Merry Christmas to you as well.
And I do apologize for not speaking French (English/Dutch/German I can do though).

Enjoy the holidays, stay healthy and have fun with the Arduino 😉 

andre

Andre

Hello Hans

Many thanks for the sketch

one part works division by 4 then all blocks

But its probably me the problem not yet competent for this type of programming

I am 70 years old and I started 6 months ago I continue my tests

for christmas photos how to do because 1st time in my life on a forum

I am registered on the forum

once again well thank you for the example I will try to do the sketch

I wish you a happy and merry christmas

Andre

Since I'm not sure how comfortable you are with code, here a started point on how I have done this in one of my other projects:

1. I recommend using the FastLED library, if you haven't already.
2. Fill the strip with the initially desired pattern (one time only).
3. Shift all LEDs one position (in a loop).
4. Fill in the "new" blank LED with the color you need (in the same loop as step 3).

So step 2 could look something like this (assuming you have defined red, green and blue):

CRGB firstColor = CRGB(255,0,0); // define color of 1st LED
CRGB otherColor = CRGB(0,0,0);   // define color of other 3 LEDs

for(int i=0; i<NUM_LEDS; i=i+4) {
  led =firstColor; 
  for(int j=1; j<4; j++) {
    leds = otherColor;
  }
}

Step 3 is very easy with memmove8 (once you know this function exists).
It takes 3 parameters: Destination, Source, Size, where size is the CRGB size times the number of LEDs we'd like to move:

memmove8( &leds, &leds, (NUM_LEDS-1) * sizeof(CRGB) );

So this moves all LEDs one position, where leds moves to leds, leds to leds, etc.

The only thing we now need to do is give leds the correct color. This can be done with a confusing function, or we can simply copy the 4th LED.

Leds: X 0 0 0 X 0 0 0 X 0 0 0 X etc

becomes

Leds: ? X 0 0 0 X 0 0 0 X 0 0 0 etc

So we need to determine "?", which is the same color as the position + 4 (marked blue).
So in each step we do this followed by a delay that will influence how fast this effect will go:

leds = leds;
delay(500); // 500 ms = ½ second delay

So all combined this effect would look something like this:

CRGB firstColor = CRGB(255,0,0); // define color of 1st LED
CRGB otherColor = CRGB(0,0,0); // define color of other 3 LEDs

for(int i=0; i<NUM_LEDS; i=i+4) {
  led = firstColor;      // set LED 0 of the pattern (counting starts with zero)
  for(int j=1; j<4; j++) {  // set LEDs 1, 2 and 3 of the pattern
    leds = otherColor;
  }
}

while(true) {
  memmove8( &leds, &leds, (NUM_LEDS-1) * sizeof(CRGB) );
  leds = leds;
  delay(500); 
}

I hope this will get you started, if not please feel free to ask questions here in this forum topic 😊 

Note: I have not tested this specific code and typed it all from memory, so there could be typos - I hope not though 😉 

Hello Hans

Nice work and explanation for a novice like me
I have 20,000 led Christmas exterior decorations donated 1500 rgb on Chinese programmer
i have an arduino mega 2560 and your script is working amazing
But I’m wondering if I can program a string of 96 rgb leds blinking in 4 state
example 1-5-9-13 until 96
               2-6-10-14 “”
               3-7-11-15 “”
               4-8-12-16 “”
this like simple led garland programmers
sorry i don’t speak english hence google translator
thank you for your response desolé mauvais manipulation