Advice for an LED flag design

Discussion in 'Digital Circuit Design' started by Inglorious89, Oct 15, 2016.

  1. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    Hey y'all, I started a thread a few months ago about an LED American flag I wanted to make. Now that I have the money for the project and have done a bunch of testing, I wanted some advice on the numbers I found and calculated to make sure that this is gonna work before I drop a couple of hundred dollars on LEDs and other parts.

    The attached photo has most of the info I've gathered.

    I'm planning on using this power supply: https://www.amazon.com/Dunlop-ECB00...d-3035-4a40-b691-0eefb1a18396&pf_rd_i=desktop

    And here are the LEDs I'm planning on using:
    Blue
    https://www.digikey.com/product-det...-BGF-CS0U0352/C4SMC-BGF-CS0U0352CT-ND/6138519
    Red
    https://www.digikey.com/product-det...-RJF-CT0W0BB2/C5SMF-RJF-CT0W0BB2CT-ND/6138570
    White
    https://www.digikey.com/product-detail/en/cree-inc/C513A-WSS-CY0Z0231/C513A-WSS-CY0Z0231-ND/5120069

    My basic question is this: are the numbers I got for the amount of current each group needs and the total current correct, and with the design I have will the LEDs light up and be about the same brightness? Any other suggestions or advice would also be nice.

    Thanks!


    EDIT: I seem to have gotten the answers I needed elsewhere, so for now unless someone has some big discovery or important piece of information for me the discuss is mainly going to float around the housing for the flag (although if you have any suggestions for that lemme know).
     
    Last edited: Oct 17, 2016
  2. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,540
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    Numbers?
     
  3. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    For some reason the photo I attached isn't coming up. Either way, here it is with all of the numbers I found.

    http://i.imgur.com/LPHwy1f.png
     
  4. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
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    I responded to your same query on Electronics Point. Out of curiosity, how many forums did you post this on?
     
  5. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    Only two. I'm assuming that's a big no-no in your book? I'm sorry if I'm causing trouble but I'm just trying to get as much information as I can as soon as I can versus posting it on one website, waiting a week for responses, then asking around at another one week later. Just trying to be efficient is all.
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
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    No, it's not a problem. People do it from time to time for the reasons you cited and it only get's noticed by those of us who are active on multiple forums. The only point of etiquette I would suggest is that if and when you reach a final solution in one forum, you post a link to it in the others so people won't spin their wheels needlessly on your behalf.
     
  7. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    Here is a picture of one I recently built.
    US FLAG.jpg
    It has over 300 LED's the LED are all 5MM, and it works on 24V at about 100mA. I is approximately 8" long and 4" wide. I have revised it and I am waiting for the new circuit boards to be delivered. Both versions use strings of LED's. The Red stripes have 8 per list with a resistor. The whites in both the star field and the stripes have 5 per string, and the blue in the star field have 7 per string.
     
    Last edited: Oct 16, 2016
    Sinus23 and KJ6EAD like this.
  8. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
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    Picture?
     
  9. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    Oooh, that's quite nice. What did you use for the "backboard" of sorts (that is, what's behind the LEDs holding them in place)? I have a few ideas for my flag but nothing concrete.
     
  10. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    oops I made a mistake
     
  11. SLK001

    Well-Known Member

    Nov 29, 2011
    819
    228
    And what mistake did you make?
     
  12. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    It's not my day, as I made another mistake. On the flag shown all the LED's in the star field are 3mm.
    I used a printed circuit board for mounting the LED's. I first was going to use a large solder type proto board and then I could not
    decide to bend the leads together for the strings or use wire wrap wire. I finally decided on a circuit board. So I laid it out and sent
    the file to a PCB house to make the boards.
    I made some errors on the layout and had to correct them to get all the LED's to light up. After building two of the first design I decided to
    redesign and used all 5mm LED's. In the process I reduced the number of blue LED's in the star field to make all the blue strings the same
    # of LED's
     
  13. k7elp60

    Senior Member

    Nov 4, 2008
    478
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    I Forgot to post the diagram in my first post
     
  14. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    Where do you go for your printed circuit boards? I'm assuming you're going to need a program to design the board itself as well. If so, then can you tell me which one you use? I'd love to see if it's possible for me to replicate what you're doing in regards to making circuit boards.
     
  15. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
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    I've had good results mounting LEDs on corrugated polypropylene signboard and on foamcore. If you use a thin walled core drill to make tight-fitting holes and sandwich the back, covering the wiring, with another board, it looks good and is reasonably durable.
     
  16. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    I have used expresspcb.com. When I decided to do the new flag I downloaded a different PCB software to do it because the cost at express pcb is a little high. I tried and tried the other software but could not get used to it so I went back to express pcb and revised the old layout to the new. I plan to get the gerber files on the revised layout. This will make the PCB's cheaper. I'm thinking of making a kit for this project.
    The thing that is not shown is the dimming circuits for each of the colors of LED's, There is 4 dimmers, on for blue, on for the red and two for the white LED's, those in the star field and those in the stripes.
    On of the things I made sure of is that all the LED's in each string and in each group were the same intensity. This was achieved by using good quality of LED's. I tried some of the packages on EBAY and was disappointed with the LED's I changed part numbers for the blue and white
    LED's on the revised flag. Since I am doing 2 at a time I have some good LED's of white and red for one flag, so if you want them I can save
    you some money.
    As far as the PCB is concerned, once I get the gerber file I can check prices at some different PCB houses and let you know the cost if that is the way you want to go.
    If you want a picture of my layout to duplicate I may be able to email that too you
     
  17. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
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    Where do you go to get those materials? I tried looking them up online but wasn't able to find many online retailers that had appropriate sizes.
     
  18. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
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    I don't know where you are but here I can get foamcore at art and craft supply stores and I can get corrugated polypropylene signboard at sign shops and plastics stores.
     
  19. Inglorious89

    Thread Starter New Member

    Feb 12, 2016
    13
    0
    Guess I'm going shopping over the weekend then. Thanks for giving me a few ideas for materials.
     
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