Any idea why this code isn't working? Other examples work using the same setup.

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1

Any idea why this code isn’t working?

Other examples work using the same setup.

Thanks

Phil

#include “FastLED.h”
#define DATAPIN 11
#define CLOCKPIN 13
#define NUMPIXELS 100

CRGB leds[NUMPIXELS];

void setup() {
Serial.begin(9600);
FastLED.addLeds<APA102, DATAPIN, CLOCKPIN, RGB>(leds, NUMPIXELS);
FastLED.setBrightness(255);

}// setup

void loop() {
for (int i = 1; i <= 10 ; i++) { // loop through first 10 pixles

leds[i] = CRGB(255, 0, 0);

FastLED.show();
FastLED.delay(1000 / 30);

} // for loop

}// loop

2

Hi
The first pixel is 0, not 1.

Also you never turn any pixel off, or dim any pixels so this code looks as though it’ll just set pixels 1 to 10 red. Then they’ll stay red.

Is this the behaviour you’re seeing?

3

@Phil_Spitler What’s not working?

As Jeremy mentioned, you’re not darkening or clearing the pixel data anywhere so once it’s filled pixel 1 thru 10 red the first time through the main loop, nothing will change after that.

4

I would expect the first 10 LEDs to be Red but actually no LEDs turn on.

5

Actually, it was a power issue. When I used external power instead of USB it worked

6

Yes, 100 pixels is probably too much to try to power by USB.

7

I was actually only illuminating the first 10 but it was still too much

8

Note that even pixels that are off still use a tiny bit of power. It all adds up.

9

Actually the power they use when off is actually not that tiny, it adds up even more quickly.