Using millis instead of delay with ledpatterns

Projects Programming
1

So I found this code for a nice pattern, but it has delays:

#include "FastLED.h"

#define NUM_LEDS_PER_STRIP 11

CRGB redLeds[NUM_LEDS_PER_STRIP];

CRGB blueLeds[NUM_LEDS_PER_STRIP];


void setup() {
  // tell FastLED there's 60 NEOPIXEL leds on pin 10
  FastLED.addLeds<NEOPIXEL, 12>(redLeds, NUM_LEDS_PER_STRIP);


  // tell FastLED there's 60 NEOPIXEL leds on pin 12
  FastLED.addLeds<NEOPIXEL, 13>(blueLeds, NUM_LEDS_PER_STRIP);

}

void loop() {

  StripShow();
   
}

void StripShow(){


  
  for(int i = 0; i < NUM_LEDS_PER_STRIP; i++) {
    
  
    // set our current dot to red, green, and blue
    redLeds[i] = CRGB::Red;
    redLeds[i+1] = CRGB::Red;
    blueLeds[i-1] = CRGB::Blue;
    blueLeds[i-2] = CRGB::Blue;
    FastLED.show();
    // clear our current dot before we move on
    redLeds[i] = CRGB::Black;
    redLeds[i+1] = CRGB::Black;
    blueLeds[i-1] = CRGB::Black;
    blueLeds[i-2] = CRGB::Black;

    delay(100);
    }
   
    for(int i = NUM_LEDS_PER_STRIP-1; i >= 0; i--) {
    
    FastLED.show();
    
    }
  }

So I tried to get rid of them because that's important for where I'm going to implement the code.

#include "FastLED.h"

#define NUM_LEDS_PER_STRIP 11

CRGB redLeds[NUM_LEDS_PER_STRIP];

CRGB blueLeds[NUM_LEDS_PER_STRIP];


unsigned long interval= 500;  // the time we need to wait
unsigned long previousMillis=0;


void setup() {
  // tell FastLED there's 60 NEOPIXEL leds on pin 10
  FastLED.addLeds<NEOPIXEL, 12>(redLeds, NUM_LEDS_PER_STRIP);


  // tell FastLED there's 60 NEOPIXEL leds on pin 12
  FastLED.addLeds<NEOPIXEL, 13>(blueLeds, NUM_LEDS_PER_STRIP);

}

void loop() {

  StripShow();
   
}

void StripShow(){

  unsigned long currentMillis = millis();
  if ((unsigned long)(millis() - previousMillis) >= interval) {
  previousMillis = millis();
  
  for(int i = 0; i < NUM_LEDS_PER_STRIP; i++) {
    
    redLeds[i] = CRGB::Red;
    redLeds[i+1] = CRGB::Red;
    blueLeds[i-1] = CRGB::Blue;
    blueLeds[i-2] = CRGB::Blue;
    FastLED.show();
    
    redLeds[i] = CRGB::Black;
    redLeds[i+1] = CRGB::Black;
    blueLeds[i-1] = CRGB::Black;
    blueLeds[i-2] = CRGB::Black;
    
    }
   
    for(int i = NUM_LEDS_PER_STRIP-1; i >= 0; i--) {
    
    FastLED.show();
    
    }
  }
 }

But it doesn't work like the other one. In my head it works because everytime there has been gone by enough time (interval) a leds lights up and fades, but instead it flickers like it's got epilepsy.

2

I think the time condition is wrong. Try:

unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
      previousMillis = currentMillis;