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LED's for model truck

Robert (Bob) Haynes

Mar 7, 2015
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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
 

davenn

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Sep 5, 2009
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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
 

Robert (Bob) Haynes

Mar 7, 2015
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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
 

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Gryd3

Jun 25, 2014
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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
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?
 

davenn

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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
 

Robert (Bob) Haynes

Mar 7, 2015
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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.
 

Gryd3

Jun 25, 2014
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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.
Play with it and let us know!
 

Robert (Bob) Haynes

Mar 7, 2015
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Play with it and let us know!
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
 

davenn

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

Arouse1973

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Dec 18, 2013
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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
 

Robert (Bob) Haynes

Mar 7, 2015
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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
 

Gryd3

Jun 25, 2014
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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?
View attachment 19563 View attachment 19564
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.
 

Robert (Bob) Haynes

Mar 7, 2015
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Mar 7, 2015
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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
 
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