555 Chip to keep power on for 1min?

Discussion in 'The Projects Forum' started by rokz_2005, May 15, 2011.

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  1. rokz_2005

    Thread Starter Member

    May 14, 2011
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    Hi guys, how can I activate a switch by pressing it once but I want the power to flow continuously for 1min I was told to use a 555 timer on a bistable layout.

    Which components would I need exactly. It is to run on a 12v DC power supply.

    Thank you
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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  3. simo_x

    Member

    Dec 23, 2010
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    This circuit should work fine
    [​IMG]
    Pin 4 goes to Vcc.. Take a look at 555 datasheet.
    Regards,
    Simo
     
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  4. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    A 555 timer in bistable mode will keep the output on until you reset it. What you want is a 555 in monostable mode (like the one simo_x posted). Here's one that is more complete:
    [​IMG]
    A 1000uF capacitor and a 56K resistor should give you a delay of about a minute. If you want it exact, I suggest you get a 100K variable and set it to where it gives a 1 min. output.

    EDIT: Forgot to mention-- Put a normally-open push-button switch between "trigger" and gnd, with a pull-up resistor (about 4.7K)
     
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  5. radiohead

    Active Member

    May 28, 2009
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    how much current will your load draw? You might want to consider using a relay so your 555 doesn't heat up too much.
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    I started to comment about the lack of pull up resistor, then saw your edit. It is a major flaw. The pull up resistor is not optional, and it wasn't too long ago I had to argue about it in another thread.
     
  7. rokz_2005

    Thread Starter Member

    May 14, 2011
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    Yup I do. Basically my circuit involves 3 feature.
    1 double tap the switch to activate power
    2 after activating power, I want the power to run con
    3 to press the button again to break the circuit. to stop the 1min run
     
  8. rokz_2005

    Thread Starter Member

    May 14, 2011
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    That is wicked, thanks a whole bunch mate. I shud b making my circuit this weekend :):)
     
  9. rokz_2005

    Thread Starter Member

    May 14, 2011
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    To be honest i'm not sure yet.
    The input power is 12 volt. I'm making a little entertainment feature for my ride :)
     
  10. rokz_2005

    Thread Starter Member

    May 14, 2011
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  11. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Lets continue in the other thread and stop scattering with all the threads.

    Bertus
     
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