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Modding Rainbow LED

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

  1. wengi

    wengi New Member

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    Luxeon*9 modification

    Hi all,

    first of all i would like to thank macroman for his circuit and all of the rest of you for your ideas.

    I am going to use 9 Luxeon Star Leds (1W) with the circuit.
    To do so, i made some modifications.

    Please have a look at [see EDIT2]

    i added a voltage regulator and stronger transistors.
    The parts are ordered but i would like to ask you for help and ideas.
    So if anyone of you finds a bug or thinks there can be made some improvements: Let me know!

    I will post a part list, the eagle files and some photos when i finished my project.

    Wengi

    EDIT:

    The circuit is complete but i have a timing prob. I will try to change the capacitors and VR1 to make it slower. Also the fading of the Luxeon Stars seems to be a little difficult.

    EDIT2:

    The Prob: Ib (~35mA) of the transistors is too high at Ic=350mA for lumileds. The 4029 does not manage to load the capacitors higher than ~7V. That's not enough. i will change the whole circuit. No luck :-(
     
    Last edited: 10 May 2006
  2. junkyjorje

    junkyjorje New Member

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    wrong transistor type?

    wengi,

    I am pretty sure your problem is that you used BJT (Bipolar Junction Transistor) transistors. they work by increasing Ic depending on a ratio of Ib. For example (this is just made up, the current values do not correspond to a real transistor!), if you want Ic to be 10mA, then you need Ib to be .1mA and if you want Ic to be 1000mA then you need Ib to be 10mA. the ratio is not linear, but there is a direct link between them.
    what you should get are FET (Field Effect Transistor) transistors. There is still a relationship between the Ib and Ic in these transistors, but it can be safely ignored because Ib can be SOOOOO SMALL and still fully turn on the transistor that any cmos device (the counter chip) will easily supply the required current and the transistor will still fully turn on.
    The fact that you modded this mod (get the pun? :D ) suggests that you know about electronics, maybe you just overlooked the transistor types when you were purchasing/sampling. For other people out there, any transistor with *FET* in its name or "features" list is a FET transistor, including MOSFET, TRENCHFET...
    If anyone wants to get stronger transistors that will be compatible, just google for "power mosfets" and browse around. there are tons out there, its not hard to find one rated for the current/voltage that your working with.



    GsJosh,

    your problem could be related to a number of things:
    1. wrong transistor types/put in backwards (this is a common problem).
    2. counter burned/soldered in a way that it constantly outputs the binary number 111.
    ... actually thats all that i can think up of off the top of my head lol. if you have a camera handy, a couple of pictures (from different angles showing all of your soldering) of your circuit would be helpful in debugging. Also, plz provide some links to datasheets of the parts that you used. Alldatasheet.com is a really nice site to look up datasheets. btw, encase you were worried about the different ending letters on your chips, those letters just signify different operating temperatures or package sizes or details like that, not different functionality. So basically your chips should work fine with this mod.
    PS, if you want a simple trick to making clean(er) circuits, just push all of your parts into a piece of thin cardboard (posterboard) in the layout that you want it. Then just solder the pins and wires on the underside of the cardboard. be careful not to use too much solder or to touch the cardboard with the iron as it will burn the cardborard and maybe start a fire (take necessary precautions and work carefully and safely of course, and DONT SOLDER ON CARPET OR FABRIC!)

    ok. it was past my bedtime when i wrote this so it could be completely unintelligeble. dont be shy about asking me to re-word anything.
     
  3. wengi

    wengi New Member

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    Hi junkyjorje,

    thanks for your hint. You are absolutely right. I simply did not read the specs of the transistors with enough care. I will change them.

    Thanks for your help :thumb:

    wengi
     
  4. Ernie S.

    Ernie S. New Member

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    Using Dip sockets will prevent damaging the IC's.
     
  5. spazticorange

    spazticorange New Member

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    Veroboard Design

    Hey guys... I really think this is an interesting design. I'd just like to ask all those pros out there. Currently, I'm using three seperate LEDs for the colours. Is there a special design someone can just hand draw for me so that I can figure out how to work this whole thing using just one RGB led? I managed to get a super-flux one for about 15 Malaysian ringgit. That's about USD 4.2...so please let me know ok guys? thanks...
     
  6. DirtyH

    DirtyH New Member

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    I made a small modification to my setup.

    Here is the circuit:
    [​IMG]

    And here are some pictures of the result:

    This is the 3-way-switch. Here can I choose the following options:
    left - automatic fading, like before
    middle - off
    right - bypass of the fading part, simple on/off switching of the LED
    [​IMG]


    These are the 2-way-switches for control of the LED
    [​IMG]
    [​IMG]
     
  7. MidnghtDrgn

    MidnghtDrgn New Member

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    Whered you pickup that enclosure at?
     
  8. DirtyH

    DirtyH New Member

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    Conrad Elektronik, a german electronic store
    its the same like Radioshack on your side of the earth i think ;)
     
  9. NetVamp

    NetVamp New Member

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    Hi, sorry Im getting this rather old topic back up, but I got a question to a modification I plan.
    Im trying to do something like DirtyH, but since his layout ist death I cant see how he has done it.
    I want a switch to turn from automatic fading to manual chosing.
    I know where I have to put in the 3 Switches for the single LEDs, but Im not sure where to put a switch to stop the fading function but I have a guess.
    Im just not sure if the way I want to do is, doesnt destroy the transistors.


    I want to build in a Switch that disconnects the +12V from all the Collectors and reroutes it direct to the LED resistors.
    That means the transistor has no connect on the collector pin, but will get a +12V input on his emitter pin. The base pin will stay as it is.
    The question is, does the 12V input on the emitter pin damage the transistor?

    I hope that I was able to give you a image of what I plan to do.
    If not tell me and I try to draw what I want to do.

    Thx

    Edit: I just thought of another way to describe it ;)
    If I reroute +12V to R1 (or any other of LED resistors) do I have to disconnect the emitter from R1 or can that connecting stay, without damaging the transistor?

    Edit2: So I draw the modification I plan into the BitTech Schematic, hope thats okay.
    [​IMG]
    The red crosses mark the position where I want to disconnect the line with a switch, the green lines are the new route the switch enables.
    Does that work for the transistors? Or will I blow it up that way ;)

    Edit3: And another question, if I plan to use multiple LEDs on one transistor, do I have to recalculate the transistor base resistor? Or are the 10k Ohm always about right?
     
    Last edited: 2 Dec 2006
  10. PhilGG

    PhilGG New Member

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    IC2 QW20W no longer available

    Hi there

    Just discovered this great little project. Unfortunately, Maplin no longer do the QW20W IC required. Does anyone know of a suitable alternative?

    Thanks

    Phil
     
  11. DirtyH

    DirtyH New Member

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  12. sh_bmw

    sh_bmw New Member

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  13. DirtyH

    DirtyH New Member

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    edit:
    nevermind, got it working ;)
     
  14. Avner

    Avner New Member

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    the 4029 can probably be replaced by a simple 4017 counter with diodes at the outputs, that will set the pattern.

    i'm planing posting here my idea of enlarging this circuit, that is talking of cascading 10 units of this rgb led circuit, and running them as a chaser (using a 4017)
    that way ill have a chaser of 10 (or more) RGB leds, that will fade into new colors one after the other.
    that way, i have only one 555 timer, which set the clock to the 4017 counter, and the 4017 on its turn, will jump signals to subsequent 4029 rgb led controller telling it to switch to the next color....

    more soon
     
  15. Avner

    Avner New Member

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    Project update

    OK,

    so my idea was to take the RGB LED control a bit further and use PWM for driving the LEDs.
    that way the fade can be more accurate and linear.

    I'm done with the electronics part, and next step is the housing and cooling of the LEDs module

    please read more and watch pictures on my blog: RGB PWM LED control driver

    Comments are welcomed

    [​IMG]
     
  16. thehippoz

    thehippoz New Member

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    hehe I might put one together just for the hell of it.. thanks
     
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