[Solved] External power issues on NodeMCU - ws2812B works, ws2813 doesn't

Other Hardware LEDs and Multiplexing
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SOLVED:
comments indicated I did not need to use the resistors on the signal line IF I was also using the logic level shifter. removing the parallel resistors (because I didn't have a single lower ohm resistor on hand) solved the issue immediately.

PLEASE NOTE:
In the diagram below, I could not find an image for WS2813 LED STRIP, which we know, has 2 signal inputs.
Thats what the 2 green wires are for. When using a WS2812B strip, only 1 green wire would be present coming from the logic level shifter.

GIVEN:

input power supply is a verified 5.5v, 8amp
the green LED is turned on by the sketch when it starts up - so I know something is running, even though I may not see any visible LED activity
My test sketch is just a simple light chaser. # LEDs is set to 50. I don't make ANY changes in the sketch, nor do I re-complile/upload when changing from WS2812B to WS2813 (its supposed to be compatible).

ISSUE:
Having trouble getting my new 2813 strip to work. Adding a Logic Level shifter was the key to getting my 2812B working using external power. I got my new product in the mail, plugged in the 3 leads from the 2812B setup ,and added the extra signal wire, and got nothing.

If I disconnect external power, and use USB to connect & power everything, my sketch runs, green LED turns on (in under 1 second), everything is fine.

If I power with EXTERNAL supply, the 2812 1m 144LED strip works perfect.
Plug in the new 2813 and LED strip is blank, but sketch runs and Green LED comes on.
Disconnect external power, don't change anything else, plug in USB power and Voila, all fine.

SUPER NOTE: When I think the 2813 is "dead", If I disconnect one of the two Signal lines AT THE STRIP and touch it to myself, I get random flickering. Power IS RUNNING through the strip, so I think the issue is the signal. I even tried moving signal lines to one of the other unused channels on the shifter. Of course, that not the issue cause if I plug only USB in, it works fine. (logically, eliminating a faulty shifter channel, or faulty signal wires). this shifter has a red LED under it to indicate power and that is on regardless of how Power is being applied.

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You are using a "bidirectional" I2C level shifter module.

Don't! Wrong device.

Use a 74HC04 with two gates cascaded - inverting twice as a buffer. Connect the unused gates' inputs to ground.

I also think you have that diagram botched - I see two 1k resistors in parallel between NodeMCU and level shifter. The "470 Ohm" resistor regularly mentioned goes between the level shifter and the LED strip. In fact, it is not necessary with that sort of level shifter anyway and where you have placed it would prevent it from working at all. Both the 470 Ohm resistor and that capacitor need to be connected at the actual termination of the strip.

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In addition you have no resistor in series with that green LED at the top.

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Grumpy_Mike:
In addition you have no resistor in series with that green LED at the top.

thx, and YES, I know that. was not worried about that.

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was not worried about that.

Why were you not worried about that, don’t be a numpty.

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Paul__B:
You are using a "bidirectional" I2C level shifter module.

Don't! Wrong device.

Use a 74HC04 with two gates cascaded - inverting twice as a buffer. Connect the unused gates' inputs to ground.

I also think you have that diagram botched - I see two 1k resistors in parallel between NodeMCU and level shifter. The "470 Ohm" resistor regularly mentioned goes between the level shifter and the LED strip. In fact, it is not necessary with that sort of level shifter anyway and where you have placed it would prevent it from working at all. Both the 470 Ohm resistor and that capacitor need to be connected at the actual termination of the strip.

Ahh, thx for reply, but...

  1. the diagram IS accurate

  2. I had the parallel resistors that way because I used to have NO shifter.
    And it would work with USB power, but not external (WS2812B).
    Upon adding the shifter, external power started working immediately
    2b) unlikely to acquire 74HC04 anytime soon

  3. didn't realize no need for resistors if using a shifter

  4. doesn't prevent it from working as shown - works in 3 out of 4 scenarios (2812b, ext & usb, 2813 usb)

  5. am using this setup per this project:
    GitHub - bruhautomation/ESP-MQTT-JSON-Digital-LEDs: (OBSOLETE) ESP8266 MQTT JSON Digital LEDs for Home Assistant

7

Grumpy_Mike:
Why were you not worried about that, don’t be a numpty.

  1. I have seen diagrams (fritzing, that I can supply) that show a LED hooked up the way I have it, so I did it that way 1st
  2. don't have room for a resistor there
  3. don't have the required resistor in hand
  4. whats the worst that can happen, fry the $0.01 resistor
  5. its just temporary to show me that something was actually happening, while I was getting no light output. If the LED lights always activated, then I'd need no visual feedback that the sketch was running. I'll remove this in production

(so frustrating - can someone remove the 100 msg/5 minute limit from my account?)
(not sure what a numpty is - is it like a Scouser)

8

ok, removing the parallel resistors now achieves success.
am still using the logic level shifter and all powers up correctly on external power.
thx

9
  1. I have seen diagrams (fritzing, that I can supply) that show a LED hooked up the way I have it, so I did it that way 1st

All of those were written by morons and deserve to be shot.

  1. don't have room for a resistor there

Then make room for one or abandon your project.

  1. don't have the required resistor in hand

Then your project is on hold until you get one.

  1. whats the worst that can happen, fry the $0.01 resistor

No the worst that can happen / has already happened is that you burn out the output pin of your processor. You have already damaged it by doing this and reduced the expected life of the output pin. While it might not fail next week it will fail.

  1. its just temporary to show me that something was actually happening, while I was getting no light output. If the LED lights always activated, then I'd need no visual feedback that the sketch was running. I'll remove this in production

Production - with such a knowledge of electronics?

(not sure what a numpty is - is it like a Scouser)

It could be argued that all Scousers are numpties, it does not mean all numpties are scousers :- Urban Dictionary: Numpty

http://www.thebox.myzen.co.uk/Tutorial/LEDs.html

10

thx
removed the LED and resistors just came in, so will use from now on.
thats a fantastic read about LEDs - very informative - thank you

"production" - as in live/installed, vs testing on the kitchen table

in programming, its in test or production - production not implying being marketed or sold

i've nothing really against Scousers - but Mackems - now them are numptys