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Topic: Weird WS2812B Problem (Read 84 times) previous topic - next topic



I wanted to make an ambient backlight project for my monitor with programmable LED strips, but I've ran into a really irritating problem:

Apparently the FastLED signal data is sent, but the LEDS dont light up unless I connect the ground probe of my (turned off) multimeter to the signal wire.

I connected my Adruino Pro Micro directly to USB, D+ & D- directly to the Atmega, +5V to the RAW pin and used common ground for the Microcontroller and WS2812 LED strip.

Shorting the signal pin to the common ground yields no results, pull-down resistors of various sizes for the data wire didn't work either, different USB power supplies also didnt make a difference as well as changing the arduino pins.

I'm guessing there is a pretty simple solution to this, but I just cant find it  :o

I've used an arduino nano before and everything worked flawlessly, except I couldnt directly solder the USB wires to it.

Heres a video showing the problem:


Please help   :smiley-roll-sweat:


Jun 13, 2018, 09:39 pm Last Edit: Jun 13, 2018, 09:40 pm by xl97
What are D+ & D-?

Neopixels are dead simple to connect.. (not sure of the issue)

1.) If powering it form USB.. you probably do not have enough current..
2.) You only need to connect 1 wire the Arduino boiard of your choice..  the digital I/O line..  the +5v should come from a REGULATED +5v power source.. (usb may work with a handful of leds.. but not a full strip I doubt)..
3.) GND should be the GND used by the battery source and also shared with the Arduino.

It also doesnt look like you have the resistor on the I/O pins fromt he Arduino.. nor any CAPS on the power lines for the led strip.

It is recommended to do so.

Post a schematic or a hand drawn wiring diagram on how you have things set up..  nobody can tell form the shaky video.

Also,....that soldering looks a mess.. perhaps clean it up.. or try with one strip at first.. then daisy chain on the others?

Could just be a bad (cold) solder joint..


Jun 14, 2018, 01:34 am Last Edit: Jun 14, 2018, 01:39 am by Southpark
I wanted to make an ambient backlight project for my monitor with programmable LED strips, but I've ran into a really irritating problem:
Just got to realise that this 'weird' and 'irritating' problem is caused by yourself. The issue doesn't appear to be due to any of the hardware modules you have. It's just something or some things that you haven't done properly - that's the likely issue. Probably better to just say that you're trying to do some fault-finding for your project.

First, turn off the power to your whole system. And then get your multimeter, and put it in electrical-continuity mode, and then see whether the ground of your arduino and the ground voltage supply and the ground of your LED strip are all electrically connected together.

Also, I do agree that the soldering work can be improved significantly. Using better soldering techniques can cut down on solder joint issues.

An accurate and adequately detailed circuit diagram will definitely help to home-in on the issue.


This video explains soldering: https://www.youtube.com/watch?v=SFKYUi3p8zY

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