Apparatus and method for manually encoding a magnetic stripe

A hand-held, light-weight wand for magnetically encodes digital information onto a magnetic stripe or track. Pre-printed timing marks adjacent the magnetic strip, detected by an optical sensor contained in the wand, are used to generate timing signals which control the encoding of the data onto the magnetic stripe. Six rotary thumb-wheel switches are used to dial in a six digit decimal number to be encoded. A write push button switch in the wand body is depressed as the wand is passed along the magnetic stripe. A second pass of the wand along the magnetic stripe reads back the previously encoded signal which is compared the number still dialed into the thumb-wheel switches. If the comparison is favorable, a "successful read" LED also located in the body of the wand is illuminated to signal the operator that the desired number has been correctly encoded. A desktop version of the manual magnetic encoder and an alternate version of the encoding wand using a small numeric keypad for data entry are also shown.

FIELD OF THE INVENTION 
The present invention relates to an apparatus and method for encoding a 
digital signal onto a magnetic medium, and more specifically to a 
hand-held wand for encoding a signal on a magnetic stripe and to a method 
for using the hand-held wand which insures that the encoded signal will be 
readable by compatible magnetic reading equipment. 
BACKGROUND OF THE INVENTION 
The use of magnetic media, specifically "mag stripe" media is well known. 
Magnetic stripes are found on the back of almost all bank credit, debit or 
access cards for use in accessing ATMs or transacting sales at a merchant. 
Similar stripes are well known on employee badges for controlling access 
to buildings and other facilities. This mag stripe technology is useful 
for transporting machine-readable information in a variety of other ways. 
For the aforementioned and similar applications, the information encoded 
on the mag stripe is generally permanent (e.g., an account number, a 
personal identification number or the like). The encoding of such 
information is typically done at a central facility, such as a bank, 
personnel office, etc. The information will then remain unchanged 
throughout the life of the item bearing the mag strip. Mag stripe reading 
technology is both inexpensive and plentiful. The holdback to wider use of 
this mag stripe technology is the encoding process. 
Reading an encoded signal from a mag stripe is relatively easy. An encoded 
mag stripe is passed by a magnetic read head (i.e., "swiped"). In most 
applications, the user moves the mag stripe past the read head. This means 
that the instantaneous speed of the stripe past the read head is subject 
to significant variation in speed, not only from user to user, but during 
any single swipe operation as well. The mag stripe reading systems today 
are highly tolerant of these speed variations. Unless the speed of the 
stripe past the head is either too slow to induce a readable signal in the 
read head, or so fast that circuitry can't discern the magnetic pulses, an 
accurate read is usually accomplished. This happens because the spacing of 
the bits along the mag stripe is uniform, and timing or synchronizing 
signals are inherent in the encoded magnetic signal. 
Writing (encoding) the magnetic signal onto the stripe is another matter. 
In order to provide a relatively uniform spacing of magnetic pulses along 
the stripe or track, the velocity of the mag stripe relative to the 
magnetic write head must be essentially constant. This is easily achieved 
in devices where either the write head or the magnetic media are moved by 
a motor-driven transport mechanism. Such mechanisms are both bulky and 
relatively expensive. If it were easier and/or cheaper to encode mag 
stripes, a great number of new applications for the technology would 
present themselves. However, the equipment to perform the magnetic 
encoding has heretofore been too expensive and/or bulky to make locally 
available for these types of application. Several applications are 
discussed which could benefit from mag stripe technology. 
Batch "cards" often accompany lots of parts through a manufacturing site. 
More often than not, a printed batch number must be visually read and 
processed by a human at each work station where the batch of parts is to 
be processed. 
Another area where batch-type identification is required is in warehouse 
operations. Here, individual parts or items are "picked" to make up an 
order, each order having a unique order number. Much paperwork is required 
to follow these orders though the warehouse and to see that the orders are 
properly shipped either to an outside customer or to the correct location 
internally. In addition, each part or item usually has a part number which 
must be tracked for inventory control. 
In offices, batches of mail, complex documents, or other batch-type jobs 
are also often identified by a routing slip containing an identification 
number. Again, printed identification numbers must be assigned and affixed 
to each job. Human error may subsequently occur in reading these generally 
hand-written identification numbers. 
Each of these types of application could greatly benefit from the available 
of low-cost, portable mag stripe writing technology. 
DISCUSSION OF THE PRIOR ART 
U.S. Pat. No. 5,157,246 for SPEED CONTROL FOR MANUAL SCANNING CARD 
READER/WRITER; issued Oct. 20, 1992 to Tomoyuki Nakanishi teaches a 
typical apparatus for the manual encoding and reading of information to 
and from a magnetic card. A speed-governed roller is used to insure that a 
constant media velocity is maintained as the magnetic card is manually 
conveyed past the magnetic read/write head. The constant velocity insures 
uniform spacing of magnetic pulses which facilitates accurate read-back of 
the encoded information. The magnetic encoder wand system of the instant 
invention differs significantly from the system taught by Nakanishi. The 
inventive wand is manually passed over the surface of a magnetic strip. No 
mechanism such as a governor roller is required to accurately encode 
information onto the magnetic stripe. The inventive wand can be used to 
encode mag stripes affixed to large items such as cartons or the like 
since it may be freely moved into contact with magnetic media on any small 
flat surface. 
Another U.S. Pat. No. 5,307,423 for MACHINE RECOGNITION OF HANDWRITTEN 
CHARACTER STRINGS SUCH AS POSTAL ZIP CODES OR DOLLAR AMOUNTS OF BANK 
CHECKS; issued Apr. 26, 1994 to Om P. Gupta teaches the use of pre-printed 
bar codes in a "reserved" area. These bar codes contain information about 
the format of the field of hand-printed characters which are to follow. 
Additional non-machine-readable alignment marks used as templates allow 
proper drawing of hand-written characters on a prescribed area of the face 
of a document. In contradistinction, the magnetic encoding apparatus and 
method of the instant invention use regular, pre-printed timing marks 
along the length of a magnetic strip. No information is encoded in the 
timing marks; rather they function to control the encoding of magnetic 
bits along the magnetic stripe or track. Also, unlike the Gupta system, 
the instant invention requires no motor-driven mechanism to transport 
documents past a scanner read station. Gupta does no encoding, magnetic or 
otherwise, on the document but simply optically reads hand-written 
characters. 
U.S. Pat. No. 5,452,143 for APATUS AND METHOD FOR READING BINARY DATA 
FROM A MAGNETIC STRIPE; issued Sep. 19, 1995 to Shinya Kamagami discloses 
a typical magnetic stripe data reader having means for avoiding extraneous 
clock data signals. No provision for actually encoding magnetic signals on 
a mag stripe is taught. In contradistinction, the apparatus and method of 
the instant invention are intended specifically to write or encode 
information magnetically on pre-existing magnetic stripes. The inventive 
magnetic encoding apparatus relies on optically-sensed timing marks 
proximate the magnetic stripe. A built in check feature allows for reading 
the encoded data to insure that it has been properly encoded. 
U.S. Pat. No. 5,461,239 for METHOD AND APATUS FOR CODING AND READING 
INFORMATION IN DIFFRACTION GRATINGS USING THE DIVERGENCE OF DIFFRACTED 
LIGHT BEAMS; issued Oct. 24, 1995 to Peter S. Atherton teaches the 
encoding of information in diffraction gratings using a bar code or a 
pixelgram strategy. Upon illumination, each facet of the diffraction 
grating produces a light beam which may be machine read by a plurality of 
detectors. By altering the surface of the diffraction grating, information 
may be recorded or erased. On the other hand, the magnetic encoding wand 
system of the present invention does not rely on the modification of the 
surface of a diffraction grating to encode information. Neither does the 
inventive wand require a plurality of sensors to read the encoded 
information from the surface. While Atherton discloses the possible use of 
a bar coded diffraction grating parallel to a magnetic stripe for an 
application such as a highly secure credit card, the bar code comprises 
optical diffraction gratings, not pre-printed timing marks. The purpose of 
the diffraction gratings is to actually contain optically-encoded data, 
not to provide a timing system for encoding information onto the magnetic 
stripe. 
It is therefor an object of the invention to provide a hand-held magnetic 
encoding wand for encoding digital information onto a magnetic stripe. 
It is a further object of the invention to provide a magnetic encoding wand 
having a built-in optical sensing system for reading pre-printed timing 
marks adjacent to and along the length of the magnetic stripe. 
It is yet another object of the invention to provide a magnetic encoding 
wand having a read-back feature to insure that the correct pattern has 
been encoded onto a magnetic stripe. 
It is yet a further object of the invention to provide a magnetic encoding 
wand having self-contained data input means for generating the information 
to be encoded onto the magnetic stripe. 
It is a still further object of the invention to also provide a desktop or 
surface-mounted version of the magnetic encoder having the 
previously-described features and/or functions. 
SUMMARY OF THE INVENTION 
The present invention features a hand-held, light-weight wand for 
magnetically encoding digital information onto a magnetic stripe or track. 
Pre-printed timing marks adjacent to and along the length of the magnetic 
stripe are detected by an optical sensor contained in the wand and are 
used to generate timing signals for controlling the encoding of the data 
onto the magnetic stripe. Six self-contained rotary thumb-wheel type 
switches are used to "dial in" a six digit decimal number to be encoded. A 
write push button switch in the wand body is depressed as the wand is 
passed along and in contact with the magnetic stripe. A second pass of the 
wand along the magnetic stripe without the write push button depressed, 
reads back the previously encoded signal. If the data read back matches 
the number still dialed into the thumb-wheel switches, a "successful read" 
LED, also in the body of the wand, is illuminated to signal the operator 
that the desired number has been correctly encoded.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Generally speaking this invention relates to the manual encoding of digital 
information onto magnetic media, and more particularly to a hand-held, 
light-weight wand for magnetically encoding digital information onto a 
magnetic stripe or track. 
Referring first to FIG. 1, there is shown generally at reference number 10, 
a simplified schematic representation of a magnetic encoding wand or 
stylus. A cylindrical housing 12 is used to support and contain a magnetic 
read/write head 14 at a first distal end of housing 12. An optical sensor 
16 is located proximate magnetic read/write head 14. Optical sensor 16 is 
a self-contained, reflective unit with a focused light source (not shown) 
on one side of sensor 16 and a photo transistor or similar light-sensitive 
transducer (not shown) on the second side. One or more lenses (not shown) 
may also be contained in sensor assembly 16. A commercially available 
sensor assembly such as catalog number HEDS-1500 manufactured by Hewlett 
Packard has been found suitable for this application. Other strategies for 
"reading" the pre-printed timing marks could be implemented. For example, 
if the timing marks were printed with the same magnetic ink used for the 
magnetic stripe, an additional magnetic read head could be employed to 
read the timing marks magnetically. Another possibility would be using a 
conductive ink for the printing of the timing marks which could then be 
sensed by passing a current through a pair of contacts brushing over the 
timing marks. Disposed along housing 12 are a write push button switch 18 
and a "Successful Read" indicator 20. It should be obvious that the shape 
and size of housing 12 may be varied to meet a particular operating 
requirement and also that the placement of write switch 18 and/or 
indicator 20 may be varied without deviating from the true scope and 
spirit of the invention. Push button switch 18 may be any of a variety of 
suitable switches well known to those in the circuit design art. In the 
preferred embodiment. Indicator 20 is an LED although other visual or 
audible indicators could be employed. A plurality of thumb-wheel switches 
22 are located adjacent the second distal end of housing 12. A bank of six 
switches 22 has been chosen for purposes of disclosure but any reasonable 
number of switches 22 could be employed depending on particular operating 
requirements. In the preferred embodiment, each switch 22 generates a 
single digit of a decimal number to be encoded onto a magnetic stripe (not 
shown) but other strategies or other switch type could also be employed. 
Switches 22 such as catalog number T20-01A manufactured by Cherry 
Electrical Products have been found suitable, although some modifications 
are necessary to adapt the switches to the wand structure. In alternate 
embodiments, an external data source could be connected to encoding wand 
10 via wire, IR link or other communications means well know to those of 
skill in the art. In other alternate embodiments, an optical reader could 
be utilized to supply the data. Housing 12 also contains a battery (not 
shown) which provides power to the circuitry of encoding wand 10. In the 
preferred embodiment, a 3.6 volt lithium battery has been chosen although 
other power sources including either rechargeable or disposable batteries 
could also be employed. 
Referring now to FIG. 2, there is shown a functional block diagram of the 
encoding wand of FIG. 1, shown generally at reference number 30. Optical 
sensor 16 is connected to optical amplifier and signal conditioning 
electronics 32. The output of optical electronics 32 is connected to 
timing generator 34. The output of magnetic read/write head 14 is 
connected to a switch 36. Switch 36 functionally connects head 14 to 
either the input of sense amplifier 38 or the output of write electronics 
40 depending upon the whether a read or write function is currently being 
performed. Switch 36 could either be controlled by push button switch 18 
or could physically be part of push button switch 18. Switches 22 are 
connected to the input of an encoder circuit 42. The output of encoder 42 
is connected to one input of write electronics 40. The output of timing 
generator 34 is connected to a second input to write electronics 40. Write 
push button 18 is connected to a third input to write electronics 40. The 
output of sense amplifier 38 is connected to an input of decoder circuit 
44. The output of decoder 44 is connected to the first input of comparator 
46. The second input of comparator 46 is connected to the output of 
encoder 42. The "Successful Read" indicator 20 is connected to the output 
of comparator 46. It should be obvious to those of skill in the circuit 
design art that all the digital functions could readily be performed by a 
simple microprocessor (not shown) running microcode stored in PROMS s 
or similar suitable non-volatile storage devices (not shown). 
Referring now also to FIG. 3, there is shown a schematic representation of 
a typical magnetic stripe or track, reference number 60. Mag stripe 62 is 
shown as an elongated region which is formed of a readily magnetizable 
material as is well known to those of skill in the art. A plurality of 
pre-printed timing marks 64 are located adjacent to and along the length 
of magnetic stripe 62. Timing marks 64 may be printed using the same 
magnetic ink used to form track 62 although timing marks generally need 
not have any special magnetic properties. Alternately, timing marks 64 may 
be printed using any ink having a color discernable by the optical sensor 
assembly 16 (FIGS. 1 and 2). Track 62 and timing marks 64 may be deposited 
on any suitable surface such as an envelope, card, package surface, or the 
like. 
In operation, magnetic encoding wand 10 is moved along mag stripe 62 (FIG. 
3). As optical sensor 16 passes each pre-printed timing mark 64 (FIG. 3) 
disposed along mag stripe 62, a timing pulse 102 is generated. As the 
swipe of mag stripe 62 begins, the first (left-most) timing pulse 104 
indicates the start of a magnetic encoding operation. The first character 
to be magnetically encoded on mag stripe 62 has previously been selected 
by setting the left-most switch 22 to the desired digit 0-9. It should be 
obvious that with the use of a four-bit encoding scheme, the full 
hexadecimal character set 0-F could be encoded. In the embodiment chosen 
for purposes of disclosure, a simple 4-bit binary code is used for 
encoding the character. Such a 4-bit code allows for the encoding of 
digits 0-9. Obviously, other coding schemes could be employed including a 
7 or 8-bit code which would allow encoding the full ASCII character set, 
or a 3-bit code (octal) would permit the encoding of characters 0-7. 
Assuming that write push button switch 18 is depressed as the swipe 
commences, a magnetic pulse 106 (a "start bit") is written in synchronism 
with first timing pulse 104. Assuming that the first character chosen for 
encoding is the digit "1", the binary code representation would be 0001. 
An upward magnetic pulse represents a binary one while a downward magnetic 
pulse represents a binary zero. Following magnetic pulse 106, four 
additional magnetic pulses 108, each synchronized with a corresponding 
timing pulse 102, are written. Magnetic pulses 108 represent the "0001" 
binary code necessary to represent the decimal digit "1". At the next 
timing pulse 110, another start bit 112 is written and the encoding of a 
second character consisting of magnetic pulses 114 begins. The second 
character illustrated is a decimal "2" (binary "0010"). Four additional 
characters are encoded, decimal characters 3, 4, 5, and 6 (bits 116, 118, 
120, and 122), respectively. It will be obvious to those of skill in the 
art that any number of different encoding schemes such as gray code as are 
well known could be used in place of a simple binary encoding scheme. 
Also, check strategies such as parity bits, and/or a CRC system could also 
be implemented if operating requirements warranted the added complexity. 
Because the writing of each magnetic pulse is "clocked" by the generation 
of a timing pulse 102, the speed with which the mag stripe is "swiped" by 
the operator is not critical. Overall speed which may vary from person to 
person, or speed variation during a single swipe are generally compensated 
for by the inventive self-timing strategy. A second pass of the wand along 
the magnetic stripe (without push button 18 depressed) reads back the 
previously encoded signal. If the read data matches the data still dialed 
into the thumb-wheel switches 22, a successful read LED 20 also in the 
body of the wand, is illuminated to signal the operator that the desired 
number has been correctly encoded. 
It is possible to equip the reading tip of wand 10 with a cover assembly 
(not shown) if required to prevent excessive wear on the wand in some 
environments. Such a cover could be designed to mechanically protect the 
tip. It is also possible to arrange a flip back cover which would simply 
move out of the way as wand 10 was moved along the mag stripe 62. 
Referring now to FIGS. 5a and 5b, there is shown, generally at reference 
number 150, schematic representations of an alternate, desktop or 
surface-mounted embodiment of the inventive magnetic encoding system. A 
slot 152 is provided to accept a thin carrier (not shown) having a mag 
stripe printed thereon. An operator pulls the carrier through slot 152 
past a optical sensor (not shown) and a magnetic read/write head (not 
shown) which function identically to those already described hereinabove. 
The same operating controls previously described, write push button switch 
18', successful read indicator 20' and thumb-wheel switches 22' as 
disposed upon the housing. It will be obvious to those having industrial 
design and human factors design skills that a wide variety of case 
structure and control placements will be possible in practicing the method 
of the present invention. 
Referring now to FIG. 6, there is shown a diagram of an alternate 
embodiment of the magnetic encoding wand of the invention, reference 
number 200. Most features of the alternate embodiment of the wand are 
identical to that originally described hereinabove. A housing 12 is used 
to support and contain a magnetic read/write head 14 at a first distal end 
of housing 12. An optical sensor 16 is located proximate magnetic 
read/write head 14. Optical sensor 16 is a self-contained, reflective unit 
with a focused light source (not shown) on one side of sensor 16 and a 
photo transistor or similar light-sensitive transducer (not shown) on the 
second side. One or more lenses (not shown) may also be contained in 
sensor assembly 16. A commercially available sensor assembly such as 
catalog number HEDS-1500 manufactured by Hewlett Packard has been found 
suitable for this application. Disposed along housing 12 are a write push 
button switch 18 and a "Successful Read" indicator 20. Push button switch 
18 may be any of a variety of suitable switches well known to those in the 
circuit design art. In the preferred embodiment. Indicator 20 is an LED 
although other visual or audible indicators could be employed. A small 
numeric keypad 202 replaces thumbwheel switches 22 (FIG. 1) as the data 
input device. A small LED display 204 is located proximate numeric keypad 
202. In this embodiment, keypad 202 is used to enter the required digits 
to be encoded. As each digit is entered on keypad 202, it is displayed in 
sequence on LED display 204. Housing 12 also contains a battery (not 
shown) which provides power to the circuitry of encoding wand 200. As in 
the preferred embodiment, a 3.6 volt lithium battery has been chosen 
although other power sources including either rechargeable or disposable 
batteries could also be employed. 
Since other modifications and changes varied to fit a particular operating 
requirements and environment will be apparent to those skilled in the art, 
the invention is not considered limited to the example chosen for purposes 
of disclosure, and covers all changes and modifications which do not 
constitute a departure from the true spirit and scope of the invention. 
Having thus described the invention, what is desired to be protected by 
Letters Patent is presented in the subsequent appended claims.