I am trying to build a simple circuit using CD4013 flip-flops that use a combination of two 12vdc pulses within a set period of time to close a relay. I'm thinking of 4 pulses in a unique pattern such as P1-P1-P2-P1. Logically, when the first pulse comes in, it would trigger the first flip-flop and start a timer. If the following pulses arrive within the time period in the proper order, the relay would energize. If not, the circuit would reset and wait for the next P1 pulse. I found a schematic as a starting point and revised it to come up with the attached. It doesn't guarantee the exact combination (P1-P1-P2-P1) but it does force two P1 pulses only before the P2 pulse. I am using modeling software to test the circuit but have a problem with the auto-reset after the solenoid is activated. According to the original lock circuit, the R12/C2 timer circuit is supposed to reset the lock through diode D1. If I close SW4, the circuit doesn't work at all. If I leave it open, the circuit works but does not auto-reset. Any ideas?
Also, what would be the easiest and/or best way to put a timer on the overall circuit that would require the proper input (P1-P1-P2-P1) within 5 seconds or the circuit resets?
Also, what would be the easiest and/or best way to put a timer on the overall circuit that would require the proper input (P1-P1-P2-P1) within 5 seconds or the circuit resets?
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