Abstract:
A theft deterrent device includes a source of deterrent fluid, a valve for gating release of deterrent fluid from the source, an electronic circuit including a motor for opening and closing the valve, a switch for electrically activating the device and a logic device responsive to a motion detector in the protected area for providing an electronic signal only while motion occurs in the protected area and responsive to the switch for activating the electronic circuit during the simultaneous occurrence of the device being in the electrically activated condition and the electronic signal being provided by the logic device to open the valve and discharge deterrent fluid from the source into the protected area. In an add-on mode of operation, the switch is preferably a component of an existing alarm system for the protected area. In a stand-alone mode of operation, the switch is preferably a radio transmitter remote from the device. In a special mode of operation useful to protect a motor vehicle, the device also includes a switch responsive to the rotation of a drive shaft of the vehicle for preventing activation of the valve motor electronic circuit while the shaft is rotating. The radio transmitter activates the electronic circuit regardless of the detection of motion in the protected vehicle. The receiver further responds to the transmitter to activate a warning device in the protected vehicle advising the intruder that deterrent fluid is going to be discharged into the protected vehicle.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to theft deterrents and more particularly concerns a theft deterrent usable independently or in conjunction with an existing alarm system to discharge or introduce a deterrent fluid or sound into a protected area. 
     A device for discharging deterrent fluid or sound into a protected area is disclosed in U.S. Pat. No. 4,958,142 issued to Carol L. Sayers on Sep. 18, 1990. In the &#39;142 patent, the device is connected to an existing alarm system and discharges deterrent fluid into a protected area at the end of a predetermined time after the existing alarm system is triggered. Deterrent fluid is discharged for a predetermined time period. When discharge terminates, the device automatically resets for subsequent intrusions. 
     The &#39;142 patent device is usable exclusively as an addition to an existing alarm system. The device makes no provision for remote control by the owner. If the existing alarm system has been inadvertently triggered, deterrent fluid will be discharged for the full predetermined time of operation of the device unless the alarm is affirmatively interrupted by the user before the predetermined time delay has elapsed. The device is directly responsive to the triggering of the existing alarm and therefore is not independently responsive to motion in the protected area. Since the device discharges continuously for four minutes and then fully resets the system for a future intrusion, if an intruder opens windows and/or doors to exhaust the deterrent fluid from the protected area without subsequently performing an existing alarm triggering act, no further deterrent fluid will be introduced into the protected area by the device. The device is disclosed solely for use in a motor vehicle. No account is taken as to whether the protected vehicle is in operation at the time the deterrent fluid is discharged. No warning is given to an occupant of a moving vehicle that deterrent fluid is going to be imminently discharged into the vehicle. No opportunity to evacuate the vehicle prior to such a discharge is given to the occupant. 
     It is, therefore, an object of this invention to provide a theft deterrent device which may be effectively used in any enclosed area. It is also an object of this invention to provide a theft deterrent device which can be used in stand-alone or add-on applications. A further object of this invention is to provide a theft deterrent device which is triggered by motion in the protected area whenever the device is in an activated condition. Another object of this invention is to provide a theft deterrent device which is operable by remote control by the user. It is also an object of this invention to provide a theft deterrent device which will not place the fluid discharge or sound introduction circuit into an activated condition unless the demand for activation has been continuously made for a predetermined period of time. Yet another object of this invention is to provide a theft deterrent device usable to protect a motor vehicle. It is a further object of this invention to provide a theft deterrent device that will not discharge deterrent fluid into a moving motor vehicle. Still another object of this invention is to provide a theft deterrent device which warns the occupants of a motor vehicle of the impending discharge of the deterrent fluid into the vehicle. And it is an object of this invention to provide a theft deterrent device which intermittently discharges deterrent fluid or introduce deterrent sound into a protected area as long as motion is detected in the protected area. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an anti-theft device is provided which will interrupt a break-in by discharging or introducing a sufficient quantity or volume of a deterrent fluid, such as pepper gas, tear gas or the like, or sound into a protected area to cause an intolerable level of discomfort to the intruder. The embodiment of the device herein described includes an electronic ‘brain’ automatically operating the system, an optional remote control permitting manual operation of the device, a motion detector input triggering operation of the activated system, a release mechanism such as a motor operated valve, a control circuit gating the deterrent fluid into the protected area, a battery and a deterrent fluid source. When triggered, the gas, liquid or particles (generally referred to as deterrent fluid) are injected or discharged into the protected room, car, safe or other area. The injection or discharge can be intermittently repeated within a certain time interval so that the area cannot be cleared of the deterrent fluid by merely rolling down or opening a window. An optional time delay prevents inadvertent operation of the fluid discharge circuit by remote control. Another optional time delay allows a protected motor vehicle to be evacuated before the deterrent fluid is discharged. The device can be used as an add-on unit with an existing burglar alarm system or as an independent unit. 
     In one embodiment, the device is secured in a lockable steel box approximately 1″×4″×6″ and is electrically connected to the output of the existing burglar alarm system. If the electrical connection is interrupted while the alarm is deactivated, a line error is reported without releasing deterrent fluid. The device may be mounted in a closet, attic or other area and a deterrent fluid discharge tube extended from the device into the protected area. The device may be mounted in an HVAC system having its fan configured to operate when deterrent fluid is released so as to dispense the fluid into the room or area controlled by the HVAC unit. The device may be hidden in or behind pictures, paintings, vases, lamps or other objects located in the room/area to be protected and connected to the existing burglar system. An abort switch may be secreted in the system to permit interruption of the injection or discharge of deterrent fluid. 
     In another embodiment, the device also includes a motion detector so that no deterrent fluid will be released into the protected area until motion is detected. In this embodiment, the deterrent fluid can be sprayed directly at an intruder. Motion within five to ten feet of the device, or one to two feet in a motor vehicle application, would trigger the release of deterrent fluid in an activated system. 
     In a third embodiment, the device operates as an independent unit activated by a motion detector and a remote control. Red and green lights indicate the activated or deactivated status of the device, respectively, preferably intermittently blinking and in an “off” condition for the majority of the time. This embodiment is specially suited for use in motor vehicles. In motor vehicle applications, release of deterrent fluid is prevented while the motor vehicle is in motion. Furthermore, a deterrent fluid pipe line valve concealed in the vehicle proximate the deterrent fluid source permits the user to manually assure that deterrent fluid cannot be released while the user is operating the vehicle. 
     Preferably, the device includes a source of deterrent fluid, a valve for gating release of deterrent fluid from the source, an electronic circuit including a mechanism such as a motor for opening and closing the valve, a switch for electrically activating the device and a logic device responsive to a motion detector in the protected area for providing an electronic signal only while motion occurs in the protected area and responsive to the switch for activating the electronic circuit during the simultaneous occurrence of the device being in the electrically activated condition and the electronic signal being provided by the logic device to open the valve and discharge deterrent fluid from the source into the protected area. The electronic circuit can cause the motor to open and close the valve intermittently during the simultaneous occurrence above described or can cause the motor to remain open continuously during that simultaneous occurrence. In an add-on mode of operation, the switch is preferably a component of an existing alarm system for the protected area, the switch being normally open when the existing alarm system is activated but not triggered. In a stand-alone mode of operation, the switch is preferably a radio transmitter remote from the device with a receiver responsive to the transmitter switching the device to an electrically activated condition. 
     In a special mode of operation useful to protect a motor vehicle, the device also includes a switch responsive to the rotation of a drive shaft of the vehicle for preventing activation of the valve motor electronic circuit while the shaft is rotating. In this special mode, a radio transmitter remote from the device signals a receiver responsive to a first operation of the transmitter to activate the electronic circuit when the vehicle drive shaft is not rotating regardless of the detection of motion in the protected vehicle. Preferably, a first time delay circuit delays activation of the electronic circuit until the transmitter has been continuously activated for a first predetermined time period and a second time delay unit delays activation of the electronic circuit for a second predetermined time period after the first predetermined time period has elapsed. It is also preferred that the receiver further responds to the first operation of the transmitter to activate a warning device in the protected vehicle after the first predetermined time period has elapsed to advise the intruder that deterrent fluid will be discharged into the protected vehicle after the second predetermined time period has elapsed. Also, in this special mode, the receiver responds to a second operation of the transmitter to deactivate the electronic circuit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
     FIG. 1 is an electrical block diagram of a preferred embodiment of the deterrent device; 
     FIG. 2 is an electrical schematic diagram of a preferred embodiment of the system-activated indicator circuit of the deterrent device; 
     FIG. 3 is an electrical schematic diagram of the preferred embodiment of the motor-vehicle-moving override circuit of the deterrent device; 
     FIG. 4 is an electrical schematic diagram of a preferred embodiment of the inadvertent operation prevention circuit of the deterrent device; 
     FIG. 5 is an electrical schematic diagram of a preferred embodiment of the evacuate vehicle time delay circuit of the deterrent device; and 
     FIG. 6 is an electrical schematic diagram of a preferred embodiment of the fluid release circuit of the deterrent device. 
     While the invention will be described in connection with a preferred embodiment and method of operation, it will be understood that it is not intended to limit the invention to those embodiments or methods. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
    
    
     DETAILED DESCRIPTION 
     Looking first at FIG. 1, the theft deterrent device includes a select implementation circuit  10 , a mode selection switch  20 , an AND gate  30 , a NOR gate  40 , a system-activated indicator circuit  50 , a motor-vehicle-moving override circuit  60 , a radio remote circuit  70 , an inadvertent operation prevention circuit  80 , an evacuate-vehicle time delay circuit  90 , a NAND gate  100  and a fluid release circuit  110 . 
     The select implementation circuit  10  permits the user to implement the deterrent device as an add-on to an existing alarm or as a stand-alone unit. It includes a double throw switch  11  having its common point  12  connectable between a stand alone position  13  and an add-on position  14 . The add-on position  14  is connected through a circuit protector  15  and an activation switch  16  to ground and through a resistor  17  to a voltage source. Preferably, the activation switch  16  is a component of the existing alarm system (not shown) to which the deterrent device is added. 
     The user may select the mode of operation of the device by use of the digital mode switch  20 . As shown in the preferred embodiment, the switch  20  has an input  20 - 1  connected to the common point  12  of the implementation switch  11 , an input  20 - 2  connected to the stand-alone position  13  of the implementation switch  10 , an input  20 - 3  connected to a motion detector  21  located in the area to be protected or on the lockable steel box containing the device components, inputs  204  and  20 - 5  connected to a positive voltage source  22  and an input  20 - 8  connected to a radio signal receiver  71 . The mode switch  20  permits the user to choose an add-on mode of operation, a stand-alone mode of operation or a special add-on mode of operation. 
     The configuration of the theft deterrent device is best understood in relation to each of its three operational modes. 
     Add-on Mode 
     In the add-on mode of operation, the deterrent device is connected to an existing alarm system (not shown). The mode switch  20  is configured with inputs  20 - 1 ,  20 - 3  and  20 - 4  closed. The AND gates  30 - 2 ,  30 - 5  and  30 - 9  are connected through resistors to ground (not shown) at points  32 ,  35  and  39 , respectively. The implementation switch  11  is in the add-on position  14 . If the device is to be used to protect the contents of a motor vehicle, the motor vehicle moving override circuit  60  is configured to prevent release of deterrent fluid while the motor vehicle is moving. In the add-on mode, when the existing alarm system is activated, the activating switch  16  is automatically opened and a logic 1 is given through the implementation switch  11  and the mode switch  20 - 1  to the AND gate input  30 - 1 . If movement subsequently occurs in the protected area, the motion detector M provides a 1 through mode selection switch  20 - 3  to the AND gate input  30 - 2 . This results in a 1 being transmitted from an AND gate output  30 - 3  to an AND gate input  30 - 4 . Since a 1 is also provided through the mode switch  20 - 4  to an AND gate input  30 - 5 , a 1 is then transmitted from an AND gate output  30 - 6  to a NOR gate input  40 - 2 . This causes a NOR gate  40 - 1  to flip from 1 to a logic 0, opening the indicator circuit  50  and providing a 1 to an AND gate  30 - 10 . If the device is not used with a motor vehicle or if the device is used with a motor vehicle but the vehicle is not moving, an AND gate  30 - 9  will already have a 1 from the override circuit  60 . Therefore, an AND gate  30 - 8  becomes 1 and activates the fluid release circuit  110 . Deterrent fluid is then released into the protected area. The operation of the fluid release circuit  110  is hereinafter explained. Preferred embodiments of the general mode indicator circuit  50  and the motor vehicle-moving override circuit  60  are hereinafter explained in detail. 
     Thus, in the add-on mode, if the existing alarm is activated and motion occurs in the protected area, the fluid discharge circuit is activated. The diffusion of deterrent fluid will be terminated if motion ceases or if the alarm is disconnected. 
     Stand-alone Mode 
     In the stand-alone mode of operation, the deterrent device is used independently of any other system. The mode switch  20  is configured with inputs  20 - 1 ,  20 - 3  and  20 - 4  closed as in the add-on mode, but the implementation switch  11  is in the stand-alone position  13 . The motor vehicle override circuit  60  is configured to prevent release of deterrent fluid into a protected motor vehicle while it is moving, as in the add-on mode. In the stand-alone mode, the user activates the system by use of the radio remote  70  having a receiver  71  connected at point  71  to the NOR gates  40 - 11  and  40 - 12 . Operation of the radio remote  70  changes NOR gates  40 - 11  and  40 - 12  from 1 to 0. NOR gate  40 - 13  thus becomes 1 which is applied to the mode switch  20 - 1  through the implementation switch  11 . The AND gate  30 - 1  receives the 1 from the mode selection switch  20 - 1  and the device thereafter operates identically as described above in the add-on mode. Preferably, the remote circuit  70  includes a light emitting diode (LED)  73  connected to a positive voltage source. The LED  73 , when lit, indicates that the system is activated and will discharge deterrent fluid if motion is detected in the protected area. Preferably, sequential operations of the remote  70  will flip-flop the device  70  into and out of the activated condition and the LED  73  on and off. 
     Special Add-on Mode 
     In the special add-on mode of operation, the deterrent device is connected to an existing alarm system (not shown) in a motor vehicle and is configured to deal with a hijack situation as well as to protect the vehicle contents. The mode switch  20  is configured with inputs  20 - 1 ,  20 - 2 ,  20 - 3 ,  20 - 4 ,  20 - 5  and  20 - 8  closed and with the implementation switch  11  in the add-on position  14 . In the special add-on mode, the device is connected identically as in the add-on mode and operates in the same manner, but additional operations are being performed as hereinafter explained. AND gates  30 - 10 , 30 - 12  and  30 - 13  are connected through resistors to ground (not shown) at points  36 ,  37  and  38 , respectively. With the mode switch  20 - 5  closed, a 1 is present at the AND gate  30 - 13 . If the operator uses the radio remote control, the NOR gates  40 - 11  and  40 - 12  get a 0 resulting in a 1 at the NOR gate  40 - 13  which in turn provides a 1 through the mode switch  20 - 2  to the AND gate  30 - 12 . Since the mode switch  20 - 5  already provides a 1 at the AND gate  30 - 13 , the AND gate  30 - 11  provides a 1 to a NAND gate  1004 . The remote signal also provides a 0 through the mode switch  20 - 8  to the inadvertent operation prevention circuit  80 . This circuit  80  provides a time delay, preferably of approximately ten seconds, such that, if the remote  70  is held in a closed condition for the time delay period, a NAND gate  100 - 1  will flip from 1 to 0. Thus, a NAND gate  100 - 8  will flip from 0 to 1 and be maintained in this condition even if the remote is released. In this activated condition, the evacuate vehicle time delay circuit  90  receives a 1 from a NAND gate  100 - 11 . The evacuate vehicle time delay circuit  90  preferably provides an approximately twenty second delay period after the radio remote  70  has been operated and before deterrent fluid will be released into the vehicle. At the end of the time delay period, the evacuate vehicle time delay circuit  90  causes the NOR gates  40 - 8  and  40 - 9  to change to 0 and a NOR gate  40 - 10  to change to a 1 which is transmitted to a NOR gate  40 - 3 . This causes the NOR gate  40 - 1  to flip from 1 to 0, operating the indicator circuit  50  and providing a 1 at the AND gate  30 - 10 . As soon as the motor vehicle is in a stationary condition, the motor vehicle override circuit  60  will operate to provide a 1 at the AND gate  30 - 9 , and the AND gate  30 - 8  will therefore get a 1 and activate the fluid release circuit  110 . In this configuration, deterrent fluid will be released into the vehicle in response to the radio remote  70  even if no movement has been detected by the motion detector  21 . If the user operates the radio remote  70  a second time, the NAND gate  100  will be reset and discharge of deterrent fluid into the motor vehicle will be terminated. It is anticipated that an audible or visible signal within the motor vehicle will advise the occupant that when the delay time has elapsed, deterrent fluid will be discharged into the vehicle, thus giving the occupant an opportunity to exit the vehicle before this occurrence. 
     System Activited Indicator Circuit 
     A preferred embodiment of the system activated indicator circuit  50  is illustrated in FIG.  2 . The base of a PNP transistor  51  is connected through a resistor  52  to the NOR gate output  40 - 1 . The emitter of the transistor  51  is connected to a positive voltage source. When the NOR gate  40 - 1  flips from 1 to 0, the collector of the transistor  51  drives the AND gate  30 - 10  to a 1 and also drives the light emitting diode  53  through a resistor  54  to indicate that the device is activated. 
     Motor-vehicle-moving Override Circuit 
     A preferred embodiment of the motor vehicle moving override circuit  60  is illustrated in FIG. 3. A normally open switch  61  is connected through a circuit protector  62  to an AND gate input  30 - 9 . The normally open switch  61  is of a type such as may be connected to a motor vehicle wheel or axle and will stay in the open condition while the motor vehicle is moving, thus preventing operation of the fluid release circuit  110 . The switch  61  will flip to the closed condition when the motor vehicle ceases to move. Closing the switch  61  therefor flips the AND gate  30 - 9  to 1, permitting operation of the fluid release circuit  110 . 
     Inadvertent-operation Prevention Circuit 
     A preferred embodiment of the inadvertent-operation prevention circuit  80  is illustrated in FIG.  4 . In the special add-on mode, mode switch  20 - 8  provides a 0 to the base of a PNP transistor  81 . The emitter of the transmitter  81  is positively biased and the bases of a pair of NPN transistors  82  and  83  are connected to the collector of the PNP transmitter  81  through a resistor  84 . The emitter of the NPN transistors  82  and  83  are grounded. The collector of the first NPN transistor  82  is connected to a switch  114  in the fluid discharge circuit  110  and through an LED  85  to the positive voltage source. The collector of the second NPN transmitter  83  is connected through one resistor  86  to the positive voltage source and through a second resistor  87  to a grounded capacitor  88  and to a NAND gate  100 - 1 . 
     When the remote  70  is operated, the receiver at point  72  causes the transistor base to become 0. Thus, transistors  81 ,  82  and  83  are all on. If the remote  70  is maintained in continuous operation for a preselected period of time, the capacitor  88  discharges through the resistor  87  and the second NPN transistor  83  to cause the NAND gate  100 - 1  to flip from 1 to 0. A light emitting diode  85  indicates that the fluid release circuit  110  will be activated if motion occurs in the protected area. The capacitor  88  and resistor  87  are selected to provide the desired time delay between operation of the remote  70  and operation of the switch  114  in the fluid release circuit  110 . An approximately ten second delay is preferred, but the actual time will depend on the particular application of the device. 
     Evacuate-vehicle Time Delay Circuit 
     The preferred embodiment of the evacuate-vehicle time delay circuit is illustrated in FIG.  5 . The circuit  90  consists of an NPN transistor  91  having its base connected through a resistor  92  to the NAND gate  100 - 11 . The emitter of the NPN transistor  91  is grounded. The collector of the NPN transistor  91  is connected through a variable resistor  93  and a capacitor  94  to ground and through the variable resistor  93  to the NOR gates  40 - 8  and  49 - 9 . The collector is also connected to a positive voltage source through a resistor  95  and an LED  96  across the resistor  95 . Even if the remote  70  is disconnected after the time delay provided by the inadvertent operation prevention circuit  80 , the capacitor  94  will discharge through the resistor  93  and the NPN transistor  91  and, after the preselected time determined by the variable resistor  93  and the capacitor  94 , will change the NOR gates  40 - 8  and  40 - 9  to a 0, thus assuring that the fluid discharge circuit  110  will operate after the preselected time. This delay affords an opportunity for the occupant, when alerted by an in-vehicle audible or visible warning, to evacuate the vehicle before deterrent fluid is discharged. The light emitting diode  96  indicates to the user that the selected time delay has elapsed and that deterrent fluid is being released into the protected area. 
     Fluid Discharge Circuit 
     A preferred embodiment of the fluid discharge circuit  110  is illustrated in FIG.  6 . An NPN transistor  111  has a grounded emitter and has its base connected through a resistor  112  to the AND gate  30 - 8 . The collector of the NPN transmitter  111  is connected through a main fluid release switch  113  to a positive voltage source. A secondary fluid release switch  114  is connected between the positive voltage source and the inadvertent operation prevention circuit  80 . A motor  121  operates the fluid valve  141 , opening and closing the valve  141  during each rotation of the motor shaft. The motor  121  also simultaneously operates a pair of switches  122  and  123 , one normally opened and the other normally closed. The motor  121  is connected to a power source such as a battery  124  through the normally closed motor switch  123  and a normally open switch  125 . The switch  125  is operated in response to the main switch  113  in the fluid discharge circuit  110 . Thus, once motion occurs in the protected area and the protected area is not a moving motor vehicle, the motor  121  will operate until the normally closed motor switch  123  opens and the normally opened motor switch  122  closes. The motor  121  is also connected to the battery  124  through a selector switch  126  either through the normally opened motor switch  122  or through a normally opened secondary switch  127  operated by the secondary switch  114  in the inadvertent operation prevention circuit  80  and the normally opened motor switch  122 . Thus, when the normally opened motor switch  122  is closed and the normally closed motor switch  123  is opened, the motor  121  will operate if the selector switch  126  is connected directly to the normally opened motor switch  122 . In this event, the motor  121  will continue to operate, turning the flow of deterrent fluid on and off as long as the motor  121  continues to operate. However, if the selector switch  126  is connected through the secondary switch  127 , the motor  121  will not continue to run unless the secondary switch  114  is operated by the inadvertent operation prevention circuit  80 . Thus, the motor  121  will operate for only one half turn and the deterrent fluid will be continuously rather than intermittently released. 
     Thus, when the fluid discharge circuit  110  is operated through the AND gate  30 - 8 , and the selector switch  126  is in the desired position, the motor  121  will run until the normally closed motor switch  123  opens, at which point the motor  121  will stop. The fluid valve  141  will remain open regardless of the existence of any additional movement in the protected area and deterrent fluid will be continuously discharged into the protected area. When the main switch  113  operates and the selector switch  126  is in the direct position, the motor  121  will continue to run as long as the switch  113  is energized. In this condition, the fluid valve  141  opens and closes during each turn of the motor  121  and, as long as there is movement in the area protected, the motor  121  will continue to run and the fluid discharge valve will continue to open and close. In the radio remote operation, when the mode switch  20 - 8  is closed and the switch  125  is in the indirect position, the fluid discharge valve  141  will remain in an open condition. If the remote button is operated for approximately one second, a 0 will be applied through the remote mode switch  20 - 8  to the transistor  81  in the inadvertent operation prevention circuit  80 . When this happens, the circuit  80  causes the switch  114  to be energized and power will be provided to the motor  121  through the selector switch  126 , the secondary switch  127  associated with the switch  114  and the normally opened motor switch  126  and will return to the start position if no further movement occurs in the protected area. 
     Conclusion 
     A prototype of the anti-theft device which has been satisfactorily tested employs the following components: 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Component 
                 Number 
                 Description 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Motion Detector 
                   
                 Radio Shack Cat No. 49-425 
               
               
                 Remote Control 
                 70 
                 Radio Shack Cat. No. 61-2667 
               
               
                   
                   
                 Receiver/Transmitter Wireless Remote 
               
               
                   
                   
                 Switch 
               
               
                 Spray Box 
                   
                 Tear Gas and Pepper Gas 
               
               
                 Batteries 
                 124 
                 Two 1.5 volt for motor 
               
               
                 Battery 
                 Not 
                 9 Volt for Motion detector 
               
               
                   
                 shown 
               
               
                 Switches 
                 113 and 
                 5 Volt PC Relays 
               
               
                   
                 114 
               
               
                 AND Gate 
                 30 
                 CD 74 HTC 08 E Dip 
               
               
                 NOR Gate 
                 40 
                 CD 74 HTC 02 E Dip 
               
               
                 NAND Gate 
                 100 
                 CD 74 HTC 00 E Dip 
               
               
                 Transistor 
                 51 
                 CEN 424 EBC PNP 
               
               
                 Transistor 
                 81 
                 CEN 424 EBC PNP 
               
               
                 Transistor 
                 82, 83 
                 N 524 MPS A05 NPN 
               
               
                 Transistor 
                 91 
                 NP 930 EBC NPN 
               
               
                 Transistor 
                 111 
                 N 524 MPS A05 NPN 
               
               
                   
               
             
          
         
       
     
     While the invention has been described in conjunction with specific embodiments and methods of operation thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.