Abstract:
The present invention is directed to a security apparatus for a firearm including a frame, a power source, a firing chamber adapted to receive a round of ammunition having a primer oriented adjacent a distal end thereof, and a trigger assembly for selectively initiating communication between an ignition system and the primer. The security apparatus further comprises an authorization device for selectively generating a pass signal indicating that an operator of the firearm is an authorized operator, and a firearm sensor for selectively generating a control parameter signal indicating an operational mode of the firearm. An electronically programmable locking device receives the authorization signal and the control parameter signal, and permits communication between the ignition system and the primer only if the authorization signal generates the pass signal and the control parameter signal indicates the firearm is in a standby mode.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of pending U.S. application Ser. No. 09/206,013, filed Dec. 4, 1998, herein incorporated by reference in its entirety, and further some of the material disclosed herein is disclosed and claimed in the following pending U.S. patent application Ser. No. 09/205,391, filed Dec. 4, 1998, entitled “FIRE CONTROL SYSTEM FOR NON-IMPACT FIRED AMMUNITION”, which is commonly assigned to the owner of the present application. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains generally to firearms, and more particularly to firearms having an integrated security apparatus. 
     BACKGROUND OF THE INVENTION 
     In conventional firearms, either a striker or a hammer and firing pin is provided for detonating percussion primers. Although many advances in conventional firearm design have been made over the years, the underlying principle of ignition by impact is based on technology essentially optimized in the last century. Percussion primers in today&#39;s ammunition and the complexity of moving parts in a firearm having a mechanical fire control system are key design constraints in implementing significant improvements in safety, performance and reliability using conventional technology. 
     The complexity of moving parts in a mechanical fire control system is especially problematic in a handgun having multiple chambers, such as a revolver, in which a cylinder is rotatable about its centerline on a center pin, and pivotable on a yoke in order to insert and remove the cartridges. 
     Although electronic components have been designed into the ignition systems of firearms, generally the electrical components either supplement or displace existing parts of the mechanical firing mechanism. The percussion primer is still detonated in the conventional manner, e.g., by impact from a firing pin or striker. U.S. Pat. No. 4,793,085 Electronic Firing System for Target Pistol, for example, shows a pistol in which a mechanical trigger bar is displaced by a solenoid. U.S. Pat. No. 5,704,153 Firearm Battery and Control Module describes a firearm incorporating a microprocessor in an ignition system for a firearm using conventional percussion primers. 
     Electronic safety mechanisms have been developed for use in revolvers as well as pistols, as illustrated in U.S. Pat. No. 4,970,819 Firearm Safety System and Method, in which actuation of the firing mechanism is blocked until a grip pattern sensing means on the handgrip of the firearm provides a signal to a microprocessor that corresponds to a prestored grip pattern. Typically, however, the electronic safety system of the &#39;819 patent adds an additional layer of complexity to the revolver, by blocking but not replacing, the conventional mechanical firing mechanism for firing percussion primers. 
     Electronics have also been designed into ignition systems for firearms that use non-conventional primers and cartridges. U.S. Patent No. 3,650,174 for Electronic Ignition System for Firearms describes an electronic control system for firing electrically primed ammunition. The electronic control of the &#39;174 patent, however, is hard-wired and lacks the multiple sensor interfaces or the programmable central processing unit that is found with the present invention. U.S. Pat. No. 5,625,972 for a Gun With Electrically Fired Cartridge describes an electrically fired gun in which a heat-sensitive primer is ignited by a voltage induced across a fuse wire extending through the primer. U.S. Pat. No. 5,272,828 for Combined Cartridge Magazine and Power Supply for a Firearm shows a laser ignited primer in which an optically transparent plug or window is centered in the case of the cartridge to permit laser ignition of the primer. Power requirements and availability of fused and/or laser ignited primers are problematic however. 
     U.S. Pat. No. 5,755,056, for Electronic Firearm and Process for Controlling an Electronic Firearm shows a firearm for firing electrically activated ammunition having a round sensor, and a bolt position sensor. The technology of the &#39;056 patent, however, is limited to a firearm with a bolt action. 
     OBJECT AND SUMMARY OF THE INVENTION 
     It is one of the objects of the present invention to provide a gun capable of achieving major improvements in performance and safety through the use of an all electronic fire control system that has the capability to interface with a wide variety of safety and fault detection sensors and to integrate the sensor data to verify authorized and safe firing conditions prior to ignition. 
     It is a further object of the present invention to utilize a security apparatus of a firearm to verify that a proposed operator is authorized to fire the firearm. 
     It is a further object of the present invention to utilize the security apparatus of a firearm to verify that a plurality of firearm sensor parameters indicate that the firearm is in a firing mode. 
     It is a further object of the present invention that the security apparatus will not enable firing of the firearm unless the operator is an authorized operator and the firearm is in a firing mode. 
     It is a further object of the present invention that the security apparatus prohibits generation of a firing signal until it is verified that the operator is an authorized operator and the firearm is in a firing mode. 
     It is a further object of this invention to provide a firearm with superior performance by eliminating the mechanical forces associated with the mechanical linkages and the impact fired ammunition, which tend to pull the firearm off target. 
     Another object of the present invention is to provide a firearm having an electronic fire control system with all of the aforementioned safety and diagnostic features that can be implemented in either a pistol, a revolver, or a multiple chambered firearm. 
     Still another object of the present invention to is provide a firearm of the foregoing type which is adaptable for use with several types of ammunition, including electrically fired, optically fired and other types of direct energy initiated ammunition. 
     The present invention is directed to a security apparatus for a firearm including a frame, a power source, a firing chamber adapted to receive a round of ammunition having a primer oriented adjacent a distal end thereof, and a trigger assembly for selectively initiating communication between an ignition system and the primer. The security apparatus further comprises an authorization device for selectively generating a pass signal indicating that an operator of the firearm is an authorized operator, and a firearm sensor for selectively generating a control parameter signal indicating an operational mode of the firearm. 
     An electronically programmable locking device receives the authorization signal and the control parameter signal, wherein the programmable locking device permits communication between the ignition system and the primer only if the authorization signal generates the pass signal and the control parameter signal indicates the firearm is in a standby mode. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of a firearm used with ammunition having electrically ignitable primer; 
     FIG. 2 is a schematic illustration of an ignition system having an electronic control; 
     FIG. 3 is an elevational view of a pistol having an electronic fire control system of the present invention; 
     FIG. 4A is a schematic illustration of a fingerprint apparatus provided with the firearm of FIG. 3; 
     FIG. 4B is a typical fingerprint pattern read by the fingerprint apparatus of FIG. 4; 
     FIG. 5 is a block diagram of an electronic control system of the present invention; 
     FIG. 6 is a block diagram of a preferred embodiment of a user authorization device adaptable for use with the present invention; 
     FIG. 7 is an elevational view of a mock magazine used as an authorization key; 
     FIG. 7A illustrates a series of selector switches positioned on a bottom surface of the mock magazine show in FIG. 7; 
     FIG. 7B is a schematic illustration of an alternative embodiment of the selector switches of FIG. 7A; 
     FIG. 8 is a block diagram of a power supply system of the electronic control system of the present invention; 
     FIG. 9 is a block diagram of an ignition system of the electronic control system of FIG. 5; 
     FIG. 10 is a block diagram of a rear grip sensor utilized with the present firearm; 
     FIG. 11 is a block diagram of an information display system utilized in the firearm of the present invention; 
     FIG. 12 depicts icons used by the information display system of FIG. 11; 
     FIG. 13 is a high level block diagram of a control algorithm used with the present firearm; 
     FIG. 14 depicts an algorithm for a cold start routine used in the control algorithm of FIG. 13; 
     FIG. 15 depicts another algorithm used with the control algorithm of FIG. 13, when a positive grip sense interrupt is detected; 
     FIG. 16 depicts a User Authorization algorithm used with the control algorithm of FIG. 13; 
     FIG. 17 depicts a Trigger Initiation algorithm used with the control algorithm of FIG. 13; 
     FIG. 18 depicts a Negative Grip Sense algorithm used with the control algorithm of FIG. 13; 
     FIG. 19 is a schematic view of a multiple chambered handgun having an electronic fire control system; 
     FIG. 20 is a schematic front view of the firearm of FIG. 19 in an ‘open’ position; 
     FIG. 21 is a schematic rear view of the firearm of FIG. 19 in an ‘open’ position; 
     FIG. 22 is a schematic view of a revolver having the electronic control system of the present invention; and 
     FIG. 23 is a schematic view of the revolver of FIG. 22 in an ‘open’ position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Recently developed reliable, chemically conductive, non-impact primers, such as the Conductive Primer Mix™ developed by Remington Arms Company and described in U.S. Pat. No. 5,646,367, are suitable for small arms such as rifles, handguns and shotguns. These non-impact primers have made possible the development of a fully electronic, microprocessor controlled firearm of the present invention. Significant improvement in the reliability and accuracy of powder detonation are achieved by eliminating the requirement for an electromechanical interface between the electronic control and the ammunition. As seen hereinafter, the non-impact primers allow for implementation of a wide range of new safety features, including self-diagnostics, and intelligent sensing of such inputs as biometric authorization, safe firing conditions, and ammunition presence. 
     Referring to FIG. 1, in a firearm of the present invention, when a trigger  10  is pulled, a transfer bar  12 , or equivalent transfer device, activates trigger detection circuitry  11  within an electronic ignition system  15 . In the preferred embodiment, the trigger detection circuitry  11  uses two high reliability trigger switches  14 , 16 . The electronic ignition system  15  of the present invention is programmed to deliver an electrical signal  17  to a round of ammunition  5  having a chemically conductive non-impact primer  24  only if safe and authorized firing conditions have been detected. 
     To simulate the feel of a mechanical trigger, a spring resistance is incorporated into the mechanical linkage between the trigger and the trigger switches. In the preferred embodiment, the spring resistance is a force of 3-4 lbs. over approximately 0.150 to 0.200 inches of trigger travel or until the trigger switches are activated. At the transition point, when the trigger switches are activated, the spring resistance preferably increases to approximately 8 lbs. Other combinations of forces and trigger travel distances may be implemented, depending on the requirements of the user. An additional measure of safety is derived from sensing trigger recovery for a predetermined distance in order to preclude unintentional switching. In the preferred embodiment, double throw switches are used to sense both trigger activation and trigger recovery. Other embodiments, such as the use of an extra switch, may be used to sense trigger recovery. 
     As depicted in FIG. 2, the electronic ignition system  15  is comprised of an electronic control system  20 , which is the primary subject of the present invention, and an ignition probe  22  that forms the interface between the electronic control system  20  and a non-impact electrically ignitable primer  24  of which the chemically conductive primer referenced above is the preferred embodiment. The electronic control system described herein is readily adaptable for use with other types of non-impact direct energy primers. The ignition probe  22  is the subject of the commonly-owned copending patent application Ser. No. 09/205391, filed Dec 4, 1998, entitled “FIRE CONTROL SYSTEM FOR NON-IMPACT FIRED AMMUNITION”, referenced above. 
     Referring now to FIG. 3, a first embodiment of the firearm of the invention is a pistol  1 , more specifically comprising a unitary polymer frame  4 , a trigger  10  pivotable about a transverse pin  2  rearwardly to move a trigger bar  12 , or other transfer device, which is operably connected to trigger switches  14 , 16 . The frame  4  is adapted to receive a metal slide  6  removably fitted into the frame for slidable reciprocal movement therealong. The slide  6  is secured for such movement by longitudinally spaced pairs of metal rails  8  partially embedded in the polymer of the frame. The rails provide durable metal-to-metal contact and may be used as a system ground for the electronic fire control system. Alternatively, a metal pin embedded in the firearm frame can be used for the same purpose. A chamber  3  is disposed within the breech end of a barrel  13  that is housed in the forward portion of the slide  6  and interfits within a recess provided in the upper portion of the frame  4  to hold the barrel  13  in a given longitudinal position relative to the slide  6 . An ignition probe  22  is adapted to move longitudinally within the barrel  13  to make electrical contact with the electrically ignitable ammunition  5  in the chamber  3 . An information display  19  is disposed at the rearward portion of the frame for displaying critical information to the user such as ready-to-fire, low battery power and diagnostic information 
     A portion of the frame comprises a handgrip  9  that extends downwardly and rearwardly relative to the longitudinal axis of the bore or barrel and forward portion of the frame  4 . The handgrip  9  has a pressure sensitive rear grip sensor  18  disposed at the rear portion of the handgrip to detect that the firearm is being handled. A front grip sensor  20   a  is optional and is located on the front of the handgrip  9 . The handgrip  9  has a central cavity or magazine well  21  for receiving a magazine  23  that contains the unfired ammunition. The magazine  23  also contains a primary battery  27  which provides power to the electronic circuitry. Also located within one or more auxiliary cavities  25  within the handgrip and frame is the electronic fire control system  28 , having a micro-controller  30 , and a user authorization device, preferably an embedded fingerprint authorization apparatus  34 . In the preferred embodiment a slot  26  for reading the fingerprint pattern of an authorized user is located in the back-strap area of the handgrip  9 . 
     As shown in FIG. 4A, in the firearm of the present invention, a finger  7  or thumb is swept horizontally across a slot  26  in the handgrip  9  of the firearm, and a fingerprint pattern,  29  such as that shown in FIG. 4B, is read by the finger-print authorization apparatus  34  and compared to prestored patterns. In the preferred embodiment the finger or thumb can be swept either right to left or left to right to allow for ambidextrous use. 
     FIG. 5 is a block diagram of the electronic control system of the present invention. As more fully described below, the electronic control system includes a microcontroller  30 , capable of receiving external inputs from a plurality of sensors, an options interface  42  capable of interfacing with at least four additional sensor inputs, a power supply system  36 , an information display system  38 , and an ignition system  40  which provides the 150 Vdc firing pulse  45  to the electrically ignitable ammunition  5 . In the preferred embodiment the microcontroller  30  is operably connected to trigger switches  14 ,  16 , a Round-In-Chamber sensor  52  and a battery status sensor  53 . The options interface  42  receives inputs from the rear grip sensor  18 , the front grip sensor  20   a,  a magazine/battery (or clip/battery depending on the embodiment) presence sensor  50  and a user authorization device. The user authorization device is an important aspect of the present invention. Although the user authorization device may be an embedded fingerprint apparatus  34 , as described herein, other user authorization devices, such as an RF scanner, a combination lock, or an electronic key, can be implemented to perform the same function. 
     Referring still to FIG. 5, the microcontroller  30  is preferably an 8-bit Microchip® PIC16C715, or equivalent, which is normally in a SLEEP, or power saving, mode when the firearm is not in use, and ‘wakes up’ when an external interrupt from a grip sensor, or other sensing means, detects that the firearm is being handled. The microcontroller, with integrated analog-to-digital (A/D) converters, 2K bytes of program memory (EPROM), 128 bytes of data memory (RAM) and 13 I/O pins, coordinates the timing and execution of all events, and is programmed, as more fully described below, to enable firing only upon verification of authorized firing status. In the preferred embodiment, the options interface  42  is a four channel analog to digital interface integrated into the Microchip® microcontroller. There are numerous alternative devices, however, with quite different memory and I/O configurations that would be equally useful in the present application. 
     As shown in FIG. 6., the user authorization device is preferably an embedded fingerprint apparatus  34  comprising a scanning element  35 , such as the Thomson-CSF FingerChip)™ FC15A140 fingerprint reader, and an Enrollment Database having a Digital Signal Processor (DSP)  37  programmed to compare and match the fingerprint pattern read by the scanning element  35  to previously stored patterns. The DSP  37  transmits a pass/fail signal  39  to the microcontroller  30  through the options interface as depicted in FIG.  5 . Scanning, image processing, and verification preferably occurs in user perceived real time (less than 50 msec). Like the microcontroller  30 , the embedded fingerprint apparatus is in a SLEEP mode to conserve power when not in use. 
     Enrollment of an authorized fingerprint requires the use of an authorization key. FIG. 7 is a schematic illustration of an authorization key  40   a.  In the preferred embodiment, the authorization key is a mock magazine or clip having a fixed electronic password that is communicated to the central microcontroller  30  through an RF non-contact proximity interface  49  or through a direct connection. In the preferred embodiment, up to five fingerprints can be authorized for one firearm, allowing the user to choose between enrolling several fingers on either hand, or to enroll other authorized users. Positioned on the bottom of the authorization key  40   a  are a plurality of enrollment selector switches  48  and two LEDs  51 , 54  to indicate the success or failure of the enrollment attempt, as depicted in FIG.  7 A. Other embodiments of the enrollment selector switches  48 , using a single LED or buttons or using a Liquid Crystal Display  41 , as shown in FIG. 7B, for example, will occur to those skilled in the art. The electronic control is programmed to identify a valid password and verify that the chamber is unloaded and the firing circuitry disabled during the enrollment process. 
     Referring now to FIG. 8, the power supply system  36  of the present invention is shown schematically. Power to the ignition system  40  for firing the electrically ignitable primer  24  and for all other system requirements is derived from the primary battery  27 , and a secondary or standby battery  56 . In the preferred embodiment, the primary battery  27  is a 3 volt DC lithium battery disposed at the bottom of the ammunition magazine or clip  23 . Because the primary battery  27  is removed with the magazine/clip  23 , a secondary standby power source is provided to enable the microcontroller to perform minimal self-test and display functions when the magazine/clip  23  is removed. In the preferred embodiment, the standby battery  56  is a small rechargeable cell which is recharged when the magazine/clip  23  is placed in the firearm. Other power sources having comparable temperature performance range, power density, and shelf life can also be used. 
     A battery presence sensor  50  comprising two pairs of contacts  74  and  76  between the magazine/clip and the firearm frame detects the presence of the battery. A closed circuit in both pairs of contacts  74 ,  76  indicated that the magazine/clip has been inserted into the magazine well or central cavity  21  of the firearm. When the magazine/clip  23  is removed, an open circuit between the firearm frame  4  and the magazine/clip  23  at contacts  74  and  76 , signifies the absence of the magazine/clip  23  and causes the microcontroller  30  to disable the fire control system according to the logic flow chart depicted in FIG.  17 . When the magazine or clip  23  is removed, a round in the chamber cannot be discharged. The signal from the battery presence sensor  50  is transmitted to the microcontroller  30  through the options interface  42  as shown. Those skilled in the art will recognize that several other embodiments of the battery presence sensor  50  are possible. 
     FIG. 9 is a schematic illustration of the Ignition System  40  of the present invention. Using conventional techniques, the ignition system  40  converts the low level dc input from the batteries in the power supply system  36  to a 150 Vdc firing pulse  45  of sufficient duration, preferably one millisecond minimum, to fire the electrically ignitable ammunition. In the preferred embodiment, 150 Vdc is stored across 4.7 μf capacitor that is discharged when the microcontroller  30  transmits a one millisecond fire enable signal to the ignition system  40 . Unlike an ignition system in a bolt action rifle, for example, in the ignition system of the present invention, the capacitor must be able to be recharged and ready to fire again within a minimum of 150-200 milliseconds. 
     In the preferred embodiment, the trigger  10  simultaneously activates two high reliability sealed micro-switches within the electronic control system. The first micro-switch signifies to the microcontroller  30  that a decision to fire has been made. The output of the first micro-switch is debounced using an integrator circuit before it is input to the microcontroller  30  in order to prevent unintentional activation of the fire enable signal. When the microcontroller  30  detects a valid trigger signal from the first micro-switch, a fire enable signal in the form of a one millisecond square wave is transmitted by the microcontroller  30  to the ignition system  40  through the second micro-switch. The width of the square wave transmitted to the ignition circuit corresponds to the duration of the 150 vdc firing pulse applied to the electrically ignitable ammunition. Use of the second micro-switch provides a measure of redundancy to ensure against a false trigger signal resulting from a switch failure or other system malfunction. 
     In the preferred embodiment, ignition is inhibited by the control logic for at least 150 milliseconds between rounds. The 150 millisecond cycle time is designed to ensure that any unintentional trigger activity that may occur due to recoil, hesitation or inertia is ignored by the ignition system  40 . The 150 milli-second cycle time provides a measure of safety without affecting performance since, typically, even an exceptionally skilled user cannot intentionally shoot faster than 200 milliseconds between rounds. 
     Those skilled in the art will recognize that several alternative trigger switching methods may be utilized as well. One such method is to use a Giant Magnetoresistive (GMR) sensor to determine the position of a metal linkage operably connected to the trigger. Such a GMR sensor, used in combination with a single trigger switch, can be implemented to provide a precise and fail-safe fire enable signal to the ignition system. Other alternative methods that will occur to those skilled in the art involve the use of piezo-electric or strain gage devices. 
     The ignition system  40  described above is based on ignition by capacitive discharge. Other embodiments of an ignition system capable of delivering firing energy to the electrically ignitable primer in user perceived real time will occur to those skilled in the art. One such alternative is a two stage ignition system, in which the first stage is a pulse width modulated discontinuous dc-to-dc converter and the second stage is a pulse generator capable of generating pulses of sufficient voltage and duration to fire the electrically ignitable ammunition 
     In the preferred embodiment, the ignition system  40  incorporates circuitry to detect the power remaining in the battery. A signal representing a battery status  43  signal is transmitted from the ignition system  40  to the microcontroller  30  which is programmed to provide a low battery warning to the user sufficiently in advance of the time the battery must be replaced in order to enable the firearm to function for an extended period of time on battery reserves. In the preferred embodiment, the low battery warning is indicated by a message or icon on the information display  19  as shown in FIG.  12 . 
     Referring still to FIG. 9, the ignition system  40  also incorporates a Round-In-Chamber sensor  52  for detecting the presence or absence of a chambered round. Detection of a chambered round is accomplished by sensing the impedance of the connection between the ammunition and the firing circuit using a low voltage (below the no-fire threshold) sensing current. To optimize energy transfer and power conservation, the duration of the firing pulse can be adjusted based on the impedance of the chambered round. A signal from the Round-in-Chamber sensor  52  is transmitted to the microcontroller  30  which is programmed, as shown in FIG. 17 below, to read and integrate all sensor data and display the appropriate icon (See FIG. 12) on the information display  19  to inform the user as to the presence or absence of a chambered round. 
     By detecting the impedance of the connection between the ammunition and the firing circuit, the Round-In-Chamber sensor  52  also permits the detection of a present but defective round prior to firing. The Round-In-Chamber sensor  52  can, therefore, warn the user of worn, defective, or contamination build-up within the firearm. The microcontroller  30  is programmed to disable firing in the event a defective round is detected. 
     FIG. 10 depicts the Rear Grip Sensor  18  schematically. An optional Front Grip Sensor can be implemented in substantially the same manner. As noted above, when the firearm is not in use, the electronic control system  20  is in a suspended SLEEP mode to conserve power. The firearm ‘wakes up’ when the pressure sensitive Front or Rear Grip sensor  18 / 20   a  detects the firearm is being handled and sends an interrupt to the microcontroller  30  through the options interface  42 . In the preferred embodiment, the Rear Grip Sensor  18  comprises a plurality of switches  72  arrayed along the backstrap area of the firearm as shown in FIG.  3 . In addition to providing a ‘wake up’ function, the rear grip sensor  18  has a dedicated microcontroller  68 , preferably a Microchip® PIC 16C71574 or equivalent, programmed to read the pattern of signals from the switches  72  and determine if the firearm is being handled with an intent to fire. A firm grip, adequate to keep the firearm under control during discharge, must be sensed by the Rear Grip Sensor  18  in order to fire. Firing is therefore disabled if the firearm is being handled by a child or someone with a very poor or unintentional grip. 
     Referring to FIG. 11, the information display system  38  of the firearm is depicted schematically. Through the information display system  38 , information on a variety of system parameters, including battery status, Round-In-Chamber status, or ready-to-fire status, for example, is presented to the user. The information display system  38  comprises generally an information display  19  and a display driver  58 . The information display  19  can be implemented using a combination of a low power, always active, Liquid Crystal Display (LCD) for icons depicting system parameters and a Light Emitting Diode (LED) for a ready-to-fire light. The display driver  58  is programmed to load preset messages to the information display  19  based on control signals received from the microcontroller  30  and is preferably a dedicated microcontroller, such as the Microchip® PIC16C715. Other embodiments of the information display system  38  will occur to those skilled in the art. 
     The information display system  38  preferably uses a simple set of internationally understood icons, as depicted in FIG. 12. A padlock  61  indicates the system will not fire because an unauthorized user is handling the firearm. A flashing padlock indicates the firearm is awaiting authorization. A bullet icon, which can be displayed alone  63  or with a line through it  65 , signifies whether a live round is in the chamber. A bullet icon with a red LED indicates that a live round is in the chamber and the firearm is authorized and capable of firing. A battery icon  67  is used to signify low battery power. A triangle with an exclamation point  69 , or alternatively, all icons flashing, symbolizes a system malfunction has been detected. 
     Referring to FIG. 13, a high level block diagram of the control logic  70  of the present invention is depicted. As shown, the firearm is normally in either a SLEEP mode  71  or a STANDBY mode  73  unless the firearm is undergoing a cold start  66  which occurs when the firearm is used for the first time or the batteries are replaced. A cold start algorithm is depicted in FIG. 14 below. 
     Referring still to FIG. 13, the transition from SLEEP mode to STANDBY mode occurs when a grip sense interrupt is detected by the microcontroller, which event causes the firearm to go through a “Positive Grip Sense Wake-Up” algorithm (Block  78  and FIG.  15 ). The firearm will transition to the STANDBY mode only if a “User Authorization” algorithm (Block  77  and FIG. 16) is successfully completed. Once in STANDBY mode  73 , the firearm will fire when a “Trigger Firing Event” (Block  75  and FIG. 17) occurs. If the firearm is in STANDBY mode and the microcontroller detects a “Negative Grip Sense Event” (Block  64  and FIG.  18 ), the firearm will return to SLEEP mode  71  as shown. 
     Referring to FIG. 14, the algorithm for a cold start or battery replacement routine is shown. The cold start algorithm  80  is followed if the firearm has never been used or the battery is replaced. As shown, the control logic first performs an internal self-test  81 . If a fault is detected an error indicator will be displayed  82  and the firearm will enter SLEEP mode  83 . If the internal self-test is successful, all icons on the information display will be displayed for approximately three-seconds  84 , the Round-in-Chamber and the battery status will be updated,  85  and  86  respectively, the firearm status will be set to UNAUTHORIZED  97  and the firearm will enter SLEEP mode  88 . As programmed, firing is disabled during the cold start algorithm  80 . 
     Referring to FIG. 15, when a positive grip sense interrupt  90  is detected, the electronic fire control system will first perform an internal self-test  91 . If the self-test routine detects a system fault a system malfunction symbol will be displayed  92  and the firearm will revert to SLEEP mode  93 . If the self-test is successful, all icons will be displayed for approximately three-seconds  94  and the padlock symbol on the information display will flash  95  as the User Authorization algorithm  96  depicted in FIG. 16 is performed. If the User Authorization algorithm cannot be successfully performed for any reason, the firearm status will be set to UNAUTHORIZED  97  and the firearm will revert to SLEEP mode  98 . If the user is authorized, as determined by the User Authorization algorithm  96 , the control will interrogate and update the Round-in-Chamber status, battery status, and magazine status  99 . If the firearm is ready to fire  100 , the ready-to-fire indicator on the information display will be illuminated  102  and the firearm will enter STANDBY mode  104 . In the event that an error is detected, the display will be updated accordingly  101  and the firearm will revert to SLEEP mode  103 . The firearm is programmed not to discharge unless the user has been properly enrolled and authorized according to the algorithm depicted in FIG.  16 . 
     Referring to FIG. 16, the algorithm to Interrogate User Authorization  110  is depicted schematically. As indicated, the control first determines, by the presence or absence of the enrollment key  112 , whether the intent of the user is to enroll an authorized user or to authorize a previously enrolled user. If the enrollment authorization key is present, a PIN access code associated with the authorization key is verified  132 , the fingerprint scanner is activated  134  for a predetermined time, preferably ten-seconds  136 , during which time the finger-print of the user is scanned. From the raw scanned data, the fingerprint image is reconstructed and processed  138  and stored  148  in memory. The algorithm is then reset  149  to the beginning  110 . 
     If the enrollment key  112  is present, the user may verify a previously enrolled fingerprint using the same method. When the fingerprint image has been reconstructed (Block  138 ) and formatted (Block  139 ), it is compared with a previously enrolled fingerprint  140  for verification  142  and the algorithm is then reset  146  to the beginning  110 . If the fingerprint image does not match, an error message will be displayed  144  on the information display and the algorithm reset as shown  146 . 
     Referring still to FIG. 16, if the enrollment key is not present  112 , the firearm is programmed to authorize use only if the user&#39;s fingerprint matches a previously stored fingerprint pattern. As shown, the fingerprint scanner is activated  114  for a predetermined period of time, preferably  10  seconds, during which time the fingerprint of the user is scanned  116 . The raw scanned data is then reconstructed  118  and processed  120  and compared with previously stored patterns  122 . If there is a match, the lock status is set to AUTHORIZED  124  and the firearm returns  126  to the main control program (FIG. 13) and enters STANDBY mode. If there is no match, the lock status is set to UNAUTHORIZED  128 , disabling the firearm, as the firearm returns  130  to the main control program (FIG.  13 ). 
     FIG. 17 is a schematic illustration of the Trigger Initiation algorithm  150 . As shown, when the firearm is in STANDBY mode, ready to fire, and the trigger is pulled, the electronic control polls a series of internal and external parameters including the grip sensors  151 , the user authorization signal  152 , the magazine presence sensor  153 , the round in chamber indicator  154 , and the energy available to fire  155 . If any system parameters are not in the proper state, the electronic control is programmed to update the information display  156  with the appropriate error message and abort firing  157 . If all system parameters indicate the firearm is authorized and ready to fire, a fire enable signal  159  is transmitted to the ignition system to discharge the electrically ignitable ammunition. 
     Referring to FIG. 18, when the firearm is in STANDBY mode, and the grip sensors detect that the firearm is no longer being handled, the firearm will revert to SLEEP mode as indicated. If a negative grip sense interrupt is received from the grip sensors  170  while the firearm is in STANDBY mode, the electronic control will monitor the input of the grip sensors for a positive grip  172  for a predetermined time, preferably ten-seconds  174 , and if a positive grip is not detected, the electronic control will set the lock status to UNAUTHORIZED  176 , initiate a grip sensor self-test routine  177  and revert to SLEEP mode  180 . In the event that a positive grip sense is detected within the predetermined time, the firearm will return to STANDBY mode, ready to fire. 
     In a second embodiment, the electronic fire control system, described above, is implemented in a multiple chambered gun depicted in FIGS. 19-21. Referring to FIG. 19, the multiple chambered handgun  160  comprises generally a frame  161  which includes a handle portion  163 , having a rear grip sensor  164  and optionally a front grip sensor  165 . The handle  163  has a central cavity  168  for receiving a clip  162  that houses the primary battery  166  which provides the primary power to the electronic circuitry. 
     Referring to FIG. 20, the multi-chambered handgun  160  has a barrel  167  adapted to receive several cartridges within a plurality of longitudinal bores  169 . A plurality of ignition probes  171 , in axial alignment with the longitudinal bores  169 , are positioned to fire the cartridges in a predetermined sequence. 
     Referring to FIG. 21, the barrel  167  is hinged to the frame through a hinge assembly  173  and is pivotable about a hinge pin  175 . When the firearm is ‘open’, as shown, the empty brass or cartridge cases may be removed, and the firearm reloaded. The barrel  167  may then be swung back into the ‘closed’, or firing position, and locked with locking mechanism  178 . An information display  179  is disposed above the handle as shown. As in the first embodiment, the preferred user authorization means is an embedded fingerprint apparatus  181  located, as shown, in the backstrap area of the handle. 
     In yet another embodiment, the electronic fire control system described above is implemented in a revolver. The revolver embodiment of the present invention is shown generally at FIG.  22 . The revolver  200  comprises generally a frame  202  which includes a handle portion  204 , having a rear grip sensor  206  and optionally a front grip sensor  208 . The handle  204  has a central cavity  210  for receiving a clip  212  which contains a primary battery  214 . The revolver  200  has a rectangular opening or window  220  adapted to receive a cylinder  222 . An information display  226  is disposed above the handle as shown. As in the other embodiments, a slot  228  for reading the fingerprint of the authorized user is disposed in the backstrap area of the firearm. As shown in FIG. 23, the cylinder includes a plurality of longitudinal bores  216  which are adapted to position, in sequence, cartridges (not shown) to the firing position in axial alignment with the barrel  218  and an ignition probe  219 . The cylinder  222  is rotatable about its centerline on a center pin  223 . The cylinder  222  is also pivotable on a yoke  224 . When the cylinder is ‘open’, the empty brass or cartridge cases may be removed and the cylinder reloaded. It may then be swung back into the window  220 , ready for firing upon determination of safe and authorized firing conditions. 
     While the present invention has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art, that various modifications to this invention may be made without departing from the spirit and scope of the present invention.