Hello! I'm having trouble with my LED strip that I purchased from Aliexpress (link

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Hello!

I’m having trouble with my LED strip that I purchased from Aliexpress (link in comments later). This was recommended from a Youtuber so I decided to buy the same strip as he did.

Supposedly, it is an APA102 chipset, with a Clock pin, Data pin, and Pwr and GND.

I’m using this code call:
FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, GRB>(leds, NUM_LEDS);

with everything properly declared (variable-wise and such). I tried running the calibration code (and other existing code) and I’m getting sporadic color changes.

I’m using the entire strip (30 leds/m, so 150 in all with a proper dedicated power supply), also an Arduino Uno. Can anyone help?

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This is the strip in reference (I didn’t want to put in in the post to make it seem as spam): http://www.aliexpress.com/item/5M-5050-SMD-APA102-Individually-Addressable-RGB-Color-150-Led-Strip-Light-DC-5V-Tube-waterproof/32225757279.html

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So that ended up lighting up the entire strip, with the ends flickering colors. I’m starting to believe I wasn’t given an APA102 chipset strip? I also tried changing the color order from GBR to RGB with no avail.

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No dice - the entire strip still lights up, with some minor flickering. The end of the strip randomly changes colors (but in pastel form).

The other side of the strip (pwr and gnd) aren’t connected to anything.

Also, thanks for commenting and helping me out in anyway you can! I really hope I don’t have to go through the hassle of returning this order…

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I will say it’s possible the power supply may be acting up. I switched DC-to-screw terminal adapters and got a different result. Still generally the same (some flickering and such) but less of the strip lit up.

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Another update: Just unplugged it and tried again. Entire strip lit up. Not entirely sure what’s going on here. Hoping it’s not the strip.

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What power supply are you using, and how is it connected?
And double checking… do you have the ground from the strip connected to the ground of the UNO?

Is it flickering all over, or only after a certain point down the strip?

Also, even if you have the color order incorrect, you shouldn’t get any flickering at all, just different colors then you would expect.

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Also make sure that your clock and data lines aren’t wired backwards (he says, having done this more times than he can count)

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I think this may have solved it! The grounding wire that was “soldered” onto the wire is bad. I tested out a rainbow code while touching a grounded cable to the other negative terminal on the strip, and it worked beautifully!

Interestingly enough, if I leave the arduino on, and either the GND or Data pins in, the strip will still light up red, although very faintly. Uploading new code to the Arduino required me to pull the GND plug from the arduino and back in again (haven’t tried with the data pin yet)

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Ah, if grounding fixed your problem then you don’t have the clock and data lines backwards

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@Daniel_Garcia Oh, believe me I had it backwards the first time, and let’s just say I blinded myself with that light!

@marmil I’m using a 5v 10a power supply that has been confirmed with other DIY users. Also, I just grounded the strip and it works! Although, uploading new code to the arduino requires me to pull the pins from the arduino and plug them back in.

Pulling the power supply also leaves the strip on very faintly with a red color.

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There’s still some interesting behavior going on here. As if the memory in the chips get confused or something.

EDIT: LEDs that are in the array (or even out of it) that aren’t supposed to be on have a dim red color.

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I don’t think you should not need to unhook anything to upload new code.
Are you powering the UNO with USB or from the external source?

Also… word of warning so you don’t burn out pixels on your strip:

  • When a strip is powered separately from the controller, power On the strip and controller at the same time, or make sure the strip is powered first.
  • And similarly, make sure they are both turned Off together, or make sure the controller is powered Off first.
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Marc,

Thank you for the tips! I am powering the Uno with a 12v 1a adapter. When I am uploading code it is powered via USB only. Would that explain the dim red glow/weird behavior near the end of the strip? I will be double checking the output of the 5v 10a adapter to be sure

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If the leds are still plugged in to the uno they will try to draw power from it while you are programming. If you are going to remove power from the uno for programming you should completely disconnect the leds.

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For testing purposes and to reduce the number of variables in the system, try removing the 12V supply for now and just power the UNO from USB. Make sure the grounds from your 5V supply and UNO are connected.
When wired this way are you able to upload code?

Check the voltage from your 5V supply. Use a multi meter to measure the voltage at the start of your strip, and also at the end of your strip.

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Marc, yup!

My multimeter is currently at school, so I’m unable to get a hold of it.
Just a quick question, is it possible to power both ends of the strip simultaneously?

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Yes. You can use the same power source, OR if it’s a second 5V power source you will need to break the positive (+) line somewhere along the strip. (In the middle for example.) You do not need to break the ground line. All the grounds should always be connected.

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Marc,

Thanks! I’ll give it a shot. So far, the strip behaves correctly to an extent.
Near the end of the strip, it’s erratic with the colors (running the Rainbow demo it seems accelerated). On that end it is grounded, with the positive end connected to the power supply.

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I turned down the amount of LEDs from 150 to 120. The ones that are unused stay a bright white, and the strip behaves correctly. There is some minor flashing here and there.