Author Topic: Pixelnet strobe controller  (Read 6701 times)

Offline tbone321

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Re: Pixelnet strobe controller
« Reply #45 on: February 07, 2016, 02:22:12 PM »
The green is just a direct connection to earth via the the grounded input AC cord.  Its handy if you are working with a static mat but otherwise no big deal.
Actually reading the manual, the Green is DC Ground, Black is Negative voltage rail and Red is positive voltage and it appears to allow for -30v.

The cheap one allows you to set the current limit value whereas the only does true constant current.......

Actually, that's not what it says at all.  There is in fact a difference between DC- and ground but that doesn't mean that the supply can deliver a negative voltage.  The center terminal is green which is the color code for earth ground and may in fact be at a different potential from the DC ground but nowhere in the manual does it say that the supply is capable of supplying a negative voltage short of reversing the positive and negative leads. 

Offline AussiePhil

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Re: Pixelnet strobe controller
« Reply #46 on: February 07, 2016, 03:09:35 PM »
I don't have that specific unit, so you could be right, but where do you see that?  The schematic shows its connected to earth and has capacitors to each rail which will block DC, right?   Specs list only 0-30v, not -30v. 
Other more expensive units with a green GND post may have the capability you describe, but I don't see it in this unit.  I'm not sure we're looking at the same thing here.

The user manual has a dot point saying Positive or negative polarity, and labels the black terminal the Negative terminal, the clear implication that it does -30v, however the rest of the specs and manual is so light on it could be anything :)


Quote
Again, I don't have that specific unit so you could be right.  But the display has indicators for CV or CC mode which leads me to believe its CC capable...at least well enough for hobby use.   If you can set a current value and it fluctuates the voltage to keep that current level isn't that a constant current supply? What do you mean "the other does true constant current"?
Not arguing, just trying to understand.

That's OK, not convinced I can describe current limit v constant current anywhere near well enough to put an argument that they are different, however this page does explain it... http://powersupply.blogs.keysight.com/2013/01/the-difference-between-constant-current.html

For general hobby use the difference is likely not an issue but it does show why the more expensive one is more expensive :)

Offline pixelpuppy

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Re: Pixelnet strobe controller
« Reply #47 on: February 17, 2016, 10:58:34 AM »
I was going to grab an assortment of these leds in different kelvins so I could do some playing too.  But its the Chinese new year right now so mine will have to wait... :-[
Following up on my previous post...

I received my assortment of leds.  I got 3k, 4k, 6k, 10k, and 20k.  As I expected, it is very hard to see the difference from one to the next (3k-4k, 4k-6k,6k-10k,10k-20k) although there is a visible difference between the low end and the high end.  The 6k leds in the middle looked like a pure white to me with the lower end (3k-4k) looking a little yellower and the high end (10k-20k) looking a little bluer (as expected).

They are all plenty bright, but just for grins, I pulled out my LUX meter.  I ran each led at 500mA and took a reading 2 inches above the led (leds pointed up).    The LUX slowly increased from the 3k-4k-6k leds but took a big jump on the 10k led and then started dropping back down on the 20k led.  This is not conclusive, but my quick-and-dirty test results have the 10k as being the brightest (and also a very pure-looking white color).  Note that I was not running these at full current (500mA vs 700mA)

3k@500ma@2" = 12000lx
4k@500ma@2" = 12500lx
6k@500ma@2" = 13000lx
10k@500ma@2" = 19000lx
20k@500ma@2" = 16000lx

BTW, I am still seeing spots while I type this so appologies for any typo's  8)
Vixen and xLights for sequencing / FPP for scheduling and playing / Falcon controllers for pixels / DIY controllers for everything else

Offline zwiller

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Re: Pixelnet strobe controller
« Reply #48 on: February 18, 2016, 08:46:16 AM »
THANKS for posting.  Good info.  Lux meter was a nice touch!  Just want to confirm these were the 3w chips @ 5v (500ma).  I see spots fooling with mine too even not trying to look at them.  I think alot of folks underestimate these little guys...
Sam

Last year's video: https://vimeo.com/150560653

Offline pixelpuppy

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Re: Pixelnet strobe controller
« Reply #49 on: February 18, 2016, 03:40:03 PM »
Just want to confirm these were the 3w chips @ 5v (500ma).

Yes 3w leds but not @ 5v.  I tested them with a constant current power supply set at 500mA and no other components (i.e. no current limiting resistor).  The voltage was around 3.4v so I was only testing them at about 1.7watts. 

As you know, they get hot pretty quick if you run them at full current. My lux numbers were just for comparison between the different kelvin options.  They all will be brighter if you run them at full current.

 

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