Abstract:
A method for the secure reading of answers to questions or quires by an RFID reader that were made by marking answers with a pencil or ballpoint pen on a material. The questions are securely transmitted because an identification on the material indicates the order of the transmitted questions or from which electrical contacts the answers correspond to.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Reference is made to commonly assigned co-pending patent application Ser. No. 10/430,922 filed May 7, 2003, entitled “METHOD FOR FIELD PROGRAMMABLE RADIO FREQUENCY IDENTIFICATION DEVICES TO PERFORM SWITCHING FUNCTIONS” in the names of Thomas J. Foth, Brian M. Romansky, Andrei Obrea, Jeffrey D. Pierce, and Anand V. Chhatpar; and U.S. Pat. No. 6,869,020 B2 filed May 7, 2003, entitled “METHOD FOR FIELD PROGRAMMABLE RADIO FREQUENCY IDENTIFICATION TESTING DEVICES FOR TRANSMITTING USER SELECTED DATA” in the names of Thomas J. Foth, Brian M. Romansky, Jeffrey D. Pierce, Andrei Obrea. 
   FIELD OF THE INVENTION 
   This invention relates to electronic circuits and, more particularly, to the accurate and secure reading of answers to questions or quires that were made by connecting electronic circuits with a pencil or ballpoint pen. 
   BACKGROUND OF THE INVENTION 
   From the invention of paper thousands of years ago to the present date, paper has been used as the preferred medium by individuals and societies for the recording, processing and storage of information. With the introduction of computers into society, many of the functions previously performed exclusively with paper are now being accomplished by writing information on paper and entering the written information into a computer. Typically, the information written on paper is entered into computers by optically scanning the paper. Often the paper is contained in an envelope that has to be opened before the envelope is scanned. Thus, the foregoing method of entering information into computers is inconvenient and time consuming. 
   Another method utilized by the prior art for entering information that was contained in an envelope into a computer, without opening the envelope involved the use of radio frequency identification (RFID) tags. The RFID tags were programmed to contain digital information either during the manufacturing of the read only memory portion of the RFID integrated circuit, or in the field using electromagnetic radio frequency signals to store information in the nonvolatile memory portion of the RFID tag. A RFID tag does not require contact or line-of-sight to operate. RFID tags can function under a variety of environmental conditions, and provides a high level of data integrity. RFID tags utilize radio frequency signals to transfer information from the RFID tag to a RFID reader. Thus, radio waves are used to transfer information between the RFID tag and the RFID reader. A disadvantage of the foregoing is that the information transmitted by the RFID tag may be incorrect. 
   Another disadvantage of the foregoing was that an unauthorized observer might read the transmitted information. 
   SUMMARY OF THE INVENTION 
   This invention overcomes the disadvantages of the prior art by providing a method that allows the accurate and secure reading of answers to questions or queries by an RFID reader that were made by marking answers with a pencil or ball point pen on a material. The material may be any cellulose type product, i.e., paper, cardboard, chipboard, wood or plastic, fabric, animal hide, etc. The marked entered information may be corrected by erasing the written information with an eraser and writing new information on the paper with a pencil or ballpoint pen. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of a prior art RFID circuit; 
       FIG. 2A  is a drawing of a circuit  24  that replaces memory array  21  of  FIG. 1  showing how programming of the bits may be accomplished by making the bits externally available for programming RFID circuit  10 ; 
       FIG. 2B  is a drawing of a circuit  300  that is an alternate representation of circuit  24 , that replaces memory array  21  of  FIG. 1  showing how programming of the bits may be accomplished by making the bits externally available for programming RFID circuit  10 ; 
       FIG. 3  is a drawing showing sensor circuit  25  of  FIG. 2A  in greater detail; 
       FIG. 4  is a seller furnished form to be completed by a buyer returning goods to a seller; 
       FIG. 5  is a drawing showing how a modified RFID circuit may be attached to a piece of paper in order to permit a user to answer various types of questions; 
       FIG. 6  is a drawing modifying the circuit of  FIG. 5  to permits a user to answer the various questions posed in  FIG. 5  in a different order; 
       FIG. 7  is a drawing modifying the circuit of  FIG. 5  to permits a user to answer the various questions posed in  FIG. 5  in the same order; 
       FIG. 8  is a drawing modifying the circuit of  FIG. 5  by deleting lines  500 ,  501  and  502  and contacts  482 ,  483  and  484  so that the order of the questions in paper  465  and the lines and contacts connections will be determined by what is stored in memory  21  of  FIG. 1 ; 
       FIG. 9  is a flow chart that illustrates the manner in which the lines of  FIG. 8  may be constructed; 
       FIG. 10  a flow chart that illustrates how the lines of  FIG. 9  are read; and 
       FIG. 11  is a cross sectional view of a laser line printer. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings in detail, and more particularly to  FIG. 1 , the reference character  10  represents a prior art RFID circuit. Circuit  10  may be the model MCRF 200 manufactured by Microchip Technology, Inc. of 2355 West Chandler Blvd, Chandler, Ariz. 85224. RFID reader  11  is connected to coil  12 , and  12  is coupled to coil  13 . Coil  13  is connected to modulation circuit  14 . Modulation circuit  14  is connected to clock generator  15  and rectifier  16 . Modulation control  17  is coupled to modulation circuit  14 , clock generator  15  and counter  18 . Counter  18  is coupled to column decode  20 . Row decode  19  is coupled to memory array  21 , and array  21  is coupled to modulation control  17 . It would be obvious to one skilled in the art that a battery may be used to supply power to circuit  10 . 
   Reader  11  has a transmitter mode and a receiver mode. During the transmit mode of reader  11 , reader  11  transmits a radio frequency signal for a burst of time via coil  12 . After the transmission of a signal by reader  11 , reader  11  turns into a receiver. Coil  12  is inductively linked with coil  13 , and coil  13  receives the radio frequency signal from coil  12  and converts the aforementioned signal into inductive energy, i.e., electricity. When coil  13  has sufficient energy, coil  13  will cause clock generator  15  to generate timing pulses which drive counter  18 . Counter  18  drives row decode  19  which causes memory array  21  to read the fixed bit data pattern stored in memory array  21  one bit at a time. As the data bits are being read by array  21 , the data bits are transmitted to modulation control circuit  17 . Control circuit  17  sends the data bits to reader  11  via modulation circuit  14  and coils  13  and  12 . 
     FIG. 2A  is a drawing of a circuit  24  that replaces memory array  21  of  FIG. 1  showing how programming of the bits may be accomplished by making the bits externally available for programming RFID circuit  10 . A plurality of sensor circuits  25  is contained in circuit  24 . Sensor circuits  25  are labeled SC 1  SC 2  SC 3  . . . SC n . Line  29  is connected to SC 1  and graphite contact  52  and line  30  is connected to SC 2  and graphite contact  53 . Line  31  is connected to SC 3  and graphite contact  54  and line  32  are connected to SC n  and graphite contact  55 . There is a sensor circuit  25  for each graphite contact. The description of  FIG. 4  will describe how information may be entered into circuit  24  via graphite contacts  52 - 55 . SC 1  has an input  33 , which enables the data output  34 . Input  33  is connected to one of the n lines  37 , and data output  34  is connected to data line  36  and pull up resistor  35 . Data line  36  is connected to modulation control  17  ( FIG. 1 ). 
   When counter  18  selects the value  1 , column decode  20  will enable line  33 , which will cause the same logic level that is on graphite contact  52  to be placed on data output  34 . When line  33  is not selected, the value on graphite contact  52  does not have any influence on the data output line  34 . Enable outputs  33  for SC 1  . . . SC n  are bundled together in lines  37  so that only one line  37  is turned on at a time. Lines  37  are connected to column decode  20 . Column decode  20  is connected to counter  18 , and counter  18  is connected to row decode  19 . Counter  18  generates a sequence of numbers from 1 through n to enable a different line  37  in sequential order. Thus, data line  36  will receive the data outputs  34  from SC 1  . . . SC n  at different times. 
     FIG. 2B  is a drawing of a circuit  300  that is an alternate representation of circuit  24 , that replaces memory array  21  of  FIG. 1  showing how programming of the bits may be accomplished by making the bits externally available for programming RFID circuit  10 . Circuit  300  includes AND gates  301 ,  302 ,  303  and  304  and OR gate  305 . 
   One of the inputs of AND gate  301  is connected to column decode  20  and the other input to AND gate  301  is connected to one of the ends of resistor  322 , one of the ends of diode  306  and one of the ends of diode  314 . The other end of resistor  322  is connected to ground. The other end of diode  306  is connected to one of the terminals of toggle switch  310 , and the other end of toggle switch  310  is connected to row decode  19 . The other end of diode  314  is connected to one of the terminals of toggle switch  318 , and the other end of toggle switch  318  is connected to row decode  19 . 
   One of the inputs of AND gate  302  is connected to column decode  20 , and the other input to AND gate  302  is connected to one of the ends of resistor  323 , one of the ends of diode  307  and one of the ends of diode  315 . The other end of resistor  323  is connected to ground. The other end of diode  307  is connected to one of the terminals of toggle switch  311 , and the other end of toggle switch  311  is connected to row decode  19 . The other end of diode  315  is connected to one of the terminals of toggle switch  319 , and the other end of toggle switch  319  is connected to row decode  19 . 
   One of the inputs of AND gate  303  is connected to column decode  20 , and the other input to AND gate  303  is connected to one of the ends of resistor  324 , one of the ends of diode  308  and one of the ends of diode  316 . The other end of resistor  324  is connected to ground. The other end of diode  308  is connected to one of the terminals of toggle switch  312 , and the other end of toggle switch  312  is connected to row decode  19 . The other end of diode  316  is connected to one of the terminals of toggle switch  320 , and the other end of toggle switch  320  is connected to row decode  19 . 
   One of the inputs of AND gate  304  is connected to column decode  20 , and the other input to AND gate  304  is connected to one of the ends of resistor  325 , one of the ends of diode  309  and one of the ends of diode  317 . The other end of resistor  325  is connected to ground. The other end of diode  309  is connected to one of the terminals of toggle switch  313 , and the other end of toggle switch  312  is connected to row decode  19 . The other end of diode  317  is connected to one of the terminals of toggle switch  321 , and the other end of toggle switch  321  is connected to row decode  19 . 
   Column decode  20  and row decode  19  function by taking the selected output at logic one, i.e., a high level and keeping all the other outputs at logic zero, i.e., a low level. The output of AND gates  301 - 304  are connected to the input of OR gate  305 , and the output of OR gate  305  is data that is connected to the input of modulation circuit  17 . If switches  310 ,  311 ,  312  and  313 , respectively, remain open, AND gates  301 - 304 , respectively, will have a “zero” output. If switches  310 ,  311 ,  312  and  313 , respectively, are closed, AND gates  301 - 304 , respectively, will have a “one” output. The output of AND gates  301 - 304 , respectively, will be read when switches  318 - 321 , respectively, are closed. 
     FIG. 3  is a drawing showing sensor circuit  25  of  FIG. 2A  in greater detail. The negative input of comparator  41  is connected to line  29 , and the positive input of comparator  41  is connected to line  38 . Comparator  41  may be a LM339N comparator. One end of line  38  is connected to a 2-3 volt reference voltage, and the other end of line  38  is connected to one of the ends of resistor  39 . The other end of resistor  39  is connected to the positive input of comparator  41  and one of the ends of resistor  40 . The other end of resistor  40  is connected to the input of NAND gate  42 , the output of comparator  41  and one of the ends of resistor  43 . The other end of resistor  43  is connected to a source voltage to act as a pull up resistor. The other input to NAND gate  42  is enable output  33 . The output of gate  42  is data output  34 . Resistor  39  may be 47,000 ohms, and resistor  40  may be 470,000 ohms. Resistor  43  may be 1,000 ohms. Comparator  41  has a positive feedback to provide a small amount of hysteresis 
   Sensor circuit  25  is a differential circuit that accommodates variations in the conductivity of the conductive material. The conductive material may be used as a voltage divider to produce V ref  on line  38  under the same conditions experienced by paper in  on line  29 . Thereby, nullifying the effects of varying resistance in the conductive material. It will be obvious to one skilled in the art that sensor circuit  25  may replace switches  310 - 313  and  318 - 321  of  FIG. 2B . 
     FIG. 4  is a seller-furnished form to be completed by a buyer returning goods to a seller. RFID circuit  10  is attached to paper  50  by means of a conductive adhesive such as an anisotropic adhesive (not shown). The seller places a returned goods identification number  51  on the form to identify the buyer by writing the invoice number for the purchased goods on paper  50  in a manner that number  51  may be read by a RFID reader. Graphite contacts  52 ,  53 ,  54  and  55  and lines  56 ,  57 ,  58 ,  59  and  60  are printed on standard bond paper, standard photocopier paper, standard computer paper, etc., by a standard computer printer like the model Desk Jet 880C printer manufactured by Hewlett Packard using a Hewlett Packard 45 black ink cartridge. Rectangles  61 - 63  are printed by a standard computer printer like the DeskJet 880C printer manufactured by Hewlett Packard using a Hewlett Packard 78 tri-color cartridge and any combination of the cyan, magenta, and yellow inks. 
   If the buyer decides to return a shirt to the seller, the buyer uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ballpoint pen to fill in rectangle  61 . If the buyer decides to return pants to the seller, the buyer fills in rectangle  62  with a graphite pencil, and if the buyer decides to return shoes to the seller, the buyer fills in rectangle  63  with a graphite pencil. If the buyer changes his/her mind regarding the goods to be returned or makes a mistake in filling in one of the rectangles, the buyer could erase the penciled marking in the rectangle with a pencil eraser so that a RFID reader would only read what the buyer indicated on the finished form. The buyer would insert the finished form into a package (not shown) containing the returned goods, and the seller would be able to read the completed form when he/she receives the package with a RFID read without opening the package. 
     FIG. 5  is a drawing showing how a modified RFID circuit may be attached to a piece of paper in order to permit a user to answer various types of questions. RFID circuit  466  is attached to paper  465  by means of an adhesive (not shown). RFID circuit  466  is the same as RFID circuit  10  with circuit  24  replacing memory array  21  of  FIG. 1  with different graphite contacts. Graphite contacts:  467 - 484  and  504 , lines  485 - 503  are printed on paper  465  by a standard computer printer like the model Desk Jet 880C printer manufactured by Hewlett Packard using a Hewlett Packard 45 black ink cartridge. Rectangles A through O are printed by a standard computer printer like the DeskJet 880C printer manufactured by Hewlett Packard using a Hewlett Packard 78 tri-color cartridge and any combination of the cyan, magenta, and yellow inks. 
   Rectangle “A” appears on line  485 , which is connected to contact  467  and rectangle “B” appears on line  486 , which is connected to contact  468 . Rectangle “C” appears on line  487 , which is connected to contact  469  and rectangle “D” appears on line  488 , which is connected to contact  470 . Rectangle “E” appears on line  489 , which is connected to contact  471  and rectangle F is connected to line  490  which is connected to contact  472 . Rectangle “G” appears on line  491 , which is connected to contact  473  and rectangle “H” appears on line  492 , which is connected to contact  474 . Rectangle “I” appears on line  493 , which is connected to contact  475  and rectangle “J” appears on line  494 , which is connected to contact  476 . Rectangle “K” appears on line  495 , which is connected to contact  477  and rectangle “L” is connected to line  496  which is connected to contact  478 . Rectangle “M” appears on line  497 , which is connected to contact  479  and rectangle “N” appears on line  498 , which is connected to contact  480 . Rectangle “O” appears on line  499 , which is connected to contact  481 . Line  500  is connected to contact  482  and line  501  is connected to contact  483 . Line  502  is connected to contact  484 . Lines  500 ,  501  and  502  will indicate the order of the questions listed on paper  465 . For instance, line  500  may represent 2 0  and line  501  represents 2 1 . Line  502  would represent 2 2 . Thus, line  500  is printed by a standard computer printer to connect to line  503 , the questions listed in paper  465  are in the order shown in  FIG. 5  and may be identified as identification number  1 . It would be obvious to one skilled in the art, that letters or alphanumeric characters, etc may also represent the identification number. Line  503  is connected to contact  504 . 
   If the user is a male, the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ballpoint pen to fill in rectangle “A”. If the user has blue eyes and weighs 160 pounds, the user, the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ball point pen to fill in rectangles “C” and “H”. If the user is forty-two years old and earns over $100,000 a year the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ball point pen to fill in rectangles “L” and “O”. If the user changes his/her mind regarding the answer to one of the questions or makes a mistake in filling in one of the rectangles, the user could erase the penciled marking in the rectangle with a eraser so that a RFID reader would only read what the user indicated last. 
     FIG. 6  is a drawing modifying the circuit of  FIG. 5  to permits a user to answer the various questions posed in  FIG. 5  in a different order. Lines  500 ,  501  and  502  will indicate the identification of the questions listed on paper  465 . For instance, line  500  may represent 2 0  and line  501  represents 2 1 . Line  502  would represent 2 2 . Lines  500  and  501  are printed with a standard computer printer. Line  500  is connected to line  503  and line  501  is connected to line  503 . Hence, the questions listed in paper  465  are in the order indicated by identification  3 . Thus, when a RFID reader read the answers that the user indicated by using a graphite pencil or ballpoint pen to fill in one or more rectangles A-O, the answers to the questions would depend on their order. 
   If the user is a male, the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ballpoint pen to fill in rectangle “K”. If the user has blue eyes and weighs 160 pounds, the user, the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ball point pen to fill in rectangles “M” and “C”. If the user is forty-two years old and earns over $100,000 a year the user uses a graphite pencil, i.e., number 2, HB, etc., or a Paper Mate® black ball point pen to fill in rectangles “G” and “J”. Thus, if someone is receiving to the answers to the questions being transmitted to the RFID reader they would be unable to ascertain what the answers to the questions are since the answers may be transmitted in many different orders. 
     FIG. 7  is a drawing modifying the circuit of  FIG. 5  to permits a user to answer the various questions posed in  FIG. 5  in the same order. Lines  500 ,  501  and  502  will indicate the order of the questions listed on paper  465 . For instance, line  500  may represent 2 0  and line  501  represents 2 1 . Line  502  would represent 2 2 . Line  502  is printed with a standard computer printer. Line  502  is connected to line  503 . Hence, the questions listed in paper  465  are in the order indicated by identification  4 . To the user i.e., the person answering the questions the order of the questions in identification  4  is the same order as order of the questions in identification  1 . However, when a RFID reader reads the answers that the user indicated by using a graphite pencil or ballpoint pen to fill in one or more rectangles A-O, the answers to the questions would depend upon the connection of rectangles A-O to contacts  467 - 481 . Hence, if someone is receiving to the answers to the questions being transmitted to the RFID reader they would be unable to ascertain what the answers to particular questions are since the answers to the questions will be transmitted by different contacts. 
   Rectangle “A” appears on line  486 , which is connected to contact  468  and rectangle “B” appears on line  487 , which is connected to contact  469 . Rectangle “C” appears on line  488 , which is connected to contact  470  and rectangle “D” appears on line  489 , which is connected to contact  471 . Rectangle “E” appears on line  490 , which is connected to contact  472  and rectangle F is connected to line  491  which is connected to contact  473 . Rectangle “G” appears on line  492 , which is connected to contact  474  and rectangle “H” appears on line  493 , which is connected to contact  475 . Rectangle “I” appears on line  494 , which is connected to contact  476  and rectangle “J” appears on line  495 , which is connected to contact  477 . Rectangle “K” appears on line  496 , which is connected to contact  478  and rectangle “L” is connected to line  497  which is connected to contact  479 . Rectangle “M” appears on line  498 , which is connected to contact  480  and rectangle “N” appears on line  499 , which is connected to contact  481 . Rectangle “O” appears on line  485 , which is connected to contact  467 . 
     FIG. 8  is a drawing modifying the circuit of  FIG. 5  by deleting lines  500 ,  501  and  502  and contacts  482 ,  483  and  484  so that the order of the questions in paper  465  and lines and contacts connections will be determined by what is stored in the non volatile portion of memory  21  of  FIG. 1 . The questions listed in paper  465  are in the order shown in  FIG. 5  and  FIG. 8  and may be identified as identification number  1 , which will be stored in the non-volatile portion of memory  21 . It would be obvious to one skilled in the art that the identification number may be changed for different question orders. 
     FIG. 9  is a flow chart that illustrates the manner in which the lines of  FIG. 8  may be constructed. The program begins in block  520 . Then the program goes to block  521  where the material, i.e., paper is ingested by a ink jet printer. Now the program goes to block  590  where the identification number stored in the memory of RFID circuit  466  that was affixed to material  455  is read by RFID reader  11 . At this point the program goes to decision block  522 . Block  522  determines whether or not the identification number is unique, i.e., has not been used before. If block  522  determines that the identification number is unique, the program goes to block  523  where the computer causes a printer to print lines randomly connecting rectangles A-O to contacts  467 - 481  ( FIG. 7  on material  465 . Then the program goes to block  526  where the line pattern and the identification number are recorded in the memory of a computer. If block  522  determines that the identification number is not unique, the program goes to block  524  where the computer looks up previous line patterns that were not printed on material  465 . Then the program goes to block  525  to print one of the line patterns that has not been printed. Now the program goes to block  527  and ends. 
     FIG. 10  a flow chart that illustrates how the lines of  FIG. 9  are read. The program begins in block  530 . Then the program goes to block  531  where the RFID memory is read. Now the program goes to block  532  where the identification number is looked up in a database contained within the computer. Then the program goes to block  533  where the line pattern is retrieved. Now the program goes to block  534  where the responses are decoded using the line pattern. Then the program ends in block  535 . 
     FIG. 11  is a cross sectional view of laser line printer  591 , which has a tray  592 . Printer  591  may be the Laser Jet 2200 manufactured by Hewlett Packard that has been modified to include a RFID reader  11 . As printer  591  ingests paper with RFID circuit  466  affixed thereto, RFID reader  11  reads the identification number contained in RFID circuit  466 . 
   The above specification describes a new and improved method for the secure reading of answers to questions or queries by an RFID reader that were made by marking answers with a pencil or ball point pen on a material. It is realized that the above description may indicate to those skilled in the art additional ways in which the principles of this invention may be used without departing from the spirit. Therefore, it is intended that this invention be limited only by the scope of the appended claims.