CA1195754A - Apparatus and method for determining the position of a driven coil within a grid of spaced conductors - Google Patents
Apparatus and method for determining the position of a driven coil within a grid of spaced conductorsInfo
- Publication number
- CA1195754A CA1195754A CA000426890A CA426890A CA1195754A CA 1195754 A CA1195754 A CA 1195754A CA 000426890 A CA000426890 A CA 000426890A CA 426890 A CA426890 A CA 426890A CA 1195754 A CA1195754 A CA 1195754A
- Authority
- CA
- Canada
- Prior art keywords
- coil
- conductors
- sampling
- conductor
- induced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/046—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by electromagnetic means
Abstract
Abstract of the Disclosure A digitizing system includes a first plurality of spaced parallel grid conductors and a second plurality of spaced parallel grid conductors orthogonal to the first plurality of spaced parallel grid conductors. The location of a movable coil arranged on a pen or cursor is determined for each plurality of grid conductors coarsely by sampling the voltage induced in one of the grid conductors from a signal applied to the coil to determine whether the coil is above or below this grid conductor.
Through careful selection, a very few grid conductors can be sampled to quickly locate the two grid conductors immediately adjacent to the center of the driven coil. The ratio of the voltages present on these two grid conductors is matched against a list of known ratios representing various positions between the two grid conductors.
Through careful selection, a very few grid conductors can be sampled to quickly locate the two grid conductors immediately adjacent to the center of the driven coil. The ratio of the voltages present on these two grid conductors is matched against a list of known ratios representing various positions between the two grid conductors.
Description
RIS: a h APPARAT~S A~JD METHOD FOR DETER~ ING THE
POSITION OF A DRIV~ COIL, WIT~TI~J A GRID
OF SP~CED CON~UCTORS
~ack~round of the Invention his invention relates to a method and apparatus for 5 determininq the position of a coil with respect to a grid of spaced conductors and more particularly to such instruments which are relatively simple and low cost.
Various high resolution apparatus for translating a position of a movable instrument, such as a pointer or pen, into 10 electrical signals for transmission to a local or remote utiliza-tion device are well known in the art.
U. S. Patent No. 4,210,775, assigned to Talos Systems, Inc., pertains to a digitizer in which an instrument, such as a pen having a coil disposed about a nosepiece located immediately 15 above the writing tip of the pen, is utilized in conjunction with a tablet comprising a grid of conductors, including a group of parallel spaced conductors oriented in an X direction and a group of parallel spaced conductors oriented in a Y direction. The pen tip is moved along a worksheet disposed on a support surface 20 containing the grid of conductors. An oscillator applies a signal of predetermined constant frequency and amplitude to the coil. The coil is inductively coupled to the conductors of the grid, thereby inducing signals in the conductors. In accordance with electromagnetic theory, the magnitude and phase of the 25 signals induced in the respective grid conductors depend on the location of the conductors with respect to the pen tip. The grid conductors in each group are sequentially scanned to sequentially couple the induced signals to a differential amplifier by means of multi~lexing circuitrv. The multiplexing circuitry selects 30 the respective grid conductors in response to an address decoder.
7~a The address decoder is Ariven by a scan co~nter. The scan counter is incremented by a .siqnal produced by a divider circuit driven by the oscillator. A position counter is incremented in response to the oscillator as the X and Y qroups of grid conductors are sequentially scanned. ~ phase sensitive detector 5 responsive to the output of the amplifier produces a positive signal having a step-like envelope as grid conductors approaching one side of the pen tip are sequentially scanned. The phase sensitive detector also produces a negative signal having a step-like envelope as conductors on the opposite side of the pen 10 tip are sequentially scanned in a direction away from the pen tip. The signal produced by the phase sensitive detector is filtered to produce a characteristic wave shape signal having a positive peak as the scannincl approaches the pen tip. The filtered signal falls steeply across the zero axis to a negative 15 peak as the scanninq passes under the pen tip, and decreases as the scanning continues in the direction away from the pen tip.
The filtered signal is differentiated and compared to a predetermined threshold level to produce a stop pulse. The stop pulse is utilized to disable the position counter. At this point 20 the contents of the position counter represent the location of the pen tip with respect to the X group of grid conductors and are loaded into an output register. The contents of the output register are then outputted to a utilization device. The scan counter and the position counter are reset and the conductors Of 25 the Y sroup of grid conductors are scanned in a similar manner to produce a digital position number representing location of the pen tip with respect to the Y group of conductors.
Other patents which employ multiplexers to sequentially scan the respective X and Y conductors of groups of parallel spaced 30 conductors and assigned to Talos Systems, Inc. include ~. S.
Patent l~umber5 4,1~5,165 and 4,260,852. While all of these patents which emplov multiplexers to sequentially scan the ~ri~l conductors produce desirable results in a satisfactory manner, the equiplnent to accornplish these results are relatively complex and costly. 5 Accordingly, it is an object of this invention to provide a simplified and lower cost digitizer.
Summary of the Invention Briefly described and in accordance with one embodiment thereof, the invention provides a digitizinq system and method 10 for converting a position of an instrument, such as a pen or cursor, to an electrical signal representing a position of the instrument with respect to a grid of conductors. The instrument generally includes a coil for coupling electrical signals to a qrid of conductors including a group of parallel spaced 15 conductors oriented in an X direction and a group of-parallel spaced conductors oriented in a Y direction. In one embodiment of the invention sixty-four parallel spaced conductors are arranged in both the X and Y directions with a constant spacing bet~Jeen conductors. Typically, the conductors are deposited on a 20 printed circuit board with the conductors in the X direction deposited on one side of the printed circuit board and the conductors in the Y direction deposited on the other side of the printed circuit board; however, alternatively, wires or other conductors may be embedded or disposed upon some other 25 non-conducting surface.
The pen or cursor which operates in conjunction with the grid conductors comPrises a coil of wire wound on a non-metallic form.
An oscillator applies a signal to the coil of a predetermined frequency, typically 100 Khz. Typically, the coil operates at 12 30 ~olts at 150 milliamps. The rnore current, the larger the signal 57~
induced in the conductors of the grid, however, heating problems limit the amount of current which can be applied to the coil.
The coil is inductively coupled to the conductors of the grid, thereby inducing signals in the conductors. In accordance with electromagnetic theory, the magnitudes and polarity of the 5 signals induced in the respective grid conductors depends upon the location of the conductors with respect to the coil.
A multiplexing circuit is employed to sample the signal from the center conductor of the X direction array of conductors. By determining whether the signal is of a positive or negative 10 polarity, the location of the coil with respect to the grid conductors is known, that is, whether the coil lies ahove or below the sampled center conductor. The multiplexer then samples the signal from the center conductor of the half section ~upper or lower) in which the coil is located, and again, by 15 ascertaining whether the signal is positive or negative, a determination is made in which quarter section the coil is located. Additional readings are taken in the same fashion until it is ascertained that the coil lies between two adjacent X
direction conductors. 20 If the coil is exactly equidistant between the two conductors, the magnitude of signal induced in each conductor will be equal and opposite in polarity, and therefore, it is known that the coil is, in fact, precisely in the middle of the two conductors. When the coil is not equidistant between the two~25 conductors, the magnitude of the signal from the two conductors will increase or decrease. That is, one will increase, the other will decrease.
The exact coil position is then determined by forming a ratio of the induced signal from the two conductors and comparing this 30 ratio with values stored in a look-up table. ~Since ratios hetween the two signals are employed rather than using absolute values, any variation in signal strength from the coil to the conductors will have no effect on the measurement. Also, the measurements will be frequency and phase insensitive.
A like set of measurements is then made sampling signals from the Y direction array of conductors to precisely locate the coil S
with respect to the Y direction array of conductors.
~rief Description of the Drawinqs The above-mentioned and other features and objects of the invention will become more apparent by reference to the following description taken in con~unction with the accompanying drawings, 10 in which:
Fig. l is an illustration of the grid conductors of a digitizer illustrating the manner in which the location of a coil contained within the grid is ascertained;
Figs. 2 and 3 are circuit diagrams of a digitizer processor 15 in accordance with the principles of this invention; and Fig. 4 is a diagram of a circuit for sampling the signals from the grid conductors of Fig. l to apply the signals therefrom to the circuit of Figs. 2 and 3.
Description of a Preferred Embodiment 20 Referring now to Fig. 1 of the drawings, there is illustrated thereby, schematically, the grid conductors of a tablet. This tablet typically contains sixty-four parallel conductors (numbered 1-64) arranged in the X direction and sixty-four parallel conductors ~numbered 65-128) arranged in the Y 25 direction. Assuming the location of a coil at position l~ during one moment in time, the function of the digitizer is to determine that location precisely. In accordance with this invention, an ac signal is applied to the coil and is inductively coupled to the conductors. X conductors on one side of the coil will have a 30 positive signal induced therein, while X conductors on the opposite side of the coil will have a negative signal induced therein. Thus, by noting the polarity of the signal induced in a ~57~
particular conductor beinq sampled, it is readily ascertained that the coil is either above or below such conductor.
In accordance with the principles of this invention, the signal inductively coupled rom the coil to a conductor in the middle of the tablet is sampled, for example, conductor 32. When S
the signal on that conductor is sampled, it is determined by the polarity of the signal that the coil is, in fact, above the conductor 32 and within the area containing the conductors 1-32.
Accordingly, it is not necessary to sample any signals induced in conductors 33-64. The next sampling is taken at a conductor in 10 the center of the upper half of the tablet such as conductor 16.
By noting the polarity of the signal from conductor 16, it is ascertained that the coil is, in fact, above conductor 16, and therefore, in the upper ~uarter of the tablet, namely somewhere between conductors 1 through 16. The next sampling is taken at, 15 for example, conductor 8 and, by denoting the polarity it is ascertained that the coil lies within an area containing conductors 1-8. The next sampling occasions a measurement to be made of the signal on conductor 4 and by the polarity of the signal, it is determined the coil is, in fact, above conductor 4 20 and located somewhere between conductors 1 through 4. A
measurement is-then made of the signal at conductor 2 and by noting a different polarity from those previously measured, it is ascertained that, in fact, the coil is located below conductor 2.
The equipment then samples conductor 3 and judging from the 25 polarity of the sampled signal, it is ascertained that the coil is above conductor 3. Thus, with only six samples the course location of the coil (within two conductors) has been ascertained. This is contrasted to sampling all sixty-four conductors as in other systems. 30 Accordingly, it is now known that the coil lies between i7~;~
conductors 2 and 3. If the signals measured at conductors 2 and 3 are equal, then it is ~nown that the coil is equally distant from conductors 2 and 3. However, if the signals are not equal then a ratio is taken of the signals obtained from the sampling of conductors 2 and 3, and thi~ ratio is compared in a loo~-up 5 table with values stored therein to determine the precise location of the coil. Since ratios are employed rather than absolute values of the signals sampled from conductors 2 and 3, the system is amplitude, frequency and phase insensitive. After determining the position of the coil with respect to conductors 1 10 through 64, the same procedure is carried out with respect to the Y direction conductors 65 through 128 to locate the coil precisely in the other direction.
The circuitry for carrying out this procedure is set forth in Figs. 2, 3 and 4. Figs. 2 and 3 include all of the circuitry 15 necessary except for the conductor sampling means which is employed to sample the necessary ones of the conductors 1 through 128, and this is shown in Fig. 4 of the drawings. The conductor sampling means connects conductors of the tablet to the circuitry of Figs. 2 and 3. 20 In the example set forth above, the signals from conductors 64, 32, 16, 8, 4, 2 and 3 are successively appIied to an input 12 of the digitizer circuit of Figs. 2 and 3. Each of these signals is amplified and filtered at circuit 14 in order to provide proper operating signal levels for the system. The output from 25 amplifier and filter circuit 14 is applied to a synchronous detector 16 to convert the input ac signal to a dc signal. The output from synchronous detector 16 is applied to an amplifier and smoothing filter 18. Circuit 18 smoothes any ripples in the output from the synchronous de~ector 16 and further amplifies the 30 dc signal.
The output from the amplifier and smoothing filter circuit 18 is applied to an analog-to-digital converter 20 which converts the dc voltage output from circuit 18 to a binary number. This binary number is applied to a microprocessor 22. The binary number is utilized in the microprocessor 22 to determine which 5 conductor of the tablet to sample next in accordance with the stored program therein. The output from microprocessor 22 at pins 27 through 33 are the addresses of the conductors of the tablet to be sampled and these are applied to the sampling circuit of Fig. 4. These are the addresses of the conductors to 1( be connected to the input 12. The program stored in the microprocessor determines which conductor of the tablet to sample next as well as developing the ratios of the specific conductors to be compared to the values in the look-up table to determine the position of the coil in the X direction. Signals are also ~15 applied to input 12 from respective Y conductors to determine location of the coil in the Y direction as well. Connections from pins 1, 6, 8, 10-19, 35 and 39 of microprocessor 22 are coupled to a UART 24 to communicate with auxiliary equipment such ~
as a computer or terminal. The outputs from UART 24 are taken 20 from TTL to RS232C via interfaces 25 and 27.
An output 28 from the microprocessor is a 400 KHz signal which is applied to a divider 30 to divide the signal by four to nrovide a 100 XHz signal. This signal is applied via line 32 and transistor 34 to synchronous detector 16 as a reference input 25 thereto. Transistor 34 converts and level shifts the signal from divider 30. The 100 KHz signal is also applied to a push-pull amplifier 36 with the outputs therefrom being applied to the coil to drive the coil in push-pull.
The circuit for sampling the sixty-four X (numbered 1-64) and 30 the 64 '~ (numbered 65-128) conductors is shown in Fig~ 4. The ~5~
circuit includes two one-of-eight selectors 40 and 42 and sixteen switchinq circuits, eight for switching to or sampling appropriate X conductors and eight for switching to or sampling appropriate Y conductors, only two of each being shown, for simplicity of explanation. 5 ~ switching circuit 44 connects a selected one of the X
conductors 1-8 to the input 12 of the circuit of Figs. 2 and 3 via a line 46 and a switching circuit 48 connects a selected one of the X conductors 49-64 to the same input via line 46. Similar switching circuits (not shown) are employed to connect selected lC
ones of the conductors 9-48 to the input 12.
Switching circuit 50 is employed to connect a selected one of the Y conductors 65-72 to input 12 via line 46 and switching circuit 52 is used to connect a selected one of the Y conductors 121-128 to input 12 via line 46. Other switching circuits (not 15 shown) are employed to connect selected ones of the conductors 73-120 to the input 12.
The inputs to the sampling circuit of Fig. 4 are received from the output of microprocessor 22 along lines 54, 56, 58, 60, }
62, 64, 66 and 68. The input along line 54 indicates that Y ; 20 conductors are to be sampled and is thus applied to ~he one-of-eight selector 42 for the Y conductors. The input at line 62 denotes that X conductors are to be sampled and is accordingly coupled to the one-of-eight selector 40 for the X conductors.
The one-of-eight selector 40 determines which of the eight X 2 conductor switching circuits, including switching circuits 44 and 48, is to be enabled while the one-of-eight selector 42 selects the appropriate one of the eight switching circuits for the Y
conductors, including switching circuits 50 and 52. This selection of an appropriate switching circuit is made by the 3( selectors 40 and 42 in accordance with address command received from microprocessor 22 along lines 56, 58 and 60 which is coupled to both of the selectors 40 and 42.
The other inputs to the sampling circuit from the microprocessor is the input on lines 64, 66 and 6~. These inputs are applied to all of the switching circuits including switching 5 circuits 44, 48, 50 and 52, and selects which of the eiqht conductors coupled to a particular switching circuit is to be coupled to the output line 46.
The computer program for operating microprocessor 22 is written in assembly lan~uage and is as follows: 1( ~S75~
8048 ~SsEMrlLER
SYSTEM EauATES
WIRE INFORMATION
0020 XMID EQU 2011 ;ADDR OF X MIQrlLE WIkE
OOAO YMILI EaU OF~OH ;ADIIR OF Y PlIDrlLE IJIRE
0020 OFFSET Enu 20H ;WIRE ~ OFFSET VALUE
WlkE VOLTAGE STORAGE ADrlRESS
0020 IJOLT Eau 20H ;f!~QDR OF VOLT R~M STORAGE
POINT PARA~lETERS STORAGE ADrlRESSES
0022 XPAR EQU ;~2H ;X PAkAllETERS STORAGE AQnR
0025 YPAR VOLTAGE BIAS ;r PARAnETERS STORAGE ADQR
0080 E~IAS EOU 080H ;UIRE OFFSET VOLTAGE
0003 t5 QIS
0007 OkG 7H;
oooa 93 PSRETs RETR
0009 C5 INIT~ SEL RBO
OOOC 140EI . CALL FSFsET ;kESET INT-IN-F'ROG FLAG
OOOE 75 ENTO CLK ~ENA8LE CLOCI; TO UART
OOOF 8A10 ORL P2,~10H ~SELECT UART
0011 E1903 MOV R1,-3 0013 ~380 MOV A,~BOH ;SELECT QLAr 0015 91 MOVX eR1,A
0016 8B00 MOV RO,~O ;SELECT 9~00 ElAU
0018 ~'30C MOV A,40CH
001A 90 MOVX eRo,~
001E~ 1a INC RO
OOlC 27 CLR
001D 90 MOVX eRo,A
OOlE 2303 MMovx ~R173~ ;SELECT 8 EIITs, ETC~
0021 8904 MOV R1,~4 00''3 27 CLR fl 0024 91 MOVX ek1,A
0025 90 MOVX ekO,A
;
; EXPLANATION OF STRATEor ; THERE AkE 2 STATES, EACH REaUIkING DIFFERENT fROCFS5ING.
;
; STATE A - POS VALUE < ABS NEG VALUE
; STATE B - FOS VALUE ~ OR = ABS NEG VALUE
; STATE A, ~ISTANCE = ~ OF POS WIRE*200 MILS+LOOK UP TAbLE VAL
; STATE B, bISTANCE = ~ OF FOS WIRE ~ 200 MILS t 199 - LUTV
;
0100 OkG lOOH
0100 A5MAIN~ CLR Fl ;kESET XZY FLAG~SELECT X AXIS) OtOl BC20 MOV R4,~XMID ;GET MIDIILE X WIkE
0103 tl5LOOPO~ CLR FO ;kESET SIGN FLAG
0104 hb20 MOV R5,~0FFSET ;GET INITIAL OFF5ET t 0106 BE05 MOV R6,~5 ;SET UP LOOP COUNTER
0108 FbLOOPl: MOV A,kS ;GET OFFSET
010A 67RkC A ~2 OFFSET
OlOB AbMOV k5,A SAVE NEW OFFSET ~
OlOC 546C CALL OUTWRE ~ ,TUkN ON WIkE i,CONVERT
010E FC~OV A,R4 ;GET WIRE ~
010F F616 JC INCWRE IF I VOLT,INCR WIkE 4 0111 37DECWRE: CPL A ;SUBTRACT OFFSET
0112 6~Arlb A,RS
0114 2417 JMP CONTO ;CONTINUE
0116 6DINCWREI Anrl A,RS ;ADD OFFSET
0117 ACCONTO: MOV k4,A SAVE L~TEST WlkE
OllB EE08 DJNZ R6,LOOPI ,DEC AND LOOP
OllA FCMOV A,k4 ;SAVE WIRE ~ IN kl Ollk A9MOV Rl,A
OllC S46C ` CALL OUTWkE TURN ON LATEsT WIkE *,CONVERT
OllE B820 MOV hO,~VOLT ;GET VOLT STOkAt3E ArlDR
0120 F629 JC PLUS jIF VOLT AT UIkE ~ +~JUMP
0122 37MINUS: CFL A ;SAVE ABS VhL OF VOLT t~
0123 ~0nov eko~A
0124 CCbEC k4 POINT TO WIkE t-l 0125 FCMOV A,R4 ,SAVE IT AS LAST LIRE
012$ A9MOV kl,A
0127 242C JMP CONTl ;CONTINUE
0129 AOPLUS: ~OV ekO,A ;SAVE UOLTAGE I~ ALlDk 012A 95CPL FO ;SET SIGN FLAG
012B lCINC R4 : jPOINT TO WIkE ~1 012C 546C CONTl: CALL OUTWkE ;TURN ON WIkE ~l,CONVERT
012E B632 JFO ABS2 ;TAKE ABS VAL,VOLT~
0130 2433 JMP CONT2 ;CONTINUE
0132 37 ABS2~ CPL A ;TAKE ABS VAL OF VOLTAGE
0133 ~821 CONT2: MOV kO,~VOLt~l ;SAVE AbS UOLT OF WlkE~ t 0135 AO MOV CRO,A
5'7~
Ot36 B63b JFO , CONT3 ;CONTINUE
013B C8 nEC Rb ;POINT TO VO-T (~) .
0139 243F JMP CONT4 ;CONTINUE
013P 8R20 CONT3: MOV RO,~OLT ;~0 ~OLTIt~
013D FO MO~ A,eRO
013E 18 INC RO jPOINT TO VOLT ~
013F 37CONT4: CPL A ;SUBTR APS NEG VOLT
0140 bOADn A,eRO
OI42 F649JC LARNEG ;IF CARRY,CNEG~ VOLT~ POS VOLT
0144 5416LARFOS: CALL LGEPOS jSOL~E FOR kAT10-(NEG*256)/POS
0146 B5CLR FO ;kESET SIGN FLAG
0147 244DJnp CONT5 jCONTINUE
0149 542rl LARNEG: CALL LGENEG ;SOLVE FOk RATIO=(POS*256)/NEG
014b 85CLR FO ;SET SIGN FLAG
014n AACONT5: MO~ R2,~ ` :
014E BllOO MO~ R3,~00H ;CLEAR SlGN FLAG(~SIGN) 0150 B654JFO CONT6 ~CONTINUE
0152 BBFFno~ R3,~0FFH ;SET SIGN REG ~- SIGN~
0154 765ACONT6: JFl SAVY ;Fl SET,SA~E Y PAR~METERS
0156 B8 2 nov RO,~XPAR ;GET X PAkAMETERS AllrlR
0158 245C JMP SAVPAR ;SA~E THE P~RAMETEkS
015A RB?5 SA~Y~ MO~ RO,tYPAR ;GET r PARAMETRS ~D~IR
015C F9 SA~PQR: MO~ A,Rl ;GET WIRE
015B AO MOV ekO,A jSAVE IT
015F FA MOV A,R2 ;GET RATIO
0160 ~0 MO~ eRO,A ;SAVE IT
0161 lB INC RO
0162 F~ MOV A,R3 ;GET SIGN llYTE
0163 ~0 MOV eRo A ;SA~E IT
0164 766b JFl PRINT ~Fl SET,Y COOR~ JUST COMPLETEI
0166 B5 CPL Fl ;SET X/Y FLAG
0167 BCAO MOV R4,~YMIrl ,GET MIIIDLE Y WIRE
0169 2403~ JMP LOOPO ;SEARCH FOR Y COOR~
016B 5450PRINT: CALL CRLF
016~1 BH24 MO~ RO,~XPAR~2 ;PRINT X COOR~IINATE016F 347C CALL OUTPUT
0171 DB2C MO~ R3,~
0175 B827 no~ RO,4YPARt2 ;PRINT Y COORIIIN~TE
0177 ~5 CLR Fl ;SET FLAG FOR Y COOR~lNATES
017A 2qO0 JMP MAIN ;~0 IT hLL ~GAIN
017C FOOUTPUTs MOV A,eRO ;GET SIGN
017E C8DEC RO ;POINT TO WIRE
017F F2BC JB7 SIGNEG ;JUMP IF SIGN WAS NEGATIVE
~5~
Oi~l FO SIGNPS~ MOV ~,~RO jGET WIRE ~
OlS2 549b CALL COARSE ;PRINT TENS, ONES, IEC. POINT
0184 5402 CALL OUTCH ;PRINT T~NTHS
018~ 18 INC kO ;POINT TO aUOTIENT
0187 FO MO~ ~,eRO ;GET aUOTIENT
0188 E3 MOVP3 A,eA jLOUK UP COkR ~I5P }N TAbLE
Ola9 54b4 CALL HEXASC ;PRINt HUNnRENTHS, THOUS~NDTHS
018b 83 RET
018C fO SIGNEG: ~W A,eRO ;GET UIRE
018h 549h CALL COARSE
018F 18 INC R3 ;ADVANCE TO NEXT WIRE
019~ 18 . INC RO
0193 FO MOV A,eRO
0194 E3 MO~P3 A,eA
0195 37 CPL A jSUbT VALUE FkOM NEXT WIRE POS
0197 0399 ~DD ~,~99H
0199 S4~4 CALL HEXASC
019b 83 RET
0200 rrt20 SPACE: MOV R3,~
0202 sAlo OUTCH: ORL P2,~10H ;SELECT UART
0204 }~05 MOV Rl,~5 020~ 81 MOVX A~ekl ;GEr STATUS INTO ACC
0207 9AEF ANL P2,~0EFH jDESELECT U~RT
0209 r120~ J~S NoTr15Y
020B 4402 JMP OUTCH ~LOOP TILL UART NOT ~USY
02011 8A10 NOTBSY: ORL P2,~10H ;SELECT UART
020F E1900 nov Rl, ~0 0211 FkMOV A,R3 ~GET C~ARACTER TO BE PRINTED
0212 71novx eRlrA ;PRrNT IT
0213 sQEF ANL P2,40EFH ;DESELECT UART
0216 rt61F LGEFOSs JFo OK2 ~IF t,RVSE POS ~ NEG VOLT(ST
0218 P820 MOV RO~VOLT ~GET VOLTS ArlnR
021A FOMOV A~eRo ~GET Arls NEG INTO R4 021~ ACMOV R4,A
021C 15INC RO ;POINT TO POS VOLT Arlnk 0210 4424 Jnp OK3 -CONTINUE
021F ~821 OK2: MOV RO,~VOLT+l ;GET VOLT ~417-l~ ArlrlR
0221 FO MOV A,eRO ;GET A~S NEG INTO R4 0222 AC MOV R4, A
0223 CS rlEc RO ;POINT TO POS VOLT ADDR
0224 FO OK3s M04 A,~RO ;SAVE FOS VOLT ~N R5 022s Arl MOV Rs~A
0226 547S CALL nIvl6 iRATID=(NEG*2s6)7po8 0228 E62C JNC 0~4 022A 23FF nov A,~OFFH
022c G3 OK4~ RET
;
; FRrNTs ASCII CHARACTER IN R3. R7 ~R~ sTRoYErl.
;
022tl rt636 LGENEG: JFO ON2 STATE A
022F Et821 MOV RO,~VDLT~l ,FOI~T TO VOLT (~ ) ADrlR
0231 FOnov A~eRo ;GET POS VOLT INTO R~
0232 ACMOV R4,A
0233 C8rlEc RO ;PDINT ro VOLT ~) ADbR
0234 443~ JMP ON3 ;CONTINUE
0236 ~820 ON2: MOV RO,~VOLT ;POINT TO VOLT ~4) ArlrlR
0238 FO MOV A,eRO ;GET POS VOLT INTO R4 0239 AC ~oV R4,A
023A 18 INC RO ;POINT TO VOLT (~t/-l~ ~rlrlR
023E1 FO ON3: MOV A,eRO ;GET Ar1s NEG VQLT INTO Rs 023C Arl ~OV R5,A
023~ 5475 CALL rlIvl6 ;R~TIO=~POS*25~)7NEG
~95~
;
; CONVERTS L0UEk 4 BITS IN ACC TO ASCII CHARACTEk ~Nb ; PRINTS rT. R3, ACC DESTkO~'ED.
0~-0 530F~SCII: ANL A,~OFH ;MASK IN LO~Ek 4 RlTS
0242 0330 Ar,l, ~,t30H ;CONYEkT TO ~SCII
~ 44 ~MUV R3,A ;AIIJUST RESULT IF 3A TO 3F
024~; OlC~ An~ A,~OC6H
024' FkMOV A,R3 024A 0307 ADD A,~
024C AB 0~: MO~ R3,A
0:4D 5402 CALL OUTCil PRINT ASCII CHAR
024F 8~ RET
;
' , PRINTS CR, LF. ~CC DESTROYED.
0250 r~oo CRLF: MOV R3,~01lH jL0AD CR
0252 54~2 CALL OUTCH ;PkINr Il 0:'54 ~I~OA MO~ R3,~0~H jL0AII LF
0~56 5402 CALL OUTCH
;
, STPRTS AXD CONYEklER, WAITS, EXITS UITH RESULT IN ~CC.
0259 `7~EF ADCDNYs ANL P't~0EFH ;SELECT A/rl 025~ 90 MOVX eRo, A ;START CONYEkTER
0'5C 5h5C UT1 $ ~WAI7 O'SE 80 . MOYX A,C'RO jGET rlATA
025F 8A10 URL P2,~10H ;DESrLECT A~D
0~o3 03aO Allrl A,~I~IAS ;OFFSET THE VOLTAGE
;
; MOYES A DYTE INTO 2 NI8bLES ANrl F'RINT8 THEM. ENTER U~
; DATA IN ACC. ACC, R3, R4 ~ESTk0YErl.
0~64 AC HEXASCs MOY R4,A
0'6S 47 SWAP A ;GEl' UF'PER NI8~LE
0266 ~440 CALL A~CII ;CONVEkT AND PRINT
0268 FC ~O~ A,R4 02h9 544d ChLL ASCI1 ~C0NVErtT AND PRINT LOWER NI~
026rl 83 RET
;
; oUT~urS WlkE ADr~RrSS ~ND WAITS F0k 5ETTLINri ~57~
026C FC OUTWkE: MOV A.h4 0270 F.F70 OUTL k7,~30H ;WAIT
227i2 83S9 FC~EATL ABCONV ;DO A7ll CON~
AT6 E~NTR~ VIt~E RouTIl`~E
; ACC ~ LOWER 8 rt}TS OF ~I}VIDEND
; R4 3 UPPER B aITS OF n}~l}DEN
~ R5 - DlVISOR
; AT EXIT, ; ACC I B DITS OF RESULT
; R4 = REMAINbER
` ; R5,R7 DESTROYED
0276 bFOB D}V16~ XCH A,R4 0'79 ~ cArl~ A,RS
0'7~ F6UO cpcL rIVIA
02Bl Y7DIVIAt nD D}VIB
02B3 F7RXLcCH ,R4 0~84 2C ~ XCH A,R4 028- F7RLC tt 02B6 E6sD cJpNL D}VYE
028h 37cApD~D A,R5 028~ 4495 D}VIE: CPL A)IVIC
028F 37 cFDrL A~R5 0~92 6~ ADr~ AI'VICD
0295 lCDIVIC: INC R4 029B 97CLR R7,tIVILP
., 029~ 769F COARSE: JF1 XCOOR~
~ 9~
029D 03CO A~lD A,~-40H ;OFFSET WIRE ~ IF Y COOR~
029F ~bFF XCOORIl: ~0~ R3,~0FFH ;CEEAR INCH COUNTER - l 02Al l~ LOOF'3: INC R3 ;COUNT INCHES IN R3 O"A2 03F~ A~ID A,3-5 OZA4 F6AI JC LOOF'3 02A6 0305 AtlIl A,~S ;RESTORE DATA
O"A8 97 CLR C ;MULT ~Y TWO
02A9 F7 RLC A ;ACC = .0, .2, .4, .6, .C
02AA AD MO~ R5,A ;STOfi'E TENTHS IN R5 02A~ F~ MO~ A,R3 jGET TENS ANn ONES
02AC 03F6 AnD A,~-lO ;CON~ERT TO ~CD
02AE E6~2 JNC OKl 02~0 0306 ADD A,~b 02~2 030A OKt: ADD A,~IO
02~4 5464 CALL HEXASC ;PRINT TENS ANII ONES
02~6 ~2E ~0~ R3,*-.' ;PRINT DECI~AL POINT
02~8 5402 CALL OUTCH
02~A Fn ~0~ A,RS ;GET TENTHS
02~h 0330 ADD A,~30H ;CON~ERT TO ASCII
02DD A~ ~OV R3,A ;PUT TENTHS INTO R3 O~E 83 RET
1~9~7~4 , 100 MIL IIATA TABLE
; PEN CAL r BRATION
0300 0000010~ n~ 0,0,1,1,2,2,3,3,4,4,5~5,~,6,7,7 0310 07080809 rlB 7,8,8,9,9,10H,lOH,llH
031R 11121213 DB llH,12H,12H,13H,13H,14H,14H,lSH
0320 15161617 ~B lSH,16H,16H~17H,17H,17H,laH~18H
032~ 19192020 nk 19H,19H,20H,20H,21H,21H,22H,q2H
0330 23232424 llr( 23H~23H,24H,24H,24H,25H,25H,26H
0338 26272727 U~ 26H~27H ! 27H,27H,28H,28H,29H,29H
0340 30303131 r~B 30H,30H,31H,31H,32H,32H,32H,33H
0348 33343435 DB 33H,34H,34H,35H,35H,36H r 36H,36H
0350 3737383a IIB 37H,37H,38H,38H,39H,39H,40H,40H
0358 40414142 llrt 40H,41H,41H,42H,42H,43H,43H,43H
0360 44444545 ~rt 44H~44H,45H,45H,46H~46H~46H,47H
0368 4~484848 nB 47H,48H,48H,48H,49H,49H,SOH,50H
0370 '1515152 nB SlH,51H,51H,52H,52H,53H,53H,53H
0378 5454r~555 Db 54H,54H,55H,55H,55H,56H,56H,57H
03R0 57575858 ll~ 57H,57H,58H,58H,59H,S9H,59H,60H
0`388 ~0616161 11~ 60H,61H~61H,61H~62H,62H,62H~63H
0390 63646464 ~k 63H,64H,64H,64H,65H,65H,66H,66H
0398 66676767 ~Ih 66H,67H,67H,67H,6aH,6RH,68H,69H
03A0 69707070 DB 69H~70H,70H,70H,7111,71H,71H,72H
03A8 72727373 llh 72H,72H,73H,73H,74H,74H,74H,75H
03~0 75757676 rlB 75H,75H,76H.76H,76H 77H,77H,77H
03B8 7B787879 D~ 78H,78H,78H,79H,79H 79H,80H,BOH
03C0 80818181 nB 80H,81H,81H,81H,82H,R2H,82H,83H
03C8 83838484 ~IB 83H,83H,84H,84H,84H,R5H,85H,85H
03D0 86868687 n~ 86H,86H,8~/1,87H~87H,87H,88H,88H
03~8 88888989 IIB 88H,88H,89H,89H,89H,90H,90H,90H
03E0 91919191 IIB 91H~91H,91H,91H,92H,92H,92H,93H
03E8 93939394 Brl 93H~93H~93H~94H,94H,94H,95H,95H
03F0 95959696 IIB 95H,95H,96H,96H,96H,97H,97H,97H
03F8 97989898 IIB 97H,98H,98H,98H~98H,99H,79H,99H
While I have described above the principles of my invention in conjunction with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation of the scope of my invention as set forth in the accompanying claims. 5
POSITION OF A DRIV~ COIL, WIT~TI~J A GRID
OF SP~CED CON~UCTORS
~ack~round of the Invention his invention relates to a method and apparatus for 5 determininq the position of a coil with respect to a grid of spaced conductors and more particularly to such instruments which are relatively simple and low cost.
Various high resolution apparatus for translating a position of a movable instrument, such as a pointer or pen, into 10 electrical signals for transmission to a local or remote utiliza-tion device are well known in the art.
U. S. Patent No. 4,210,775, assigned to Talos Systems, Inc., pertains to a digitizer in which an instrument, such as a pen having a coil disposed about a nosepiece located immediately 15 above the writing tip of the pen, is utilized in conjunction with a tablet comprising a grid of conductors, including a group of parallel spaced conductors oriented in an X direction and a group of parallel spaced conductors oriented in a Y direction. The pen tip is moved along a worksheet disposed on a support surface 20 containing the grid of conductors. An oscillator applies a signal of predetermined constant frequency and amplitude to the coil. The coil is inductively coupled to the conductors of the grid, thereby inducing signals in the conductors. In accordance with electromagnetic theory, the magnitude and phase of the 25 signals induced in the respective grid conductors depend on the location of the conductors with respect to the pen tip. The grid conductors in each group are sequentially scanned to sequentially couple the induced signals to a differential amplifier by means of multi~lexing circuitrv. The multiplexing circuitry selects 30 the respective grid conductors in response to an address decoder.
7~a The address decoder is Ariven by a scan co~nter. The scan counter is incremented by a .siqnal produced by a divider circuit driven by the oscillator. A position counter is incremented in response to the oscillator as the X and Y qroups of grid conductors are sequentially scanned. ~ phase sensitive detector 5 responsive to the output of the amplifier produces a positive signal having a step-like envelope as grid conductors approaching one side of the pen tip are sequentially scanned. The phase sensitive detector also produces a negative signal having a step-like envelope as conductors on the opposite side of the pen 10 tip are sequentially scanned in a direction away from the pen tip. The signal produced by the phase sensitive detector is filtered to produce a characteristic wave shape signal having a positive peak as the scannincl approaches the pen tip. The filtered signal falls steeply across the zero axis to a negative 15 peak as the scanninq passes under the pen tip, and decreases as the scanning continues in the direction away from the pen tip.
The filtered signal is differentiated and compared to a predetermined threshold level to produce a stop pulse. The stop pulse is utilized to disable the position counter. At this point 20 the contents of the position counter represent the location of the pen tip with respect to the X group of grid conductors and are loaded into an output register. The contents of the output register are then outputted to a utilization device. The scan counter and the position counter are reset and the conductors Of 25 the Y sroup of grid conductors are scanned in a similar manner to produce a digital position number representing location of the pen tip with respect to the Y group of conductors.
Other patents which employ multiplexers to sequentially scan the respective X and Y conductors of groups of parallel spaced 30 conductors and assigned to Talos Systems, Inc. include ~. S.
Patent l~umber5 4,1~5,165 and 4,260,852. While all of these patents which emplov multiplexers to sequentially scan the ~ri~l conductors produce desirable results in a satisfactory manner, the equiplnent to accornplish these results are relatively complex and costly. 5 Accordingly, it is an object of this invention to provide a simplified and lower cost digitizer.
Summary of the Invention Briefly described and in accordance with one embodiment thereof, the invention provides a digitizinq system and method 10 for converting a position of an instrument, such as a pen or cursor, to an electrical signal representing a position of the instrument with respect to a grid of conductors. The instrument generally includes a coil for coupling electrical signals to a qrid of conductors including a group of parallel spaced 15 conductors oriented in an X direction and a group of-parallel spaced conductors oriented in a Y direction. In one embodiment of the invention sixty-four parallel spaced conductors are arranged in both the X and Y directions with a constant spacing bet~Jeen conductors. Typically, the conductors are deposited on a 20 printed circuit board with the conductors in the X direction deposited on one side of the printed circuit board and the conductors in the Y direction deposited on the other side of the printed circuit board; however, alternatively, wires or other conductors may be embedded or disposed upon some other 25 non-conducting surface.
The pen or cursor which operates in conjunction with the grid conductors comPrises a coil of wire wound on a non-metallic form.
An oscillator applies a signal to the coil of a predetermined frequency, typically 100 Khz. Typically, the coil operates at 12 30 ~olts at 150 milliamps. The rnore current, the larger the signal 57~
induced in the conductors of the grid, however, heating problems limit the amount of current which can be applied to the coil.
The coil is inductively coupled to the conductors of the grid, thereby inducing signals in the conductors. In accordance with electromagnetic theory, the magnitudes and polarity of the 5 signals induced in the respective grid conductors depends upon the location of the conductors with respect to the coil.
A multiplexing circuit is employed to sample the signal from the center conductor of the X direction array of conductors. By determining whether the signal is of a positive or negative 10 polarity, the location of the coil with respect to the grid conductors is known, that is, whether the coil lies ahove or below the sampled center conductor. The multiplexer then samples the signal from the center conductor of the half section ~upper or lower) in which the coil is located, and again, by 15 ascertaining whether the signal is positive or negative, a determination is made in which quarter section the coil is located. Additional readings are taken in the same fashion until it is ascertained that the coil lies between two adjacent X
direction conductors. 20 If the coil is exactly equidistant between the two conductors, the magnitude of signal induced in each conductor will be equal and opposite in polarity, and therefore, it is known that the coil is, in fact, precisely in the middle of the two conductors. When the coil is not equidistant between the two~25 conductors, the magnitude of the signal from the two conductors will increase or decrease. That is, one will increase, the other will decrease.
The exact coil position is then determined by forming a ratio of the induced signal from the two conductors and comparing this 30 ratio with values stored in a look-up table. ~Since ratios hetween the two signals are employed rather than using absolute values, any variation in signal strength from the coil to the conductors will have no effect on the measurement. Also, the measurements will be frequency and phase insensitive.
A like set of measurements is then made sampling signals from the Y direction array of conductors to precisely locate the coil S
with respect to the Y direction array of conductors.
~rief Description of the Drawinqs The above-mentioned and other features and objects of the invention will become more apparent by reference to the following description taken in con~unction with the accompanying drawings, 10 in which:
Fig. l is an illustration of the grid conductors of a digitizer illustrating the manner in which the location of a coil contained within the grid is ascertained;
Figs. 2 and 3 are circuit diagrams of a digitizer processor 15 in accordance with the principles of this invention; and Fig. 4 is a diagram of a circuit for sampling the signals from the grid conductors of Fig. l to apply the signals therefrom to the circuit of Figs. 2 and 3.
Description of a Preferred Embodiment 20 Referring now to Fig. 1 of the drawings, there is illustrated thereby, schematically, the grid conductors of a tablet. This tablet typically contains sixty-four parallel conductors (numbered 1-64) arranged in the X direction and sixty-four parallel conductors ~numbered 65-128) arranged in the Y 25 direction. Assuming the location of a coil at position l~ during one moment in time, the function of the digitizer is to determine that location precisely. In accordance with this invention, an ac signal is applied to the coil and is inductively coupled to the conductors. X conductors on one side of the coil will have a 30 positive signal induced therein, while X conductors on the opposite side of the coil will have a negative signal induced therein. Thus, by noting the polarity of the signal induced in a ~57~
particular conductor beinq sampled, it is readily ascertained that the coil is either above or below such conductor.
In accordance with the principles of this invention, the signal inductively coupled rom the coil to a conductor in the middle of the tablet is sampled, for example, conductor 32. When S
the signal on that conductor is sampled, it is determined by the polarity of the signal that the coil is, in fact, above the conductor 32 and within the area containing the conductors 1-32.
Accordingly, it is not necessary to sample any signals induced in conductors 33-64. The next sampling is taken at a conductor in 10 the center of the upper half of the tablet such as conductor 16.
By noting the polarity of the signal from conductor 16, it is ascertained that the coil is, in fact, above conductor 16, and therefore, in the upper ~uarter of the tablet, namely somewhere between conductors 1 through 16. The next sampling is taken at, 15 for example, conductor 8 and, by denoting the polarity it is ascertained that the coil lies within an area containing conductors 1-8. The next sampling occasions a measurement to be made of the signal on conductor 4 and by the polarity of the signal, it is determined the coil is, in fact, above conductor 4 20 and located somewhere between conductors 1 through 4. A
measurement is-then made of the signal at conductor 2 and by noting a different polarity from those previously measured, it is ascertained that, in fact, the coil is located below conductor 2.
The equipment then samples conductor 3 and judging from the 25 polarity of the sampled signal, it is ascertained that the coil is above conductor 3. Thus, with only six samples the course location of the coil (within two conductors) has been ascertained. This is contrasted to sampling all sixty-four conductors as in other systems. 30 Accordingly, it is now known that the coil lies between i7~;~
conductors 2 and 3. If the signals measured at conductors 2 and 3 are equal, then it is ~nown that the coil is equally distant from conductors 2 and 3. However, if the signals are not equal then a ratio is taken of the signals obtained from the sampling of conductors 2 and 3, and thi~ ratio is compared in a loo~-up 5 table with values stored therein to determine the precise location of the coil. Since ratios are employed rather than absolute values of the signals sampled from conductors 2 and 3, the system is amplitude, frequency and phase insensitive. After determining the position of the coil with respect to conductors 1 10 through 64, the same procedure is carried out with respect to the Y direction conductors 65 through 128 to locate the coil precisely in the other direction.
The circuitry for carrying out this procedure is set forth in Figs. 2, 3 and 4. Figs. 2 and 3 include all of the circuitry 15 necessary except for the conductor sampling means which is employed to sample the necessary ones of the conductors 1 through 128, and this is shown in Fig. 4 of the drawings. The conductor sampling means connects conductors of the tablet to the circuitry of Figs. 2 and 3. 20 In the example set forth above, the signals from conductors 64, 32, 16, 8, 4, 2 and 3 are successively appIied to an input 12 of the digitizer circuit of Figs. 2 and 3. Each of these signals is amplified and filtered at circuit 14 in order to provide proper operating signal levels for the system. The output from 25 amplifier and filter circuit 14 is applied to a synchronous detector 16 to convert the input ac signal to a dc signal. The output from synchronous detector 16 is applied to an amplifier and smoothing filter 18. Circuit 18 smoothes any ripples in the output from the synchronous de~ector 16 and further amplifies the 30 dc signal.
The output from the amplifier and smoothing filter circuit 18 is applied to an analog-to-digital converter 20 which converts the dc voltage output from circuit 18 to a binary number. This binary number is applied to a microprocessor 22. The binary number is utilized in the microprocessor 22 to determine which 5 conductor of the tablet to sample next in accordance with the stored program therein. The output from microprocessor 22 at pins 27 through 33 are the addresses of the conductors of the tablet to be sampled and these are applied to the sampling circuit of Fig. 4. These are the addresses of the conductors to 1( be connected to the input 12. The program stored in the microprocessor determines which conductor of the tablet to sample next as well as developing the ratios of the specific conductors to be compared to the values in the look-up table to determine the position of the coil in the X direction. Signals are also ~15 applied to input 12 from respective Y conductors to determine location of the coil in the Y direction as well. Connections from pins 1, 6, 8, 10-19, 35 and 39 of microprocessor 22 are coupled to a UART 24 to communicate with auxiliary equipment such ~
as a computer or terminal. The outputs from UART 24 are taken 20 from TTL to RS232C via interfaces 25 and 27.
An output 28 from the microprocessor is a 400 KHz signal which is applied to a divider 30 to divide the signal by four to nrovide a 100 XHz signal. This signal is applied via line 32 and transistor 34 to synchronous detector 16 as a reference input 25 thereto. Transistor 34 converts and level shifts the signal from divider 30. The 100 KHz signal is also applied to a push-pull amplifier 36 with the outputs therefrom being applied to the coil to drive the coil in push-pull.
The circuit for sampling the sixty-four X (numbered 1-64) and 30 the 64 '~ (numbered 65-128) conductors is shown in Fig~ 4. The ~5~
circuit includes two one-of-eight selectors 40 and 42 and sixteen switchinq circuits, eight for switching to or sampling appropriate X conductors and eight for switching to or sampling appropriate Y conductors, only two of each being shown, for simplicity of explanation. 5 ~ switching circuit 44 connects a selected one of the X
conductors 1-8 to the input 12 of the circuit of Figs. 2 and 3 via a line 46 and a switching circuit 48 connects a selected one of the X conductors 49-64 to the same input via line 46. Similar switching circuits (not shown) are employed to connect selected lC
ones of the conductors 9-48 to the input 12.
Switching circuit 50 is employed to connect a selected one of the Y conductors 65-72 to input 12 via line 46 and switching circuit 52 is used to connect a selected one of the Y conductors 121-128 to input 12 via line 46. Other switching circuits (not 15 shown) are employed to connect selected ones of the conductors 73-120 to the input 12.
The inputs to the sampling circuit of Fig. 4 are received from the output of microprocessor 22 along lines 54, 56, 58, 60, }
62, 64, 66 and 68. The input along line 54 indicates that Y ; 20 conductors are to be sampled and is thus applied to ~he one-of-eight selector 42 for the Y conductors. The input at line 62 denotes that X conductors are to be sampled and is accordingly coupled to the one-of-eight selector 40 for the X conductors.
The one-of-eight selector 40 determines which of the eight X 2 conductor switching circuits, including switching circuits 44 and 48, is to be enabled while the one-of-eight selector 42 selects the appropriate one of the eight switching circuits for the Y
conductors, including switching circuits 50 and 52. This selection of an appropriate switching circuit is made by the 3( selectors 40 and 42 in accordance with address command received from microprocessor 22 along lines 56, 58 and 60 which is coupled to both of the selectors 40 and 42.
The other inputs to the sampling circuit from the microprocessor is the input on lines 64, 66 and 6~. These inputs are applied to all of the switching circuits including switching 5 circuits 44, 48, 50 and 52, and selects which of the eiqht conductors coupled to a particular switching circuit is to be coupled to the output line 46.
The computer program for operating microprocessor 22 is written in assembly lan~uage and is as follows: 1( ~S75~
8048 ~SsEMrlLER
SYSTEM EauATES
WIRE INFORMATION
0020 XMID EQU 2011 ;ADDR OF X MIQrlLE WIkE
OOAO YMILI EaU OF~OH ;ADIIR OF Y PlIDrlLE IJIRE
0020 OFFSET Enu 20H ;WIRE ~ OFFSET VALUE
WlkE VOLTAGE STORAGE ADrlRESS
0020 IJOLT Eau 20H ;f!~QDR OF VOLT R~M STORAGE
POINT PARA~lETERS STORAGE ADrlRESSES
0022 XPAR EQU ;~2H ;X PAkAllETERS STORAGE AQnR
0025 YPAR VOLTAGE BIAS ;r PARAnETERS STORAGE ADQR
0080 E~IAS EOU 080H ;UIRE OFFSET VOLTAGE
0003 t5 QIS
0007 OkG 7H;
oooa 93 PSRETs RETR
0009 C5 INIT~ SEL RBO
OOOC 140EI . CALL FSFsET ;kESET INT-IN-F'ROG FLAG
OOOE 75 ENTO CLK ~ENA8LE CLOCI; TO UART
OOOF 8A10 ORL P2,~10H ~SELECT UART
0011 E1903 MOV R1,-3 0013 ~380 MOV A,~BOH ;SELECT QLAr 0015 91 MOVX eR1,A
0016 8B00 MOV RO,~O ;SELECT 9~00 ElAU
0018 ~'30C MOV A,40CH
001A 90 MOVX eRo,~
001E~ 1a INC RO
OOlC 27 CLR
001D 90 MOVX eRo,A
OOlE 2303 MMovx ~R173~ ;SELECT 8 EIITs, ETC~
0021 8904 MOV R1,~4 00''3 27 CLR fl 0024 91 MOVX ek1,A
0025 90 MOVX ekO,A
;
; EXPLANATION OF STRATEor ; THERE AkE 2 STATES, EACH REaUIkING DIFFERENT fROCFS5ING.
;
; STATE A - POS VALUE < ABS NEG VALUE
; STATE B - FOS VALUE ~ OR = ABS NEG VALUE
; STATE A, ~ISTANCE = ~ OF POS WIRE*200 MILS+LOOK UP TAbLE VAL
; STATE B, bISTANCE = ~ OF FOS WIRE ~ 200 MILS t 199 - LUTV
;
0100 OkG lOOH
0100 A5MAIN~ CLR Fl ;kESET XZY FLAG~SELECT X AXIS) OtOl BC20 MOV R4,~XMID ;GET MIDIILE X WIkE
0103 tl5LOOPO~ CLR FO ;kESET SIGN FLAG
0104 hb20 MOV R5,~0FFSET ;GET INITIAL OFF5ET t 0106 BE05 MOV R6,~5 ;SET UP LOOP COUNTER
0108 FbLOOPl: MOV A,kS ;GET OFFSET
010A 67RkC A ~2 OFFSET
OlOB AbMOV k5,A SAVE NEW OFFSET ~
OlOC 546C CALL OUTWRE ~ ,TUkN ON WIkE i,CONVERT
010E FC~OV A,R4 ;GET WIRE ~
010F F616 JC INCWRE IF I VOLT,INCR WIkE 4 0111 37DECWRE: CPL A ;SUBTRACT OFFSET
0112 6~Arlb A,RS
0114 2417 JMP CONTO ;CONTINUE
0116 6DINCWREI Anrl A,RS ;ADD OFFSET
0117 ACCONTO: MOV k4,A SAVE L~TEST WlkE
OllB EE08 DJNZ R6,LOOPI ,DEC AND LOOP
OllA FCMOV A,k4 ;SAVE WIRE ~ IN kl Ollk A9MOV Rl,A
OllC S46C ` CALL OUTWkE TURN ON LATEsT WIkE *,CONVERT
OllE B820 MOV hO,~VOLT ;GET VOLT STOkAt3E ArlDR
0120 F629 JC PLUS jIF VOLT AT UIkE ~ +~JUMP
0122 37MINUS: CFL A ;SAVE ABS VhL OF VOLT t~
0123 ~0nov eko~A
0124 CCbEC k4 POINT TO WIkE t-l 0125 FCMOV A,R4 ,SAVE IT AS LAST LIRE
012$ A9MOV kl,A
0127 242C JMP CONTl ;CONTINUE
0129 AOPLUS: ~OV ekO,A ;SAVE UOLTAGE I~ ALlDk 012A 95CPL FO ;SET SIGN FLAG
012B lCINC R4 : jPOINT TO WIkE ~1 012C 546C CONTl: CALL OUTWkE ;TURN ON WIkE ~l,CONVERT
012E B632 JFO ABS2 ;TAKE ABS VAL,VOLT~
0130 2433 JMP CONT2 ;CONTINUE
0132 37 ABS2~ CPL A ;TAKE ABS VAL OF VOLTAGE
0133 ~821 CONT2: MOV kO,~VOLt~l ;SAVE AbS UOLT OF WlkE~ t 0135 AO MOV CRO,A
5'7~
Ot36 B63b JFO , CONT3 ;CONTINUE
013B C8 nEC Rb ;POINT TO VO-T (~) .
0139 243F JMP CONT4 ;CONTINUE
013P 8R20 CONT3: MOV RO,~OLT ;~0 ~OLTIt~
013D FO MO~ A,eRO
013E 18 INC RO jPOINT TO VOLT ~
013F 37CONT4: CPL A ;SUBTR APS NEG VOLT
0140 bOADn A,eRO
OI42 F649JC LARNEG ;IF CARRY,CNEG~ VOLT~ POS VOLT
0144 5416LARFOS: CALL LGEPOS jSOL~E FOR kAT10-(NEG*256)/POS
0146 B5CLR FO ;kESET SIGN FLAG
0147 244DJnp CONT5 jCONTINUE
0149 542rl LARNEG: CALL LGENEG ;SOLVE FOk RATIO=(POS*256)/NEG
014b 85CLR FO ;SET SIGN FLAG
014n AACONT5: MO~ R2,~ ` :
014E BllOO MO~ R3,~00H ;CLEAR SlGN FLAG(~SIGN) 0150 B654JFO CONT6 ~CONTINUE
0152 BBFFno~ R3,~0FFH ;SET SIGN REG ~- SIGN~
0154 765ACONT6: JFl SAVY ;Fl SET,SA~E Y PAR~METERS
0156 B8 2 nov RO,~XPAR ;GET X PAkAMETERS AllrlR
0158 245C JMP SAVPAR ;SA~E THE P~RAMETEkS
015A RB?5 SA~Y~ MO~ RO,tYPAR ;GET r PARAMETRS ~D~IR
015C F9 SA~PQR: MO~ A,Rl ;GET WIRE
015B AO MOV ekO,A jSAVE IT
015F FA MOV A,R2 ;GET RATIO
0160 ~0 MO~ eRO,A ;SAVE IT
0161 lB INC RO
0162 F~ MOV A,R3 ;GET SIGN llYTE
0163 ~0 MOV eRo A ;SA~E IT
0164 766b JFl PRINT ~Fl SET,Y COOR~ JUST COMPLETEI
0166 B5 CPL Fl ;SET X/Y FLAG
0167 BCAO MOV R4,~YMIrl ,GET MIIIDLE Y WIRE
0169 2403~ JMP LOOPO ;SEARCH FOR Y COOR~
016B 5450PRINT: CALL CRLF
016~1 BH24 MO~ RO,~XPAR~2 ;PRINT X COOR~IINATE016F 347C CALL OUTPUT
0171 DB2C MO~ R3,~
0175 B827 no~ RO,4YPARt2 ;PRINT Y COORIIIN~TE
0177 ~5 CLR Fl ;SET FLAG FOR Y COOR~lNATES
017A 2qO0 JMP MAIN ;~0 IT hLL ~GAIN
017C FOOUTPUTs MOV A,eRO ;GET SIGN
017E C8DEC RO ;POINT TO WIRE
017F F2BC JB7 SIGNEG ;JUMP IF SIGN WAS NEGATIVE
~5~
Oi~l FO SIGNPS~ MOV ~,~RO jGET WIRE ~
OlS2 549b CALL COARSE ;PRINT TENS, ONES, IEC. POINT
0184 5402 CALL OUTCH ;PRINT T~NTHS
018~ 18 INC kO ;POINT TO aUOTIENT
0187 FO MO~ ~,eRO ;GET aUOTIENT
0188 E3 MOVP3 A,eA jLOUK UP COkR ~I5P }N TAbLE
Ola9 54b4 CALL HEXASC ;PRINt HUNnRENTHS, THOUS~NDTHS
018b 83 RET
018C fO SIGNEG: ~W A,eRO ;GET UIRE
018h 549h CALL COARSE
018F 18 INC R3 ;ADVANCE TO NEXT WIRE
019~ 18 . INC RO
0193 FO MOV A,eRO
0194 E3 MO~P3 A,eA
0195 37 CPL A jSUbT VALUE FkOM NEXT WIRE POS
0197 0399 ~DD ~,~99H
0199 S4~4 CALL HEXASC
019b 83 RET
0200 rrt20 SPACE: MOV R3,~
0202 sAlo OUTCH: ORL P2,~10H ;SELECT UART
0204 }~05 MOV Rl,~5 020~ 81 MOVX A~ekl ;GEr STATUS INTO ACC
0207 9AEF ANL P2,~0EFH jDESELECT U~RT
0209 r120~ J~S NoTr15Y
020B 4402 JMP OUTCH ~LOOP TILL UART NOT ~USY
02011 8A10 NOTBSY: ORL P2,~10H ;SELECT UART
020F E1900 nov Rl, ~0 0211 FkMOV A,R3 ~GET C~ARACTER TO BE PRINTED
0212 71novx eRlrA ;PRrNT IT
0213 sQEF ANL P2,40EFH ;DESELECT UART
0216 rt61F LGEFOSs JFo OK2 ~IF t,RVSE POS ~ NEG VOLT(ST
0218 P820 MOV RO~VOLT ~GET VOLTS ArlnR
021A FOMOV A~eRo ~GET Arls NEG INTO R4 021~ ACMOV R4,A
021C 15INC RO ;POINT TO POS VOLT Arlnk 0210 4424 Jnp OK3 -CONTINUE
021F ~821 OK2: MOV RO,~VOLT+l ;GET VOLT ~417-l~ ArlrlR
0221 FO MOV A,eRO ;GET A~S NEG INTO R4 0222 AC MOV R4, A
0223 CS rlEc RO ;POINT TO POS VOLT ADDR
0224 FO OK3s M04 A,~RO ;SAVE FOS VOLT ~N R5 022s Arl MOV Rs~A
0226 547S CALL nIvl6 iRATID=(NEG*2s6)7po8 0228 E62C JNC 0~4 022A 23FF nov A,~OFFH
022c G3 OK4~ RET
;
; FRrNTs ASCII CHARACTER IN R3. R7 ~R~ sTRoYErl.
;
022tl rt636 LGENEG: JFO ON2 STATE A
022F Et821 MOV RO,~VDLT~l ,FOI~T TO VOLT (~ ) ADrlR
0231 FOnov A~eRo ;GET POS VOLT INTO R~
0232 ACMOV R4,A
0233 C8rlEc RO ;PDINT ro VOLT ~) ADbR
0234 443~ JMP ON3 ;CONTINUE
0236 ~820 ON2: MOV RO,~VOLT ;POINT TO VOLT ~4) ArlrlR
0238 FO MOV A,eRO ;GET POS VOLT INTO R4 0239 AC ~oV R4,A
023A 18 INC RO ;POINT TO VOLT (~t/-l~ ~rlrlR
023E1 FO ON3: MOV A,eRO ;GET Ar1s NEG VQLT INTO Rs 023C Arl ~OV R5,A
023~ 5475 CALL rlIvl6 ;R~TIO=~POS*25~)7NEG
~95~
;
; CONVERTS L0UEk 4 BITS IN ACC TO ASCII CHARACTEk ~Nb ; PRINTS rT. R3, ACC DESTkO~'ED.
0~-0 530F~SCII: ANL A,~OFH ;MASK IN LO~Ek 4 RlTS
0242 0330 Ar,l, ~,t30H ;CONYEkT TO ~SCII
~ 44 ~MUV R3,A ;AIIJUST RESULT IF 3A TO 3F
024~; OlC~ An~ A,~OC6H
024' FkMOV A,R3 024A 0307 ADD A,~
024C AB 0~: MO~ R3,A
0:4D 5402 CALL OUTCil PRINT ASCII CHAR
024F 8~ RET
;
' , PRINTS CR, LF. ~CC DESTROYED.
0250 r~oo CRLF: MOV R3,~01lH jL0AD CR
0252 54~2 CALL OUTCH ;PkINr Il 0:'54 ~I~OA MO~ R3,~0~H jL0AII LF
0~56 5402 CALL OUTCH
;
, STPRTS AXD CONYEklER, WAITS, EXITS UITH RESULT IN ~CC.
0259 `7~EF ADCDNYs ANL P't~0EFH ;SELECT A/rl 025~ 90 MOVX eRo, A ;START CONYEkTER
0'5C 5h5C UT1 $ ~WAI7 O'SE 80 . MOYX A,C'RO jGET rlATA
025F 8A10 URL P2,~10H ;DESrLECT A~D
0~o3 03aO Allrl A,~I~IAS ;OFFSET THE VOLTAGE
;
; MOYES A DYTE INTO 2 NI8bLES ANrl F'RINT8 THEM. ENTER U~
; DATA IN ACC. ACC, R3, R4 ~ESTk0YErl.
0~64 AC HEXASCs MOY R4,A
0'6S 47 SWAP A ;GEl' UF'PER NI8~LE
0266 ~440 CALL A~CII ;CONVEkT AND PRINT
0268 FC ~O~ A,R4 02h9 544d ChLL ASCI1 ~C0NVErtT AND PRINT LOWER NI~
026rl 83 RET
;
; oUT~urS WlkE ADr~RrSS ~ND WAITS F0k 5ETTLINri ~57~
026C FC OUTWkE: MOV A.h4 0270 F.F70 OUTL k7,~30H ;WAIT
227i2 83S9 FC~EATL ABCONV ;DO A7ll CON~
AT6 E~NTR~ VIt~E RouTIl`~E
; ACC ~ LOWER 8 rt}TS OF ~I}VIDEND
; R4 3 UPPER B aITS OF n}~l}DEN
~ R5 - DlVISOR
; AT EXIT, ; ACC I B DITS OF RESULT
; R4 = REMAINbER
` ; R5,R7 DESTROYED
0276 bFOB D}V16~ XCH A,R4 0'79 ~ cArl~ A,RS
0'7~ F6UO cpcL rIVIA
02Bl Y7DIVIAt nD D}VIB
02B3 F7RXLcCH ,R4 0~84 2C ~ XCH A,R4 028- F7RLC tt 02B6 E6sD cJpNL D}VYE
028h 37cApD~D A,R5 028~ 4495 D}VIE: CPL A)IVIC
028F 37 cFDrL A~R5 0~92 6~ ADr~ AI'VICD
0295 lCDIVIC: INC R4 029B 97CLR R7,tIVILP
., 029~ 769F COARSE: JF1 XCOOR~
~ 9~
029D 03CO A~lD A,~-40H ;OFFSET WIRE ~ IF Y COOR~
029F ~bFF XCOORIl: ~0~ R3,~0FFH ;CEEAR INCH COUNTER - l 02Al l~ LOOF'3: INC R3 ;COUNT INCHES IN R3 O"A2 03F~ A~ID A,3-5 OZA4 F6AI JC LOOF'3 02A6 0305 AtlIl A,~S ;RESTORE DATA
O"A8 97 CLR C ;MULT ~Y TWO
02A9 F7 RLC A ;ACC = .0, .2, .4, .6, .C
02AA AD MO~ R5,A ;STOfi'E TENTHS IN R5 02A~ F~ MO~ A,R3 jGET TENS ANn ONES
02AC 03F6 AnD A,~-lO ;CON~ERT TO ~CD
02AE E6~2 JNC OKl 02~0 0306 ADD A,~b 02~2 030A OKt: ADD A,~IO
02~4 5464 CALL HEXASC ;PRINT TENS ANII ONES
02~6 ~2E ~0~ R3,*-.' ;PRINT DECI~AL POINT
02~8 5402 CALL OUTCH
02~A Fn ~0~ A,RS ;GET TENTHS
02~h 0330 ADD A,~30H ;CON~ERT TO ASCII
02DD A~ ~OV R3,A ;PUT TENTHS INTO R3 O~E 83 RET
1~9~7~4 , 100 MIL IIATA TABLE
; PEN CAL r BRATION
0300 0000010~ n~ 0,0,1,1,2,2,3,3,4,4,5~5,~,6,7,7 0310 07080809 rlB 7,8,8,9,9,10H,lOH,llH
031R 11121213 DB llH,12H,12H,13H,13H,14H,14H,lSH
0320 15161617 ~B lSH,16H,16H~17H,17H,17H,laH~18H
032~ 19192020 nk 19H,19H,20H,20H,21H,21H,22H,q2H
0330 23232424 llr( 23H~23H,24H,24H,24H,25H,25H,26H
0338 26272727 U~ 26H~27H ! 27H,27H,28H,28H,29H,29H
0340 30303131 r~B 30H,30H,31H,31H,32H,32H,32H,33H
0348 33343435 DB 33H,34H,34H,35H,35H,36H r 36H,36H
0350 3737383a IIB 37H,37H,38H,38H,39H,39H,40H,40H
0358 40414142 llrt 40H,41H,41H,42H,42H,43H,43H,43H
0360 44444545 ~rt 44H~44H,45H,45H,46H~46H~46H,47H
0368 4~484848 nB 47H,48H,48H,48H,49H,49H,SOH,50H
0370 '1515152 nB SlH,51H,51H,52H,52H,53H,53H,53H
0378 5454r~555 Db 54H,54H,55H,55H,55H,56H,56H,57H
03R0 57575858 ll~ 57H,57H,58H,58H,59H,S9H,59H,60H
0`388 ~0616161 11~ 60H,61H~61H,61H~62H,62H,62H~63H
0390 63646464 ~k 63H,64H,64H,64H,65H,65H,66H,66H
0398 66676767 ~Ih 66H,67H,67H,67H,6aH,6RH,68H,69H
03A0 69707070 DB 69H~70H,70H,70H,7111,71H,71H,72H
03A8 72727373 llh 72H,72H,73H,73H,74H,74H,74H,75H
03~0 75757676 rlB 75H,75H,76H.76H,76H 77H,77H,77H
03B8 7B787879 D~ 78H,78H,78H,79H,79H 79H,80H,BOH
03C0 80818181 nB 80H,81H,81H,81H,82H,R2H,82H,83H
03C8 83838484 ~IB 83H,83H,84H,84H,84H,R5H,85H,85H
03D0 86868687 n~ 86H,86H,8~/1,87H~87H,87H,88H,88H
03~8 88888989 IIB 88H,88H,89H,89H,89H,90H,90H,90H
03E0 91919191 IIB 91H~91H,91H,91H,92H,92H,92H,93H
03E8 93939394 Brl 93H~93H~93H~94H,94H,94H,95H,95H
03F0 95959696 IIB 95H,95H,96H,96H,96H,97H,97H,97H
03F8 97989898 IIB 97H,98H,98H,98H~98H,99H,79H,99H
While I have described above the principles of my invention in conjunction with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation of the scope of my invention as set forth in the accompanying claims. 5
Claims (20)
1. Apparatus for determining the position of a transmitting coil with respect to a grid of spaced parallel conductors located adjacent to the transmitting coilt comprising:
means for sampling the signals induced in only a selected small percentage of the conductors so as to successively reduce the possible position of the coil to smaller and smaller areas until the position is determined to be the intermediate two of the conductors; and means responsive to the signals induced in the two conductors to determine the precise position of the coil.
means for sampling the signals induced in only a selected small percentage of the conductors so as to successively reduce the possible position of the coil to smaller and smaller areas until the position is determined to be the intermediate two of the conductors; and means responsive to the signals induced in the two conductors to determine the precise position of the coil.
2. Apparatus as defined in claim 1, wherein said sampling means includes means for sampling the signal induced in a first of the conductors located in substantially the middle of the grid so as to determine that the coil is located in one particular half of the grid.
3. Apparatus as defined in claim 2, wherein said sampling means includes means for sampling the signal induced ln a second of the conductors located in substantially the middle of the half of the grid determined to contain the coil so as to determine that the coil is located in one particular quarter of the grid.
4. Apparatus as defined in claim 3, wherein said sampling means includes means for sampling the signal induced in other conductors to further reduce the area in which the coil is located to an area intermediate two conductors.
5. Apparatus as defined in claim 4, wherein said sampling means includes means for making suGcessive determinations of the course position of the coil prior to determining which of the other conductors are to be sampled.
6. Apparatus as defined in claim 1, wherein said means responsive includes means for establishing a ratio of the signals induced in the two conductors and means for comparing the ratio with predetermined ratios indicative of precise coil position location.
7. Apparatus as defined in claim 1, wherein said sampling means includes means for ascertaining the polarity of the signals induced in the conductors to denote on which side of a sampled conductor the coil is located.
8. Apparatus for determining the position of a transmitting coil with respect to a pair of spaced parallel conductors located adjacent to the transmitting coil, comprising:
means for measuring the signals induced in each of the conductors;
means for establishing a ratio of the signals induced in the conductors; and means for comparing the ratio with a listing of prede-termined ratios indicative of precise coil position location.
means for measuring the signals induced in each of the conductors;
means for establishing a ratio of the signals induced in the conductors; and means for comparing the ratio with a listing of prede-termined ratios indicative of precise coil position location.
9. Apparatus for determining the position of a transmitting coil with respect to a plurality of spaced parallel conductors located adjacent to the transmitting coil, comprising:
means for sampling the voltage induced in a first one of the parallel conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the first conductor which does not contain the coil;
means for sampling the voltage induced in a second of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any of the parallel conductors on the other side of the second conductor which does not contain the coil;
means for sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
means for generating a ratio of the voltages induced in said two particular conductors; and means for comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
means for sampling the voltage induced in a first one of the parallel conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the first conductor which does not contain the coil;
means for sampling the voltage induced in a second of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any of the parallel conductors on the other side of the second conductor which does not contain the coil;
means for sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
means for generating a ratio of the voltages induced in said two particular conductors; and means for comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
10. Apparatus for determining the position of a transmitting coil with respect to a plurality of spaced parallel conductors located adjacent to the transmitting coil, comprising:
means for sampling the voltage induced in a first one of the parallel conductors which is near the middle of the plurality of conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially half of the conductors located on the side of the first conductor which does not contain the coil;
means for sampling the voltage induced in a second of the parallel conductors which is near the middle of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially quarter of the conductors located on the side of the second conductor which does not contain the coil;
means for sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
means for generating a ratio of the voltages induced in said two particular conductors; and means for comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
means for sampling the voltage induced in a first one of the parallel conductors which is near the middle of the plurality of conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially half of the conductors located on the side of the first conductor which does not contain the coil;
means for sampling the voltage induced in a second of the parallel conductors which is near the middle of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially quarter of the conductors located on the side of the second conductor which does not contain the coil;
means for sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
means for generating a ratio of the voltages induced in said two particular conductors; and means for comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
11. A method for determining the position of a transmitting coil with respect to a grid of spaced parallel conductors located adjacent to the transmitting coil, comprising the steps of:
sampling the signals induced in only a selected small percentage of the conductors so as to successively reduce the possible position of the coil to smaller and smaller areas until the position is determined to be intermediate two of the conductors; and responding to the signals induced in the two conductors to determine the precise position of the coil.
sampling the signals induced in only a selected small percentage of the conductors so as to successively reduce the possible position of the coil to smaller and smaller areas until the position is determined to be intermediate two of the conductors; and responding to the signals induced in the two conductors to determine the precise position of the coil.
12. The method as defined in claim 11, wherein said sampling step includes sampling the signal induced in a first of the conductors located in substantially the middle of the grid so as to determine that the coil is located in one particular half of the grid.
13. The method as defined in claim 12, wherein said sampling step includes sampling the signal induced in a second of the conductors located in substantially the middle of the half of the grid determined to contain the coil so as to determine that the coil is located in one particular quarter of the grid.
14. The method as defined in claim 13, wherein said sampling step includes sampling the signal induced in other conductors to further reduce the area in which the coil is located to an area intermediate two conductors.
15. The method as defined in claim 14, wherein said sampling step includes means for successively determining the coarse position of the coil prior to determining which of the other conductors are to be sampled.
16. The method as defined in claim 11, wherein said responding step includes establishing a ratio of the signals induced in the two conductors and comparing the ratio with predetermined ratios indicative of precise coil position location.
17. The method as defined in claim 11, wherein said sampling step includes ascertaining the polarity of the signals induced in the conductors to denote on which side of a conductor the coil is located.
18. A method for determining the position of a transmitting coil with respect to a pair of spaced parallel conductors located adjacent to the transmitting coil, comprising the steps of:
measuring the signals induced in each of the conductors;
establishing a ratio of the signals induced in the conductors; and comparing the ratio with a listing of predetermined ratios indicative of precise coil position locations.
measuring the signals induced in each of the conductors;
establishing a ratio of the signals induced in the conductors; and comparing the ratio with a listing of predetermined ratios indicative of precise coil position locations.
19. A method for determining the position of a transmitting coil with respect to a plurality of spaced parallel conductors located adjacent to the transmitting coil, comprising the steps of:
sampling the voltage induced in a first one of the parallel conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the first conductor which does not contain the coil;
sampling the voltage induced in a second of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the second conductor which does not contain the coil;
sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
generating a ratio of the voltages induced in said two particular conductors; and comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
sampling the voltage induced in a first one of the parallel conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the first conductor which does not contain the coil;
sampling the voltage induced in a second of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the parallel conductors on the other side of the second conductor which does not contain the coil;
sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
generating a ratio of the voltages induced in said two particular conductors; and comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
20. A method for determining the position of a transmitting coil with respect to a plurality of spaced parallel conductors located adjacent to the transmitting coil, comprising the steps of:
sampling the voltage induced in a first one of the parallel conductors which is near the middle of the plurality of conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially half of the conductors located on the side of the first conductor which does not contain the coil;
sampling the voltage induced in a second of the parallel conductors which is near the middle of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially quarter of the conductors located on the side of the second conductor which does not contain the coil;
sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
generating a ratio of the voltages induced in said two particular conductors; and comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
sampling the voltage induced in a first one of the parallel conductors which is near the middle of the plurality of conductors so as to determine on which side of the first conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially half of the conductors located on the side of the first conductor which does not contain the coil;
sampling the voltage induced in a second of the parallel conductors which is near the middle of the parallel conductors located on the side of the first conductor which contains the coil so as to determine on which side of the second conductor the coil is located thereby eliminating any necessity of sampling the voltage induced in any of the substantially quarter of the conductors located on the side of the second conductor which does not contain the coil;
sampling the voltage induced in selected others of the parallel conductors so as to coarsely locate the coil as being between two particular conductors;
generating a ratio of the voltages induced in said two particular conductors; and comparing said ratio with a predetermined set of ratios to determine the fine position of the coil.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US6-400511 | 1982-07-21 | ||
| US06/400,511 US4423286A (en) | 1982-07-21 | 1982-07-21 | Apparatus and method for determining the position of a driven coil within a grid of spaced conductors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195754A true CA1195754A (en) | 1985-10-22 |
Family
ID=23583902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000426890A Expired CA1195754A (en) | 1982-07-21 | 1983-04-28 | Apparatus and method for determining the position of a driven coil within a grid of spaced conductors |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US4423286A (en) |
| JP (1) | JPS5924390A (en) |
| AU (2) | AU570206B2 (en) |
| CA (1) | CA1195754A (en) |
| CH (1) | CH661807A5 (en) |
| DE (1) | DE3315353C2 (en) |
| FR (1) | FR2532089B1 (en) |
| GB (1) | GB2124389B (en) |
| IT (1) | IT1197638B (en) |
| NL (1) | NL8302567A (en) |
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| GB0317370D0 (en) | 2003-07-24 | 2003-08-27 | Synaptics Uk Ltd | Magnetic calibration array |
| GB0319945D0 (en) | 2003-08-26 | 2003-09-24 | Synaptics Uk Ltd | Inductive sensing system |
| US7265303B2 (en) * | 2003-12-17 | 2007-09-04 | Microsoft Corporation | Electromagnetic digitizer sensor array |
| WO2008139216A2 (en) | 2007-05-10 | 2008-11-20 | Cambridge Integrated Circuits Limited | Transducer |
| US8411053B2 (en) * | 2008-12-18 | 2013-04-02 | Einstruction Corporation | Dual pen interactive whiteboard system |
| GB2488389C (en) | 2010-12-24 | 2018-08-22 | Cambridge Integrated Circuits Ltd | Position sensing transducer |
| GB2503006B (en) | 2012-06-13 | 2017-08-09 | Cambridge Integrated Circuits Ltd | Position sensing transducer |
| KR102541545B1 (en) * | 2016-01-19 | 2023-06-09 | 삼성디스플레이 주식회사 | Electronic pen sensing device and display panel including the same |
| JP2022072810A (en) | 2020-10-30 | 2022-05-17 | ヤマハ発動機株式会社 | Clutch device and saddle-riding type vehicle equipped with the same |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3466646A (en) * | 1965-06-29 | 1969-09-09 | Rca Corp | Analog position to binary number translator |
| US3598903A (en) * | 1968-06-06 | 1971-08-10 | Ibm | Position-identifying device |
| US3832693A (en) * | 1971-08-29 | 1974-08-27 | Fujitsu Ltd | System for reading out the coordinates of information displayed on a matrix type display device |
| JPS5319380B2 (en) * | 1972-11-20 | 1978-06-20 | ||
| US4029899A (en) * | 1974-11-20 | 1977-06-14 | National Research Development Corporation | Position indicator |
| JPS5913074B2 (en) * | 1976-06-30 | 1984-03-27 | セイコーインスツルメンツ株式会社 | coordinate reading device |
| US4210775A (en) * | 1978-07-03 | 1980-07-01 | Talos Systems, Inc. | Method and apparatus for digitizing the location of an instrument relative to a grid |
| US4185165A (en) * | 1978-07-03 | 1980-01-22 | Talos Systems, Inc. | Low noise system and method for sequentially sensing induced signals in digitizer grid conductors |
| US4243843A (en) * | 1979-02-22 | 1981-01-06 | Summagraphics Corporation | Coarse position digitizer |
| US4260852A (en) * | 1979-05-24 | 1981-04-07 | Talos Systems, Inc. | Up/down scanning digitizing apparatus and method |
-
1982
- 1982-07-21 US US06/400,511 patent/US4423286A/en not_active Expired - Lifetime
-
1983
- 1983-04-28 CA CA000426890A patent/CA1195754A/en not_active Expired
- 1983-04-28 DE DE3315353A patent/DE3315353C2/en not_active Expired - Fee Related
- 1983-04-29 IT IT48190/83A patent/IT1197638B/en active
- 1983-05-16 CH CH2659/83A patent/CH661807A5/en not_active IP Right Cessation
- 1983-06-27 AU AU16283/83A patent/AU570206B2/en not_active Ceased
- 1983-07-08 FR FR8311415A patent/FR2532089B1/en not_active Expired
- 1983-07-13 JP JP58126304A patent/JPS5924390A/en active Granted
- 1983-07-18 NL NL8302567A patent/NL8302567A/en not_active Application Discontinuation
- 1983-07-21 GB GB08319682A patent/GB2124389B/en not_active Expired
-
1988
- 1988-04-21 AU AU15064/88A patent/AU1506488A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| DE3315353A1 (en) | 1984-01-26 |
| GB2124389A (en) | 1984-02-15 |
| GB2124389B (en) | 1985-09-11 |
| AU1506488A (en) | 1988-08-11 |
| NL8302567A (en) | 1984-02-16 |
| JPS5924390A (en) | 1984-02-08 |
| US4423286A (en) | 1983-12-27 |
| GB8319682D0 (en) | 1983-08-24 |
| DE3315353C2 (en) | 1994-04-21 |
| US4423286B1 (en) | 1993-05-25 |
| JPH0425569B2 (en) | 1992-05-01 |
| AU570206B2 (en) | 1988-03-10 |
| IT1197638B (en) | 1988-12-06 |
| FR2532089B1 (en) | 1988-02-19 |
| FR2532089A1 (en) | 1984-02-24 |
| CH661807A5 (en) | 1987-08-14 |
| AU1628383A (en) | 1984-01-26 |
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| MKEC | Expiry (correction) | ||
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