Programmable infrared signal beacon

A portable signal beacon adapted to be worn on the body so as to provide a discernable signal to a remote observer during low light conditions. The signal beacon includes a lightweight housing containing a light source, such as a bank of infrared LEDs. A signal generating device is also contained within the housing, wherein the signal generating device controls the activation of the light source and provides the light source with one of a plurality of different flashing sequences. At least one selection switch is provided that enables the user of the beacon to select which of the plurality of flashing sequences will be transmitted by the light sources.

FIELD OF THE INVENTION 
The present invention relates to signal beacons carried by soldiers or 
woodsmen to provide a visual locating signal during low light conditions. 
More particularly, the present invention relates to signal beacons that 
can be programmed to signal one of a number of coded messages, either in 
the visible light range of the spectrum or the infrared range of the 
spectrum. 
BACKGROUND OF THE INVENTION 
Flashing lights have long been used to send signals at night or to indicate 
the presence of an object in the darkness. For example, Paul Revere was 
signaled by a light that the British were coming. Airplanes use flashing 
strobes so that they can be seen at night, and tall structures are adorned 
with flashing lights so airplanes can identify those structures in the 
darkness. The advantages of using flashing lights to send a signal include 
the fact that flashing lights are far more economical to use than radio 
wave based or radar based signalling systems. But perhaps the largest 
advantage of using light signals is that light signals immediately tell 
the receiver of the signal the exact location of the source of the signal 
without the need of sophisticated electronic equipment. As such, a pilot 
does not have to look at a radar screen to see a tall structure, rather 
the flashing lights allow the pilot to see the structure with his/her own 
eyes. 
As a result, the use of flashing lights is the signaling medium of choice 
in situations where the purpose of the signalling is to quickly and 
inexpensively identify the location of a person or an object in the dark. 
See for example, U.S. Pat. No. 5,117,766 to Nechushtan et al., entitled 
PERSONNEL MARKER where small lights are used to identify the position of 
soldiers on maneuvers in the dark. An obvious disadvantage of using lights 
to identify people or objects in the dark, is that in military 
applications such signal lights reveal the location of soldiers and 
objects to the enemy. As such, the use of a visible light on a soldier, 
such as is shown like that in the Nechushtan patent, is fine for training 
but would be disastrous in a real combat environment where the enemy could 
easily see the location of soldiers in the darkness. A paradox is therefor 
created in military applications wherein a system is required to allow 
friendly forces to identify objects and each other at night but not allow 
unfriendly forces to do the same. 
A solution to this paradox comes from the fact that most U.S. Military 
forces, both airborne and land based, that operate at night are commonly 
equipped with night vision devices that convert infrared, near-infrared 
and/or low intensity, low frequency visible light into an easily viewable 
image. By flashing an infrared light, only people looking at the source of 
the signal with night vision equipment would be able to see the signal. An 
example of one situation that has adopted the inared solution is shown in 
U.S. Pat. No. 4,912,334 to Anderson, entitled INFRARED AIRCRAFT BEACON 
LIGHT. The Anderson patent discloses infrared aircraft beacons that enable 
pilots with night vision goggles to fly in formation and see the 
surrounding aircraft in a manner that does not give away the position of 
the aircraft to enemy forces on the ground. A similar system is disclosed 
in U.S. Pat. No. 5,159,480 to Gordon et al., entitled INFRARED WIDEBEAM 
COMMUNICATION TRANSMITTER, wherein navel ships send and receive infrared 
light signals that can only be viewed by a person using a night vision 
device. 
Outside of the military, night vision devices are not widely used. As such, 
outside the military there are few location signaling devices that operate 
within the infrared region of the spectrum. Consequently, in a domestic 
setting there are very few sources of light that can only be viewed 
through the use of a night vision device. The use of an infrared location 
beacon in a domestic setting would therefore be a highly unusual 
occurrence. Accordingly, infrared beacons would be an effective way to 
identify a single person or object in a city, suburban or rural setting in 
a landscape that contains numerous other light sources. 
It is therefore an object of the present invention to provide an infrared 
beacon signaling device that can be carried by an individual and can be 
used to send a detectable infrared signal without regard to the presence 
of other light sources or the lack thereof. 
It is a further object of the present to provide an infrared signaling 
device that can be worn on the body and activated in a time of distress. 
It is yet another object of the present invention to provide a programmable 
infared signalling device that can transmit a number if preprogrammed 
coded signals depending upon the needs of the persons utilizing the 
signalling device. 
SUMMARY OF THE INVENTION 
The present invention is a portable signal beacon adapted to be worn on the 
body so as to provide a discernable signal to a remote observer during low 
light conditions. The signal beacon includes a lightweight housing 
containing a light source, such as a bank of infrared LEDs. A signal 
generating device is also contained within the housing, wherein the signal 
generating device controls the activation of the light source and provides 
the light source with one of a plurality of different flashing sequences. 
At least one selection switch is provided that enables the user of the 
beacon to select which of the plurality of flashing sequences will be 
transmitted by the light source. The light source may generate either 
infrared light and/or visible light. If a light source is used that 
generates visible light, a filter cap is provided that attaches to the 
beacon housing over the light sources. The filter cap permits only 
infrared light therethrough. Thus, by placing the filter cap over the 
light source, the signal beacon can be selectively altered between a 
visible light beacon and an infrared light beacon.

DETAILED DESCRIPTION OF THE PRESENT INVENTION 
Although the present invention programmable infrared beacon can be attached 
to any object or can be carried on any part of the body, the present 
invention is especially suited to be worn as an arm band or hat band 
assembly, Accordingly, the present invention will be described as part of 
a band assembly that can be worn around the arm or around a hat in order 
to set forth the best mode contemplated for the invention. 
Referring to FIG. 1 one preferred embodiment of the present invention 
programmable infrared beacon 10 is shown as part of a band assembly 12. 
The infrared beacon 10 is contained within a generally rectangular shaped 
housing 14. An infrared light source 16 extends upwardly from the top 
surface 17 of the housing 14. As will later be explained, the infrared 
light source 16 is capable of transmitting pulses of infrared light in one 
of several signaling sequences that are stored in an electronic memory or 
in a custom signaling pattern entered by the operator of the device. A 
large push button 20 is disposed on the housing 14 in an area that is 
easily accessed by the operator of the device. As will also be later 
explained, the push button 20 enables the operator to access signaling 
sequences stored in memory or enter a custom signaling pattern to be 
transmitted. An optional speaker port 23 is disposed on the housing 14. 
The speaker port 23 protects a speaker element that provides an audible 
signal that is indicative of the light signal being emitted by the light 
source 16. This enables a person using the infrared beacon to identify the 
signal being transmitted, even if that person cannot see or comprehend the 
light signal being emitted. 
In the shown embodiment, the infrared beacon 10 is joined to a band element 
22 to create the overall band assembly. The band element 22 is a flexible 
support that couples to the beacon housing 14 so as to provide a 
convenient surface upon which to attach a strap 25 to the infrared beacon 
10. The band element 22 shown has a plurality of slots 24 formed through 
its structure on either sides of the infrared beacon 10. The strap 25 can 
be weaved through the slots 24 so as to provide a secure attachment 
between the band element 22 and the strap 25. The strap 25 is preferably 
elastic having hook and loop fasteners 26 at its two ends, thereby 
enabling the strap to be placed around a variety of different sized arms 
or hat bands. 
Referring to FIG. 2, it can be seen that inside the beacon housing 14 is 
disposed a printed circuit board 30, a battery 32, and a plurality of 
light emitting diodes (LEDs) 34. The printed circuit board 30 contains the 
control logic used to flash the LEDs 34, as will be later explained. The 
push button 20 extends into the housing 14 and is coupled to the circuit 
board 30. As such, the push button 20 is the only variable input used to 
actuate and control the circuitry contained on the circuit board 30. In 
the shown embodiment, the battery 32 is a commercially available 9 volt 
battery that is coupled to the circuit board 30 within the beacon housing 
14. The battery 32 is accessed through a removable elastomeric grommet 38 
that plugs an access port 39 on the bottom of the beacon housing 14. It 
will be understood that the use of a 9 volt battery is merely exemplary 
and any other battery or series of batteries can be used depending upon 
the power requirements of the LEDs 34 and the circuit board 30. An 
optional speaker element 21 or another such indicator may also be coupled 
to the circuit board 30. In the shown embodiment, the speaker element 21 
aligns with speaker port 23 in the housing 14 and provides an audible 
signal that identifies what light signal is being emitted by the LEDs 34. 
The LEDs 34 extend through the beacon housing 14 so as to be visible from a 
point external the housing 14. In the preferred embodiment, the LEDs 34 
extend through the top surface 17 of the beacon housing 14. The LEDs are 
oriented to emit light up and away from the top surface 17 of the housing 
14. As a result, if the infrared beacon 10 is worn on a person's body so 
that the top surface 17 of the housing 14 faces skyward, the light emitted 
from the LEDs 34 will be directed essentially skyward. The LEDs 34 can 
either emit visible light or can emit purely infrared light. In the 
preferred embodiment, the LEDs 34 emit visible light at the red end of the 
visible spectrum, wherein the light emitted includes component frequencies 
in the near infrared region. A filter cover 40 is provided that filters 
out the visible light emitted by the LEDs 34, thereby permitting only the 
infrared frequencies to be transmitted. The filter cover 40 is preferably 
removable from the beacon housing 14. As a result, the operator of the 
infrared beacon 10 can control what type of signal is being transmitted by 
selectively removing the filter cover 40. For example, if the beacon 
operator wanted to transmit a visible signal to people not having night 
vision devices, the filter cover 40 can be removed. However, if the beacon 
operator wants to transmit an infrared signal visible only via night 
vision devices, the filter cover 40 can be left in place. 
It will be understood that if the LEDs 34 produce only infrared light, then 
the filter cover 40 need not be used. Rather, the filter cover 40 could 
merely be a transparent cover that helps protect the infrared LED's 34 
from damage. To operate the infrared beacon 10, the operator engages the 
push button 20. Depending upon the number of times the push button 20 is 
depressed and/or the sequence by which the push button 20 is depressed, 
the beacon operator can recall a preprogrammed signal sequence or enter a 
custom signal sequence. Referring to FIG. 3 one preferred embodiment of 
the control logic used by the infrared beacon is illustrated. As can be 
seen as push button 20 is depressed, the signal passes through a 
debouncing circuit 50 to an N State Counter 52 that counts the number of 
times the state of the push button changes in a given unit of time. Once 
the number (N) of push button depressions has been counted, a Decoder 54 
converts the count number into binary code. Depending upon the code 
entered, via the push button 20, one of two interactions can occur. A ROM 
memory 56 is provided that contains a number of preprogrammed signal 
sequences. The signal sequences can be recalled from ROM memory 56 by the 
appropriate binary code input. Looking at FIG. 4 in conjunction with FIG. 
3, it can be seen that if the push button 20 were pushed once, the binary 
code 001 would be produced. This binary code retrieves the signal for 
"S.O.S." from ROM memory 56. Similarly, if the push button 20 were pushed 
twice, the binary code 010 would be produced which would retrieve the 
signal for "WATER" from the ROM memory 56. Once the appropriate signal is 
retrieved from memory, the signal is read by a Code Signal Generator 58 
that converts the signal into the appropriate morse code signal. The morse 
code signal is then read by the LED Driver 59 that flashes the LEDs 34 in 
the appropriate sequence. The flashing sequence may repeat indefinitely 
until stopped or may repeat for a predetermined period of time . 
In FIG. 4, it can be seen that the Decoder 54 provides a three bit binary 
code that provides eight possible entries. As has been mentioned, some of 
the entries correspond to preprogrammed signals stored in memory such as 
S.O.S., WATER, FOOD, DANGER and the like. However, at least one of the 
binary code entries triggers a second interaction, wherein the Decoder 54 
interacts with a temporary programmable memory 55. The temporary 
programmable memory 55 is capable of temporarily storing a custom signal 
code of a predetermined length. Using the push button 20, a custom morse 
code signal can be entered and stored within the temporary programmable 
memory 55, wherein the custom morse code can be repeatedly transmitted via 
the LEDs 34. In this manner, a person wearing the infrared beacon can 
transmit a custom signal to any person observing the infrared beacon with 
a night vision device. 
Since the shown embodiment of the infrared beacon has only a single push 
button 20 to input information, it may be difficult for the person using 
the infrared beacon to remember how many times the push button 20 has been 
engaged. Accordingly, the present invention may come equipped with an 
optional audible or visual indicator. In FIG. 3 a tone generator 62 is 
shown coupled to speaker 21. The tone generator 62 is coupled to the code 
signal generator 58 wherein the tone generator 62 generates a tone 
indicative of the code being flashed. For example, the tone generator 62 
may generate tones in morse code that correspond to the morse code signal 
being transmitted. Alternatively, the tone generator 62 may generate a 
tone indicative of the eight possible signal choices shown in the 
preferred embodiment. The use of a tone generation is merely exemplary. In 
alternate embodiments the tone generator can be replaced by a voice 
synthesizer that states the message being sent or a LCD display that 
displays the message being sent. 
In an alternate embodiment of the present invention infrared beacon, its 
circuitry can be simplified to reduce the complexity and cost of the 
device. Referring back to FIG. 1, the infrared beacon 10 may just have the 
ability to transmit one or two message signals. These message signals may 
be generated by pulse generator circuits hard wired directly on the 
circuit board, thereby eliminating the need for memory cells and 
sophisticated N stage counter circuits. For instance, in one preferred 
embodiment of the infrared beacon 10, the beacon has the ability only to 
transmit two signals. One of those signals is a periodic strobe used to 
identify the location of the beacon. The second signal is a S.O.S. morse 
code signal, identitying the need for help. As with previous embodiments, 
the signal choice is selected via the push button 20. When the push button 
20 is depressed once, the periodic strobe begins. When the push button 20 
is pressed twice, the S.O.S. signal begins. In such an embodiment, the use 
of a signal indicator is not required since the operator of the beacon is 
offered only two selections from which to choose. Furthermore, if the 
signal is being transmitted in any visible light frequency, the operator 
can easily ascertain whether the signal being transmitted is the periodic 
strobe or the morse code signal. 
It will be understood that the embodiments of the infrared beacon described 
above are merely exemplary and that a person skilled in the art may make 
many variations and modifications to those embodiments using functionally 
equivalent components and circuitry. More specifically, it should be 
understood that numerous circuits can be developed that are capable of 
generating a predetermined morse code signal. Any such circuit 
controllable by at least one push button can be used in conjunction with 
this invention. All such variations and modifications are intended to be 
included within the scope of the present invention as defined in the 
appended claims.