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LED's for model truck

Discussion in 'LEDs and Optoelectronics' started by Robert (Bob) Haynes, Mar 7, 2015.

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  1. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    I am new to electrinics and really don't have a clue what I am doing. I am trying to put 19 LED's of various colours in a wood model truck. I have tried a circut that I found in the internet but it won't work for me. It only lights up five LED's. I am using a wall wort 12V 2A supply through the circut as shown and am a bit afraid to modify the circut so I won't blow all the LED's. I really need help, if anyone out there can give me a hand it would be appreciated.

    IMG_0001[1].JPG IMG_0003[1].JPG schematic[1].jpg IMG_0006.JPG
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    hi Bob,
    welcome to the forums :)

    not sure what the coil or the transistor and bits are for ?
    was it supposed to be a flashing LED system ?

    problem one ( ignoring for a moment the coil and transistor and bits)

    19 LEDs in series each with a voltage drop of ~ 2 to 3 Volts = around 47V
    and you are supplying 12V .... see the problem
    you need to break them up into sets of only say 6 sets of 3 in series ( that would be 18 LEDs total)
    you would also need some series resistors for current limiting


    see this help resource on this site for using LEDs
    https://www.electronicspoint.com/resources/got-a-question-about-driving-leds.5/

    its likely to answer many questions :)


    Dave
     
  3. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    Hey Dave,
    This circut was originally to be powered with a 9 V dry cell and run 10 various colour LED's. It was from a site talkingelectronics.au. I thought that if I went up to 12 V it would power mor lights. I was obviously wrong. I did think that LED's were current driven at about 20 MA and voltage under 3 V. I have more reading to do by the looks of things.
    Thanks for your link, I'll follow up.

    Bob
     

    Attached Files:

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  4. Gryd3

    Gryd3

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    Jun 25, 2014
    Well. If you are willing, the LED's can be grouped together in smaller strings that CAN be powered without any of that magic.
    You have a 12V power supply, so you could chain together 1 - 9 LEDs. I know this is less than you have.. but you can power more than one chain at the same time!
    You can make almost as many 'chains' as you want, as long as the power supply can handle the current, which looks like it's rated for 2A... so you have LOTS of play room.
    Do you want ALL the leds to stay on ? or do you want to be able to turn different 'sets' on and off?
     
  5. BobK

    BobK

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    Jan 5, 2010
    davenn likes this.
  6. davenn

    davenn Moderator

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    yeah I had already sent him to the powering LEDs resource .... see my earlier post ;)

    he said he was going to have a look
     
  7. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    Hi Gryd3.
    I do want all the lights on at once. I have 2 white (headlights) 8 amber running lights and 7 red tail lights. I am reading and trying to understand more as Dave suggested but it is slow going. Thanks for all the help I'll keep reading and trying new things. I am on the road for a few days and may be a bit slow to respond to these threads but I am great-full for all the response. I am willing to try any suggestions.
    Bob.
     
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  8. Gryd3

    Gryd3

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    Jun 25, 2014
    Play with it and let us know!
     
  9. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    Hi again
    I have read quite a bit as Dave suggested and things are working out OK so far. The hardest part now is getting the LED's and wires in the truck and hiding all the wiring. Thanks for all your help. I'll post a picture on this forum when I complete.
    Bob
     
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  10. davenn

    davenn Moderator

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    good to hear :)
    looking forward to seeing a final pic of the model all lit up :)
     
  11. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Yeah me too. I love this sort of thing. I know its on a larger scale but earlier this year I saw the UK Coca Cola lorry, very cool.
    Adam
     
  12. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    Hi it's me again;
    It took more time than I thought to wire all the LED's through the solid wood truck. There are a total of 21 lights in all. Thanks to your help pointing me in the right direction. A bit of patience and some reading worked out for me. My nephew loves the outcome and says it makes the perfect night light. Now, does anyone know how to build an electronic level indicator for my fifth wheel?
    IMG_0012.JPG photo.JPG
     
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  13. Gryd3

    Gryd3

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    Wow, very nice!

    As far as the level is concerned... the only thing I can think of is an accelerometer and microprocessor... but there has got to be a simpler method.
     
  14. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Oh yeah love it!
     
  15. Robert (Bob) Haynes

    Robert (Bob) Haynes

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    Mar 7, 2015
    Thanks for your kind input. I was sort of kidding about the levelling device for the fifth wheel. I barley understand ohms law. I have tried to source an electronic incineometer but they are about $165.00 US. Not in my price range.

    Thanks again,

    Bob
     
    Arouse1973 likes this.
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