I'm wanting to build a 10x10 matrix with a string of WS2812B's (Apparently called

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I’m wanting to build a 10x10 matrix with a string of WS2812B’s (Apparently called NEOPIXEL, but bought them from AliExpress). I can’t seem to get them to work!

Power supply is a 5V10A output, Arduino is an Uno. Ground & -V have been connected, one wire goes to Arduino ground, the other to LED strip ground. The +V is connected to the LED strip +V, and the data input on the strip is linked to (Digital) pin 6. I’m trying the very simple code:

#include “FastLED.h”

    CRGB leds[1];
    void setup() { FastLED.addLeds<NEOPIXEL, 6>(leds, 1); }
    void loop() {
            leds[0] = CRGB::White; FastLED.show(); delay(30);
            leds[0] = CRGB::Black; FastLED.show(); delay(30);
    }

But it doesn’t work. Nothing turns on.
Sometimes, I see a brief flash of (I think all) LEDs in what seems to be various colors when I (dis)connect the V+ or V-, but can’t reproduce it.

Any help would be greatly appreciated! (Please let me know if more info is required)

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Have you checked that the data pin is connected to data in?

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Yeah, it’s directly connected. I checked that it enters the strip from the correct side, too. I’m assuming that the datapin #6 that you define in the code refers to the Digital pin 6. (According to https://arduino-info.wikispaces.com/file/view/ArduinoUNO-900.jpg/421496636/ArduinoUNO-900.jpg, it might also be nr 4, but i’ve tried them all, and didn’t see any effect so far :slight_smile: )

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Your delays, whilst you’ll be able to see them, will be proper annoying after about 10 seconds… Give your headache a rest and change those 30s to 250s, also, not the issue!

I think the code allows quite a lot of tweaking, but if I personally am running 1 line of LEDs on one arduino, I use SDA and SCK. Your ws2812b is (as described) so I’d wire into 27.

I don’t think it matters, but the fastled code has capability for neopixel and ws2812b, and if you’ve got Ws I’d use that;
{ FastLED.addLeds<WS2812B, 27>(leds, 1); }

It’s 27 on the Uno pin out diagram, tis the one closest to the reset button

If these don’t work, then I would quickly go through the different single wire chips to see if what they have supplied is “differently described” is wrong

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First of all your only telling the board that you have 1 LED even though you actually have 100. Second of all you are only telling the board to turn the first LED white then black.

Also, you can use FastLED.delay(30); instead of doing show then the delay.

I’d recommend looking at the blink example since its pretty much what you’re trying to do here. Once you get a feel for how the code works you can move onto adding a for loop to turn on all of the LEDs or use fill_solid()

Hopefully that helps you get things going.

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Argh, my reply didn’t get posted… Short version then:
Thanks a lot! Will have to try later tonight, but we’ll see what happens. This was indeed the ‘base code’ I wanted to get working before expanding to more LEDs.
Not sure what the difference is between, say, pin 6 and the SCK/SDA pins since I’m not that at home in programming, but I’ll give it a try!

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It works - and it doesn’t.
I actually had 2 50-LED chains and decided to try the other one. That one works just fine. (Using pin 13 btw, I appear to have an older Uno that doesn’t recognize pin 27 :slight_smile: )
As for the first chain: Disconnecting all three wires, then connecting data and ground, will provide a brief chain-long blink as soon as I connect the power. Dis- and reconnecting the power again doesn’t do anything until ground & data have been disconnected again. I suspect I might have damaged something in there :\ Will continue with the working chain for now, and will see later whether I can fix the other chain by removing the first LED (let’s hope that’s the only one broken)

Thanks a lot people :slight_smile:

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Any luck getting things to work? How do you have the power hooked up?

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@Brian_Lewis yes, it turned out to be a “simple” case of defective LED strip (not sure whether DOA or because of something I did though). The second strip worked totally fine without any problems.

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What kind of project is it you are creating?
I also have a 10x10 2812B led “cake” that I thought would be nice as pixel art.
Having some trouble with getting all of the leds to lit… seems that some of them are broken.

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Glad to hear you got it working. If you aren’t already, I’d suggest injecting power in a few other places other than just the start of the strip. This will prevent issues like flickering or wrong colors from being displayed.

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I was inspired by one of the typical led matrix tables, but planned to do it without the actual table feet so I coukd put it on a wall. 50*50cm. I bought the strips so i wouldnt have to solder all separate LEDs but now have to figure out how to mount the leds since the wiring between them is longer than my “cell size”, and im not sure how sharp i can bend the wires ^^

If you have a few leds not working I (with my limited experience :wink: ) think they’re broken, since the rest works fine. But i guess replacing them shouldnt be too difficult, apart from ordering and waiting?