Microcomputer controlled combination lock security system

Abstract

A security system includes a microcomputer with an auxiliary read-only memory and a key device including a similar read-only memory, each of the read-only memories containing corresponding pluralities of corresponding binary combination codes. Under the control of the microcomputer the codes are read and compared. If the combination and the sequence do not compare, the system will not unlock and an alarm will be generated. The read-only memories are of the programmable type, so that changes in the combinations and sequences can be accomplished easily. A plurality of visual indicators and an audible alarm provide the user and personnel in the secure area with information concerning the status of the system.

What is claimed is: 
     
       1. A security system for restricting access to a secure area to authorized persons, comprising, in combination: (a) a microcomputer containing a first, selectively programmable read-only memory;   (b) a key device having mounted thereon a second, selectively programmable read-only memory;   (c) each of said first and second memories containing corresponding pluralities of corresponding, multi-digit, combination codes arranged in corresponding sequences;   (d) key reader means connected to said microcomputer and having a receptacle for receiving therein a portion of said key device to establish electrical connections between said key device and said microcomputer;   (e) means governed by said microcomputer for transferring data from said key device to said microcomputer;   (f) a controlled access device governing physical access to said secure area; and   (g) circuit means connecting said microcomputer and said access device, said microcomputer being effective to compare said multi-digit combination codes, one complete code at a time, and to compare said code sequences stored in said first and second memories and to control said circuit means to enable said access device when and only when such comparison shows equality of said multi-digit combination codes and their sequence.   
     
     
       2. A security system according to claim 1 wherein said second memory comprises a chip which is selectively programmable and reprogrammable by external programming means after mounting on said key device. 
     
     
       3. A security system according to claim 2 wherein said controlled access device comprises a deadbolt movable between retracted and extended positions by a reversible electric motor controlled by said circuit means. 
     
     
       4. A security system according to claim 3 and further including means to control said circuit means to halt operation of said deadbolt during movement thereof in response to improper operation of said security system. 
     
     
       5. A security system according to claim 1 and further including means controlled by said microcomputer for providing electrical power through said electrical connections only after verification of insertion of a proper key device into said receptacle. 
     
     
       6. A security system according to claim 1 and further including a battery mounted on said key device for supplying operating power for said circuit means through said key device, said battery having an initial, predetermined charge to render said key device operable for a predetermined time. .Iadd. 
     
     
       7.  A self-monitoring security system for selectively preventing and permitting movement of a closure member between open and closed positions, said system comprising: a) a deadbolt movable from an extended to a retracted position for permitting movement of said closure member from said closed to said open position thereof;   b) a reversible electric motor operatively connected to said deadbolt for movement thereof between said extended and retracted positions in response to actuation of said motor;   c) a microcomputer including memory means programmed to generate a first output signal in response to a first input signal, generated in response to matching of a code pre-programmed in said memory means by a code inserted in a code-receiving device, when said closure member is in said closed position and said deadbolt is in said extended position;   d) circuit means connecting said microcomputer to receive said first input signal and further connecting said microcomputer to said motor for actuation thereof to move said deadbolt toward said retracted position in response to said first output signal;   e) said memory means being further programmed to generate a plurality of individual, time-spaced output signals in response to a respective plurality of time-spaced input signals; and   f) means for generating said plurality of time-spaced input signals in response to a predetermined sequence of movements of said deadbolt between said extended and retracted positions and of said closure member between said open and closed positions member. .Iaddend. .Iadd.8. The security system of claim 7 wherein said means for generating said plurality of input signals includes a first limit switch actuable in response to said deadbolt reaching said retracted position. .Iaddend. .Iadd.9. The security system of claim 7 wherein said means for generating said plurality of input signals further includes a second limit switch actuable in response to said deadbolt reaching said extended position. .Iaddend. .Iadd.10. The security system of claim 8 wherein said means for generating said plurality of input signals further includes a switch responsive to said open and closed positions of said closure means. .Iaddend. .Iadd.11. The security system of claim 7 wherein said means for generating said plurality of input signals further includes time-responsive means operable to generate one of said plurality of output signals upon expiration of a predetermined time period. .Iaddend. .Iadd.12. The security system of claim 7 and further including an alarm device actuable in response to detection of absence of at least one of said plurality of input signals by   
     
     
        said microcomputer. .Iaddend. .Iadd.13.  The security system of claim 12 wherein said alarm device is at a location remote from said security device. .Iaddend. .Iadd.14. A self-monitoring security system including a deadbolt member movable between extended and retracted positions to lock and unlock, respectively, a closure member movable between open and closed positions to permit and prevent access to a secured area, said security system comprising: a) means for generating first and second electrical signals in response to said deadbolt being in said extended and retracted positions, respectively;   b) means for generating third and fourth electrical signals in response to said closure member being in said open and closed positions, respectively;   c) a microprocessor including memory means responsive to said first, second, third and fourth electrical signals to generate a plurality of output signals; and   d) circuit means responsive to said output signals for controlling movement of said deadbolt. .Iaddend. .Iadd.15. The security system of claim 14 and further including means for generating a fifth electrical signal in response to expiration of a predetermined time period between generation of at least one pair of said first, second, third and fourth electrical signals. .Iaddend. .Iadd.16. The security system of claim 15 and further including a reversible electric motor operable to move said deadbolt between said extended and retracted positions in response to actuation by said circuit means, and wherein said fifth electrical signal is effective to cease actuation of said motor by said circuit means. .Iaddend.