What's the best way to address a specific range of LEDs in a strip

Archive FastLED Archive
1

What’s the best way to address a specific range of LEDs in a strip for a specific amount of time? Say I want to do
leds[5 through 10] = CRGB:: white for x number of milliseconds
Then leds[5 through 10] = CRGB:: black for x number of milliseconds.
I’m trying to make some Orange and white strobing lights in specific places in some LED strips.

2

Maybe not the best way, but here’s one example that might give you ideas for using EVERY_N to toggle colors. Another thing would be to toggle a variable that is then checked elsewhere.
EVERY_N_MILLISECONDS (10) {
myToggle = !myToggle;
}

3

@marmil ok thank you! I’ll try some things out later tonight and see what I come up with.

4

@Kyle_Halvorson ​ I forgot to mention that if you use EVERY_N_MILLISECONDS_I then you could also have different on and off times if you wanted to. Just update the http://timingObj.setPeriod whenever you toggle the color.

5

Ok that makes sense, thank you!

6

I can’t seem to figure out why this won’t toggle, do I have something in the wrong place? Trying to get a general idea of how to “flash” it.
// Marc Miller, Jan 2016

#include “FastLED.h”
#define NUM_LEDS 44

//CRGB leds[NUM_LEDS]; // Not using this. Using CRGBArray instead.
CRGBArray<NUM_LEDS> leds;

CRGBSet partA(leds(0,22)); // Define custom pixel range with a name.
CRGBSet partB(leds(22,44)); // Define custom pixel range with a name.

CRGB colorA(242,75,0); // Define a custom color, Orange
CRGB colorTwo(255,255,255); // Define a custom color, White

boolean Atog = true;
//-------------------------------------------------------------
void setup() {
FastLED.addLeds<WS2812B, 9 ,GRB>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
FastLED.setBrightness(255);
}

//-------------------------------------------------------------
void loop()
{ EVERY_N_MILLISECONDS(500) {
Atog = !Atog;
}

if(Atog == true){
partA = colorOne;
}
if(Atog == false){
partA = CRGB (0, 0, 0);
}

partA = colorA;  // set partA pixel color.

//partB = colorTwo; // set partB pixel color.

FastLED.show();
//EVERY_N_MILLISECONDS(1500){ // Swaps the two custom colors.
// CRGB temp = colorOne;
// colorOne = colorTwo;
// colorTwo = temp;
//}
}

7

Every time through the loop, no matter what Atog is, you’re setting partA = colorA.

Also your part B’s last number is past the number of LEDs you’re using.

8

Figured it out,
partA = colorA; // set partA pixel color.
Shouldn’t have been there at all… Duh…

9

Also can you use http://gist.github.com for sharing code. Easier to read and line numbers can be referenced.

10

Oh right, because “0” is counted isn’t it? Should be
CRGBSet partB(leds(22,43));

11

Yeah, i’ll set up an account, Probably should’ve a while ago… I’ve needed it.

12

You don’t actually need an account, but you might as well so you can save and share stuff easily. :slight_smile: