| 摘要 |
An electronic lock security system includes a coded key and a multiple position key receiver switch having a code sensing circuit for generating signals indicative of the key's code. A decoder compares the key's code to a preset code and when a match is determined outputs a control code to a switch control circuit. A switch control circuit includes flip-flops for remembering when switch positions intermediate the off and last positions have been accessed and output control signals upon receipt of the decoder's control signal. The flip-flop outputs are consecutively ANDed together down to the last position to permit operation of a power switch to provide working power to a solenoid operated device only when all positions of the multiple key receiver have been accessed during operation. For a typical automobile ignition switch having OFF, ACCESSORY, ON, and START positions, power switches are connected to the accessory and on positions outputs of the switch control for supplying power to solenoid operated devices. Also, to prevent connecting an auxiliary battery to the starter solenoid, or other methods of bypass such as hot wiring, etc., an enable switch circuit is provided for connection as closely as possible to the starter solenoid switch. The enable circuit produces a unique voltage for passage through a comparator to bias on a transistor switch connected in series with the starter's solenoid. |
