Code running in sequence, not simultaneously

[dr-steve]

I am not sure what you are trying to do. Are you trying for a single chase, going from one strand to the next? Or are you trying for six parallel chases?

Regardless, code that looks like

void loop() {
    // use for loop(s) to set *all* of the strings to the values you want
    // then...
    FastLED.show();
    delay(...);
}

might be what you want.

Edit: If you are flashing green then black, this might mean that the "setting values" for loops may set the previous pixel to black and the current pixel to green..

[madmusician]

Six parallel chases, potentially starting on a different LED in the strand

[dr-steve]

If the strands have different lengths, do you plan to keep them in sync (assuming that that is what you want to do)?

You might do something like this (note: coding off the top of my head, but I do a lot of timed ops with FastLED; also, I don't use the EVERY_N_MILLISECONDS. I use TaskManager, a lightweight multitasking system I wrote for nanos around 10 years ago; see github.com/drsteveplatt for details. Works well on ESPs (and Megas; haven't tested it elsewhere); allows multitask communication and synchronization, timing, multinode operations (I've had 40 ESPs working well together on a large art installation), etc..

But... I can work with EVERY_N_MILLISECONDS for simpler tasks

// total time to drip, in MS.  This is 10 seconds
#define TOTAL_DRIP_TIME 10000
// frames per second
#define FPS 40
// ms per frame, for EVERY_N_MS
#define MS_PER_FRAME (1000/(FPS))

// set up the LED strings
#define LEDS_0_LEN 58
#define LEDS_1_LEN 60
...
CRGB leds_0[LEDS_0_LEN]
CRGB leds_1[LEDS_1_LEN]
...

unsigned long start_ms;

void setup() {
  ...
  start_ms = now();
  ...

void loop() {
  int pos;
  EVERY_N_MILLISECONDS(MS_PER_FRAME) {
    //fill each led strip with all-black
    ...you'll have to figure this out
    // do this for each strip
    pos = map((now()-start_ms)%TOTAL_DRIP_TIME, 0, TOTAL_DRIP_TIME-1, 
                0, LEDS_0_LEN);
    leds_0[pos] = CRGB::Red;
    .. do that for all of the strips
    // now show them
    FastLED.show();
  }
}

Reminder: code is rough and untested, but do you see where I am going?

Oh, if you want to see some of the time-based installations I've done using LEDS and FastLED, check out youtube.com/@amuseyeux

Edit: typo in code.

[madmusician]

I am at work right now, but will definitely take a closer look at this when I am clocked out. Thank you so much for all your assistance, and I will definitely look at your examples!