Power led slot turn

Discussion in 'The Projects Forum' started by dragalic, Dec 1, 2011.

  1. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    i have power led
    10W
    input 12V 900mA-1000mA

    I want to make slot turn on and slot turn off of at least 10min
    (when i turn on the let it should start slowly and for 10+min to get its maxium, same when i turn off)

    is this posible, and if someone can give me some schematics,

    thanks
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Use a voltage controlled pulse width modulated[PWM] to control brightness, & triangle wave generator to control PWM, [ 555 ? ].
     
  3. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    its so simple when you write it
    but im litlle beginner, so any schematic will be helpfull
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    If you were a bit more clear as to what you want I could help.

    I have a tutorial on the subject. You will have to learn to read schematics though.

    LEDs, 555s, Flashers, and Light Chasers

    Suggestion: enter your approximate location in your profile so it would show up on the posts, it helps people cater the parts to your needs.
     
  5. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    litl bad in english byt will make it more clear (will put location now)

    its slow turn on/off
    take a look at the video, i want that for at least 5-10min, (may be more if cant)
    http://www.youtube.com/watch?v=gKykP936tWA
    for power led
    12V 900mA

    i take a look there, but all its on normaln led 20mA (not something on 12V 900mA)

    can this work and how much slow it could be
    [​IMG]
     
  6. Wendy

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    Mar 24, 2008
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  7. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    not by itself, i want slow turn on when i turn power on, and slow turn off when i turn off the power
     
  8. Wendy

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    Mar 24, 2008
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    I helped a gentleman with something similar about a year ago. I'll point the thread out when I get a chance.

    Several points though, when you turn the power off what is going to light the LEDs up while they fade? This means you will not be turning power off for this circuit. It is going to need power while the LEDs are on.
     
  9. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    ok thats not problem, but some triger to know when its need to slow turn off
     
  10. Wendy

    Moderator

    Mar 24, 2008
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    OK, we'll modify this schematic...

    [​IMG]

    from this thread...

    LED fade in/ fade out

    from this post...

    http://forum.allaboutcircuits.com/showpost.php?p=344698&postcount=49

    I spent the 1st half of that thread correcting the same misunderstanding that I made about your request.

    I will redraw this schematic when I have time to fit your needs, basically removing all the LED chains and replacing it with your single LED.

    As with the other one, you will need 12 V on it while it is fading, which means permanently more or less.
     
  11. dragalic

    Thread Starter New Member

    Dec 1, 2011
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  12. Wendy

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    While the LED is on it will have that draw. When it is fading it will not.

    I do need to redraw the schematic. It will take about a day to get done.
     
  13. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    cool, take your time, this its not urgent for me
     
  14. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    p.s. if need i can add one more power suply, just if its posible slow turn on/off to be via power suply
     
  15. Wendy

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    Mar 24, 2008
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    [​IMG]

    All resistors are ¼W.

    The current regulator LM317 and R9-R17 can be replaced with a commercial buck puck (google it) for much greater efficiency (as in a lot less current) and the LED will still get 900ma.

    The LM317T will require good heatsinking, as it will get very hot at maximum brightness.
     
    Last edited: Dec 5, 2011
  16. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    cool, so should i make example a or example b
    couse the difirence ive seen its
    or example b use 2 power suply, one for on/off and one for constantly suply the board

    and u2b its lm393, right
     
  17. Wendy

    Moderator

    Mar 24, 2008
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    It is ½ of a LM393, the U2A is the other half. Some parts (capacitors and U2A) of the schematic are the same for both function, so I only drew them once.

    Example A is for a toggle switch, Example B is for a second power supply to cause the LED to lighten and darken.
     
  18. T.Jackson

    New Member

    Nov 22, 2011
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    What are you drawing your schematics in?
     
  19. Wendy

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  20. dragalic

    Thread Starter New Member

    Dec 1, 2011
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    thanks, i will try to draw the board and send here picture to take a look
    about the power suply i use 1000mA and led need 900mA is it ok to use LM317 and R9-R17 and not searching for some commercial buck puck
    and second power suply for turn on/off does need to be 1000mA or can be less, i got a lot 350mA adapters, so could use one of them
     
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