RGB Mood light

Discussion in 'General Electronics Chat' started by R!f@@, Jan 10, 2012.

  1. R!f@@

    Thread Starter AAC Fanatic!

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    Something I stumbled upon and I used the code for something else and now I want more.

    I made some mod's and used in another manner
     
    Last edited: Jan 10, 2012
  2. R!f@@

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    Jens...can you make some PCB's for me ?
     
  3. nerdegutta

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    Just say the word, and I'll have them in the mail in no time. :)

    Thus, we should agree on some minor details; sizes, mounting holes, casings, and such.
     
  4. R!f@@

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    Here is what I have in mind jens

    But first I like to know whether u can get the LM78L05 regulator easily.

    I attached the eagle file so u can board it. If you need any foot prints let me know.

    The PIC is a 8 pin DIL package type. It is what I have
    The LM7805 is T0-92 and so are the transistors.
    Caps are SMD.
    1K R's are SMD.
    Other R's are 0.25W or 7.5mm hole distance types.
    Pad's are Pad's used to hook up wires.

    PCB needs to be as small as possible.
    Cramp it in there.
     
    Last edited: Jan 10, 2012
  5. nerdegutta

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    I have at least 5 of them, and my local supplier have more...
    Mounting holes? 2 or 4?

    Are the NPN's TO-92 or SOT-23, I think I have 2N2222 and 2N3906 (or is it 3904 that is NPN...) in SOT-23.

    Any particular placing on the PADs?

    What size are the SMD? 1206, 0804, 0402...?
     
    Last edited: Jan 11, 2012
  6. R!f@@

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    * No mounting holes.

    *Pads can be aligned at the sides. Supply and Switch on one side, LED pads on the opposite.

    *SMD's are 0805 resistors.. capacitor can also be that too. Make the 100nf caps pads compatible to 0805 and 2.5mm apart holes.

    This way I can use a ceramic or an SMD.

    About the rest, u can sent these with the PCB's

    I like you to get me LM78L05 - 50 pcs. ( I need to stock it)

    I need to change the transistor package . If you can, get me any SMD type transistor u can buy from there, working voltage is 12V, Current needs to be around 500mA.
    The PCB should be as small as possible.

    Let me know the price of the transistor with 100 pcs qty

    Do not worry about soldering, I can pretty much solder anything but a BGA.

    The LED resistors are 0.25W types, with 7.5mm hole distance.
     
  7. nerdegutta

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    Suggestions?

    Anyone?
     
  8. t06afre

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    BCV 47 perhaps. Can handle high current and take some heat. It also have high hFE factor. And cheap
     
  9. nerdegutta

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    Thanks. I'll check it out.
     
  10. nerdegutta

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    OK.

    First take:
    [​IMG]

    Dimensions: 40.2 x 24.6mm.

    How's this, R!f@@?

    It can be a challenge to solder the DIL08, both sides of the PCB...
     
    Last edited: Jan 11, 2012
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  11. t06afre

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    Oh sorry BCV 47 is a darlington transistor. And at 100 mA the Collector-emitter saturation voltage is 1 volt. At 500mA this will probably be higher. And it will most probably take to much heat in the long run. The max Total power dissipation is 360 mW. I think perhaps R!f@@ is asking for to much power dissipation for a sot-23 package. And I think we have to move to a sot-223 package. What do you think
    R!f@@
    [​IMG]
     
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  12. Markd77

    Senior Member

    Sep 7, 2009
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    BC817-40 transistor is giving 0.292V V_C_E at 500mA in LTSpice for a power of 146mW with the 1K resistor on the base to 5V. Max dissipation at 25C is 225mW.
    It's probably cutting it a bit fine, I also don't know how to check what hFE LTSpice is using for the transistor (real ones should be 250-630).
     
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  13. tom66

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    May 9, 2009
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    Why not use an NMOS, like NTR4170N? (A favourite part of mine, good price & reasonably low on-resistance.)
     
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  14. R!f@@

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    NMOS, is it a MOSFET.

    If it is logic level, it will suite. The LED's a PWM driven. So from what I have seen, the LED's I am using are not tophat's. They are RGB PLCC6 Led's. A BC548 last's indefinitely with 2 strings of 3 LED's. Perhaps 500mA was a bit too much when I said it. I just don't want the circuit to generate heat as it will be used in a somewhat vibrating environment.

    The smaller the Circuit the better. I bet even a 100mA SOT package will suffice.
    BC548 is 100mA and it is doing fine in my current app. I dunno about going for SOT-23 from a TO-92 will do to power dissipation. I thing SOT will handle less power even at 100mA.

    Jens.
    Sorry but the board is bigger than what I made using vero. I think I manage to do a 20mm by 20mm board with TO-92's.

    Cramp it up. If you can put the SMD's just under the PIC. Get rid of any empty space.

    One thing is important... Jens u need to be able to buy the transistor and the regulator from ur local store. Cause I will need them with the PCB's. I think you should know how much Qty I will need. LM78L05 for each PCB plus 10 more.
    I rounded up some figure. I need to cut the cost down as I am leaving to the north again. I will be taking the PCB's with me if they arrive.
    And the Transistor or what ever is used to drive the LED's, u can figure out how much I will need from the PCB plus add 20 more of it.

    If you can try and see if you can reduce the board size by using TO-92 packages. here am going for BC types Tr's.
     
    Last edited: Jan 12, 2012
  15. nerdegutta

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    Like I said:"First take".

    20 x 20mm? Interesting. I will go for it when I get back home later today.

    I was also thinking switching to To-92 transistors, and putting the through-hole resistors vertical.
     
  16. Tenderness

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    Jan 12, 2012
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    Code can practical?
     
  17. R!f@@

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    What ?

    @ Jens.

    The height of the finished PCB will be the DIL height. I don't have any room more than the height of the PIC package
    Vertical resistors is a no no....but slightly slanted resistors might do. Like when you bring the holes a bit close but not right next to each other ...get my point.
     
  18. nerdegutta

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    Will the uC be in a socket? (Trying to buy some height.:))

    Hmm... Yes, I understand what you mean. I can use a smaller resistor footprint, and you slant the resistor a bit. I'll give it a try.

    Why not vertical?
     
    Last edited: Jan 12, 2012
  19. t06afre

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    It is no problem soldering a dip in a hobbyist two layers PCB. Another idea may be to move the non SMD resistors from the board to the cable. Depending on which PIC R!f@@ use. The pullup resistors to the MLR pin may be omitted. As many PICs do have a option to pull the MCLR pin high internally
     
  20. nerdegutta

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    When I made the 25 led chaser, I soldered DIP sockets. I placed all the pads/traces going to the DIP on one layer, and had a via, connecting the two layers, really close. That went really well.

    Moving the resistors to the cable is a nice idea. Let's hear what R!f@@ has to say about that.

    The pull-up on MCLR; I was planning to move inside the DIP socket. If he is going to use a socket...
     
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