Nutcracker: Current meter for animations

smeighan

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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



produces this current graph





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





and see the current change



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.



caretaker said:
sjb said:
With not having any smart strings yet, I am trying to understand this. So sorry if this is a dumb question, but what does a 15 amp socket have to do with smart strings. Are they not powered by a 12 volt DC power supply from the hub??


Steve
You are correct. 60amps at 12 volt DC is a lot different than 60 amp at 120 volts AC. Sean if your mega tree draws between 58 and 60 amps then you will need just one 15 amp circuit for the power supply to your Smart String hub.

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
 

AussiePhil

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Messages
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Location
Canberra, ACT, Australia
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
 

smeighan

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Joined
Jan 19, 2012
Messages
1,109
Location
4217 Greenfinch Dr CO 80126
AussiePhil said:
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

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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