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Nutcracker: Current meter for animations

Discussion in 'xLights (Nutcracker)' started by smeighan, Mar 8, 2012.

  1. smeighan

    smeighan Dedicated Elf

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    I was wondering how much current my future megatree would be consuming. I know when i gave the option to set a background color that there would be a jump in current draw. All picels having a color would increase current, but by how much.


    So ..


    I now loop through each frams and look at every pixel. I look to see the highest RGB value and change that to a 0-100%. This is the V in an HSV model. I then multiple the percentage by the current draw of a single pixel.


    The wiki page, http://www.diylightanimation.com/wiki/index.php?title=Equipment#Smart_Strings, says that the pixels draw 29ma. But
    http://www.aliexpress.com/fm-store/701799/209889132-495657175/50-node-LED-pixel-string-DC12V-input-new-model-IP68.html
    says they draw 56-60 ma.


    So until someone tells me differently i am assuming 60ma for a full on pixel.


    Having done this math, i know how much each strand of the tree uses during each frame of the animation.


    I then made an animated gif of the current draw. It is interesting to change parameters in the effect model and see how it effects the current draw for the whole tree.




    _POST
    username f
    user_target AA
    effect_class spirals
    effect_name CURRENT
    number_spirals 4
    number_rotations 2
    spiral_thickness 3
    window_degrees 360
    start_color #FF1C42
    end_color #0464F5
    frame_delay 22
    direction cw
    sparkles 0
    use_background n
    background_color #0B3802
    submit Submit Form to create your target model


    submit Submit Form to create your target model
    [​IMG]


    produces this current graph
    [​IMG]




    Now I will do the same effect , but turn on background color
    _POST
    username f
    user_target AA
    effect_class spirals
    effect_name CURRENT2
    number_spirals 4
    number_rotations 2
    spiral_thickness 3
    window_degrees 360
    start_color #FF1C42
    end_color #0464F5
    frame_delay 22
    direction cw
    sparkles 0
    use_background Y
    background_color #29D107

    submit Submit Form to create your target model


    [​IMG]


    and see the current change
    [​IMG]


    Now i can plan on how many extra lines i need to run my tree. I think a 15amp socket wont do the trick.


    =============================================================================


    Postit: I have already been corrected in stating AC current and DC current are different.




    this is why i leave these things to the electrical engineers around here.


    So i found this on the web:


    Here are the recommendations for the minimum combined 12V rail amperages (and their relative PSU wattage rating) for various size computer systems:


    Small Form Factor - 15A (250W)
    Mini-Tower - 25A (300-350W)
    Mid-Tower - 35A (400-500W)
    Full Tower - 40A (600-650W)
    Dual Video Card (SLI) - 60A (850W+)



    So a full tower would draw around 5amps (600W/120V) from the AC line and produce 40amps of 12V power?


    I should clarify my web page to say current drawn on 12V Dc line.


    thanks
     
  2. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Sean

    Now this is a great addition as it can clearly show just how much current is used.

    two things

    - just list the current drawn - and state "at the supply voltage for the string" large percentage of people use 5V strings as they are more power efficient for the same current than a 12v string.
    ie 100 count string
    100 x 60ma = 6A x 5V = 30W
    100 x 60mA - 6A x 12V = 72W

    - maybe the graph scale on the left could be scaled to reflect the max level of full white, ie 60mA x number of pixels, this would clearly show the headroom and the max current required.

    Cheers
    Phil
     
  3. OP
    OP
    smeighan

    smeighan Dedicated Elf

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    Ill change the label to "at the supply voltage for the string"

    i was thinking i would prompt when someone is building a target model

    Number of strings?
    Number of Pixels?
    Current drawn by a pixel?
     

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