I am using Neopixel Library and a Trinket Pro 5V Microcontroller to chase first three LEDs on a strip and then burst the last 2 (could be modified based on the number of LEDs). The LEDs chase only once. See the code below. I am not sure why, even though the logic is inside the loop function, it only executes once. Any suggestions?

#include <Adafruit_NeoPixel.h>
#include "WS2812_Definitions.h"
#ifdef __AVR__
  #include <avr/power.h>

// Which pin on the Arduino is connected to the NeoPixels?
// On a Trinket or Gemma we suggest changing this to 1
#define PIN            6

// How many NeoPixels are attached to the Arduino? How many Neopixels do you want to chase (starting from the first in address 0. How many do you want to burst at the end?
#define NUMPIXELS      5

// When we setup the NeoPixel library, we tell it how many pixels, and which pin to use to send signals.
// Note that for older NeoPixel strips you might need to change the third parameter--see the strandtest
// example for more information on possible values.
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  // This is for Trinket 5V 16MHz, you can remove these three lines if you are not using a Trinket
#if defined (__AVR_ATtiny85__)
  if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
  // End of trinket special code

  pixels.begin(); // This initializes the NeoPixel library.

void loop() {

  // For a set of NeoPixels the first NeoPixel is 0, second is 1, all the way up to the count of pixels minus one.
  for(int i=0;i<NUMPIXELSCHASE;i++){

   pixels.setPixelColor(i, INDIGO);
   pixels.show(); // This sends the updated pixel color to the hardware.
   delay (200);


   pixels.setPixelColor(i, AQUA);
   pixels.show(); // This sends the updated pixel color to the hardware.

// Sets all LEDs to off, but DOES NOT update the display;
// call leds.show() to actually turn them off after this.
void clearLEDs()
  for (int i=0; i<NUMPIXELS; i++)
    pixels.setPixelColor(i, 0);

Thank you.

1 Answer 1


Your 1st pixel should go indigo & stay there, & the other 2 very briefly show Aqua before going back to Indigo. Try a longer delay than 0 at the end, and then clear them down for the next loop.

  • I agree. Those NeoPixels update quickly. A delay(0) doesn't seem very sensible.
    – Nick Gammon
    Mar 26, 2016 at 20:38

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