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30 second lag time timer

  1. Mar 5, 2009 #1

    Please could you help me with this problem;

    I need to design a timer whereby I briefly trigger it (using a push to make/push to break switch connected to a 6 v supply), there is a pause of 30 seconds and then it triggers with an output, say an LED - this stayes on for about 10 seconds then automatically extinguishes, after it has extinguished it then shuts off. It's only until I trigger the PTM/PTB switch again that the sequence begins all over.

    Please, please help.....I was hoping to possibly use a 555 timer(s) or something very simple.

    Hope you can help :cry:

  2. jcsd
  3. Mar 5, 2009 #2


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    Push to make/push to break? I assume you mean a single pole single throw momentary switch?
    If so, I would use 555 timers, or a single 556. Configure them monostable. Make one time out at 30 seconds, the other at 40 seconds. Hook the LED between the outputs, or buffered outputs.
  4. Mar 5, 2009 #3


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    Welcome to PF big_tobacco. I agree with Averagesupernova in using a couple of 555s or a 556 to generate your pulses but if you have any kind of large load to consider, you might want to use a
    http://www.factorymation.com/s.nl;jsessionid=0a010c491f434401fa96817849d4a900c5c8249efc4a.e3eSc3aPaxmLe34Pa38Ta38NaNb0?sc=2&category=100" [Broken].
    Last edited by a moderator: May 4, 2017
  5. Mar 6, 2009 #4


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    Maybe something from the Microchip http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=1009&mid=10&lang=en&pageId=74" families?

    The ATMEL equivalent is the http://www.atmel.com/dyn/products/devices.asp?family_id=607#791" family.

    They *are* simple--it's just that it's simple software instead of simple hardware.

    EDIT: But yeah, if you have any kind of large load, go with the time-delay relay as dlgoff recommends. On the other hand, depending on what sort of expertise you have, you *could* drive a triac or relay.
    Last edited by a moderator: Apr 24, 2017
  6. Mar 6, 2009 #5
    Brilliant, thank you very much for your help. I think this weekend I'll crack out the bread-board and give these a try!
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