down according to the four signals available from the touchplate. Line two contains the alphabet sorted into order of the most-used letter frequency, split left and right, and centred on an inverse for the space function between words. That alphabetical arrangement appears a little strange at first sight but is remarkably economic in cursor movement and permits a rapid location of the required letters with a little practice. Pushing the controller up when the cursor is under a desired letter or symbol causes the automatic transfer of that letter to its proper position next in the line of text, typewriter style, and pushing it up and holding it for a short time - adjustable - results also in the transfer of the additional letter, if any, from line one, which carries the second letter of the most-frequently-used letter combinations, TH, QU, and the like. Pushing down the controller brings the cursor to operate on the lower line of characters wherein lie the punctuation marks, single character rubout (inverse R), the numerals, and the EDIT facility. In the EDIT mode a second cursor can be moved left, right, up and down through the text area to define the point of operation. The commands available are: E - enter edit mode. D - delete - you then enter the number of characters to be removed. I - insert letters words and spaces - insertions are first printed at the bottom of the screen for checking T - terminate - signals the end of the EDIT mode. Insertions are transferred to the defined point and any displaced text is re-arranged. Thus by the use of only four signals not only can all the characters be chosen fairly rapidly but a degree of text modification can be achieved which would be impossible on a normal typewriter. When the text area of the screen is full, printing follows automatically and the last two lines of text are reprinted at the top of the text area to aid continuity of thought. Printing of an only part-filled screen can be achieved by a cursor-selected COPY instruction - inverse C - and pre-programmed name and address facilities are available by selecting inverse N and inverse A respectively. Inverse P provides automatic indentation of a line for a new paragraph. A later version of the program also includes 10 or so of the most popular small words, THE, IS, AND, selectable directly by cursor. Obviously that is not the end of the story. Bright new ideas seem to arise at an average of one every 30 seconds and the difficulty will be reaching the stage of final definition, when there is still a good deal more which could be done. The best of all, though, is that there is a one-fingered typewriter which works. Upper- and lower-case letters would be a great improvement and the Sinclair printer, remarkable though it is, is not really the instrument on which to frame important personal thoughts. Equally, the loading of a program from tape is something a disabled person could well do without, since it involves having to ask somebody else to do the loading. Also a file of standard letters would be a useful facility. All those problems are easily soluble, at a price, but the remarkable thing about the project is how far it has moved on interest, goodwill and no budget; and its low-cost, value-for-money aspect is an important part of its virtues. The Mark II one-fingered typewriter looks as if it should be based on a Spectrum for upper- and lower-case letters, the possibility of Microdrive loading, and potential connection to a more sophisticated printer. If possible, the program could be put into ROM instead of RAM and the loading chore eliminated entirely. It would be impossible to acknowledge everybody who contributed to the synthesis of ideas which were worked into an operating program but without a club of enthusiasts it probably would not have happened.

'There was sufficient respect for the ZX-81 to believe it was capable of doing the job but trying to develop a program seemed difficult'