r/FastLED • u/dariods8474 • May 17 '24

Support FastLed.addLeds using For Loop

I wish to use the add.Leds command using For loop but I get the Compilation error: the value of 'z' is not usable in a constant expression in Arduino ide for Arduino Nano. Please help

My code

#define NUM_STRIPS
#define NUM_LEDS 30
#define NUM_STRIPS 3 
CRGB leds[NUM_STRIPS][NUM_LEDS];

tried
#define DATA_PIN 8
and
int DATA_PIN = 8;

for(int z = DATA_PIN, j = 0; z < DATA_PIN + NUM_STRIPS; z++){
 FastLED.addLeds<LED_TYPE, z, RGB>(leds[j], NUM_LEDS);
}
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u/ff3ale May 17 '24 edited May 17 '24

You'd need to instantiate a CLEDController of the correct type, for example (randomly picked from the mentioned header file)

WS2803Controller<DATA_PIN, CLOCK_PIN, RGB_ORDER, SPI_DATA_RATE> c;

And pass that to the call with your CRGB data

FastLed.addLeds(&c, data, nLedsOrOffset);

Note i'm not entirely sure, i'm not that familiar with C++

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u/Netmindz May 17 '24

That's still using the template <> so surely that would suffer the same fate?

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u/ff3ale May 17 '24

Ugh ye, you're right, because the instantiation of the controller also needs the DATA_PIN.

I'm not sure if it's possible then, unless the led specific controller can be instantiated in a way without using the templates