make a flashing LED

Discussion in 'The Projects Forum' started by darktendencies, Jan 12, 2013.

  1. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    hi i'm relativity terrible at electronics and i need some help...

    i have been what i call a tinkerer for about 6 years and love play around with all sorts of things electrical. The one thing i still cant work out how to make is a flashing led because i lost my books with all my information.

    can anyone help me find easy to follow instructions to make one

    cheers.
     
  2. Wendy

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    Mar 24, 2008
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  3. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    uhhhhh.... more info

    i'm using 3V super bright white LED's, im only using one for the circuit but im thinking of makeing a few of the same circuit.

    i also have 4.5, 6, 9 and 12V cells if it helps

    im not worried about the blink rate as long as its around or below 3 flashes per second, if not i would like to go around 1 every 3 seconds....

    any other specs need just ask please. :)
     
  4. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    i should also add i dont have a 555 thingy
     
  5. Wendy

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    LM555 (and equivalents) cost 30¢ or so, about $1.50 from Radio Shack. One of the more common parts out there.

    So why not tell us what you want to use. You are likely going to have to buy parts anyhow. Things like semiconductors, resistors, and capacitors are not exactly off the shelf, unless you happen to go to the right stores, and these same stores will likely have 555s.

    They do sell LEDs that will flash all by themselves you know.

    Thing is, there are so many ways to do this it is up to you to tell us what you really want.
     
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  6. darktendencies

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    Jan 12, 2013
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    uhhhh wow... i dont know what radioshack is im australian not sure if that matters i have a bunch of resistors, capacitors, transistors and so on i just dont know what to put togather..
     
  7. Wendy

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    Have you read volume 6 of the AAC book on the top? There are quite a few experiments (hands on) you could use.

    You can also google "astable multivibrator", this is one of several names for this configuration.

    Forrest Mimms III got me started, his books are real gems.

    You'll note a lot of old hands have their location in the profile, this is to help locate parts. Radio Shack is a electronics chain that is everywhere in the USA. They are a bit more expensive, but you can go in and buy parts in a mall off the shelf.

    I have no idea what folks in OZ might use.
     
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  8. darktendencies

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    Jan 12, 2013
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    thanks Bill, ill give it a go
     
  9. darktendencies

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    Jan 12, 2013
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  10. ScottWang

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  11. Wendy

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    That will work, just use the collector resistors to limit the LED current. I think there is an experiment in volume 6 based off that schematic.
     
  12. vk6zgo

    Active Member

    Jul 21, 2012
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    They used to be "Tandy's" in Oz,but Woolies bought them out & combined them with Dick Smith,who don't sell parts any more.

    Your easiest option is Jaycar or Altronics.

    A lot of old stuff from the USA quotes RadioShack part numbers,which were the same at Tandy's,but are meaningless to the other suppliers.
     
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  13. darktendencies

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    Jan 12, 2013
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  14. Wendy

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    The larger the capacitor and base resistor the slower the flash rate. With a transistor astable each transistor/capacitor/resistor control one half of the flash (on / off), so you have to allow both to be large.

    With a IC only one capacitor and resistor is needed for the exact timing.

    Wikipedia has a good article on the subject, though it may be a bit advanced for you.

    The LED is also going to need a resistor to keep from burning it out (and the semiconductor).

    Tell us what parts you have and maybe we can draw something up.
     
  15. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    okay i have a bunch of LEDS that can handle up to 4.5V
    i have a huge amount of resistors i can name every value
    i have several capacitors:
    several 100uf's
    a few 10uf's
    one 33uf
    a 4.7uf
    a 220uf
    a 47uf
    a 1uf
    and last but not least a 0.47 uf
     
  16. Wendy

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    The 100µF will likely be the parts of choice, though the 220µF is promising. Transistors and resistors? Approximate ranges will do. Likely 100KΩ range is what you want. Depending on the battery, you will need under 1KΩ (X2) also.

    LEDs are not voltage devices. Please read my article chapters 1 and the 1st half of chapter 2, they are LED tutorials.

    LEDs, 555s, Flashers, and Light Chasers

    Don't forget to tell the transistors.
     
    Last edited: Jan 13, 2013
  17. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    hey I've just been on altronics and found allot of stuff i'm going to buy in the next few weeks so ill get back to you then because i will then have NE555 timer thingys and stuff in that order..... sorry to waste your time :/
     
  18. darktendencies

    Thread Starter New Member

    Jan 12, 2013
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    thanks a heap you dont know how much stuff im about to buy from altronics now that ive benn on the site
    :D soo happy right now
     
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