Your Favorite Way to Flash an LED?

Discussion in 'The Projects Forum' started by MCU88, Mar 17, 2015.

  1. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Hello...

    What is your favorite way to flash an LED? Or Two? Or Three even?

    I recently built this:

    [​IMG]

    [​IMG]
     
  2. JDT

    Well-Known Member

    Feb 12, 2009
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    A good circuit for a beginner learning electronics. Nicely made. Did you make the PCB yourself?

    To flash a single LED probably can't beat a 555.

    For flashing more LEDs in more complicated ways, you probably need some digital logic and counters. 4000 series CMOS is a good place to start.

    Then, move on to using simple micro-controllers, such as the PIC.
     
  3. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Your capacitors are backwards.
     
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  4. MCU88

    Thread Starter Member

    Mar 12, 2015
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    They work either way around actually. At least I'm sure they do... lol you'll always be able to find at least one error in my originally drawn schematics and PCBs ;)
     
  5. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Yes SIR. All original artwork and software in my projects.
     
  6. DickCappels

    Moderator

    Aug 21, 2008
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    Not meaning to get too astray from the question in the O/P, as OBW0549 said, the capacitors are backwards, only slightly reverse biased (you can confirm with your DVM). Running with even a small reverse bias the capacitors are doomed to fail.

    My favorite way to flash: An output pin from an AVR controller.
     
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  7. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Yes SIR. I will revise the schematic and upload again.
     
  8. MCU88

    Thread Starter Member

    Mar 12, 2015
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    Here is the revised schematic:

    [​IMG]
     
  9. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Much better!
     
  10. wayneh

    Expert

    Sep 9, 2010
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    FWIW, R1 and R4 can be a single resistor. Since only one LED is on at a time, they can share the current-limiting resistor.
     
  11. takao21203

    Distinguished Member

    Apr 28, 2012
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    how? connect them together?
     
  12. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Yes, you can eliminate R4, then run a jumper from the anode of LED2 to the Anode of LED1. The workings of the circuit become harder to visualize when that is done and the aesthetics of symmetry go to hell.
     
    Last edited: Mar 17, 2015
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  13. davebee

    Well-Known Member

    Oct 22, 2008
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    http://www.solarbotics.net/library/datasheets/LM3909.pdf

    I was given a pile of surplus electronics that included a couple of these chips. I probably wouldn't have bought them, but for free, they're great little LED flashers. I've used them as power-on indicators on circuits that I've tended to forget and leave on by mistake.
     
  14. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    My favorite way to flash an LED is to not include any form of current limiting.. It will flash...once :)
     
  15. alfacliff

    Well-Known Member

    Dec 13, 2013
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    my favorite way is to connect it to at least 120 vac, only one flash, but BRIGHT.
     
  16. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A Picmcro, if in doubt use a big hammer.:eek:
    Max.:)
     
  17. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    But I am sure you used a 1:1 transformer to get the 120VAC - otherwise you are out of compliance of the TOS.
     
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  18. wayneh

    Expert

    Sep 9, 2010
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    The easiest way to flash an LED is to buy one that flashes itself. Done.
     
  19. crutschow

    Expert

    Mar 14, 2008
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    I use an old overcoat.
     
    Last edited: Mar 17, 2015
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  20. Reloadron

    Active Member

    Jan 15, 2015
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    Agree, same here but unfortunately they have laws against it around these parts. I sure miss LA. :)

    Ron
     
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