|United States Patent
|Gargano , et al.
||May 13, 1997 |
Personal tracking and recovery system
Apparatus for tracking and recovering humans utilizes an implantable
transceiver incorporating a power supply and actuation system allowing the unit
to remain implanted and functional for years without maintenance. The implanted
transmitter may be remotely actuated, or actuated by the implantee. Power for
the remote-activated receiver is generated electromechanically through the
movement of body muscle. The device is small enough to be implanted in a child,
facilitating use as a safeguard against kidnapping, and has a transmission range
which also makes it suitable for wilderness sporting activities. A novel
biological monitoring feature allows the device to be used to facilitate prompt
medical dispatch in the event of heart attack or similar medical emergency. A
novel sensation-feedback feature allows the implantee to control and actuate the
device with certainty.
||Gargano; Paul A. (154 Clifton St.,
Belmont, MA 02178); Gilmore; David H. (Cayman Kai, KY); Pace;
Frank A. (Ballston Spa, NY); Weinstein; Lee (Somerville, MA)
||Gargano; Paul A. (Belmont, MA) |
||January 10, 1995|
|Current U.S. Class:
||340/573.4; 128/903; 340/539;
340/825.49; 342/465; 455/100 |
|Field of Search:
379/37-38 342/450,357,44,42,51 128/774,903,653.1,696 |
U.S. Patent Documents
||Kelly et al.
||Badylak et al.
||Lee et al.
||de Coriolis et al.
||Schlager et al.
||Morgan et al.
Dialog OneSearch Results, May 13, 1994.
Primary Examiner: Mullen; Thomas
Attorney, Agent or Firm: Hamilton, Brook, Smith & Reynolds, P.C.
1. A transceiver device implantable in a human body
comprising: a triggerable radio frequency transmitter, a power
source for powering said transmitter, triggering means for activating
said transmitter, receiver means allowing the detection of an externally
generated information signal, an antenna for effectively radiating RF
energy from said transmitter to produce an identifiable RF signal for a period
of time following activation by said trigger means, said receiver means
comprising an electromechanical device having a binary output, a digital decoder
for detecting predetermined time-encoded information in the binary output of
said electromechanical device and for providing an electrical trigger signal
representative of the presence of such pre-determined information, and
said trigger signal causing the activation of said transmitter.
2. The transceiver of claim 1, wherein said receiver means additionally
comprises a wave receiver for receiving a transmitted wave, and said
digital decoder is responsive to information in an incoming transmitted wave for
providing an electrical trigger signal representative of the presence of the
3. The transceiver of claim 2, further comprising sensory
stimulus means for providing a noticeable stimulus to alert the person in whom
the device is implanted that all or part of said incoming transmitted wave has
been detected by said digital decoder.
4. The transceiver of claim 2,
further comprising a charging regulator for maintaining the power source used to
power the transmitter at a state of peak charge.
5. The implantable
device of claim 1, wherein said receiver means additionally comprises a
sustainable power supply comprising means for picking up periodically available
external energy without external electrical contact, storing said energy for use
over time, such that the resultant stored energy is sufficient to power the
receiver means with enough regularity to ensure proper detection of information
on said incoming signal.
6. The transceiver of claim 5 wherein said
external energy pickup comprises an inductive pickup, for converting magnetic
energy to electrical energy.
7. The transceiver of claim 6, wherein said
inductive pickup is placed close to the surface of the body of the individual in
which it is implanted.
8. The transceiver of claim 5 wherein said
external energy pickup comprises an electromechanical means for converting
mechanical work of the body into electrical energy.
9. The transceiver
of claim 8, wherein said mechanical work is supplied by muscle tissue in the
body of the human in which the device is implanted.
10. The device of
claim 1, wherein said electromechanical device includes threshold-detection
11. The device of claim 1, wherein said signal decoder allows
input from more than one source of binary information.
12. The device of
claim 1, further comprising means for providing a perceivable stimulus in
response to one output from said digital decoder.
13. The transceiver of
claim 12, wherein said receiver means comprises analog circuitry for amplifying
the electrical field associated with the contraction of the human heart, and
said digital decoder comprises means for detecting the lack of a regular
14. The device of claim 1, wherein said signal decoder
provides a plurality of outputs in response to a plurality of different
pre-determined information patterns.
15. The transceiver of claim 1,
further comprising sensory stimulus means for providing a noticeable stimulus to
alert the human in whom the device is implanted that all or part of said
externally generated information signal has been detected by said digital
16. The transceiver of claim 1, further comprising sensory
stimulus means for providing a noticeable stimulus to alert the human in whom
the device is implanted that the all or part of said predetermined information
signal has been detected by said detector means.
17. The device of claim
1, wherein said digital decoder allows input from more than one source of binary
18. A system for tracking and recovering humans in
distress, comprising; a plurality of triggerable transceivers implanted
each in a human being, each transceiver having a transmitter and a
receiver, any one of said transmitters of said transceivers uniquely triggerable
to transmit a radio frequency beacon signal after the receiver of said
transceiver receives a predetermined radio frequency information signal,
a network of trigger transmitters and receivers, each being sensitive to
said radio frequency beacon signal and capable of deriving positional
information concerning the source of said beacon signal, and said
trigger transmitters being capable of transmitting a plurality of uniquely
identifiable radio frequency information signals, capable of uniquely triggering
one of the plurality of implanted radio transceivers.
19. The system of
claim 18, further comprising a plurality of mobile receivers sensitive to said
radio frequency beacon signals for providing finer positional accuracy in
determining the location of the source of said radio frequency beacon signals.
BACKGROUND OF THE INVENTION
The present invention relates, in
general, to tracking and recovery systems and systems for tracking and
recovering humans. More particularly, it discloses a system employing a
self-powered, self-maintained transceiver, small enough to be implanted in a
human, for locating, tracking, and recovering persons in distress, such as
kidnap victims, people encountering adverse circumstances while in the
wilderness, victims of heart attacks and the like.
BACKGROUND OF THE
Various apparatus and techniques for tracking and locating
animate and inanimate objects are known in the art. Recently, international
legislation has established a satellite tracking system for locating downed
aircraft and distressed seagoing vessels. This system utilizes user-activated
transmitters operating at a frequency of 460 MHz, as spelled out in the Code of
Federal Regulations chapter 47 part 90. These inexpensive transmitters are known
as Emergency Position Indicating Radio Beacons (EPIRB's). The associated
satellite network is capable of locating a transmitting EPIRB anywhere on the
face of the globe. By international agreement, this system is used only for
distressed aircraft and seagoing vessels, and all other potential uses are
U.S. Pat. No. 4,818,998 describes a vehicle tracking and
recovery system employing a transceiver (to be hidden within a motor vehicle),
and a network of fixed and mobile ground transmitters and receivers to
facilitate tracing and recovery of stolen vehicles. This system is presently in
wide use by LoJack Corporation in the United States. The system operates at a
frequency of 173.075 MHz, permanently assigned as a police radio service
frequency in 1992. The unit, mounted in an automobile, is continuously operated
as a receiver until such time as it is remotely activated, at which time it
transmits a radio beacon (similarly to the EPIRB system), facilitating tracking
and recovery. The tracking and recovery in the LoJack system is accomplished
through a network of ground based fixed and mobile receiver units, which utilize
field strength measurements and directional receivers to locate the transmitter,
as opposed to the timing and triangulation methods used by the EPIRB system. The
receiver in the automobile-mounted unit draws its power from the vehicle
battery, and utilizes a small local rechargeable battery that powers the unit
should the vehicle battery be disconnected.
U.S. Pat. No. 4,706,689,
Issued to Daniel Man on Nov. 17th, 1987, describes a device designed to be
implantable behind the ear of a human. The device transmits a coded signal
intended to enable tracking of the person outfitted with the implanted device.
The device operates continuously, and is designed to be recharged through
external contacts. It is also designed to incorporate a biological monitoring
function, such as might facilitate out-patient monitoring.
described devices all have limitations making them unsuitable as systems for the
widespread tracking and recovery of humans. The EPIRB transmitter and Lojack
transceiver are not miniaturized to the point where implantation is practical.
The techniques for manually activating the EPIRB unit also make it unsuited for
implantation. The LoJack unit requires substantial power to be supplied
continually from a vehicle battery system, and unsuited for implantation from
this point of view as well.
Daniel Man's implantable device is designed
for continuous operation, which places severe constraints on its transmission
range, even if it is only to be operated for a day at a time between battery
recharges. With a given level of background radio frequency noise, communication
theory can be used to calculate the minimum power consumption needed for
detection of an event within a given time to within a given certainty, at a
given distance from an omni-directional transmitter. The resultant average
transmission power is independent of whether the transmitter is pulsed or
continuous. Further problems arise with Man's system when a number of units are
in use in the same area. The tracking problem becomes prohibitively expensive
for many simultaneous units, and the malfunction of any unit can mask the
detectability of other units, or require significantly increased transmission
power levels for all units. Such a system would require a very expensive closely
spaced network of permanent tracking receivers with very costly hardware capable
of tracking multiple units at one time. A system where transmitters are active
all the time requires n times more bandwidth in the radio spectrum than
minimal-bandwidth system with only one transmitter transmitting at one time. The
availability of bandwidth could become quite a problem if the Man system were
put into wide use.
In addition, the implanted unit would need to be
recharged (probably daily) through contacts brought out through the person's
skin. Such an arrangement presents a significant health hazard. In addition, the
need for regular recharging puts significant restraints on the person using the
device and also heightens the users awareness of the implanted device, resulting
in a less "free and natural" state of mind. The complexity of the Man system
could result in a significant level of false alarms, and/or prohibitively high
The present invention contemplates improving upon the features
available in the aforementioned devices and makes possible a widespread tracking
and recovery system for humans in distress. The present invention will benefit
from novel features allowing it to remain implanted and functional for many
years. The device will remain in a dormant state until activated, either by the
person in whom it is implanted, or by remote means. Novel means for powering and
triggering the device will make recharging and battery replacement unnecessary.
The device meets the growing demand for a new level of safety and peace of mind.
Consequently, it is a general object of this invention to provide a new
means and method for locating, tracking, and recovering humans in distress.
Ideally, the device will bring peace of mind and an increased quality of life
for those who use it, and for their families, loved ones, and associates who
depend on them critically. Adults who are at risk due to their economic or
political status, as well as their children who may be at risk of being
kidnapped, will reap new freedoms in their every-day lives by employing the
device. Law enforcement agencies will be able to more economically protect those
at risk, those who would potentially perpetrate acts of violence against
individuals will be more effectively deterred. Those who enjoy wilderness sports
such as mountain climbing, skiing, hang gliding, etc. will enjoy new freedom
knowing that a rescue mission can be dispatched to their exact location if they
A specific object of the invention is the rapid
effective recovery of individuals who have been kidnapped. A further object of
this invention is to afford peace of mind and increased quality of life to those
utilizing the invention, and to their loved ones and dependent associates. It is
a further object of the invention to make emergency aid readily available to
those at risk in remote or urban areas. It is a further object of the invention
to reduce the cost of rescue missions to remote areas. It is further object of
the invention to facilitate a highly reliable, minimal cost, location and
recovery system with flexible features. It is a further object of the invention
to facilitate rapid, automatic deployment of medical personnel in the event of
certain medical emergencies.
This implantable tracking and recovery
device makes possible greatly increased safety for people in a variety of
situations. This increased safety leads to peace of mind and associated
increased quality of life not only for those utilizing the device but for
concerned loved ones as well. Four areas where this device will be seen to have
significant impacts are (1) safeguarding against kidnapping, and rapid recovery
of victims; (2) safety in wilderness sporting activities, where risk is inherent
and help is often not readily available; (3) personal safety in urban
environments, where one might encounter car-jackings, muggings, and the like;
(4) medical emergencies, such as heart attack or seizure.
The lives of
potential kidnap victims and their loved ones will be significantly freed up by
the peace of mind afforded by the tracking device. Along with peace of mind, the
homing device will offer the possibility of a lifestyle that would otherwise be
considered too risky. In the event of a kidnapping, law enforcement officials
could be expediently dispatched for rapid recovery of the victim.
tracking device will offer safety in such activities as hiking, mountain
climbing, skiing, and camping in remote areas. Costs of rescue missions will be
dramatically cut because searching will not be necessary. Lives will be saved
because the time from when the emergency occurs to when help arrives will be
The device will afford increased safety and peace of
mind for those in urban areas as well. The increase in gang violence, rapes,
muggings, and car jackings in recent years has generated significant increased
concern for personal safety. The use of the device will afford increased peace
of mind and will allow law enforcement to be more effective.
could be significantly prolonged if help were rapidly available in the event of
a heart attack. Unfortunately, the individual suffering the heart attack may not
recognize the symptoms of the heart attack (which may occur in sleep), and even
if the symptoms are recognized, the individual may be unable to summon help. The
use of the device with incorporated body-function monitoring capability allows
help to be rapidly dispatched, potentially saving the life of the user.
SUMMARY OF THE INVENTION
The system employs triggerable radio
beacon transmitter means designed to be implanted beneath the skin of an
individual. Biological monitoring in the device will provide means for rapidly
dispatching help in the event of a detectable medical emergency, such as a heart
attack. A unique sensation-feedback feature allows the user to control and
trigger the device with certainty, resulting in a more reliable, easily
maintained system. The device is hermetically sealed in a biologically inert
container. The device operates normally in a dormant state, and can be
externally triggered to transmit the homing beacon. There are numerous possible
embodiments of the trigger mechanism. In some embodiments of the trigger
mechanism, the device is designed to be remotely triggered. Such a feature is
desirable if the device is implanted in a small child who cannot be relied upon
to trigger the device. Remote triggering may also be desirable in instances when
an individual may be unconscious.
In one remote triggering instance, a
radio transmitter may broadcast a coded signal to a receiver within the device.
The receiver is equipped with circuitry for recognizing the coded radio signal.
In one embodiment where the device is locally triggered, the device may be
equipped with an acoustic receiver designed to detect certain sounds or a
predetermined sequence of sounds in time, such as a note progression. In this
case the device would likely be triggered by the person in whom it is implanted,
for instance by humming a given tune. Immunity to false alarms may be provided
by making the sequence long or requiring it to be repeated in a certain amount
In another embodiment, the device may be triggered by
monitoring a body function such as heart rate. If the victim were to experience
a heart attack, help would be automatically and expediently dispatched.
If the device is triggered either by an external coded radio signal or a
coded acoustic signal, or by monitoring a body function such as heart rate, the
device incorporates a micro-power analog electronic means such as a radio or
acoustic receiver or electrocardiogram monitoring circuitry, which runs off
energy collected either from body muscle by electromechanical means, or from an
external charger through electromagnetic induction coupling.
triggering means not requiring a micro-power receiver are also contemplated. In
such a case the device may be triggered by electromechanical means with a binary
output, such as a mechanical switch. Possible embodiments of such a triggering
mechanism range from a simple subcutaneous switch or combination of switches
that actuate the transmitter when pressed, to an actuator coupled to internal
body muscle, combined with digital circuitry designed to trigger the transmitter
in response to a timed sequence of actuations.
It may be desirable in
some implementations to include capabilities for both local and remote
triggering. The same individual may desire the capability of local triggering in
the event of an emergency such as a car-jacking, mugging, or kidnapping, while
desiring remote triggering capability if for some reason the situation had
rendered the individual unconscious. It may also be desirable in some
embodiments for the user to be able to disable the remote-trigger feature.
The device contains a power source capable of supplying power for the
transmitter for ample time to afford recovery of the individual in distress.
Once triggered, the device may transmit only for a predetermined interval,
allowing re-triggering later if the distressed individual is not located, or if
help takes some time to dispatch.
The small size of the device makes it
suitable for implantation in young children as well as adults. The above and
other features of the invention including various and novel details of
construction and combination of parts will now be more particularly described
with reference to the accompanying drawings and pointed out in the claims. It
will be understood that the particular personal tracking and recovery system
embodying the invention is shown by way of illustration only and not as a
limitation of the invention. The principles and features of this invention may
be employed in varied and numerous embodiments without departing from the scope
of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
depicts an overall schematic view of a system for the tracking, locating, and
recovery of humans embodying the features of the invention and including an
exemplary implantable triggerable transmitting device, remote activation
transmitter, several ground-based receiving antennae and alternate
satellite-based receiving antennae, mobile receiving unit, and associated
coordinating equipment, which combine to perform the locating and tracking
FIG. 2 is a schematic block diagram of an illustrative
implantable triggerable transmitter unit, including sensation feedback feature,
and several trigger implementations, which are used separately or in combination
in a given embodiment of the implantable device.
DETAILED DESCRIPTION OF
Referring to FIG. 1, one of a plurality of persons,
P.sub.1, is equipped with an implanted transceiver device D.sub.1 from a
plurality of devices D. A plurality of triggerable transmitters T (only one of
which is shown in FIG. 1) transmit a coded trigger signal S.sub.1, which is
picked up by the receiver section of all implanted devices D (only device
D.sub.1 being shown in FIG. 1). The receiver circuits in all devices D receive
the same coded trigger signal. However, the code in signal S.sub.1 uniquely
identifies device D.sub.1, and D.sub.1 alone responds to coded signal S.sub.1 by
transmitting a locating-and-tracking signal S.sub.2. Signal S.sub.2 is received
by at least one ground-based receiver, A.sub.1, A.sub.2, and A.sub.3, of a
plurality of receivers A, or at least one satellite receiver including SR.sub.1,
SR.sub.2, and SR.sub.3 of a plurality of receivers R.
the ground-based receivers A or the satellite receivers S are coordinated at a
tracking and locating center TLC. Equipment within the tracking and locating
center TLC uses information (for example phase, timing, field strength, etc.) of
the received signals to derive positional information about implanted device
D.sub.1. Additional positional information may be provided by a mobile receiver
MR, which may employ directional receiving means DR, and one or more antenna MA.
The mobile receiver MR may be used, for instance, to locate implantable unit
D.sub.1 within a building, a neighborhood, or a small area of wilderness,
facilitating cost effective recovery without having to map the face of the globe
Upon being triggered by signal S.sub.1, implanted device
D.sub.1 preferably transmits only for a brief interval long enough to get a
rough positional fix. When the mobile receiver MR has been dispatched, or other
rescue means have been readied, transmitter T would then re-activate implanted
device D.sub.1 for the second stage of the recovery.
FIG. 2 is a
mechanical and electrical schematic block diagram of an exemplary implantable
triggerable transceiver unit D.sub.1. The entire unit D.sub.1 is housed within a
sealed case and designated 39. The case is preferably made from or covered with
a biologically inert material such as Teflon or Titanium. Several possible
mechanisms are shown. Remote radio receiving means comprise a receiving antenna
2 and micro-power radio receiver/demodulator means 4. The triggering signal
S.sub.1 is received by antenna 2, and the resultant electrical signal is fed to
the micro-power radio receiver/demodulator means 4, which outputs a binary
signal S.sub.3 to signal decoder means 6. The signal decoder means 6 monitors
signal S.sub.3 over time, and upon detecting a certain pre-determined pattern,
sends a trigger signal S.sub.5 to timing circuit means 8. Timing circuit means 8
then applies a control signal S.sub.6 to a power switching means 7, causing
power switching means 7 to apply power from power source 14 to a beacon
transmitter 10, which may broadcast at different power levels, controlled by
signal decoder means 6.
The beacon transmitter 10 operates in response
to being actuated by power source 14, and transmits the locating and tracking
signal S.sub.2 via transmitting antenna 12. Through the incorporation of proper
input protection circuitry on the micro-power receiver 4, it is possible for
receiving antenna 2 and transmitting antenna 12 to be one and the same. These
antennae are shown as being separate in FIG. 2 for functional clarity. The
micro-power receiver means 4 is powered by energy storage means 36. Micro-power
generating means 26 may derive power from some energy source external to the
In the preferred embodiment, micro-power generating
means 26 derives power from physical work done by muscle fibers in the body.
Body muscle 30 is connected (for instance, via suturing) to linkage 28. Linkage
28 connects muscle 30 through a seal in case 39 to micro-power transducing means
26. Case 39 is mechanically anchored to another body structure (for instance
muscle, tendon, bone, etc.) to afford an opposing force to that exerted by
muscle 30. Power transducing means 26 converts the work of muscle 30 to useful
electrical energy, which is fed to energy conversion circuitry 32. Energy
conversion circuitry 32 is provided to most efficiently store the electrical
energy derived from power transducing means 26 in energy storage means 36.
Energy storage means 36 serves as an energy reservoir for micro-power circuitry
34. Micro-power receiver 4 may be implemented similarly to receiver sections
used in miniature commercial pagers. Power transducing means 26 may be a
piezoelectric device (the preferred embodiment), electromagnetic induction
device (such as a moving magnet generator), or the like. Linkage 28 is
preferably sealed to case 40 with a flexible membrane.
means 36 holds enough energy to sustain micro-power circuitry in an operational
state with enough regularity to insure proper triggering of beacon transmitter
10 in response to trigger signal S.sub.1. The duty cycle requirements of the
availability of power from energy storage means 36 may be traded off against the
length of time the activation signal S.sub.1 is sent out. In the preferred
embodiment, there is enough power available from energy reservoir 36 to power
micro-power receiver/demodulator means 4 100% of the time.
Power-switching means 7 is shown as a field-effect transistor, chosen in
the preferred embodiment because it takes no static power to keep turned on,
yielding easy interface with micro-power circuitry, and also allowing a high
degree of integration onto a single chip. Signal decoding circuitry 6 and timing
circuitry 8 are preferably CMOS logic, in order to draw minimal power. Timing
circuitry 8 is preferably powered from power source 14, in order that brief
lapses in the availability of power from energy storage reservoir 36 will not
affect the timing of beacon transmitter 10.
Signal decoder means 6 may
be made capable of detecting multiple codes to perform different functions, for
instance to activate beacon transmitter means 10 for different periods of time.
A short-time actuation might be desirable for an initial positional fix, and a
long-time actuation might be desirable for a final local recovery by a mobile
receiver. It is desirable to have different activation codes result in beacon
transmitter 10 being energized at different power levels, for instance a high
power level for the initial positional fix, where the receiving antennae may be
far away, and a lower power level during the final positional determination by a
Binary conversion means 38 converts the analog signal
derived from power transducing means 26 to a digital signal. In the preferred
embodiment, this enables body muscle 30 to be used to control the implanted
device as well as provide power to the device. Contractions of body muscle 30
cause alternating voltage signal S.sub.5 to be generated and applied to energy
conversion circuitry 32 and binary conversion means 38. For the piezoelectric
power transducing means of the preferred embodiment, binary conversion means 38
may be implemented as a voltage divider means 24 followed by Schmitt trigger
means 22. Binary conversion means 38 is powered by energy storage reservoir 36,
in order to avoid draining the standby power source 14. The output of binary
conversion means 38 feeds an input on signal decoder means 6 with a digital
signal, allowing signal decoder means 6 to be entirely digital CMOS circuitry
such as common in wristwatches, which can be made to draw so little power that
the drain on power source 14 would be inconsequential, even over a number of
Signal decoder 6 may provide different decoding functions for
data streams from different sources. For instance, signal S.sub.4, derived
locally, may be decoded to provide functions not accessible remotely, such as
shutting down micro-power receiving means 4. This may be desirable if the user
is worried about being locatable by an adverse party under certain
circumstances. Partial completion of the trigger code in data stream S.sub.4 may
be programmed to provide a perceivable sensation to the user, for instance
through vibrator means 20. This would provide means for "practicing" triggering
the device without actually sending out a signal indicating an emergency. It is
also possible to configure the device to provide the same or different
perceivable sensation through vibrator means 20 upon activation of Beacon
transmitter 10. This feedback would provide peace of mind to the user, knowing
that help was on the way. Various self-test functions may be implemented through
special codes recognized in signal stream S.sub.4.
Voltage monitor means
16 is provided to detect a low-energy state of power source 14. Voltage monitor
means 16 is preferentially powered off energy reservoir 36, ensuring that the
critical standby power source 16 is not drained by providing the voltage
monitoring function. Voltage monitor means 16 may also activate vibrator means
20 in such a way as to provide a sensation uniquely indicating low power.
It is contemplated that in one embodiment, energy reservoir 36 and power
source 14 would be one and the same. This has not been done in the preferred
embodiment for three reasons: First, the most suitable embodiment of power
source 14 is deemed to be a chemical storage battery with a long (perhaps 10
year) expected shelf life. This ensures that adequate power for beacon
transmitter 10 is available reliably, while taking very little space. Second,
regular "playing" with vibrator means 20 could, in such an instance, result in
substantially draining power source 14 for some period of time. Third,
implementing energy reservoir 36 with a different type of energy storage device
than 14 (for instance, implementing 36 as a capacitor) can allow for increased
charging efficiency over the relatively low electrochemical charging efficiency
of many batteries.
For very long term applications or to reduce the
shelf life requirements on power source 14, voltage regulator means 18 may be
provided to use surplus energy collected from power transducing means 26 to keep
power source 14 optimally charged.
It may be desirable to separate the
receiving and/or transmitting antennae 2 and 12 from the rest of the unit, in
order to allow the antennae to be closer to the surface of the body for more
efficient transmission and reception. Such mechanical alterations to the
containment of the device are within the scope of the present invention.
It is also possible for the conversion circuitry 32 to receive power
from a source external to the body, such as an electromagnetic induction source
that might be placed close to the body on a regular basis for purposes of
recharging energy reservoir 36. In such an embodiment inductive pickup means 40
receives electromagnetic energy from a source external to the body. Such
implementation is considered less desirable because it affords the user less
personal freedom, and results in a system which is less robust overall.
The drawings referred to in the specification are presented in block
diagram form. Numerous possible implementations of any given block will be
apparent to one skilled in the art. Any specific details referred to are
strictly by way of example. It will be readily apparent to one skilled in the
art that various substitutions and modifications can be made without departing
from the spirit of the invention.
* * * * *