Another 555/556 question...

Discussion in 'General Electronics Chat' started by mbohuntr, Aug 7, 2013.

  1. mbohuntr

    Thread Starter Active Member

    Apr 6, 2009
    413
    32
    Well, I built my garage alarm on a vero board using a 556 as a two purpose delay. The first is a man door delay timer so you can disarm the circuit before it goes into alarm. I intended to use the other half as a long time delay to reset or disable the entire circuit after it has sounded for some time.
    Stupid me.... I wanted the second half to stay off until the alarm sounds, then go into astable mode to start a 4017 decade counter and finally trip a transistor latch relay circuit to remove power to the rest of the circuit, shutting off the alarm. Whoops, is there any way to block the astable mode NOT using the VCC pin on the 556? (I still need the other half powered for the door circuit...) :rolleyes: DUH...... didn't see that coming....

    Thanks in advance!
     
  2. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    Use an AND gate on the output.
     
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  3. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,871
    1,394
    Ground 2Reset (pin 10).
     
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  4. mbohuntr

    Thread Starter Active Member

    Apr 6, 2009
    413
    32
    I tried to thank both of you, but the phone app is acting goofy... Thanks BOTH of you guys, ill try it out!
     
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