^InternationalE l e c t r o n i c sC o n f e r e n c eOCTOBER 6, 7, 8, 1969

P R E - C O N F E R E N C E

DIGESTAutomotive BuildingE x h i b i t i o n P a r k

Toronto, CanadaSponsored bythe Canadian RegionThe Institute of Electricaland Electronics Engineers

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Paper No. 69123 A TYPEWRITING SYSTEM FOR THE SERIOUSLY HANDICAPPED Session No. 12 ^DR. P.I.P. BOUUTON, R. PAAU, DR. K. C. SMITH |

U n i v e r s i t y o f T o r o n t o 1T o r o n t o

With improvements in nursing and medicalski l ls , a new si tuat ion has developed in whichsubs tan t ia l l y to ta l l y pa ra lyzed peop le a re be ingkept alive and given life expectancies approachingthe normal span. Perhaps the most infuriating anddisturbing problem faced by such handicappedpeop le i s the i r i nab i l i t y to commun ica te w i ththose around them. The personal i ty of such aperson remains normal or is even enhanced byreason of the struggle to make sense of l i fe insuch c i rcumstances. The chal lenge is to prov idet h e m w i t h f o r m s o f c o n t r o l o v e r t h e i r i m m e d i a t ee n v i r o n m e n t w i t h e f f e c t i v e c o m m u n i c a t i o n b o t h i n awritten and a spoken sense, and to endeavour toprovide them with a means of livelihood throughthe ach iev ing o f a wor thwh i le sk i l l .

The system to be described is a tentativestep toward alleviating the communication problemfor such handicapped individuals. It was designedfor use in the l im i t ing case o f a te t rap leg iapat ient who is con^j letely paralyzed and withoutv o c a l p o w e r .

To operate this communication system, anappropriately designed transducer is located atsome suitable control si te on the handicappedpatient's body. Any site which can provide two ort h r e e d i s t i n g u i s h e d a c t i v i t i e s i s s u i t a b l e .

The proposed system is based on the principleof developing a general instrument which can betai lored to suit many of the needs of disabled andvoiceless persons. The number and pattern ofcharacters that the patient can communicate isv a r i a b l e t o s u i t i n d i v i d u a l n e e d . A s u b s i d i a r ygoal has been to design a system which is inexpensive and re lat ive ly compact in s ize.

The proposed system consists of three units.The ma in un i t con ta ins a l l o f t he l og i c c i r cu i t r yas well as a visual display device, namely a Nixiealphanumeric tube. The second unit is a type 33Send-Receive (KSR) Teletype set . I t prov idesprinted output for the system. The third unitprovides control of the system and will containtransducers appropriate to the patient's capability. It provides control of the characters to bedisplayed visually as well as the possibility ofprintout. Both the control tmit and the teletypewriter set are connected to the main unitthrough mul t iconductor cables.

The system displays a set of pre-determinedpatterns or characters which cycle through thedisplay at a predetermined rate while the patientprovides the equivalent of a contact enclosure viat h e r e m o t e c o n t r o l . W h e n t h e c h a r a c t e r h e w i s h e sto communicate is d isplayed, the pat ient deact ivates the "swi tch" , which s tops the cyc l ing of thec h a r a c t e r .

A pa t i en t w i t h su f fic i en t capab i l i t y may t henactivate another switch to print out thejcharacterdisp layed on the typewr i ter. The pat ient may proceed to select yet another character froiji thecycl ing set and repeat the process of typing asn e e d e d . C o n t r o l i s a l s o a v a i l a b l e t o r e v e r s e t h eorder of the cycling patterns so that a patientwho overshoots the character, and has sufficientcapability, can return to the character lie wantsin a matter of one or two counts. The cycl ingrate is made adjustable to suit the capability ofe a c h i n d i v i d u a l p a t i e n t .

The black diagram of Fig. l shows the principles of operation of the typewriting system. Anad jus tab le - ra te c lock t r iggers a 6 -b i t modu lo -48synchronous up/down counter. The d i rect ion ofcount is governed by an externa l cont ro l ; A buffer output stage is used to avoid overloading thecoun te r. The charac te r decoder i s a mu l t ip le -ou tp u t r e c t a n g u l a r d i o d e m a t r i x . I t s o u t p u t f e e d stwo devices, namely, the character composit ionencoder and the te letype ASCII code generator. Inthe character composit ion encoder each input act ivates some subset of the 15 Nixie segment drivers.The selected Nix ie dr ivers then energize theappropriate segment in the Nixie tube to form thecharacter or p ic ture des i red. The ASCII codeg e n e r a t o r s i m u l t a n e o u s l y t r a n s l a t e s t h e d e c o d e routput to the required te letype code which ist ransmi t t ed th rough a su i t ab le i n te r face d r i ve r t ot h e t e l e t y p e m a c h i n e . j

Special display memory is not required sincein fo rma t i on i s f ed d i rec t l y t o t he d i sp luy f r omthe counter. Once the desired character is placedon the d i sp lay a pa t ien t who i s su ffic ien t l ycapable can enable the print command to init iatetyp ing o f the charac te r.

F ig .2 ind ica tes in schemat i c fo rm t ie c i rcuitry required to emplement the block diagramd e s c r i b e d .

Regarding the versatility and adaptability ofthe system, it may be obvious that by changing thecounter one may vary the number of displjayed patterns. By simple changes in the charactjer composi t ion mat r ix and the ASCI I encoder, d i f fe rentsets of patterns can be implemented. In! thelimiting case, only a few picture symbols may beapp rop r i a te . So t ha t i n t e r change o f c i r cu i t s canbe accomplished easi ly, al l are wired on plug-incards . Though a t p resent , cont ro l t ransducersare simple microswitches, card receptacljes areprovided for the adaptat ion of the system toother means of control including nerve c^ctivityd e t e c t i o n a n d e y e m o t i o n d e t e c t i o n . |

The main unit has been packaged into a 8" x12" X 9" high aluminum enclosure. Mater ia l costis about $400 excluding the opt ional te letypemachine which may be purchased for approx. $800.

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R e f e r e n c e s

1 . R.G. Mai l ing and D.C. C larkson, "E lec t ron icCont ro ls fo r the Tet rap leg ic" (Possum),Paraplegia, Vol .1, No.3, 1963.

2 . J .Y. Pe r ron , "Typewr i t e r Con t ro l f o r anAphas ic Quadr ip leg ic Pat ien t " , Journa l o fC a n a d i a n M e d . A s s o c . , Vo l . 9 2 , 1 9 6 5 .

3. O.E. Roy, "A Communication System for theHandicapped", Meid. Elect. Bio. Eng. Vol.3,Pe rgamon P ress , 1965 .

This work was supported in part by theN a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a u n d e r G r a n t# A - 3 1 4 8 .

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