ESP8266 NodeMCU first WS2812 LED lights up green

Question

I'm trying to power some WS2812 LEDs from my ESP8266 ESP-12E NodeMCU board (circuit here). I'm simply trying to use the NeoPixel Strandtest which works perfectly on my Arduino UNO with the same LED strip, but when I change the #define pin 6 to #define pin D4 (or 12 as GPIO) only the first LED lights up and it's green. I did throw in a 470 ohm resistor between data and DIN, but that didn't do anything different.

When I use one of the other pins, nothing seems to light up, even if I disconnect all pins and hit reset. Here is my wiring:

Don't mind the actual 3v -> 5v. It works fine with 3v. I have also tried powering it off externally. I have tried all other pins from D0 to D7 (I saw many people say "STAY AWAY FROM PIN D8"). Could my ESP8266 be dead on arrival?

Answer 1

So here comes my solution: I was playing around with NeoPixelBus by Makuna and the examples. I noticed in one of his examples, it said:

// You can also use one of these for Esp8266,

// each having their own restrictions

//

// These two are the same as above as the DMA method is the default

// NOTE: These will ignore the PIN and use GPI03 pin

//NeoPixelBus<NeoGrbFeature, NeoEsp8266Dma800KbpsMethod> strip(PixelCount, PixelPin);

So I tried outcommenting that line and used that instead, and then it worked! I've always used Neo800KbpsMethod whenever I saw NeoPixelBus being used, because that was what other people did. Notice it also said:

These will ignore the PIN and use GPI03 pin

That pin is the RX pin on my board. No other example I have seen, has used the RX pin on the board.

After 6+ hours of constant troubleshooting, I can finally power on my strip and control each LED!

Answer 2

Ok i got it working after banging my head for couple of days, i was using a Node MCU Board V3, the pin number on board were D1 D2 D3 D4 etc all other library when data was connected to D4 in code where we specify the pin number we use to write D4.

However for FASTLED codes tbe code you need to write is just 4 without the letter D and when i did the same it just worked like magic

Answer 3

Ok, I am using WS2812B with nodemcu and Fastled. Now all folks out there reading this need not worry about voltages if your led is not blinking at all. It was not working at D0, it worked for me when I changed to D1, I am not aware of issue though. Need to check that. I did not use any other component and connected directly to nodemcu. Below is the simple code for first led to blink.

#define FASTLED_ESP8266_RAW_PIN_ORDER
#include <FastLED.h>
// How many leds in your strip?
#define NUM_LEDS 3

// For led chips like WS2812, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN
// Clock pin only needed for SPI based chipsets when not using hardware SPI
#define DATA_PIN D1
#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() { 
    Serial.begin(9600);
    // Uncomment/edit one of the following lines for your leds arrangement.
    // ## Clockless types ##
    FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
    Serial.println("Setup");
}

void loop() { 
  // Turn the LED on, then pause
  leds[0] = CRGB::Red;
  FastLED.show();
  //digitalWrite(DATA_PIN, HIGH);
  delay(500);
  // Now turn the LED off, then pause
  leds[0] = CRGB::Black;
  FastLED.show();
  delay(500);
}

Answer 4

Please read and understand the manual

You say it works on an Arduino, a big difference between the Uno and ESP8266 is the voltage (and voltage regulators).

Another difference is the chip/architecture itself.

So that leads to having to debug these two factors.

Debug the power/circuit/voltage

Please check if the 3V pin of your particular dev board can supply the current for the 3 LED's. Alternatively you can try by using another 5V power supply, or the 5V from your USB or (Arduino, since that did work) to try and power the LED's.

Another problem may be that the voltage will slowly go down over the length of the strip. Your strip is small, though you also power it from 3V, increasing the effect. You can try to power it on multiple points, or from the middle.

Try using a logic level shifter to increase the logic output pin from 3V to 5V, it may not be sufficient to transmit the data. This usually isn't a problem, but you should exclude this possibility.

The guide also shows some peculiar things regarding the wiring. They say you should use a capacitor between the + and - lines. I don't see how that can fail, but you may as well try.

Also doublecheck the wiring, maybe some connector is a little loose. I've also had problems with LED strips that have been bent, the copper may come loose from the strip, or the strip may get teared a little.

You should also check with another piece of LED strip, just to be sure.

Debug the controller

It works on the Arduino, but not the ESP8266, and we have checked that it's not due to the voltages/power.

The NeoPixels have pretty strict timing, I would actually advise anyone to NOT use them. Since you can't write to the strip "pixel by pixel", you'll have to put the whole strip in memory, and then send it all at once.

Other SPI based LED strips can receive the pixels one by one, like streaming. So you can simply make a loop that sets a color and sends it (while slowly increasing color, to make an virtually infinite rainbow effect). The cool thing is that it even doesn't block interrupts from happening. (Neopixels disable interrupts, need 3 bytes per pixel, and can't do calculations between sending)

If you still want to use NeoPixels, there may be a timing issue. You can check at which clock speed you've set the ESP8266.

Also are you using ESP show with the right "is800KHz" option? espShow(pin, pixels, numBytes, is800KHz);

You may also try another ESP8266 from another manufacturer, to be sure that it's not the board. They may have used a crystal that isn't as accurate as it should be.