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Modding Rainbow LED

Discussion in 'Article Discussion' started by macroman, 27 Aug 2002.

  1. DirtyH

    DirtyH New Member

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    Last edited: 25 Apr 2009
  2. DirtyH

    DirtyH New Member

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    like Tim Allen always says: More Power... :D :D

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    Last edited: 25 Apr 2009
  3. DrPsycho

    DrPsycho New Member

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    Question about leds in series

    Small question here, please bear with the electronics n00b

    I'm trying to extend the circuit to support multiple led's, and I was thinking:

    would it be possible to connect multiple leds in series to not overload the transistor? If i'm not mistaken the current should be the same over all the leds in the chain then, and all i'd have to do is add up all the forward voltages of the leds (or just multiply it by the number of leds as they're all going to be the same) and adjust the values of the resistors accordingly.
    Is this possible or is there something i'm overlooking?
    Thanks a lot in advance
     
  4. cpemma

    cpemma Ecky thump

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    There's very little spare voltage, certainly not enough to run 2 blues in series, and very close on the red & green. Apart from the 0.7V loss across the transistor, there's a few volts lost across the 10k base resistor.

    You could try extra led + resistor strings in parallel, but it will affect the fade - heavier load=faster fade.
     
  5. dragon-fly

    dragon-fly New Member

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    well, isnt the fading effect tied to the transistor and not the actual led? if it were tied to the led in parallel, i would have to agree with you, but if you ask me, it shouldnt affect teh fade since its on the transistor. oh yes and people who have the chip stay on one colour, make sure that you haev a 100uf capacitor connected in parallel to the source (battery). if your 4029 chip is heating up and staying in one colour, make sure pin8 of your 4029 is going to ground or - and that pin 16 of that same chip goes to + of your battery. its most likely you have forgoten the midle top part of the schematic, or did not know what to make out of it and left out these all important connections.

    about the multiple leds : im assuming that you can get as many of them you want in parallel as long as you have an equivalent transistor that can support the current draw. so like, change 2n3904 NPN transistor for another higher current NPN transistor and you should be fine, unless i am mistaken. and make sure your source can support the current draw from all the LEDs.

    oh and for a longer fading effect, you just need to change C3, C4 and C5 for higher values. also, the clock generator, instead of the 555 timer, i am using a 4011 CMOS NAND Gate chip. for me, its cheaper, like 2$ cheaper. sure, its bigger but i prefer the price. took the idea off of this site : http://www.aaroncake.net/circuits/chaser.htm. Basically, you just need to take out NE555 timer, c1, vr1 and r4 and replace it with the right part of the sschematic on that site. to adjust the colour change rate, you change c1 and r1/r2 on that schematic to higher values. im using a 10 uf cap instead of c1 and a 100Kohm resistor instead of r1. adjust r2 to change the speed of the colour changes. Pug in the pin 4 from teh 4011 chip to pin 15 of the 4029 chip to complete the transfer.

    Me, to know the resistor needed for the LEDs i use, i use this program called Electronic Assistant (its free) and on this site http://www.electronics2000.co.uk/
    in the program, just go to the resistance tab and to leds series resistance calculator.

    BTW, nice pics DirtyH! love them. and nice video too!

    Please correct me if i am wrong, sorry for the long post but it seemed to me that there were many unanswered questions.
    other than that, THANK YOU MACROMAN FOR THIS GREAT IDEA!

    oh yes, i forgot, im also using mps3826 transistors instead of those proposed. does anybody know where i can find its datasheet? cz i cant seem to find it. oh and here is my version, ive added a night light type circuit so it will only light up at night :p (click on the thumbnail for a bigger image)

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    Last edited: 21 Jun 2005
  6. dragon-fly

    dragon-fly New Member

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    logically, it is possible to replace the 4029 counter with the 4017, but in reality, its going to be pretty hard to get it on a board. well, you could always try, with the order being at post 100, sorted out by DirtyH, and using 7 out of the 10 available outputs from the 4017 and linking the 8th output to reset on taht same chip. the reason why it will be so complicated is because you will have to make sure that each output only lights up the lights you want it to light up. only way i can think of it doing that would be by using 11 diodes. then theres the problem of the chip not giving out enough power. i assume that you can fix that low current chip problem with transistors, atleast thats what i would do. but like i said, teh problem is more how are you going to fit all of those diodes onto that circuit board and make it look pretty.
     
  7. simosaurus

    simosaurus New Member

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    that video of the color cycle is awesome, id love one of these for the LED ring around my power button
     
  8. konrad6

    konrad6 New Member

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    Rainbow RGB LED

    I have built the rainbow LED circuit. I built it on veroboard (you know the board with all holes in it), The only other difference is I used a LED with 4 in line legs. I hope you can help me, because when it is running, the colours are not outstanding exept for th RGB colours. The cyan and magenta colours are hard to destinguish between, and the yellow only lights up for a fraction of a second. I am using the capacitors to fade slowly. I have built the circuit 3 times, once on a prototype board and twice on veroboard so I think my circuit is layed out correctly as they all performed the same.

    Could you please tell me if the circuit is working how it is supposed to or not. The cycle of colours is, as best I can work out:
    G Y R G B CY MAG W G Y R G B WCY W G Y R G B C MAG W G Y R. Then repeats.
    I have used 250Mb download worth of internet search for another circuit but found nothing exept for someone discussing a driver circuit for yhe RGB leds, he gave no clue on how to build it exept that if you used 3 sixteen bit counters you could drive the leds with 4096 different colours!

    Thankyou for reading my story, I would like some help in the area of fixing my circuit or the new 16 bit one.

    Thankyou once again,
    Konrad Ritter.
    My Email Address Is konrad6@bigpond.net.au
     
    Last edited: 15 Jul 2005
  9. konrad6

    konrad6 New Member

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    Thankyou for replying to my request, about rainbow LED. I would require the programmed microcontroller and the circuit, the other parts I can get here in Australia could you please let me know how much it will cost and how I will be able to pay you. Thankyou very much. konrad6@bigpond.net.au .
     
  10. konrad6

    konrad6 New Member

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    Yes this is what I want exactly. Can you let me know how much money I should send you including postage and I will pay you. Thankyou, Konrad Ritter. internet adress is konrad6@bigpond.net.au. Kind regards Konrad.
     
  11. Critical Mass

    Critical Mass New Member

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    Another Rainbow Video!

    Well, I too wanted to implement this circuit, but for me it was as a night-light for my new baby daughter. I used 3 ultra-bright LEDs rather than one over-priced RGB one and it seems to have done the trick. They project the light onto the ceiling, and on a slow chase it's very calming for the baby! They ar a little too bright at the moment so I plan on throwing a pot it for good measure!

    It's still on bread-board at the mo, but plan on etching a board and boxing it up pretty soon :thumb:.

    By the way, I'm running it from a 9V battery and it's absolutely fine :clap: . In fact, there's no difference between using 12V and 9V. Need to leave it running to see how long it'll last!

    Click HERE for the video but bear in mind that it's WMV and about 2M in size!

    This shows 2 diodes per channel, but 1 was plenty!
     
  12. DirtyH

    DirtyH New Member

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    Time has passed since my search for a nice and affordable milkglasball.
    And finally I found it. Thanks IKEA. ;)

    So I did everything new. Bigger, better, nicer. :rock:

    And finally here it is:

    Assembly:

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    Lightcheck:

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    LED assembly into the stand:

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    The final product:

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    And a small video:
    http://people.freenet.de/haraldschmid/rainbow/moodball.avi [xvid - 1MB]



    :)
     
    Last edited: 25 Apr 2009
  13. <A88>

    <A88> Trust the Computer

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    Worthy of Mathmos! :D

    <A88>
     
  14. midnightrider

    midnightrider New Member

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    I am new to this board and I have been searching for information on this project for a few days now, and im glad to find people who are actually doing it. I have one question is there a way to manually select the color one would want and lock the color?
     
  15. DirtyH

    DirtyH New Member

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    Easy way:
    Forget the whole circuit.
    Take only three switches, one for each color.
    Switch to which color you like.
    Thats all. ;)


    Hard way:
    No idea... ;)
     
  16. midnightrider

    midnightrider New Member

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    Easy enough but limited on shades and colors. I guess maybe 3 diffrent pwm circuits?
     
  17. cpemma

    cpemma Ecky thump

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    Not that hard, put a SPDT switch on the line between 555 output (#3) and 4029 Clock input (#15), with common to Clock input, one throw to 555, other to ground. Stop the clock when the colour's what you want. :cooldude:
     
  18. midnightrider

    midnightrider New Member

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    Thats great but again id want the same color each time I turn it on, I guess I should state what im doing, I want to use this in a mustang I am restoring, I want this to be the cluster gauge lighting.
     
  19. Bullwinkle777

    Bullwinkle777 New Member

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    Hello, I'm new here and i'm having a problem. I want to build this very badlly. It's the coolest project I've ever seen!!! But I can't seem to locate all the parts here in the states. I can't find 4029 or the trimmer :waah: . Please don't kill me for asking. Would anyone be willing to send me the parts? I will pay in advance for the parts and for the shipping.
    Thanx!!!
     
  20. indecided

    indecided New Member

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    After over a year of waiting to build this project (I always assumed it would only work with RGB LEDs and where I used to live they were virtually unavailable) I have finally found a solution, after moving to the states. Using Superflux LEDs inspired by DirtyH, just three create a excellent spread of light.

    My only complain is that the transition seems slightly jerky. maybe a pure "random" sine generator would be in order. But nevertheless, take a look at the poor man's RGB fader...you'll see why I call it "poor man's" very soon. hint : Ikea globes are expensive and they don't really ship anyways.

    Thanks DirtyH for the inspiration!

    Click here to watch the AVI Video (3.2MB)

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