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Topic: Weird WS2812B Problem (Read 394 times) previous topic - next topic

cashilysh

Hello,

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:

https://www.youtube.com/watch?v=u5oiY2lx8Fg

Please help   :smiley-roll-sweat:

xl97

#1
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..




Southpark

#2
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.

Relign

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

TomGeorge

#4
Jun 18, 2018, 02:48 pm Last Edit: Jun 18, 2018, 02:52 pm by TomGeorge
Hi,
I agree with @Relign.


It looks like you have lost half the Din pad at the end of the array, you have probably tried to solder to the bit of track that was left.
Instead of  using your magic DMM probe, use a magic small screwdriver to push the Din yellow joint and see if the same happens.
OR
Forget the first LED element and solder to the next Din after CAREFULLY removing the first LED element.

Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

cashilysh

First of all, thanks for the tips!

I didn't really find the problem, it wasnt the solder connection, capacitor or data line resistor, however:

When I plug the arduino in with my mini USB cable it everything works just fine, but with the direct USB wire I soldered on RAW Pin, Ground PIN and USB Data wires directly to the ATmega it doenst work like I showed.

I still dont know what caused my problem but, I just use it with the mini USB now.


Thanks!

TomGeorge

First of all, thanks for the tips!

I didn't really find the problem, it wasnt the solder connection, capacitor or data line resistor, however:

When I plug the arduino in with my mini USB cable it everything works just fine, but with the direct USB wire I soldered on RAW Pin, Ground PIN and USB Data wires directly to the ATmega it doenst work like I showed.

I still dont know what caused my problem but, I just use it with the mini USB now.


Thanks!
Was that wire a 5V wire you soldered to Vraw?
If so you need at least 7V on Vraw as it is the input to the 5V linear regulator.
You connect 5V to the 5V pin of the Micro.
Please consult a circuit of a Micro to see how to treat it with care. (google)
Please post a circuit diagram of your project, this could have been solved ages ago and you have been asked for a circuit so many times.
Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....

cashilysh

Yes USB 5V to RAW, I didnt think about it beeing the cause, because the microcontroller was powered and could be programmed.

Ive got everything glued and working now, so I dont bother changing it again. Its also more modular now as the USB cable can be removed.

I actually wanted to circumvent the USB connector resistance because I will be pulling quite a bit of current with the LEDs, but it still works the way it is now even with only 5V 1A USB connection. The board does only get a bit warm.


Next time I will post a diagram of my project right away :)

polymorph

TomGeorge said:
Quote
If so you need at least 7V on Vraw as it is the input to the 5V linear regulator.
cashilysh said:
Quote
Yes USB 5V to RAW, I didnt think about it beeing the cause, because the microcontroller was powered and could be programmed.
You have your answer.

It would be better if you ran a separate line from your 5V source to the LEDs rather than pulling it through the Arduino's PCB traces.
Steve Greenfield AE7HD
Drawing Schematics: tinyurl.com/23mo9pf - tinyurl.com/o97ysyx - https://tinyurl.com/Technote8
Multitasking: forum.arduino.cc/index.php?topic=223286.0
gammon.com.au/blink - gammon.com.au/serial - gammon.com.au/interrupts

cashilysh

Well actually I did. 5V from the USB cable direcly to RAW pin and directly to the LEDs.

Maybe it didnt work because the 5V for the ATmega went into the regulator before powering it, so the Microcontroller and LEDS were working at slightly different voltages. :S

I finally added a schematic showing how it didnt work to clear things up:

https://imgur.com/a/IBGdcRT



TomGeorge

#10
Jun 27, 2018, 12:16 am Last Edit: Jun 27, 2018, 12:17 am by TomGeorge
Hi,

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

OPs diagram;

Tom... :o
Everything runs on smoke, let the smoke out, it stops running....

larryd

You cannot arbitrarily connect things up the way you think it should be wired.

Follow this diagram.



No technical PMs.
The last thing you did is where you should start looking.

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