Hello there! How can I use more than 115 leds in WS2811/12 ledstrips?

Marlus_Araujo · September 5, 2014, 5:11pm

Hello there!
How can I use more than 115 leds in WS2811/12 ledstrips?
That’s the maximum I could control and turn on when using the library.
I really appreciate if anyone can help with some tips on this.
I had the same problem using Adafruit Neopixel library too.
Thanks!

Andrew_Tuline · September 5, 2014, 5:24pm

Yes, you can use more. If you’re having problems, you may have a memory issue in your routines. For instance, the last LED in the array is leds[NUM_LEDS-1] and NOT leds[NUM_LEDS]. Be careful in your for loops or you’ll overshoot the array.

Jon_Burroughs · September 5, 2014, 6:07pm

The questions remains, what microcontroller are you using? A trinket, for example, with large animations can have a rough time with LEDS > 100.

Marlus_Araujo · September 5, 2014, 6:25pm

I’m using Arduino UNO and Arduino Mega, the same problem… could be a deffective led?

Marlus_Araujo · September 5, 2014, 6:28pm

Here is a simple code I made to test:

gist.github.com

https://gist.github.com/sulram/d106fb554bd3801d9e4a

neopixel-tail.ino

#include <Adafruit_NeoPixel.h>

#define PIN 6

Adafruit_NeoPixel strip = Adafruit_NeoPixel(200, PIN, NEO_GRB + NEO_KHZ800);

uint16_t pos = 0;
int tail = 20;

void setup() {

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Jon_Burroughs · September 5, 2014, 6:28pm

Yes, and possible power issues…how many LEDs are on the roll? If the first 100 only light up and the rest of the roll is dark, then it possibly is a defective LED or manufacturing process error.

Daniel_Garcia · September 5, 2014, 6:28pm

Possibly - I’ve certainly run hundreds, if not thousands of leds before without issue. (Though, to be fair, thousands required moving to an Arduino Due)

Marlus_Araujo · September 5, 2014, 6:30pm

Thankyou guys. I will try again with other ledstrip. I will also try to remove/jump the led #116 and check if it works

Andrew_Tuline · September 5, 2014, 6:35pm

You might also want try this (known to be working) code using the FastLED library.

github.com

FastLED/FastLED/blob/master/examples/Cylon/Cylon.ino

#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 64 

// For led chips like Neopixels, 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
#define DATA_PIN 2
#define CLOCK_PIN 13

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

void setup() { 
	Serial.begin(57600);
	Serial.println("resetting");
	LEDS.addLeds<WS2812,DATA_PIN,RGB>(leds,NUM_LEDS);
	LEDS.setBrightness(84);
}

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Kelvin_Mead · September 6, 2014, 1:18pm

i think it would help if you define “not work” by the fact you’ve used 2 libraries, i would put it to defective led/chip, but it could be a power issue also.

if you’re using the standard roll of leds, you can carefully solder some bridge wires across the offending broken led and see if the rest light up (or bend the flex until the connections touch )

Marlus_Araujo · September 8, 2014, 10:13pm

it really was a deffect LED. thank you guys for the help