Hi all, I've been enjoying playing with my first Uno and some SK6812WWA LED

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Hi all, I’ve been enjoying playing with my first Uno and some SK6812WWA LED strips. I’ve been using the FastLED library and defining/controlling them like the RGB WS2821B seems to work fine, but I have a few basic questions-

Using CHSV instead of CRGB I’m trying to control both the H (hue) and the S (Saturation), so I can adjust colour and brightness. I have part of it working but could really benefit from some expert advice :slight_smile:

  1. All LED’s will be outputting the same, how do I talk to them all without referencing each one separately like I am currently?

    leds[0] = CHSV(0,255,255);
    leds[1] = CHSV(0,255,255);
    leds[2] = CHSV(0,255,255);
    leds[3] = CHSV(0,255,255);
    leds[4] = CHSV(0,255,255);
    leds[5] = CHSV(0,255,255);

To be able to reduce this to a single line like leds[0-6] = etc

  1. I’ve got a pot adjusting the Hue value but only by using if else statements. How do I make Hue and Value a variable and set up 10 steps for each?

I’m currently doing it inefficienctly like this -

void loop() {

int val = analogRead(1);
if (val < 125) {

leds[0] = CHSV(0,255,255);
leds[1] = CHSV(0,255,255);
leds[2] = CHSV(0,255,255);
leds[3] = CHSV(0,255,255);
leds[4] = CHSV(0,255,255);
leds[5] = CHSV(0,255,255);

FastLED.show();

}
else if (val < 250) {

leds[0] = CHSV(34,255,255);
leds[1] = CHSV(34,255,255);
leds[2] = CHSV(34,255,255);
leds[3] = CHSV(34,255,255);
leds[4] = CHSV(34,255,255);
leds[5] = CHSV(34,255,255);

an so on etc.

Any support would be much appreciated.

Rob

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a87a6483c7ef49b786e2bccc92d709c6.jpeg3264×2448 1.51 MB

2

use the map function to scale the pot reading to 0…255 (you also could divide by 8); but with map you also can ‘turn’ the pot around. https://www.arduino.cc/en/Reference/Map
int gHue = map(analogRead(1), 0, 1023, 0, 255);
leds[0] = CHSV(gHue, 255, 255);
FastLED.show();

To turn it around:
int gHue = map(analogRead(1), 1023, 0, 0, 255);

3

Thank you Juergen, The map function is perfect :slight_smile:
How do I make this function assign to all the LEDs (NUM_LEDS)

At the moment I’m writing to each one individually, so it’s not ideal?

leds[0] = CHSV(gHue, 255, 255);
leds[1] = CHSV(gHue, 255, 255);
leds[2] = CHSV(gHue, 255, 255);
leds[3] = CHSV(gHue, 255, 255);
leds[4] = CHSV(gHue, 255, 255);
leds[5] = CHSV(gHue, 255, 255);

4

#define NUM_LEDS 6
CRGB leds[NUM_LEDS];
…
just look over to the post next to you
https://plus.google.com/112445599599385082979/posts/6kXny2QPWVw