Electronic vehicle locking system controller - uses pushbuttons to individually set each of three ring counters so their outputs cause NAND gate to change state and drive solenoid

摘要

The appts. uses ring counters (C1,C2,C3) which have a reset push button (PO) coupled to each of them (Z1,Z2,Z3). Each ring counter has one of its outputs wired to an input of a three input NAND gate (10), the wiring determining the preset code. The clock input of each ring counter has a push button (P1-P3) connecting it to ground. Each time a button is pushed the count advances by one. Entry is obtained by first resetting (PO) the counters, then pushing the approp. number of times on each of the push buttons to match the preset number code. When all three counters are correctly set the NAND gate changes state and actuates the solenoid (12).