U.S. patent number 3,906,449 [Application Number 05/504,931] was granted by the patent office on 1975-09-16 for paper money identifier.
Invention is credited to Frank J. Marchak.
United States Patent |
3,906,449 |
Marchak |
September 16, 1975 |
Paper money identifier
Abstract
An improved currency identifier permits recognition of various
denominations of paper currency by blind persons. The identifier
includes a housing having a tray along which money to be identified
is passed. In one embodiment, a source of light is stationed above
the tray and positioned directly under the light source is a series
of very small holes formed in the bottom of the tray. The holes are
aligned across the tray so that light from the source shines
through the center of paper currency passed along the tray, through
the holes, and onto a photoelectric cell located beneath the tray.
The photocell is connected to a relaxation oscillator circuit and
controls the oscillator frequency in accordance with the amount of
light passing through the money. The output from the oscillator is
connected to a loudspeaker which produces a tone that varies in
accordance with the output from the photocell. Since the various
currency denomination have distinct printed patterns and thus have
different light responsive characteristics, the audible sounds
produced can be identified as being representative of a specific
bill. In a second embodiment, the photocell and light source are
positioned on the same side of the bill to be identified. The light
is transmitted onto the bill and a portion of the light is
reflected onto the photocell. The reflected light is also
distinctive of a particular bill and produces an identifiable tone
pattern; however, this embodiment produces a simplified sound
pattern since the characteristics identified by the light pattern
are only taken from one side of the bill.
Inventors: |
Marchak; Frank J. (Austin,
TX) |
Family
ID: |
24008304 |
Appl.
No.: |
05/504,931 |
Filed: |
September 11, 1974 |
Current U.S.
Class: |
340/540;
340/4.14 |
Current CPC
Class: |
G07D
7/128 (20130101) |
Current International
Class: |
G07D
7/00 (20060101); H04q 005/00 () |
Field of
Search: |
;340/149A,149R
;235/61.7B ;209/111.5,111.7,111.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pitts; Harold I.
Attorney, Agent or Firm: Jones, Tullar & Cooper
Claims
I claim:
1. A currency identification apparatus for aiding blind persons in
identifying currency, comprising:
means generating a light beam;
photoresponsive means for receiving said light beam, the resistance
of said photoresponsive means varying in accordance with the amount
of light received;
means for directing said light beam along a path between said
generating means and said photoresponsive means which path includes
the currency to be identified,
capacitor means connected in electrical series with said
photoresponsive means, said capacitor means being charged through
said photoresponsive means, so that the time required to charge
said capacitor is directly proportional to the resistance value of
said photoresponsive means;
transistor means connected to said capacitor means, said transistor
being biased into conduction whenever the charge on said capacitor
reaches a predetermined level; and
loudspeaker means connected to said transistor means, said
capacitor means discharging through said speaker means to produce
an audible tone whenever said transistor conducts.
2. The currency identification apparatus of claim 1, further
including a housing for positioning said light means relative to
said photoresponsive means.
3. The currency identification apparatus of claim 2, wherein said
housing includes a tray for positioning said currency relative to
said housing and in said path of said light beam, and wherein said
light means and said photoresponsive means are on opposite sides of
said tray, said tray having at least one small aperture extending
approximately one-half inch across the center portion of said tray
so that light passes through the center portion of currency located
on said tray and impinges on said photocell.
4. The currency identification apparatus of claim 1, further
including a first resistor means in series with said
photoresponsive means and capacitor means for limiting the minimum
resistance in series with said capacitor means, thereby limiting
the highest pitched audible tone produced by said loudspeaker.
5. The currency identification apparatus of claim 1 further
including a second resistor means in series with said
photoresponsive means and said capacitor means, for limiting the
maximum resistance in series with said capacitor means, thereby
limiting the lowest pitched audible tone produced by said
loudspeaker.
6. The currency identification apparatus of claim 1, further
including a third adjustable resistor means in series with said
photoresponsive means and said capacitor means for setting the
audible tones produced by said loudspeaker to a desired frequency
range.
7. The currency identification apparatus of claim 4 further
including a second resistor means in series with said
photoresponsive means and said capacitor means for limiting the
maximum resistance in series with said capacitor means, thereby
limiting the lowest pitched audible tone produced.
8. The currency identification system of claim 7 wherein said
apparatus further includes a third adjustable resistor means in
series with said photoresponsive means and said capacitor means for
selecting a desired frequency range for the audible tones
produced.
9. The currency identification apparatus of claim 2, wherein said
housing includes tray means for positioning said currency in said
path of said light beam, and wherein said light means and said
photoresponsive means are on the same side of said tray so that
said light beam is reflected from the surface of said currency into
said photoresponsive means.
10. The currency identification apparatus of claim 9, further
including a first resistor means in series with said
photoresponsive means and capacitor means for limiting the minimum
resistance in series with said capacitor means and thereby limiting
the highest pitched audible tone produced.
11. The currency identification system of claim 10 wherein said
apparatus further includes a second resistor means in series with
said photoresponsive means and said capacitor means for limiting
the maximum resistance in series with said capacitor means and
thereby limiting the lowest pitched audible tone produced.
12. The currency identification apparatus of claim 11, further
including a third adjustable resistor means in series with said
photoresponsive means and said capacitor means for setting the
audible tones produced to a desired frequency range.
13. The currency identification apparatus of claim 1, wherein said
means for directing said light beam includes light box means
supporting said light beam generating means, and aperture means in
said box means for directing said light beam onto said
currency.
14. The currency identification apparatus of claim 13, wherein said
light box means further includes means for supporting said
photoresponsive means adjacent said light beam generating means,
and in the path of light reflected from the surface of said
currency.
15. The currency identification apparatus of claim 13, including
means for mounting said photoresponsive means adjacent said light
beam generating means and in the path of light transmitted through
said currency.
16. The currency identification apparatus of claim 13, further
including tray means for receiving said currency, said tray means
locating said currency for movement through said path, whereby upon
motion of the currency the amount of light from said light
generating means striking said photoresponsive means will vary in
accordance with variations in the printed pattern on said currency
to produce a varying output tone characteristic of said currency.
Description
BACKGROUND OF THE INVENTION
The present invention relates, in general, to currency
identification and, more particularily, to a method and apparatus
for currency identification for the blind which converts light
pattern characteristics of currency into distinctive audible tones,
identifiable by the blind.
A number of devices have been constructed to aid in the
identification of currency, and some of these devices utilize light
and photocell combinations for this purpose. In addition, numerous
devices have been constructed to aid the blind in reading printed
material by utilizing a photocell to scan the printed material and
produce an audible signal in response to the output from the
photocell. However, most of these prior art devices require a
specific orientation of the bill or printed matter within the
device before an intelligible reading can be obtained, and this in
itself produces serious problems for the blind.
Another difficulty with prior devices in that they have, in
attempting to reach a high degree of accuracy, tended to become
very complex, and thus have become expensive to purchase and
difficult to maintain in working condition, and accordingly have
not been satisfactory. Many of these devices have utilized various
mechanical indicators which easily become misadjusted and which can
thereby produce incorrect readings of currency denominations, while
others use banks of photocells which not only are expensive, but
which require complex circuitry to provide the desired
indication.
Considerable effort and expense has been expended in the prior art
to provide a highly reliable, maintenance-free, long-lasting,
accurate, and easy to use device for producing an indication of the
denomination of paper money. Such a device should provide maximum
convenience for the user, be simple in operation, and should
provide a reliable, easily identified, unique indication of the
denomination of the currency being tested.
SUMMARY OF THE INVENTION
It is, therefore, as object of the present invention to provide an
apparatus which enables the blind to identify paper currency by
converting the dark and light characteristic patterns of the
currency into distinctive, identifiable audible signals.
It is another object of the invention to provide an improved
currency-identifying apparatus incorporating a circuit for
converting light signals impinging on a photocell into audible
signals representing the impinging light pattern.
Another object of the invention is to provide a money-identifying
apparatus having a tray which receives the money, and which
provides accurate identification of the currency whether it is
placed within the receiving tray face up or face down.
Briefly, the present invention accomplishes the foregoing and other
objectives by the provision of a currency identifier which
incorporates means for distinguishing variations in the light
reflectance of the printed patterns on paper currency. The
identifier includes means for creating a predetermined light path
between a source and a photocell. The currency to be identified is
passed through this path, causing varying amounts of light to reach
the photocell, in accordance with the configurations printed on the
bill. This variation in light changes the output of the photocell,
which causes the frequency of an oscillator circuit to change. The
oscillator drives a loudspeaker, and the light variations thus
cause corresponding changes in the sounds emitted as the bill is
moved through the identifier. Each denomination of paper currency
produces a characteristic sound pattern from the apparatus of the
present invention, the sound variations corresponding to the
changes in the shades of color and the presence or absence of
printing on the portion of the bill passing through the light path
as the bill is moved through the identifier, with light colors
emitting a higher pitched sound than the darker colors.
In a first embodiment of the invention, the light path is
constructed so that light passes through the bill to the photocell.
With this arrangement, the device is sensitive to variations in the
transmission of light through the bill, and these variations are
the same whether the bill is face up or face down. The money
identifier consists of a housing shaped to provide an elongated
channel, or tray, which is adapted to receive paper currency to be
identified and which defines a path along which the currency is
drawn for identification. Mounted on the housing and extending over
a portion of the tray is a light box which carries a convenient
source of light and which includes a suitable opening for directing
light onto a selected portion of the tray. Immediately below the
light box and arranged at approximately the center of the path
followed by the currency is a series of small holes in the tray. A
photocell is located within the housing below the holes in the tray
to receive light from the source. Preferrably, the holes are
located in a straight line transverse to the path followed by the
currency, and extend about one-half inch across the center thereof,
where variations in the printed pattern are at a maximum.
As a money bill is pulled along the housing tray, it travels
through the light path defined between the light source and the
photocell, causing variations in the amount of light passing
through the bill and striking the photocell. These variations are
unique for each denomination of currency, and correspond to the
pattern printed on both sides of the bill.
Also mounted within the housing is an oscillator circuit having a
frequency of operation which is responsive to the magnitude of the
photocell resistance. The output from the oscillator is an audio
frequency which is fed to a loudspeaker mounted in the housing. The
speaker thus produces a sound which varies in frequency in
accordance with the pattern of the bill passing through the light
path of the identifier device. Since each denomination of currency
has a unique printed pattern, each will produce a unique pattern of
sound which can be identified by the user of the device to
accurately identify each denomination bill.
In a modified form of the invention, the locations of the light
source and photocell can be reversed, with the photocell being
located above the path of the bill to be identified. However, this
arrangement is less desirable than the previously described
relationship, for it makes it more difficult to replace light bulbs
when they burn out.
In another modification of the invention, both the light source and
the photocell can be placed on the same side of the path followed
by the bill to be identified, in which case the device responds to
the light reflected from the bill, rather than that which passes
through it. The light reflected to the photocell varies in
accordance with the pattern on the side of the bill facing the
photocell system, and produces a corresponding output sound. The
photocell system may be either above or below the path followed by
the currency. Although this arrangement requires that the operator
be able to distinguish between the obverse and reverse faces of
each denomination of bill, and thus may require that the operator
place the bill with the proper face up, it has the advantage of
producing a less complex sound pattern which is more easily
recognized by an operator. However, the first-described embodiment
is easier to operate, since it does not matter which face of the
bill is up, and accordingly provides a faster identification of
denomination.
BRIEF DESCRIPTION OF DRAWINGS
The foregoing and additional objects, features and advantages of
the invention will be apparent to those skilled in the art from the
following description, taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is a perspective view of the exterior housing of a currency
identifier constructed in accordance with the present
invention;
FIG. 2 is a cross-sectional view of the currency identifier of FIG.
1 taken along line 2--2, and illustrating a first embodiment of the
photocell system;
FIG. 3 is a cross-sectional view of a light box used in another
embodiment of the currency identifier constructed in accordance
with the present invention; and
FIG. 4 is a schematic diagram of a preferred form of the electronic
circuitry which can be used in the photocell systems of the
embodiments of FIGS. 2 and 3.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1 there is illustrated in perspective view a
currency identifier 10, the Figure showing the general appearance
of the exterior housing of the currency identifier of the present
invention. The identifier 10 consists of generally horizontal and
upstanding portions, 12 and 14 respectively, forming an L-shaped
housing. The housing itself may be formed of any rigid material
suitable for the purpose, such as metal or plastic. Fixed to the
top surface 15 of the horizontal portion 12 of the housing, as by
bolting or otherwise, is a tray 18, which generally is formed of
the same material as the housing, and along which money to be
identified is passed. The tray 18 positions currency relative to a
light box 20, which is fixed to the front wall of the upstanding
portion 14 of the housing by any suitable means, the light box
being cantilevered from portion 14 and extending transversely
across, but spaced above, the tray.
As shown in FIG. 2, a plurality of small apertures 22 are formed
through the center portion of the tray 18 and extend transversely
thereacross, the apertures being aligned with the light box and
being positioned across the center portion of the tray. The
apertures 22 extend across approximately one-half inch of the tray,
so that when tray 18 is used as a guide for the currency, the
apertures will underlie the central longitudinal portion of each
bill inserted into the tray and drawn under the light box 20. It
will be understood that the apertures could be replaced by a
corresponding narrow slot.
Rails 24 and 26 are provided at the left and right ends of the
tray, as viewed in FIG. 1, and serve to inform the operator of the
identifier 10 of the location of the bill with respect to the light
box 20, longitudinally along the tray. Similarly, the corner 28,
formed by the intersection of the front surface of the upstanding
portion 14 and the back edge of the tray, cooperates with a front
rail 29 formed along the front edge of the tray to center the bill
transversely on the tray and align its center with the apertures
22.
The light box 20 is offset to the left side of the housing, as
viewed in FIG. 1, so that a currency bill can be placed flat in the
tray to the right of the light box before it is drawn under box 20.
This enables a blind operator to correctly position a bill in the
tray for determining its denomination with little effort, and to
insure consistently correct operation. To the left of the light box
the tray need only be large enough to accommodate about one-half
the length of a bill, since it is not generally necessary to pass a
bill completely through the device to obtain an accurate
identification; usually the identifying sound characteristics can
be recognized from just a portion of the bill. The provision of the
end rail 24 with respect to the photocell system within the light
box permits the operator to position bills accurately under the
light box to detect specific characteristics of various
denominations.
To assist the operator in feeding the bill through the photocell
light path, the bottom of the light box near the surface of tray 18
is tapered by means of two sloped wall portions 30 and 31 (FIG. 1),
forming entry slots at the bottom edges of the light box to make it
easier for a bill to slide into the opening 32 between the light
box and the surface of tray 18, where the denomination of the bill
is to be read.
Mounted at a convenient location, such as on the top of the
upstanding housing portion 14, is a push-button switch 33 for
switching the power to the identifier 10 on and off and a
potentiometer control knob 34 for varying the tone-volume control.
The potentiometer may be rotated to increase or decrease the pitch
and volume of the audible signal produced by the present device to
adjust it to the personal preference of the operator. The functions
of switch 33 and tone-volume control 34 will be discussed again
hereinbelow.
The interior of the light box 20 is shown in FIG. 2 as
incorporating a light source 40, such as a standard prefocussed
flashlight bulb, mounted in a socket 42 which is attached by a
suitable bracket 44 to the upper surface of the light box 20. The
lamp 40 directs its beam downwardly through an aperture 46 formed
in the bottom of the light box, whereby light from the bulb is
directed onto the apertures 22. The upper surface 15 of the
horizontal housing portion 12 has a rectangular opening 48 which is
directly below and in alignment with the apertures 22 in tray 18. A
photocell 50 is mounted to the under side of surface 15, and covers
the opening 48 so that any light passing therethrough illuminates
the photocell. If desired, and in a preferred form of the
invention, some means for directing the light from source 40
through the aperture 46 and onto the photocell 50 can be used, such
as a cylindrical shroud 52 which confines the light to a downward
direction. Source 40 is electrically connected by way of lines 53
and 54 to the remaining circuit elements, to be described, housed
in an electronics package 56. Photocell 50 is also connected to
this circuitry package through lines 58 and 60. The arrangement of
the light source is such that light from source 40 shines through
aperture 46 onto the currency positioned on tray 18. Light passes
through the bill and falls on photocell 50 in accordance with the
printed pattern on the two sides of the bill. The varying light
striking the photocell causes a varying electrical resistance on
lines 58 and 60 to the processing circuitry 56.
An alternate form of the apparatus of the present invention is
shown in FIG. 3, which is a partial, front view of the housing 10,
with only the light box 20' and the tray 18' shown in section to
illustrate the relationship of the photocell system to the path
followed by the bill to be identified. Elements in common with FIG.
2 are given the numerals used in FIG. 2, while equivalent, but
different, elements are primed. Thus, the light source 40 in this
embodiment is mounted in a modified form of the light box 20' by
means of socket 42 and bracket 44, and is electrically connected to
the electronic circuitry within housing 10' by way of lines 53 and
54 which pass into the housing through an opening 56 in the front
wall of housing portion 14. Similarly, photocell 50 is connected to
the circuitry (to be described) through lines 58 and 60. In this
embodiment, the light box 20' takes a different form to accommodate
both the light source and the photocell, and incorporates a support
frame 61 connected to the upstanding portion 14 of housing 10 by
brackets 62. The frame 61 carries the light box cover portion 20'
which is removable to permit access to the photocell system mounted
on the frame. Tray 18' is fixed to the upper surface of the
horizontal housing portion 12, but does not require the small
apertures needed in the embodiment of FIG. 2, although the end and
rails 24, 26 and 29 are still provided to guide the placement of
the currency bill in the tray for exposure to the light source.
The light box 20' is formed with a complex bottom surface shape to
not only facilitate insertion of a bill between the box 20' and the
tray 18', but to direct the light from source 40 onto the bill for
reflection to the photocell. Thus, the bottom surface, as defined
by frame 61, incorporates downwardly tapered portions 63 and 64
which facilitate insertion of paper currency from the tray 18' into
space 32, and upwardly angled central portions 65 and 66 which
accommodate a slot 67 and the photocell 50, respectively. The
portions 63, 64, 65 and 66 form a generally W-shaped bottom for the
light box, with the lowest portions of the bottom being closely
spaced from the tray 18' to provide the narrow spaces 32 adapted to
receive the currency to be identified.
Light source 40 is mounted by bracket 44 to the interior of wall
63, the mounting serving to direct light from the bulb through an
aperture 67 formed in the wall 65. The aperture 67 extends
transversely across the longitudinal center axis of the tray, and
is so positioned and sized that light from the bulb will be
reflected from the center portion of the surface of any currency
positioned on tray 18' and drawn through slots 32 upwardly into the
photocell 50. It will be understood that the amount of light
reflected, and thus the output from the photocell on lines 58, 60,
will depend upon the surface characteristics of the currency; i.e.,
upon the printed pattern thereof. Changes in reflected light from
the bill cause the resistance of the photocell to change, creating
a varying output on lines 58 and 60 to the electronic
circuitry.
The electronic circuitry used in the embodiments of both FIGS. 2
and 3 is illustrated in FIG. 4, to which reference is now made. As
indicated, the present money identifier operates from a
conventional source of 115v. alternating current, as by way of a
plug 70. The A.C. input is applied by way of lines 72 and 74
through the contacts 76 and 77 of pushbutton switch 32 to the
primary winding 78 of an input transformer 80. When depressed,
pushbutton switch 32, which may be of the push-to-close,
push-to-open type, closes the circuit through the transformer 80
and turns the system on. Light source 40 is connected in parallel
across a secondary winding 82 of transformer 80. A resistor 84 in
series with the bulb limits the current passing through light
source 40 and thus serves to regulate its brightness. A full wave
rectifier consisting of diodes 88, 90, 92 and 94 is connected
across secondary winding 82 via lines 96 and 98 to provide a source
of direct current for the remainder of the circuit on lines 100 and
102. A capacitor 104 is connected across the output lines 100, 102
to provide a constant output voltage of approximately 9 volts d.c.
If desired, a 9 volt battery could be placed across lines 100, 102
as a substitute for the a.c. rectifier network.
Connected across lines 100 and 102 is an R.C. series network
consisting of a capacitor 106 which is charged through a resistor
108, photocell 50 and the adjustable resistance of a potentiometer
110 having a resistance 112 and a movable tap 114 adjustable by
means of knob 34. Variation of resistor 112 provides the
tone-volume control described above with respect to FIG. 1. A
resistor 115 may be provided across potentiometer 110 to limit the
resistance of the network. The capacity of capacitor 106 and the
value of the total resistance in series with it determines the time
required for it to charge to a preselected voltage level.
The R.C. network is connected to a unijunction transistor 116 to
control its conduction, and to form a frequency-controlled
relaxation oscillator. The junction between potentiometer 110 and
capacitor 106 is connected by way of line 118 to the emitter 120 of
transistor 116, while line 102 is connected through a bias resistor
122 to the base 2 of the transistor, indicated at 124. The base 1
connection 126 of the transistor is connected through the drive
coil 128 of a loudspeaker 130 to line 100.
When the charge across capacitor 106 builds to the emitter-to-base
breakdown voltage of transistor 116, the transistor becomes forward
biased and conducts. Capacitor 106 then discharges through line
118, transistor 116 and speaker coil 128, causing a sonic pulse.
Upon completion of the discharge, the transistor becomes reverse
biased and nonconductive until the voltage on capacitor 106 again
builds to the breakdown value. With a given value of capacitor 106,
the frequency with which the capacitor 106 charges and discharges
depends on the combined resistance values of resistor 108,
potentiometer 110, shunt resistor 115, and the resistance exhibited
by the light sensitive photocell 50.
Once the value of potentiometer 110 is set by adjusting arm 114,
the frequency of the relaxation oscillator will depend solely on
the value of the resistance of photocell 50, which resistance
varies with the amount of light striking the surface of the
photocell device, and in particular with the amount of light from
light source 40 which is transmitted through or is reflected from a
currency bill. The limiting resistors 108 and 115 establish the
minimum and maximum resistances, respectively of the R.C. network
and thus limit the maximum and minimum rates at which the capacitor
106 will charge to the breakdown voltage of transistor 116. In this
manner the maximum frequency of the oscillator, and thus the
maximum tone pitch produced by the loudspeaker, is established at a
level below the supersonic sounds which might hurt the ears of
seeing eye dogs which often accompany blind persons. The maximum
resistance of the R.C. circuit establishes the lowest tone
frequencies produced by the circuit. It will be understood that
resistor 108 and 115 may be made adjustable, if desired, to permit
compensation for variations in other components in the circuit, and
that a variable gain amplifier may be provided between the
oscillator and the loudspeaker with a volume control knob mounted
on the housing for convenient control of the sound produced by the
speaker.
In operating the money identifier of this invention, a currency
bill to be identified is placed flat in tray 18 or 18' and is
located to the right of the light box, as viewed in FIG. 1, with
the back edge of the bill against the upright portion 14 of the
cabinet and the left end of the bill against the light box. The
tray, housing, and light box are so arranged as to facilitate
convenient and consistent correct placement of the bill in the
identifier by a blind operator. Using his fingers, the operator
then feeds the bill into the space below the light box, and thus
into the path of the light beam from source 40. The bill is then
drawn steadily through the identifier so that variations in the
optical properties of the printing on the bill will cause
variations in the light path between source 40 and photocell 50. In
the first embodiment described above, the light path is through the
bill, and the variations in the pattern printed on both sides of
the bill cause corresponding variations in the resistance of the
photocell, and thus in the frequency of the sound produced by the
relaxation oscillator. In the second embodiment described above,
the light path is reflected from the surface of the bill, so that
variations in the printed pattern on only one side of the bill
cause corresponding variations in the sound produced by the
identifier. Both embodiments produce unique and identifiable
sounds, although the sound produced by the first embodiment is more
complex and thus more difficult to learn, since it is a composite
of the patterns of both sides of the bill. Although producing a
simpler sound pattern, the second embodiment may require two passes
of the bill through the device since the faces of all denominations
of bills have very similar light and dark patterns and may present
difficulties in identification. In this event, it may be necessary
to turn the bill face down and feed it through the light path again
for identification. With both embodiments there may be slight
differences in sound, depending on which end of the bill is
introduced into the path first; however the difference is slight
and not significant for purposes of bill identification since the
readings are taken along the longitudinal center of the bill.
To illustrate the manner in which the present money identifier
operates, consider a five dollar bill inserted into the FIG. 2
embodiment, where light passes through the bill. The $5.00 bill is
very symmetrical except that the word "FIVE" appears in big light
print on the face to the right of the picture of Lincoln. The back
side is perfectly symmetrical except that the illumination of the
Lincoln Memorial is from the left side and produces a light spot
between the second and third columns of the picture of the Lincoln
Memorial. The columns are light and the shadows behind them are
dark. When the picture of these columns passes thru the light beam,
alternate high and low tones are produced by the oscillator. They
are very distinct and of the same pitch and same distance apart,
especially in the center of the bill. When the bill is moved back
and forth from a point where the left edge of the bill is 3/4 inch
from the left edge of the tray to the left edge of the tray, it
sounds like someone pulling a stick along a picket fence.
When moving a $20.00 bill thru the instrument, all of the tones are
deep with very few high pitched tones. The most distinguishing
features of the $20.00 bill are the overall deep tones, the short
high tone an inch in from either end, and the alternate high and
low tones in the center of the bill near the end of the
movement.
The face of the $20.00 bill is symmetrical except for the word
"TWENTY" to the right of Jackson's picture. These letters are very
faint and do not show up clearly as the bill passes through the
instrument. The back side is symmetrical except for trees covering
the left side of the picture of the White House, but not the right
hand side. The trees are very dark and produce the low tones, lower
than any other bill. About an inch from either end, a light area
(high pitch) exists for about 1/4 inch. This occurs when the left
end of the bill is about 21/4 inches from the left end of the tray.
This makes identification between a $5.00 and $20.00 simple because
the light area on the five is about 3/4 inch long.
Another distinguishing feature of the $20.00 bill is the columns in
the picture of the White House. There are six columns and five dark
areas between them. The columns are located in the center of the
bill. An alternate high and low pitch tone can be heard when the
left edge of the bill is moved from a point 1/2 inch away from the
left edge of the tray to the edge of the tray.
The $10.00 bill creates sound patterns very similar to the $5.00
bill but does not have the alternate high and low patterns caused
by the columns on the $20.00 bill and does not have the alternate
high and low patterns in the center which are characteristic of the
$20.00 bill. The major identifying point is a dark area (low tone)
created by shadows about 1/8 inch long between two columns of the
picture of the Treasury Building. When the bill is fed into the
identifier with the back up and right side up, this low tone occurs
when the left edge of the bill is about 1 inch from the left edge
of the tray. It also occurs when the bill is inserted face up, but
with Hamilton's picture upside down. If the bill is inserted in the
other two directions, it will not appear unless the left edge of
the bill is lifted so it can pass over the left edge of the tray
about 1/4 inch.
The sounds emitted when a $1.00 bill is passed through the
instrument do not have a pattern that is as easily identified as
the other bills. The sounds are a series of high and low tones,
none of very long duration.
One distinctive feature is a light spot (high pitch) that occurs
when the left end of the bill is about 11/4 inches from the left
edge of the tray. This light area is only about 1/8 inch long and
exists on either side of the word "ONE". The areas on either end of
the bill are mostly dark (low pitched) before this area. This high
pitch is produced when either end of the bill is fed into the
instrument. Another distinctive feature is a very low tone at a
position where the left edge of the bill is about 3/4 inch from the
left edge of the tray. This is caused by a combination of a dark
area of George Washington's picture on the face side and areas of
the letter "ONE" on the back side and is heard regardless of which
end of the bill is inserted.
In similar manner, distinctive sounds are produced by various
denomination bills inserted into the device of the second
embodiment, shown in FIG. 3. Thus it can be seen that with a proper
amount of training, the present invention can be used as a valuable
aid for blind persons in accurately and quickly identifying paper
currency of various denominations. The invention is designed to
operate effectively with a minimum of training and manual effort,
and with minimum requirements for handling the bills before a
reading can be obtained. Although the invention is disclosed in
terms of specified embodiments, it will be recognized that numerous
variations and modifications of the invention can be constructed
without departing from the true spirit and scope thereof as defined
in the following claims.
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