Does the library work with cheap matrix found on aliexpress, like this one ?

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Does the library work with cheap matrix found on aliexpress, like this one ?

I am not into soldering, so I was wondering if these are a good/cheap alternative ?

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Yes, I have one of those.

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Thank you, it seemed to good to be true :wink:

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Yep! Works great.

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Is this the kind of power supply I would need ?

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@Philippe_Maegerman yes they work great, zig-zag layout.

I “test” using the laptops USB (slight flicker on full tilt) and run the panel on a good quality 15A PSU.

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@Stuart_Taylor and @Philippe_Maegerman , be aware that you can damage some USB controllers if you pull too much current from them. If you want to program your controller while testing its output live, tie the ground line of your controller to the LEDs’ ground line, leaving the +5V lines separated.

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@Luminous_Elements Thank you for the advice I always use the function set_max_power_in_volts_and_milliamps(); to ensure safety :slight_smile:
I have a 1m strip from adafruit with a 2A power supply. Now I’d like to try the 16x16 matrix and was wondering if there are recommendations about the type of power supply for higher amps. The adafruit Neopixel Überguide only mentions a “5V DC switching power supply”, I prefer double check before playing with electricity, I’m a programmer, not an engineer, and I’m willing to learn :stuck_out_tongue:

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is set_max_power_in_volts_and_milliamps(); something built into fastLED?

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Bank on 60mA per LED on full white, so for that 256 LED panel, 256 * 0.06 = 15.36A. So yes, that 5V 20A PSU would be in spec.

(Sorry for those who are waiting on the tool I’ve been promising to help with these calculations… I’ve been interrupted by an actual LED project :-P)

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And since many people use pure hues, estimate about 20ma per pixel for fully saturated colors.

So with that estimate, 256 pixels would be a bit more than 5 amps – again assuming mostly pure hues eg CHSV( anything, 255, 255);

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I have been driving these with an Arduino and the NeoPixel matrix code.

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I use these @Philippe_Maegerman - they are reliable and with 5A, you can comfortably drive 256 LEDs at full power: http://www.aliexpress.com/store/product/25W-5V-Small-Volume-Single-Output-Switching-power-supply-for-LED-Strip-light/613696_628334432.html

I have a couple of those same panels and have had no issues using one of those 5A PSUs.

I have bought a lot of PSUs from that vendor - very reliable.

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@Mike_Thornbury From what I understood, at full white, the requirements would be 0.06A * 256 = 15.36A. Am I missing something ?

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@Mark_Kriegsman I don’t understand the difference betwwen pure hues and full white, what does it mean ?

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Pure hues means brightness at 100% and a fully saturated color. for example full red led @ 100% and the other two @ 0% would leave you at ~20mA

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A pure hue is anything you get back from CHSV( hue, 255, 255) – full brightness, full saturation, pure “color” with no white or black added.

If you use fill_rainbow, for example, you get a spray of pure hues.

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Ok I got it, found the information in the library reference now ( https://github.com/FastLED/FastLED/wiki/Pixel-reference ), and I learned something new today :slight_smile: I better understand your comment about the 5A limit now, thank you.

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@Mark_Kriegsman ​ does CRGB::Green result in a pure hue?

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in that case, i have some data i will share with the group under a new post :wink: