double flash alternating flasher using 555

Discussion in 'General Electronics Chat' started by gadget25, Mar 6, 2010.

  1. gadget25

    Thread Starter New Member

    Mar 6, 2010
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    Hi Guys,

    Is it possible to make the red LED flash 2 times then stop, then make blue LED flash 2 times just using a 555 timer? Diagram will be much appreciated :)
     
  2. bertus

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    Apr 5, 2008
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  3. gadget25

    Thread Starter New Member

    Mar 6, 2010
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    Hi bertus,

    Great thank you for the link I will look at it now. :)

    Regards,
    gadget
     
  4. gadget25

    Thread Starter New Member

    Mar 6, 2010
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    Hello bertus,

    Now I have a question regarding the link you posted, it is shown on the diagrams that I have to use transistor and diodes, but it is not specified what type of transistor or diode I should use. It is not specified does this means that I can choose what type of transistor or diode I want? I would really appreciate it if you could shed me some light :D
     
  5. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    In the first picture of the post it says:
    CR = 1N4454 , 1N 914 or equivalent.
    Q = 2N222 or equivalent.

    The same components are used in the other schematics.
    Perhaps Bill will verify this.

    Greetings,
    Bertus
     
  6. gadget25

    Thread Starter New Member

    Mar 6, 2010
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    Great thanks sir, I was thinking the same thing but I just want to be sure than sorry. :)
     
  7. Wendy

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    Mar 24, 2008
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    I had a similar request for a virtually identical circuit, which I did. I'll hunt it down and post the link, but I'm about to step out the door.

    It can be done, and is fairly easy. It took 3 555s, one to select which 555 flasher was lighting up, and the other two to flash their respective LEDs.
     
  8. Wendy

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  9. gadget25

    Thread Starter New Member

    Mar 6, 2010
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  10. gadget25

    Thread Starter New Member

    Mar 6, 2010
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    Something is bugging me, what you just said is what was going in my head, 2 555 timers for the blinking for each set of LED's and the third 555 timer is used to pick which one of the 2 555 timers will run.

    Is this possible? :) Anyhow I will try to make this work, if not I will go for your circuit the 3.1 version police flasher. :)

    Many Thanks and best regards
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    Sure, but you would replace the one 555 with a couple resistors and a transistor to act as a logical inverter.

    See U2A? That's just being used as an inverter.

    So, instead of using two 556 timers, you would use one 555, one 556, and a transistor with a couple more resistors.
     
  12. Wendy

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    Mar 24, 2008
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    And wind up with more parts.

    The original article I referred to wound up gravitating to the original suggestion, a 555 and 4017.

    You could also use multivibrators and use 7 transistors. :D

    There really is a huge number of ways to do this.
     
  13. SgtWookie

    Expert

    Jul 17, 2007
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    Yep, there's lots of ways to do things; the possibilities are endless. ;)

    Speaking of keeping parts count down, I just had another look a bit ago at the thread of yours that Bertus linked to... I trimmed 72 parts from one of your schematics replacing them with 3, and it still does the same thing. ;)


    Original:
    [​IMG]

    Modification:

    [​IMG]
     
  14. Wendy

    Moderator

    Mar 24, 2008
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    There is a problem with the idea though, it assumes all the diodes (quantity and colors) are the same. We have enough trouble getting people new to electronics used to the idea that a resistor is required (What if I regulate voltage, or I want to get the parts count down).

    The idea was persued somewhat with the current regulator earlier in the article.
     
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