US6513252B1 | 2003-02-04 | |||
US6556905B1 | 2003-04-29 | |||
US20070262853A1 | 2007-11-15 | |||
US20060089790A1 | 2006-04-27 | |||
US5654686A | 1997-08-05 |
VIII. CLAIMS What is claimed is: 1. An apparatus to detect movement of a protected craft, comprising: A) at least one compass sensor assembly capable of generating a first signal that is a function of the angular displacement of the axis of said compass sensor assembly from the earth's magnetic field; and B) at least one main electronic circuit board capable of receiving said first signal, including means for determining a strength difference between said first signal and a fixed value, and further including means for sending a second signal to at least one control circuit board to activate at least one security action. 2. The apparatus of claim 1 wherein said strength difference is processed by at least one microprocessor having means for storing data and instructions to compare said strength difference with preprogrammed values. 3. The apparatus of claim 2 wherein said compass sensor assembly includes a circuit for tilt compensation. 4. The apparatus of claim 3 wherein said compass sensor assembly is selected from the group consisting of sensors using flux-gate magnetometers, magneto-inductive magnetometers, anisotropic magneto- resistive sensors, giant magneto-resistive devices, analog sensors, and Hall Effect technology. 5. The apparatus of claim 4 wherein said compass sensor assembly is able to detect a magnetic field change selected from the group consisting of direction, presence, rotation, and angle. 6. The apparatus of claim 5 further comprising at least one keypad as an input device for said at least one microprocessor. 7. The apparatus of claim 6 wherein said security actions are selected from group consisting of turn on/off lights, turn doors on/off, turn windows on/off, cut power on/off, turn on a siren, turn on horn, turn off engine, turn off fuel pump, locking power steering, calling a pager, calling a phone number, sending text over a telephone network and sending a signal to the internet. 8. A method for detecting movement of protected crafts comprising the steps of: A) establishing a reference signal strength value for an original axial position with respect to the earth's magnetic field of a protected craft by generating a signal output of a compass sensor assembly; B) periodically measuring the strength of the signal output of said compass sensor assembly corresponding to the current position signal and generating a strength difference value with respect to said reference signal strength value; C) comparing said strength difference value with predetermined values to generate an alarm output signal upon reaching or exceeding at least one of said predetermined values; D) processing said alarm output signal by a least one electronic board; and E) receiving said processed alarm output signal by a control circuit board to trigger at least one security action in an alarm system. 9. The method of claim 8 wherein said magnetic variation is comprised of a change selected form the group consisting of direction, presence, rotation, and angle. 10. The method of claim 9, wherein said control board's security actions are selected from group consisting of turn on/off lights, turn doors on/off, turn windows on/off, cut power on/off, turn on a siren, turn horn on, turn off engine, turn if fuel pump, locking power steering, calling a pager, calling a phone number, sending text over a telephone network and sending a signal to the internet. 11. The method of claim 10 wherein said compass sensor assembly is selected from the group consisting of sensors using flux-gate magnetometers, magneto-inductive magnetometers, anisotropic magneto- resistive sensor, giant magneto-resistive devices, analog sensors, and Hall Effect technology. |
II. TECHNICAL FIELD 1. Field of the Invention.
[001] The disclosure relates to the art of alarm systems.
III. BACKGROUND ART
[002] The need to protect valuables has been responsible for the design of numerous devices. Those that detect their unauthorized movement typically rely on a relatively large displacement from the original position. This may be too late. The present invention detects unauthorized rotational movements, which occur early in the commission of the wrong. Mobile transportation theft, for example, is a major problem. Some experts report that the aforementioned vehicles are stolen in the United States every 10 seconds, while others say it's one every 15 seconds. No matter which figure is correct, it still adds up to a lot of missing cars, boats and jet skies, and a lot of unhappy owners.
[003] In order to prevent the theft epidemic, the automobile industry, for example, has begun to manufacture a wide variety of alarm systems. For at least 25 years, alarms have been extremely popular, and have only become more innovative as time goes on. Because not every break-in is exactly the same, the alarm industry has devised various ways to trigger them. Some of them include door, shock, window, pressure, and tilt sensors. Door sensors trigger it if the door, trunk, or hood is opened. With shock sensors, the alarm sounds a siren if the body of the vehicle is moved or jiggled. Window sensors trigger an alarm if a window is broken. Pressure sensors are activated when the air pressure inside the vehicle is changed. Tilt sensors, deters thieves who do not even try to drive your motorcycle away, but instead attempt to load it up onto a tow truck and cart it away whole. When the bike or car is tilted to a certain degree, the alarm will sound. Most alarms today do not rely solely on one of the above types of sensors and state-of-the-art packages usually combine several types together to make your vehicle safer from theft.
[004] Some of the issues that the alarms have are that the alarm systems are too sensitive, or not "smart" enough to determine what is really a theft attempt and what is a strong wind, a thunderstorm, a wandering dog, or a child on a bike riding unsteadily by. To the point that alarm systems have become ineffective because no one really pays attention to alarms anymore. When they are triggered all the time for the slightest thing, they are not really the deterrent they intended to be. Another problem with vehicle alarms is that thieves are continually coming up with new ways to work around alarm systems, almost faster than alarm manufacturers can make systems with new features.
[005] Nowadays, more and more automobile makers are not installing car alarm systems and moving on to car immobilizers. Better and much more than just a loud siren or flashing lights, immobilizers are an improvement because they rely on computer chips in your car key, or even a hidden switch or button in your car, these immobilizers will prevent the car from being hot-wired or started in any other manual way. The problem with these systems is that losing a key with the chip inside will deprive the owner of a couple of days of use until a new key with the coded chip is expensively replaced. But if the thief gets a hold of the key with the chip, the owner is out of luck.
[006] There is a need in the alarm industry to manufacture an alarm system that is smart and reliable. The needed alarm system needs to detect that the wrongdoer is actually moving the vehicle away thus solving the false alarm/trigger concerns mentioned above. Moreover, in the alarm system arts, it would be desirable to progress from the computer chip in the key systems to systems that will detect that the actual vehicle is moving away. There is also further need to make these alarm systems detect the difference between movements that are caused by wind, water and animals from what is really a theft attempt.
[007] There is also a further need in the alarm system arts to provide for an alarm system for vessels on water that is not based on proximity check and is able to be mounted on any small vessel, even far way from the coast line, and that does not rely on a fixed hub to trigger the alarm. The improved system further solves the issue of false alarm because of unavoidable movements of currents and wind. In proximity check systems, the alarm is triggered only after the protected craft has moved a predetermined distance.
[008] More and more of the latest models of mobile phones are being equipped with such functions as GPS location indicators and navigation systems. Mobile phones with these functions make navigation easy because, in contrast to ordinary maps that use "north" as a point of reference, these systems use the direction the user is facing as the point of reference. In order to provide this function, these devices require a geomagnetic sensor to detect the direction in which users are moving. [009] Mobile phones are not usually held parallel to the earth during usage, but rather slightly tilted upward. Consequently, there is a demand for devices that are able to compensate for this tilt, in order to accurately indicate a user's location while maintaining ease of use.
[010] None of the present systems in use suggest the novel features of the present invention.
IV. SUMMARY OF THE INVENTION
[011] The present technology provides an alarm system that is triggered by a change relative to the earth's magnetic field.
[012] The present invention provides an alarm system that alerts a user upon an angular movement of the protected craft, even if it stays in position and optionally with tilt compensation features.
[013] It is yet another object of this present invention to provide such a device that is inexpensive to manufacture and maintain while retaining its effectiveness.
[014] Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. V. BRIEF DESCRIPTION OF THE DRAWINGS
[015] The foregoing summary, as well as the following detailed description of the technology, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the technology, they are shown in the embodiments, which are presently preferred. It should be understood, however, that the technology is not limited to the precise arrangements and instrumentalities shown. In the drawings:
Figure 1 depicts one embodiment of the technology, which comprises the alarm system in a block diagram.
Figure IA is a block diagram representation of an alternate embodiment including tilt compensation.
Figure 2 depicts one embodiment of the technology where the alarm system is used in one type of vehicle, namely, a vessel on water.
Figure 3 depicts one embodiment of the technology where the alarm system is used in one type of vehicle, namely, a car.
Figure 4 depicts on embodiment of the technology where the alarm system is used in one type of vehicle, namely, a vessel mounted to a trailer on land.
Figure 5 depicts one embodiment of an electronic compass sensor circuit and attached electronics. Figure 5A shows an alternate embodiment for the compass sensor circuit with tilt compensation.
Figure 6 depicts one embodiment of a main electronic circuit.
Figure 7 depicts one embodiment of a vehicle electronic control circuit.
Figure 7A shows an alternate embodiment encompassing the circuits shown in figures 6 and 7 and implementing some of the functions with software.
Figure 8 depicts one embodiment of a remote control board.
Figure 9 depicts one embodiment of an electronic keypad.
Figure 10 depicts one embodiment of the inventive method of the alarm system in a block diagram as an analog system.
Figure 11 depicts one embodiment of the inventive method of the alarm system in a block diagram as a digital system.
VI. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[016] The present technology eliminates the aforementioned challenges by using at least one electronic compass sensor circuit 102, electronic keypad 106, power supply 101, main electronic circuit 103, and electronic control circuit 104, to create a digitally based alarm system 100, as generally depicted in figure 1. The alarm system 100 is meant for moving objects to be protected, which will be referred to as crafts in general, which include bicycles, cars, motorcycles, trains, ships, boats, aircrafts, and others including movable containers. In this application, these objects will generally be referred to as "crafts". The magnetic based alarm system 100 described herein uses the earth's magnetic field 203 as a reference to compare the angular difference with axis 204 (the original resting position) and an unauthorized horizontal angular motion caused by the thief is detected, as shown in figure 2. The system comprises a magnetic field based alarm that provides for a magnetic angle that allows for some angular movement during high wind or animal movement and will only trigger the alarm when the vehicle moves to a pre-set angle therefore sensing a true theft attempt. The alarm is based on the earth's magnetic field therefore being able to be used independently anywhere and at any time. The alarm will trigger a signal to create security actions 901, which in turn will advise the user of the system that a theft attempt has occurred. Electronic compass sensor circuit 102 is represented in figure 5. An alternate embodiment is shown in figure 5A and is referenced with primed numeral 102' and includes tilt compensation.
[017] Figure 10 depicts in more detail the inventive method and concept of the system 100. The method comprises steps for determining at least one mismatch or difference between a first signal (current position) and a fixed value, V f , and further sending a second signal to at least one control circuit 104 to activate at least one security action. The first signal is sensed by at least one electronic compass sensor circuit 102. The electronic compass sensor circuit 102 includes an axis for reference. The magnetic signal may be caused by direction 902, presence 903, rotation 904, current 905, and angle 906. The first signal created by sensor circuit 102 is sequentially amplified by at least one electronic amplifier 502. The signal further processed/compared by a least one electronic circuit 103 and finally a vehicle control circuit 104 receives the processed signal variation to trigger an alarm system 100. By designing the alarm system to respond to a predetermined unauthorized motion magnitude by means of at least one electronic compass sensor circuit 102, processed signals (the strength of the signals can be voltage or current with respective differences or mismatch or variations) will be produced and sent to at least one main electronic circuit 103 and finally a series of actions 901 would take place as directed by the control circuit 104. Among the actions 901 that could be engaged is an audible alarm 701, as shown in figure 7. Equivalent actions can use a strobe alarm light or lights, disconnection of certain functions of the vehicle, such as engine starting, fuel flow, and, at the same time phone, call or internet automatic calling.
[018] The system 100 comprises compass sensor circuit 102, which depending on its physical orientation with axis 204 at the moment, will produce a voltage or current that will amount to a value particular to the initial or angular orientation 206 relative to the earth's magnetic field 203. The compass sensor circuit 102 is further connected to a power supply 101, a main electronic circuit 103 or processor board, and a keypad 106 or remote ON/OFF hand held switch, as seen in figure 9. When appropriate, a back up battery will also be installed as part of the system. Upon activating the system (arming the system) using keypad 106, the initial or angular orientation 206 of the compass is fixed to the protected craft, for example 201, 301 or 401, as shown in figures 2, 3, and 4. Any horizontal angular motion beyond a specified selected number of degrees will trigger the alarm circuit. Other input devices can be used to provide functions equivalent to those provided by keypad 106, such as remote arming devices.
[019] In at least one embodiment of the technology, keypad 106 is implemented with a commercially available electronic-type keypad. A safety code or password is selected by the owner. The keypad 106 is comprised of an independent memory system in case there is a problem with the power supply 101. The default, in one of the embodiments, in case of a power outage is that the system 100 automatically adopts its initial ARMED state. The main electronic circuit 103, in one of the embodiments, is made out of four logic "NOR" gates 601, several transistors 602, and other electrical and electronic components, as depicted in figure 6. Circuit 103 is designed to receive the voltage output Vo coming from the electronic compass sensor circuit 102 relative to the earth's magnetic field 203 and compare it to a fixed voltage V f value established as a reference when the system is turned ON (ARMED). A mismatch or difference in voltage, ΔV, is detected when a V 0 value at a given position is compared to a V f . V 0 will vary if the axis of the protected craft is rotated. If the difference in voltage (ΔV) is greater than a predetermined magnitude, then a second signal is sent to circuit 104. Circuit 104 also maintains the ARMED/DISARMED condition of the alarm system. [020] In at least one embodiment of the technology, electronic compass sensor circuit 102 detects the initial or angular orientation 206 (position) of the vehicle in its original resting position 204 and compared to the earth's magnetic field 203 sending a particular voltage output value V 0 to the main electronic circuit 103 for its processing and this initial measurement for V 0 is designated a reference voltage for a fixed (initial) position as V f . The compass sensor circuit 102 is connected to an operational amplifier 502, a timer chip 503, and several transistors 504, as depicted in figure 5, in order to produce the desired output signal results. If the craft is moved a certain pre-selected number of degrees, the electronic compass sensor circuit 102 will send a first signal voltage to the main electronic circuit 103 which determines if the voltage mismatch is such as to activate the alarm. As a complement, but not deviating from the main concept of the disclosed technology, a number of magnetic contact sensors 105 could be installed on doors and windows in addition to the electronic compass sensor circuit 102, which would then be part of the alarm system 100. The condition of the magnetic sensors 105 would also be processed by the main electronic circuit 103 to trigger the alarm.
[021] As mentioned above, in one embodiment of the technology, several magnetic sensors 105 are connected to the main circuit 103. They are sensors typically used for home security systems. These protective devices monitor the opening and closure of doors and windows 107 in the vehicle. Usually, each magnetic contact features a connection for a hardwired or wireless sensor input, making it ideal for protecting multiple windows 107 using standard contacts. In at least one embodiment of the technology, a Visonic MCT-302 sensor is used and placed on the vehicles doors. The wireless version is enabled with a unique ID code, and each magnetic door and window contact is available in several frequencies. Discreetly placed magnetic sensors 105 throughout the protected vehicle prevent breaches in opening and closing of doorways and windows. By making the magnetic sensors 105 a closed circuit, if any of the sensors are opened, the alarm is also triggered.
[022] The power supply 101 is composed of batteries of vehicles, usually 12 volts, or the system 100 also could have a separate battery. In the vehicle electronic control circuit 104, two voltage regulators are used, one of which is used to stabilize the voltage coming from the batteries and therefore powering the circuits, which requires 12 volts. The main electronic circuit 103 will take 12 volts and will convert it into 5 volts, which is needed to power the electronic compass sensor circuit 102. Several capacitors are used to stabilize and filter the different parasitic (noise) currents coming from other sources. The vehicle electronic control circuit 104 includes several relays 505 and also a timer chip 503, which will give time for turning on and off the lights of the vehicle as well as the audible alarm or horn 701, as depicted in figure 7. This is the circuit that makes sure that the vehicle does not continue with the normal navigation course. This electronic control circuit 104 will also cut the ignition to the engine as soon as the alarm is triggered by sensor circuit 102. At the same time, the lights will turn on and off in order to signal a theft attempt.
[023] Keypad 106 can be any commercially available keypad that allows for the owner to codify the code that engages the alarm system 100. It preferably needs to use a ROM based chip set that keeps into memory since data stored in ROM cannot be modified (at least not very quickly or easily). ROM refers to such types such as EPROM and flash EEPROM that can be erased and re-programmed multiple times, but do not get erased if the power is turned off or cables are cut off. [024] In one embodiment of the technology, main electronic circuit 103 comprises four logic gates 601, NOR gates. Main electronic circuit 103 further comprises several transistors and other components, as depicted in figure 6. This circuit detects any signal or voltage coming from electronic compass sensor circuit 102 and magnetic sensors 105 and, at the same time, maintains the alarm in the status ARMED or DISARMED, i.e. ON or OFF positions. If alarm system 100 is placed in the ON position after time (t) has passed, system 100 turns ARMED/ON, and now, as soon as the main electronic circuit 103 senses a difference in the voltage provided by any of the sensors 105 or circuit 102, the alarm will be triggered. By the triggering of the alarm, control circuit 104 will then be activated and circuit 104 will disrupt the preprogrammed task or security action 901, such as demobilizing the vehicle by cutting the power, locking the power steering or cutting power to the fuel pump, or turning off the engine(s). Circuit 104 will normalize and turn the aforementioned circuits on as soon as the proper code is entered into keypad 106.
[025] The electronic compass sensor circuit 102 is the main sensor of the alarm system 100. After setting the alarm system 100 into the ARMED or ON position by entering the code in keypad 106, the compass sensor circuit 102, after a set time period (in order to allow for the exiting of the vehicle), measures or finds the magnetic position 204 that the vehicle was left in originally relative to the earth's magnetic field 203. The electronic compass sensor circuit 102 measures the voltage between the earth's magnetic field 203 and the magnetic position 204 (depicted in figures 2-4 as angle θ 206 or angular orientation), converts it into a first signal, and feeds it to the main electronic circuit 103. This signal is equal to a voltage created by this angular position VQ , which in turn is the armed voltage, which also has a preset error margin of (θ = +/- A) degrees in order to allow for the vehicle to move slightly, thus solving the false alarm/trigger concerns mentioned above. If the vehicle moves more than (+) plus or (-) minus a pre-set number of large degrees B or (θ = +/- (A+B)) compared to a fixed voltage V f (a value established as a reference in the system), a mismatch voltage (ΔV) is created. If the mismatch voltage (ΔV) is greater than V f then the greater change in voltage V L will be sent to the main electronic circuit 103, which will trigger the alarm. By allowing some angular flexibility of (θ = +/- A) degrees, this allows for some movement during high wind or animal movement and will only trigger the alarm when sensing a true theft attempt, i.e. a large movement in the vehicle.
[026] In one embodiment of the technology, an electronic compass sensor circuit 102 manufactured by The Robson Company Inc., 227 Hathaway Street, Suite E, Gerard, PA 16417, trademarked Dinsmore Sensor, was used. The model 1490 magnetically indicates the four Cardinal directions (N., E, S., W.) and, by overlapping the four Cardinal directions, shows the four intermediate directions (NE, NW, SE, SW). The electronic compass sensor circuit 102 sends the angular information by measuring the earth's magnetic field using Hall-Effect technology. The sensor circuit 102 is internally designed to respond to directional change similar to a liquid filled compass. The sensor circuit 102 is able to operate tilted up to 12 degrees with an acceptable error margin. It is easily interfaced to digital circuitry, such as in the main electronic circuit 103 and microprocessors, using only pull-up resistors, as depicted in figure 5. The electronic compass sensor circuit 102 is designed to indicate the direction of the horizontal flux pattern (compass component) of the earth's field 203. Sensor circuit 102 is operated from an input voltage of 5 to 20 volts DC. Input is both spike and polarity protected. The current requirement is approximately 30 mA (0.030 amps).
[027] An alternate embodiment for electronic compass sensor circuit 102 is referred to with numeral 102' in figure 5A. Circuit 102' is implemented with an integrated circuit like those manufactured by Honeywell International, Inc., 101 Columbia Road, Morristown, NJ 07962 (www.honeywell.com) under No. HMC 6343 for a 3-axis compass with algorithms. Circuit 102' provides an output to alternate main electronic circuit 103' that incorporates the functions of circuits 103 and 104. Circuit 103' is represented in figure 7A and is discussed below. With this alternate embodiment, the accuracy of the system is improved by compensating for tilting factors, which are common in different crafts, especially boats since they are subject to movement created by waves.
[028] Circuit 103' includes a digital output derived from a differential voltage output that is a function of the direction of a reference axis with respect to the earth's magnetic field direction. Circuit 103' includes an internal microprocessor and associated storage to perform different functions such as correlation of the earth's magnetic north with the earth's geographic north in different parts of the world. The digital output of circuit 103' provides a continuous stream of data with the option to include different addresses for the master or host device, which in this case is circuit 103'.
[029] In the alternate embodiment, combined main and control circuit 103', represented in figure 7A, includes microprocessor 31, which can be implemented with a device marketed under the brand Propeller by Parallax, Inc. located at 599 Menlo Drive, Rocklin, California 95765. The "Propeller" microprocessor from Parallax Inc. performs all the primary control features of the Lookout device. It includes:
1. Monitoring and comparing current location to stored location.
2. Collect heading data from compass device.
3. Output device information to NTCS video.
4. Creating audio tones corresponding to system status and user interaction.
5. Control the internal relay based on system status.
6. Operate and interface with the PS/2 Keyboard/Keypad input device which provides textual input to the user.
7. Communication and control of Cellular and GPS devices via a serial interface.
[030] Microprocessor 31 is cooperatively connected with storage assembly 34 where data and instructions are stored to perform the necessary computer functions. Storage assembly 34 can be implemented with a serial electrically erasable PROM such as IC24LC256 manufactured by Microchip Technology, Inc, 2355 West Chandler Blvd., Chandler AZ 85224-6199. An input/output clocked serial data bus 32 (identified with letters A and B in figure 7A) is connected to circuit 102'. Circuit 103' is provided with another input 33 connected to output 35 of transceiver assembly 36 that can be implemented with an integrated circuit marketed under the No. ICL 3232 CP by Intersil Corp., located at 1001 Murphy Ranch Road, Milpitas, California 95035. From transceiver assembly 36, a post 37 in turn is connected to RS-232 port 38 to receive position information from a suitable device such as a GPS device.
[031] The sensors used for the magnetic based alarm system 100 are those typically selected from the group consisting of a range of 1 μG to 10 G, which equals the earth's field sensors or medium-field sensors. The magnetic range of medium- field sensors lends itself well to using the earth's magnetic field to determine compass headings for navigation, vehicle sensing, and measuring the derivative of the change in field. In this magnetic range, for example, the flux-gate magnetometer is the most widely used sensor for compass-based navigation systems. One of the most common types, called the second harmonic device, incorporates two coils, a primary and a secondary, wrapped around a common high- permeability ferromagnetic core. Another example used for this magnetic range is the magneto-inductive magnetometers, which is simply a single winding coil on a ferromagnetic core that changes permeability within the earth's field. The coil is the inductance element in an L/R relaxation oscillator. The oscillator's frequency is proportional to the field being measured. A static DC current is used to bias the coil in a linear region of operation. As the sensor is rotated 90° from the applied magnetic field, the observed frequency shift can be as much as 100%.
[032] In another embodiment of the technology, an anisotropic magneto-resistive (AMR) sensor is used as electronic compass sensor circuit 102. AMR sensors are well suited for measuring both linear and angular position and displacement in the earth's magnetic field. These devices are made of a nickel-iron thin film deposited on a silicon wafer and patterned as a resistive strip. The film's properties cause it to change resistance by 2%-3% in the presence of a magnetic field. In a typical configuration, four of these resistors are connected in a Wheatstone bridge to permit measurement of both field magnitude and direction along a single axis. The bandwidth is usually in the 1-5 MHz range. The reaction of the magneto-resistive effect is very fast and not limited by coils or oscillating frequencies. Another example of similar technology is the giant magneto- resistive (GMR) device. Large magnetic field dependent changes in resistance are possible in thin film ferromagnetic/nonmagnetic metallic multi-layers. Although not preferred, it would be equivalent to a person skilled in the art to manufacture a magnetic based alarm system 100 using magneto-resistive sensors such as AMR and GMR in substantially the same way and for the same purpose to obtain the same measuring result. In yet another embodiment of the technology, two analog sensors, Model 1525 and Model 1655, manufactured by The Robson Company Inc., Dinsmore Sensore Division, are used. The output is a sine-cosine curve voltage, which may be interpreted by a microprocessor, graphs, or other simple systems into directional information. This offers finite measurement capabilities in a directional application such as the one for a magnetic field based alarm system 100. Although analog sensors are not preferred, a person skilled in the art may also use them for substantially same the purpose to obtain substantially the same result.
[033] In at least one of the embodiments, the electronic compass sensor circuit 102 used is made using Hall Effect semiconductor technology. The Hall Effect is a consequence of the Lorentz force in semiconductor materials. When a voltage is applied from one end of a slab of semiconductor material to the other, charge carriers begin to flow. If at the same time a magnetic field (such as the earth's 203) is applied perpendicular to the slab, the current carriers are deflected to the side by the Lorentz force. Charge builds up along the side until the resulting electrical field produces a force on the charged particle sufficient to counteract the Lorentz force. This voltage across the slab perpendicular to the applied voltage is called the Hall voltage. It is the Hall voltage that is measured by the electronic compass sensor circuit 102 created by this angular position V 0 , which in turn is the ARMED voltage of the alarm system 100 sent to the main electronic circuit 103. Hall sensors typically use n-type silicon or GaAs for higher temperature capability due to its larger band gap. In addition, InAs, InSb, and other semiconductor materials are also used due to their high carrier mobility that result in greater sensitivity and frequency response capabilities above the 10-20 kHz typical of Si Hall sensors.
[034] In the alarm system, the aforementioned electronic compass sensor circuit 102 is connected to at least one operational amplifier 502, further connected to at least one timer chip 503, and yet further connected to at least one transistor 504, several gates, resistors, and at least one relay 505. In at least one embodiment of the technology, the said electronic components are arranged as depicted in figure 5 in order to process and respond the signals from the compass sensor circuit 102. The vehicle electronic control will then activate several security actions 901. The actions comprise air horns (these are sometimes found on the inside of the vehicle and call attention to the burglar), carjack protection (which will cause the engine to turn off and a siren to blare on your vehicle), door lock/unlock, power locks on the automobile to be operated by the alarm, starterkill (this will kill the ignition or starter of the vehicle when the alarm is activated so the thief can not go anywhere), flashing lights (with some alarm systems, the car headlights or parking lights will flash when the alarm is triggered), pagers (pagers will flash or sound off to let you know when your car alarm is triggered), and other equivalent actions.
[035] In another embodiment of the technology, a digital setup is arranged, as depicted in figure 11. The digital setup comprises at least one microprocessor 1101 which further comprises at least one actual position register 1102, at least one positional lock register 1103, at least one set- point difference 1104, at least one calculated difference register 1105, and a deviation set-point alarm output 1106 component. A HONEYWELL electronic compass sensor circuit HMC6532 102 is connected to the microprocessor 1101 through a 12C serial protocol cable. The microprocessor 1101 will receive the signals from the electronic compass sensor circuit 102, which reads the angular orientation 206 in relation to the earth's magnetic field 203 and monitor as actual position register 1102. The microprocessor 1101 will fix the position at the time of heading lock or when the user activates the alarm system in the positional lock register 1103. This value will then be compared as to a set point difference 1104 and calculated and stored in the calculated difference register 1105 and a deviation set-point alarm output 1106 will be added to this calculated difference register 1105. The microprocessor will continuously read values form the digital compass sensor circuit 102 and compare them to the deviation value by way of binary subtraction. Once a difference value 1104 is reached an output on the microprocessor will be sent and security actions 901 will be activated.
[036] The inventive technology described in figure 9 may also be attached to a vehicle tracking system; thus, if the vehicle is stolen or lost, the system manufacturer can track its whereabouts by satellite and find it quickly, usually within hours. Further attachments are, for example, the active re-arm feature, which means when the alarm has been disarmed, the alarm will automatically re-arm after a certain amount of time if a door is never opened. This prevents accidental disarms. The system 100 will automatically arm itself after the vehicle is turned off and the doors are all closed. The owners never have to remember whether or not they turned on the alarm for the car. The technology disclosed herein is especially suited for vessels on water. The technology is not based on proximity and is able to be mounted on any smaller vessel far way from the coastline that does not rely on a fixed hub or dock 207 to trigger the alarm. By giving the system some angular flexibility, it further solves the issue of false alarms caused by unavoidable movements of currents and wind while the vessel is docked.
[037] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this technology is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present technology.
VII. INDUSTRIAL APPLICABILITY
[038] It is apparent from the previous paragraphs that an earth magnetic field based alarm system is quite desirable for applications where the system is not dependent exclusively on the changes in position of the protected craft or object.