THE EASY CHAIR
`BY
`
`Jim Williams
`
`Greg Welch
`
`..
`
`:··
`
`SCEA Ex. 1035 Page 1
`
`

`
`-----
`
`THE EASY CHAIR
`
`M&y :s , t 9so
`
`WHAT IS IT?
`
`Microprocessor control l ed wheelchair
`- A1d t o handicapped (cerebral palsy victims)
`Learning tool for children wi t h inexperience in mobility
`Effective means of introduction to powe red mobil i ty
`- ~unded by Tr,e Wabash Center ( for handicapped children)
`in Wes t Laf a yette, Indiana
`
`I
`
`SPECIFICATIONS
`
`- ·Must a<l<l saf egcwrds to power ed mobi 1 i ty
`Mu!!t .int roduce a "force-free" method of input
`- Should be remo v a ble without defacing the wheelchair
`- Shoul d be adaptabl e as chi l d devel ops mntor skills
`
`DESCRIPTIONS
`,
`
`Overail bloc~ diagram 1
`' > Touch pad -
`crtr'
`::r > Ultrasoni c s
`G > Computer ~ ~~
`1 > Tone genera tor
`' > Mot·dr con~rol
`::r > Power supply
`
`. ;
`TEST RESULTS
`c
`- Touch
`' , >
`>
`c
`Motor
`>
`
`•'
`
`Pad .. ~ Ultras onics
`Verif1ed hardware operat ion <general)
`Used sof twar.e tes t . routinas
`contn;,l .
`M~nitored with · o sciltoscope
`= I~itial design produced incorrect references
`= ~edified to better meet speci~ications, and
`.allow ,for cfff!i'C!t l< range ,\ld j u stments
`- Power supply ·
`> Monitored battery voltage wi t h stora ge ' scope
`_,,.._.. = Developed plots and d etermine d that curre nt
`-~ · design was suffic i ent
`- Regulator moved outside of enclosur e for
`·reduced temperatur e
`
`TIME ACT I ON PLAN
`~ - Maj~r port ion c ompleted on time <or ahead of schedule)
`
`COST
`
`O~valopme nt cost slightly e x ceeded pro; e c ted cost (due to
`mi sc:e.ll aneoGs development e :< penses)
`
`. ... .,
`
`SCEA Ex. 1035 Page 2
`
`

`
`THE EASY CHAIR
`
`May :s, 1986
`
`WHAT I S IT?
`
`•
`
`Microprocessor controlled wheelchair
`- Aid to hand1capped (cerebral palsy victims>
`Learning tool for children with inexperience in mobility
`Effect1ve means of introduction to powered mobility
`- Funded by The Wabash Center (for handicapped ch1ldrenl
`in West Lafayet te , Inqiana
`
`SPECIFICATIONS
`
`-Must add safegaurds to powered mob ility
`- Must introduce a " f or ce-free" method of input
`Should be removable without defacing the wheelchair
`Should be adaptable as child develops motor ski l ls
`
`DESCRIPTIONS
`
`Overall block diagram
`> Touch pad
`> Ultrusonics
`> Computer
`> Ton e generator
`> Motor control
`~ Power supply
`
`TEST RESULTS
`
`- Touch Pad • Ultrasonics
`> Ver1fied hardware operation Cgenerall
`> Used software t est routines
`Motor control
`> Monitored with oscilloscope
`= Ini tial de5ign produced incorrect references
`= Modified to better meet specificat ions, and
`allow for offset & range adjustments
`- F'ower supp l y
`> Monitored battery voltage with storage 'scope
`= Developed plots and determined that current
`design was suFficient
`= Regulator moved outside of enclosur e for
`reduced temperature
`
`TIME ACTION PLAN
`
`- Major portion completed on time (or ahead of schedule>
`
`--·
`
`COST
`
`'
`
`Development cost sl1qhtly exceeded projected cost Cdue to
`miscelldn~ous development expenses)
`
`SCEA Ex. 1035 Page 3
`
`

`
`TABLE OF CONTENTS
`
`The E•s y Chair
`
`TOPIC
`
`FIGURE LIST
`ABSTRACT
`.
`INTRODUCTION
`
`THE INFRARED TOUCH PAD
`Specifications
`Block Diagram • .
`
`Detailed Bloc k Descript1ons
`The Row Decoding Block
`The Column Decoding Block
`The Extra Decod1ng Block
`The Touch Pad Block . .
`The Row/columr Detect Block
`The Menu Select Detec~ BlocK
`
`General Discussion
`
`THE ULTRASONIC RANGING SYSTEM
`Specifications
`Block Diagram . .
`
`Detailed Bloc k Descriptions
`The Directional Transducer Block
`The Tone Generator Block . . . .
`The Additional PIA and T1mer Blocks
`
`General Discussion
`
`COMPUTER AND MOTOR CONTROL
`Specifications
`Sleek Diagram .
`
`Detailed Block Descriptions
`The Computer Block
`The Motor Control Block
`
`General D1scuss1on
`
`CONCLUSION
`
`.
`
`Appendix A: EXTfiA FIGUPES
`qoo~"d~ 1 D: ~OFTWARE CUT~[NES
`Appe~olx C: SOFTWARE LISTING
`~ppcndiY 0: COSTING
`Appendix E: BIBLIOGRAPHY . .
`
`i
`
`PAGE
`
`ii
`1
`2
`
`5
`7
`
`7
`8
`8
`9
`10
`1 1.
`
`14
`16
`
`16
`18
`18
`
`19
`
`20
`21
`
`21
`22
`
`24
`
`. '
`
`1(17
`108
`
`SCEA Ex. 1035 Page 4
`
`

`
`The Easy Chair
`
`FIGURE DESCRIPTION
`
`FIGURE LIST
`
`1.0
`1.1
`
`1 ? . -
`
`1. 3
`
`THE EASY CHAIR
`. . . .
`The Easy Chair
`The Original Electrtc Wheelchatr
`Added Devices .
`•
`.
`.
`.
`.
`.
`The Easy Chair Block Diagram
`
`2 . 0
`2 . 1
`2 . 2
`2.3
`2 .4 ,.0
`2. 4. 1
`2.5
`2.6
`
`THE INFRARED TOUCH PAD
`.
`.
`.
`.
`The Infrared Touch Pad
`Touch Pad Bloc k Diagram . • . .
`Touch Pad Control Word Diagram
`Sample LED/Transistor Circuitry
`Touch Pad Schematic .
`<Touch Pad Schematic)
`Printed Circuit Board and Components
`P1ctorial ~1th cut-awav
`
`3.0
`3. 1
`3.2
`3.3
`3.4
`3 . 5
`
`4 .0
`4. 1
`4.2
`4.::'
`4.4
`4.5
`4.6
`4.7
`4.8
`4.9
`4. 10
`4. 11
`
`THE ULTRASONIC RANGING SYSTEM
`.
`.
`.
`Ranging Module
`Ultrasonic System Block Diagram
`Ranging Module Schematic
`Timing Diagram
`Tone Generator Schematic
`Additional Parallel Group Schematic
`
`Computer
`
`COMPUTER AND MOTOR CONTROL
`SCCS-85 Single Board
`Block Diagram . .
`CPU Schematic .
`.
`.
`.
`.
`.
`Memory Schemattc
`Timer Group, I/0 Addressing Group Schemattc
`Serial Group Schematic
`Parallel Group, Interrupt Group Schemati c
`Bus Connector Schematic
`Power Supply Schematic
`Motor Control Schemat1c
`Status LED's and Control Switches
`Connectors and Jacks
`
`i i
`
`PAGE
`
`1
`2
`3
`4
`
`6
`7
`8
`10
`25
`26
`1:
`'2.7
`
`15
`16
`28
`17
`29
`30
`
`22
`21
`31
`32
`33
`34
`35
`36
`37
`38
`.,.,. _._,
`39
`
`SCEA Ex. 1035 Page 5
`
`

`
`The Ea ~ y Chair : ABSTRACT
`
`P ags 1
`
`ABSTRACT
`
`The Easy Chair is a microprocessor controlled e l~ctric
`wheelchair for small childrer1 witt1 muscular disorder •· .
`
`Bec~use of the uniqU!I 1nethods of control, this s prci a l
`wheelchair c~n be used by children with bot h limited muscular
`dexterity and str eng th .
`
`Also, because of sevQr·nl mafegaurds i ncorporated into t h e
`design , even chi l dren with limited experience in mubility can
`operate the p owerf ul wheelchai r safely.
`
`The following report details the design and theory of The
`Easv Ch~ir. It is assumed that the reader has some degree of
`knowledge 1n the field of electrical engineering .
`
`FigLlre l.C•
`
`T~l8 Easy Chai r
`
`SCEA Ex. 1035 Page 6
`
`

`
`The Eas y Cha ir1 I NTRODUCTION
`
`Page 2
`
`I NTRODUCTION
`
`is a vF.r·y sign i fi cant
`Thf? development of Tha E-".SY C:llni ,-
`advancement for three main reasons. First of all , for· m.~ny years
`small children with musct•lar disord~•-s have had severly limited
`opportunit1es to acquire ~ny e~p erience in mob1lity. Secondly ,
`this lack of mobility lind ted thr opporturd tir:?s to inili<.1t.e
`communiCi;:\ti.on with o ·ttH:ws. Thirdl y , this li.ICk o ·f communicati on
`li mi t ed further their learning capabilities.
`
`The original idea for such a wheelchair belongs to Professor
`George Karlin of the Special Education department at Purdue
`University. Professor Kar·lin first conceived such a device •~hile
`working with cerebral palsy victims at The Wa bash Center,
`Lafayette, Ind iana . George Karlin also acted as a n intermediator
`bet wee n the desi gners and the physical therapists at the cen t e r .
`
`_ThE~ ide,\ behind a microprocessor· controlled •~h~•el cha ir <The
`Easy Chair) is to provide a safe mode of transportation for young
`children •~i th muscular· disor-ders surh c>.s cert?br·ul palsy. Because
`the users will be so youn'), typiCi'llly b~o to si:: years old , the
`chair was envi$ioned as being equippBd with a var iet y of special
`devices. Th~se devices ~Juuld nc:rt only allo1·1 them t·o cc·1ntrol
`wheelchair movement with only limited musclJlar fore ~ , but will
`also protect them from any undesireable circumstances.
`
`The original electr·ic NhF.>el ch·:ti r· cnmw;; l:'fl"ippr--d ~1\ til a
`Damaco 088 Add-On pol,llJr unit. Thir; unit inclL\tfes battE'ries, the
`drive units (motors and controllers), and a proportionAl joystick
`ccm·t:roll er·.
`
`Figure 1. 1
`
`Tl 1e Or i g i 1'\/.11 El ectr· i c:
`
`l•lheel c:h a i r
`
`SCEA Ex. 1035 Page 7
`
`

`
`The Eas y Chair :
`
`INTRODUCTI ON
`
`Page 3
`
`The Ea s y Chair consists of this ori gi na l wh e e lcha ir , wi th
`the a dd i tion of three e xtra devices :
`( 1 ) rm in r r •trcd l:!:!uch p •. •d
`<2 > An ultrasonic ranging ~ya t em
`(3) A computer cuntrol system
`
`These three additiorH.'Il d evicaE; m:1t o 11 l y n1a l.: o oper ation b y
`h a n d i capped c h i ldren more feasable, but they al s o give the
`wheelch a ir a n added measure of control a n d safety .
`
`F igun1 t . 2
`
`SCEA Ex. 1035 Page 8
`
`

`
`The Eafiy Chair ;
`
`INTRODUCTION
`
`Page 4
`
`Shown below is a general block diagram for The Easy Chair
`which should give t he reader ~m overall irlea or how thP dlfferent
`dev1ce3 interract.
`
`A'
`
`l)l ho.sm; c
`Modv..lt.s
`
`Motor.s
`
`Figure 1.3 The Easy Chair Block Diagram
`
`t ouch
`This repor t begins IHth the discussion of the inf r ared
`pad, 1ncluding thoughts about why such a dev1ce was chosen . Then
`it explores the design and theory of the ultrasonic ranging
`system . Finally, it addressPs the computer crn1trol svstem , along
`with the circui tr y requ1red to control the ortginal wheelchai r .
`
`SCEA Ex. 1035 Page 9
`
`

`
`Th e Easy Ch a i r: THE INFRARED TOUCH PAD
`
`THE INFRARED TOUCH PAD
`
`SPEC IF I CATI ONS
`
`The infrared touch pad is to be known as the input system
`for the control of the chair.
`It is thought of as the only
`real-time method of input to the computer control system.
`Therefore, it must meet several requi r eme nts which will allow 1t
`to be used to alter the current system c onfigurations, or just to
`control the chair .
`
`S p eci f i cat ions for t he Easy Chair were outlined b y a n
`Occupational Therapist , Ph y s ical Th e r ap i st, and a c lassroo m
`teache r fr om The Wabash Center in Lafayet te , Indiana .
`Th i s
`outlining was assist e d by George Karlin, Special Education
`project coordinator at Purdue Un1versity, Lafayette , Indiana.
`
`!)
`
`,L ~as deter~ined ~het a touch senstt1ve :nout sur,aca
`recuir:r.g ~111~al pre ssure ~oul~ bes: s u1t t,2 n~eds of ~h~
`s~a:l cn:~dren. T~e srste~ reedec t~ t e 6da~t4b!e to
`dif'erent ch:ldren, s~me of whom are incaoaole of generatin g
`high response force .
`
`2) The touch-pad should use a common medium for set-up , to
`1nc rease the indep e n~ a n c e of the system and 1ts use r s . Th is
`is t o sa y thi t
`i t s hou l d be poss1ble to s imply plug in or
`unplug the touc~-pad 1 and to sw1tch be tween the pad and th2
`curr ent joyst1ck Mith l1ttle or no ef'ort .
`
`~~
`
`It should be totally se lf-contained as a unit , elec t ronic s
`an d a l l. Again, thi s wo uld increas e the :ndepen danc e of the
`s ystem.
`
`4l The touch-pad should be constructed in such a way that it
`could be a ttached t o th e c~rrent center of'-set zount1ng ar m
`o; the whee!chal' (which swings out of the way of the userl,
`with the opt1on of r esting on the lap tra y of the cha1r .
`These two ~ethods Will result 1n the touch- pad be:ng as
`a~bidextrous as poss ibl e.
`
`51
`
`~)
`
`Th ~ un1t should be lar ge enough to be eas ily viewed and
`touched, but small enough so as not to be o'trusive to the
`user and the ~heelch ai r . A geniral touch - pad area of t en
`inch es by ten 1nches was set for Initial dir~rsions.
`- ~~ s1:e a~d l~:at~o~ s =: t~2 i~~~o!s ~, t~e t~~=~-~ad !use~
`~~ ccrtrc: t~e ~tr;::~ei-~ ~~s~ be crc~r:=~et!e. - h:: w:~l
`a ~ :~moda~2 d1f'erer~ ~anqes of ~ct1c~.
`
`SCEA Ex. 1035 Page 10
`
`

`
`Th a . Easy Ch air: THE I NFRARED TOUCH PAD
`
`Page 6
`
`7) The to uch pad ~u st be Qoi st ure pr oof . Chi ldren with s uc h
`hand i caps as cerebral pa l s y f r equen tl y h a v~ ora l motor
`pr oblems whi ch r esult in e: ce ssive dr ool i ng. Any reasonabl e
`amount of moistur e shou l d not ca use t he whee l chair to
`111al f unction .
`
`t o t al
`I n th e early desi g n stages, it had been thought t hat a
`hardware solut ion wa s
`t he onost rel1'"'ble and consi st.o:ont s o l ution
`to the probl e ms p r esen t ed for a
`t o uch pad. However aft e r
`car efull y studying that rou t e, a n d
`t esting the results , it was
`determi n ed that a combination el f <:•ppro::imately equc>l a mounts of
`har dware and soft ware would al l ow the mos t fl e:: ible des ign .
`Th e
`following sections desc r i b e the p r esent s o l ution , and h ow it i s
`i mplemented.
`
`STOP
`•
`
`I' I
`
`F1gure 2 . 0 The Infrared Tootch F"..:lcl
`
`SCEA Ex. 1035 Page 11
`
`

`
`The Easy _chair 1 THE I NFR€1_13£Q T01/.i;):L..F'e_p _______ ,_· -- - - · -.. · - - PagJLZ.
`
`BLOCK DIAGRAM
`
`It
`The bl oc k diagram for the touc h pad is shewn below.
`consists of six main blocks wt1ich includ•
`the row decoding
`(selecting) block, the column decoding b lock , the extra decoding
`block <which includes the menu-select decoding! , the touch-pad
`bl ac k , the r aw/column detec t block, and the menu-select detect
`block . Each of these blocks will be d iscussed in g reat er detail
`in the following sections.
`CSee also F i gure 2 . 4 Schematics)
`
`sees- ss
`MltROCOM PVTtR
`
`TOVCH·PAD
`
`ROW /t:.OL
`TOUtH ~t.flttT
`
`MitNU $ELH1
`T'OVt.N DtTE.tT
`
`!".TURN
`
`Figure 2 . 1 Touch Pad Bloc k Diagram
`
`I . THE ROW DECODING BLOCK
`
`The row d ecoding bloc k is one such block whor e t h~ suvon bit
`control wo rd wh ich is sent to the touch-p a d circuitry is
`interpreted to select a certa i n LED/phototransistor pair.
`
`The decoding is accom pl ished by sen~ing the lower four bi t s
`tc> t t1 ~~ pad. Th i.s nibble gives a
`of the s~Nen bit toucil-p <.ld wor· d
`zero through fifteen CF Hexl count which is used to select one of
`the si x t een roN , column or extra LEDs .
`Then by using the uppe r
`three bits, one o f
`thr·e~? ch:lp s~~le r.:t line<;; i ~5 br--CJughl: h :i. gh .
`
`SCEA Ex. 1035 Page 12
`
`

`
`Page 8
`
`The Easy Cha i r: THE INFRARED TOUCH PAD
`B.
`B,
`Dl
`63
`B'f
`Bs
`Bt.
`( ~l)
`
`\...
`~ ......,
`~
`~
`E
`0 u
`
`y sa
`pA.·,r S,,),d Word
`
`RD\IJ 5o l<~.d
`
`C.o\wnn Seled
`E-L trA. 5t.\t.et
`
`Rd u. r 1"1
`
`Figure
`
`Touch Pad Control Word D1agram
`
`l ine decoder is used.
`To accompl1sh thi s , a 74154 4 t o 16
`The out puts of this 74154 are low when they are selected , so they
`are used to provide a g r ound path for the infrared LEOs and
`phototransistors, thus allowing them to be turned on only when
`they are selected .
`
`It is appropr1ate at this time to accent the fact t hat the
`select lines are used to select both an LED and a photo(cid:173)
`transistor. With this scheme, if there is nothing bloc king the
`beam path from the LED to the phototransi stor, then the
`p~ototransistor shoul d be turned on .
`
`II. THE COLUMN DECODI NG BLOCK
`
`The column decoding bloc• functions in almost the same
`fashion as the row decoding block. The only difference 1s that
`of the select l1ne which is used to select the column decoding
`chip . Of the three s e lc t lines (which correspond to the upper
`three bits of the touch-pad word), one i s used to select the row
`decoding chip, one the column decoding chip, and one the extra
`decoding chip. The select lines use a
`'positive logic', so for
`instance to select the column pairs, the column select bit must
`be h lQh 1+5 vo l t
`, ) .
`
`!igai r . in t.h£' sa.rr.a -f ~shion "·s t 'le row decod l , g. thi-.5 block
`se l~c ts cert~1 n LED / phototrans• s tor pairs wh1ch are then
`mon1tored by the touch detect1on circuitry.
`
`III . THE EXTRA DECODING BLOCK
`
`Again , the basic fun ct ion of the eMtra decodin g b loc k is the
`
`SCEA Ex. 1035 Page 13
`
`

`
`The Easy Chair : THE INFRARED TOUCH PAD
`
`P age 9
`
`same as that of the row and column decoding block s. However,
`this block serves no one single function such as row or column
`decoding.
`
`The term e x tra is meant to r eflect the odd or ' extra '
`decoding that is done by th1s block. At the present time, it
`serves to select one of the f1ve menu- select LED/phototransistor
`pa1rs for observation.
`
`In refering to figure 2.4, it should be noted that the three
`'menu select' l ines are passed through tri-state buffers before
`they are connected to the LED/phototran sistor pairs. This 1s
`because small er LEOs and phototrans i stors h ad to be used for the
`five menu select pairs Ito fit between the column pairs in the
`pad) .
`
`These s maller phototran s istors had lower of f -state
`resistance, which caused problems when t~ ey were not selec~ed.
`Nor mally whe, a pa1r :s not selecte d , +5 volts 1s c o n n ec ted t o
`the c a thode of the LED and to the emttter of t~e phot o~r an s1stor.
`Th1 s would not a l l ow either t o b e turned on. W1th these f1 vu
`menu select pairs however, the +5 volts ( seen when not selected )
`cause d the menu-select detect circuitry to s end a touch message
`t o the computer. Therefor e, the tri-state buffers were used,
`wh i ch present an open circuit in their non-selected state.
`
`IV . THE TOUCH PAD BLOCK
`
`This bloc k contains the actual touch-pad w1th the LEOs a n d
`pho totrans1stors mounted in 1t , and the slot for the selec t ed
`me nus to be inserted into <see f1gure 41. Along the vertical and
`horizontal sides of the s unken touch area , are alternately
`mounted 32 infrared LEOs a nd 32 phototransistors, one across from
`aach LED. These pairs were alternated to reduce the amount of
`l1ght be ing rec ei v ed in error.
`
`The LEOs a n d phototransistors were carefull y al1gned so as
`t o achieve the max imum signal rec1eved when a s1gnal is sent.
`Ea ch of the cathodes of the LEOs along with the emitters of the
`pho totransistors across from them, are tied to the select lines
`of the 74 154s <see also The Row Decoder Bloc k and The Column
`Dr,Jcod e!~ Bl o ck) .
`
`The touch -pad also c ontai ns fi v e seperate pairs which are
`mounte d oerpendicular to the row a nd co lumn pa1rs , al o~g the edge
`of t - e o a d. Thesz serve t~e pu-pose o~ al!ow1ng the computer to
`~et.:c~ ""h - =~ nen"-' tiJ ,., tbe o~.d •
`.,..!-'le pc.oer menus h~va -£-i·./e
`corr e socnding holes whlc~ can be cut ooen o r :eft intact
`<closed ) , rep resent1ng zer o s and o nes .
`
`The anodes of all of the i nfrared LEOs <b o th row/column LEOs
`a nd menu-select LEDsl are tied high through a single s er ies
`
`SCEA Ex. 1035 Page 14
`
`

`
`Tha Ea&y Chai r : THE INFRARED TOUCH PAD
`
`Page 10
`
`l1m1ting resistor . Also, the cathode of each LED is connected to
`the emitter of its correspond1ng phototrans1stor .
`Th erefore,
`when the pair is selected, and the cathode and the emitter are
`both t aken to ground, t ur n ing o n the LED and a ll owing the
`photot r ansistor to b e turned on .
`
`V.
`
`THE ROW/COLUMN DETECT BLOCK
`
`This block i s where the status of each phototransistor is
`transformed into a level that can be interpreted by the computer .
`With this sig nal , the computer can determine whether the beam is
`obstruc ted or not lcorrespond1ng to a touch or no touch>.
`
`As mentioned previousl y , the collectors of all of the
`p h ototransistors are ti e d togeth er and pulled h1gh through a
`s1ngle pul l - up resistor 1100~ o h ms ) . When any o n e of the
`LED/phototrans1 stor p airs is selected, an 1nf r are d light b eam f r~m t he
`•~lected L E~ s h o uld turn the photot ransisto r on , bring i ng t h e c ollector
`1f whil e one pair i~ selectee ,
`voltage somewhere near ground .
`the beam is bloc ked, the phototr ansistor will remain turn ed o f f . In this
`case , the coll e ctor v olt ug e a pproaches +5 volts because of the
`p u ll-up resistor.
`
`+V
`
`lOO k A
`
`I SOn
`
`To
`row/co/u.Nin
`dt. fed ct'rc.u..ilry
`
`r() w /t!Dlu..mn
`Fr om
`s~ led cJrcu.itry
`
`F 1g u re =-~ Sample LED/Trans1stor S1rcuitrv
`
`':he change 1 n co! 1 e ctor vo~ tage from when a be2.m
`Seca•-tse o f
`lS tilocled to 1--1he n one 1 5 not blockad , the collactors a re u sed as
`t ho the 1,out t ~ tne row/co l umn detect c irc u1tr y . Thl$ circu1t-v
`begins with t wo comp arators which h a ve adjust able r efer ences.
`
`The first comparator is set up in an inverting fashion, so
`that when any coll ector voltage is below the reference (no beam
`bloc ked), the output of the comparator i s at positive saturation .
`However, if any col lector voltage swings above the reference , the
`
`SCEA Ex. 1035 Page 15
`
`

`
`Th e Easy Ch air: THE INFRARED TOUCH P AD
`
`Page 11
`
`output goes to negative saturation (close to ground). This
`output is then used as the input to the second comparator.
`
`This second comparator uses the same reference voltage as
`the first one, however, it is set up in a non-inverting fashion .
`The main purpose of the second comparator is to clean-up the
`signal.
`
`When the selected beam i s n o t broken , the output of the
`first c omparator
`(which i s
`t he input to the second) is high. This
`also sends t h e s e c o n d conpar a t or i n t o positive satur a tion .
`The
`out put of t h e second comparat or ,
`i s th e n sent throug h an OR gat e
`which has o ne inp u t
`t ied low, to fur t h e r cl ean i t up.
`
`This signal is then fur t her conditioned by the status of the
`row or column selects, to become the RCRET (row/column return)
`signal . This RCRET signal is then combined with the MSRET signal
`(menu-select return) to provide one single RET (return) signal
`for the computer. This signal is polled by the software as a
`s1ngle bit input to a port. By polling in this fashion, the
`computer can continuously look for a touch, and process one
`accordingly if it is encountered .
`
`VI . THE ME NU- SELECT DETECT BLOCK
`
`The circui try in the menu-select detect block is almost the
`same as the row/column detect block. The only real differences
`are first of all the size of the pull-up resistor for the
`phototransistor, and secondly the extra select signal is used
`instead of the row/column selects <for conditioning).
`
`It is appropriate at this time to note the reason for
`combining the three different chip selects <row select, column
`select, extra select) with the RCRET and the MSRET signals (see
`also the Touch-Pad Schematic). Normally if neither the row or
`column chip is selected, then the RCRET signal is high, falsely
`signaling a beam being broken. The same problem is encountered
`when the menu- select chip is not selected, the MSRET s ignal is
`high, falsely signaling a beam being broken.
`
`To elevi ate this problem, the row and column chip selects
`are AND'ed with the RCRET signal, and the e x tra chip select is
`AND'ed with the MSRET signal . With this conditioning, RCRET can
`on l y go high when either the 'row' or ' column ' ch ips are
`selected. Also, MSRET can on l y go high when the 'extra' chip is
`selected.
`
`The resulting signals are OR'd together to form a single RET
`li ne which is high whenever any selected beam is broken. This
`leaves the computer free to select either a row, column or
`menu-select (extra) beam, and then determine by polling one line
`CRETI whether or not that beam is being broken.
`
`SCEA Ex. 1035 Page 16
`
`

`
`The Easy Chain THE INFRARED TOUCH F'A,.:D:..._ _______ ----'-P-"a.'-"gc;e:._l±-2:!:!.--
`
`Shown below is a photograph of the printed circui t board
`used inside the touch pad .
`s~veral of the main i ntegrated
`circuits are labeled t:o hel p the u ser· loc:<.lt€~ <.~ny c!:llnponents on
`the board .
`
`Figure 2 . 5
`
`F'rint.c~d Ci l-cui t
`
`Bo,e~r·d <.111d Component.s
`
`SCEA Ex. 1035 Page 17
`
`

`
`Th e Easy Chair t THE INFRARED TOUCH PAD
`
`Paoe 13
`
`GENERAL DISCUSSION
`
`As was mentioned earl1er in the scope of the project, the
`original thought had been that a total hardware system would be
`best. With such a system, the computer would only have to
`respond to some sort of interrupt from the touch-pad. During its
`service request, the computer could then s1mply read which
`location had been touched. Th1s would tend to leave the computer
`more free to do other tasks.
`
`Very briefly , all of this could have been provided by using
`a hardware clock to run several counters . These counters could
`in turn select each row pair , then each column pair, and finally
`each menu-select pair Ca process now handled by the computer) .
`
`The major disadvantage to this method was that the scan
`process would be set in one certain fashion, unable to change if
`a better process was discovered. With the present method, the
`computer suppl!es the count to the pad . W1th this system, the
`count can be supolied in any order, able to change with only
`m1nor software changes.
`
`Th e current method of using infrared light beams (instead of
`some other form of detection) was decided upon for various
`reasons.
`
`tl Other touch-pad scheaes such as capicitive touch sensing , and
`pr essure sensttive •e•brane type keypads, are all affected by
`water, or saliva in this case.
`
`21 Mos t important, breaking a light beaQ requires the least
`amount of pressure of any method studied.
`
`The decision to use identical circuits for the RCRET and the
`MSRET may at f1rst seem redundant. However, because of the
`lim1ted amount of physical space between the column LEOs and
`phototransistors, smaller optical components had to be u sed.
`These smaller components required the same type of detection
`c1rcui try, w1th only the change of the pull-up resistor.
`
`So, because the two bloc ks need to be electrically isol ated,
`and because the needed gates and comparators (for duplicate
`circuitry) were in fact available, it was decided to duplicate
`t~e row/column detection for the menu-select detection .
`
`SCEA Ex. 1035 Page 18
`
`

`
`The Easy Chair1 THE ULTRASONIC RANGING SYSTEM
`
`Page 14
`
`THE ULTRASONIC RANGING SYSTEM
`
`SPECIFICATIONS
`
`The ul t rasonic rang i ng s y stem i s c o n s ide r e d a p r otect ive
`dev ice. Its ma j or function is to prevent damage to t he chair or
`injury to its operator.
`It is also necesary to protect other
`young children who mi ght be in the general area of the chair
`(innocent bystanders).
`
`When designing the ultrasonic ranging system, the following
`specifications were used as guidelines.
`
`tl The system should be able to sense an y object within
`approximately four feet of the chair, from any of four
`di fferent directions.
`
`2)
`
`3)
`
`4l
`
`5l
`
`b)
`
`It should aud i bl y war n t he user of these obs t r ucti on s, s o as
`to al l ow t i me t o ta ke c orrec t ive actions.
`
`I t shou l d also be possib l e to turn thi s audible feedbac k of f.
`
`If corrective actions are not taken in time to avoid a
`col li sion, t he chai r s hould stop automa t ically.
`
`It should be possible to place the ultrasonic units in any
`desired location on the wheelchair, and should should not
`deface it in any manner.
`
`If a major failure should occur, it s hould be possible to
`remove and retire the complete sytem without effecting normal
`operation of the wheelchair.
`
`71 Without a ma j or failure, it should be possible to turn the
`ranging system off .
`
`Sl Other than stopping the chair in an emergency, the system is
`not to ta ke offensive control at anytime as this would det er
`the user from learning to be in complete control of the
`wheelchair. !It is antic i pated that after some practice, the
`user will be able to control t he wheel cha i r without th~ use
`of t he rangi nq s ystem. )
`
`Wit h these spec ifi c ations in mind, t h e u l trasonic system
`general l y performs two main f unct i ons : It provides f eedba ck tc
`the uoar as to the approach of obstacles~ ~nd i
`t provides a
`failsafe trethod of stopping the chair shculd the ch 1 ld fai~ to
`respond to the system·s warning.
`
`SCEA Ex. 1035 Page 19
`
`

`
`The Easy Chair : THE ULTRASONIC RANGING SYSTEM
`
`Page 15
`
`Figure 3. 1)
`
`SCEA Ex. 1035 Page 20
`
`

`
`Th& Eaay Chair : THE ULTRASONIC RANG I NG SYSTEM
`
`P eg• 16
`
`BLOCK DIAGRAM
`
`The block diagram for th e Llltrasonic system (shown below)
`consists of four pri ncipal parts. These in~ludo four directional
`transducers, the tone generator, a timer to aid in distance
`calculations , and the additional I / 0 board wh1ch is the system's
`interface to t he computer . Each of these bloclcs will be
`discuss~d in g reater d r!tai l in the fo llowing sections.
`
`U I t r~ son;c.
`Tr~n£.du.cers
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`I I~ I I L,-l
`
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`
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`
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`- 10
`.:Z. "'
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`PI/I '6 '
`
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`'Z '
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`
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`
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`
`fJ C.oMpl)i.e~
`
`Tt:>/"IE
`Gf.N.
`
`I J'
`l
`
`Stopw().tch
`T imu
`
`Figure 3 . 1 Ultrasonic System Block Diagram
`
`I . THE DIRECTIONAL TRANSDUCER BLOCK
`
`The directional transducer block is the heart of the r anging
`system. It consi ts of four compl rte and ~eper~te rsnqinq
`module5. Each module contains a 50 kH=, ~00 volt elertro~ tatic
`transducer, and a small amount or drive circ uity. Eaclt module is
`capable of rang~ng from four inches to appro:· 1matelv 35 feet with
`less than two percent maximum error. <See also Figure ~.2 Ranging
`Module Schematic>
`
`Each ranging modulo contains a Texas Instruments 5N28827
`sonar ranging module . This T. I . module provides the 150 volt
`
`SCEA Ex. 1035 Page 21
`
`

`
`Page ~7
`
`bias fer the transducer and pulses the transducer with 16 cycles
`of a 50 kHz , 300 vol t waveform. This pulse can actually be heard
`with the naked ear , as it sounds like a short click. Thi&
`ultrasonic wav~form travels at the speed of sour1d <0.9 ms/foot)
`until it strikes an obst ac le and its echo returns tc the
`transducer at t he same s~J8edM
`
`The modul e provides a control a bl a blanking period to a l low
`transducer vibration to disapate before it is enabled to wa i t for
`a return ing echo . All control signals are TTL compatible , but the
`echo output is of open collector typ e and needs a pull-up
`resistor in order to get a reliable TTL signal.
`
`There are three main control signals . The !NIT• input
`starts the ranging process by sending out t he cliclc. The 8LNK*
`input defeates the internal echo blanking. And the ECHO• output
`signal s when the cli c k is r eturned. All t hree signals are active
`low , and their relati o n shi ps to e achother are dem on~trated below
`in Figure 3 . 3 Timing Diag ram.
`
`vee• - - - - I
`
`,-
`START <:.ycfe
`INIT ----.J •cLtCK"
`I"
`_j I I 16 PULSES
`
`TRAN SM IT
`(INTERNAL!
`
`BLNK
`BINH
`
`INTERNAL
`
`~c.HO .R~bJRNE"D
`
`8LA NI<ING ----.L44- Z~ M$ ... 1.----------------------
`I
`I
`;.~----------.
`ECH0 ·----~'-----·~0~·~9~~~~~/~E~t~~~~~---~~~
`
`LOW
`LOW
`I
`
`J:)i!>T"NCE.
`
`)
`
`·EXAMPLE OF A SINGLE-ECHO -M ODE CYCLE WITHOUT BLANKING INPUT
`
`Figure 3 . 3 T iming Diagram
`
`ThE1 only devat i on ·frc>m Te:·: e.s In~; tr· umem1:s de:;:;iqn c<,;\s t hi~.t
`a large capacitor was added i n parallel with the power
`connectiCJns ~:\s they enter f.~C"~.Ch tran'::;ducc~r ' s driver .. T l·'li.S ~-~~.5 done
`in order to supply the rated 2000 mA each transducer needs during
`t t1e 326 uS transmit period . This is such a rapid drain that the
`power supply could not source it through six feet o f cab ling.
`
`SCEA Ex. 1035 Page 22
`
`

`
`The Easy Chair; THE ULTRASONIC RANGING SYSTEM
`
`Pace 18
`
`II. THE TO NE GENERATOR BLOCK
`
`The tone gener ator bloc k consi sts mainly of the XR2206
`functton generator chip (capabale of switchtng between two
`selected tones) and an LM2002 , etght watt audio power ampli fter
`chip.
`<See also Figure 3 . 4 Tone Generator Schemati c)
`
`The XR2206 has the ab liti y to output two selectable tones .
`These tones are selected by switchtng the TTL l e vel at the FSY
`input. Thi s allows several types of warnings to be generated . The
`two tones are seperatl y adjustable and independent. These
`adjustments are made to R4 and R6. See Figure 3.4 Tone Generator
`Schematic . The pot entiometer R7 is a vol u me adjustment .
`
`Turning the tone off is done with the Amplitude Modulatton
`input.
`If the AM input is h el d at hal f the supply voltage, the
`output will be turned off. Control was accomp lished by switching
`a voltage div ider in and out. This voltage divider has two equal
`r~5:.Lances (in seri2sl to g~ound, creattng a reference of one
`hal~ ~t1at c~ t~P supply. The JUncltcn between the two resis~ors
`is connected to the AM
`i r.put to t~e c'"li o. An NP"J tr 'lnsi stor 1 s
`used to shunt the bottom resistor of the dtvtder when 1t is
`turned on, thus turning the o utput on Cor offl .
`Thia transistor
`is control led by a TTL level sent from the computer, allowing the
`sound to be tur'"led on and off .
`
`III. THE ADDITONAL PIA AND TIMER BLOCKS
`
`To supp ly the n~ede d output for the t one circu1t and the
`ultrasonic units, a second 8255 programable port had to be added.
`It as configured to have 20 b its of out put and 4 bits of input .
`Ports A, B, and the lower four bits of C are defined as output.
`The higher four bit s of port C defined as 1nput .
`
`Por t A controls the ul trasonics INIT* and BLNK* of each
`transducer. Port 8 outputs a digital word to be used by the motor
`control circt uts •or direction and speed control . Port C
`controls the tone generato