Hi, I am trying to use the HSV Spectrum colour map,

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Hi, I am trying to use the HSV Spectrum colour map, but FastLED is using the Rainbow colour map by default. I have read FastLED HSV Colors · FastLED/FastLED Wiki · GitHub many times but still cant work out how to change it.

I am setting up my LEDs with this code.

#include <FastLED.h>

#define LED_TYPE WS2812B
#define LED_PIN D1
#define COLOR_ORDER GRB
#define NUM_LEDS 144
#define BRIGHTNESS 255

CRGB leds[NUM_LEDS];

void setup() {
FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS);
}

Then turning on the LEDS with…

FastLED.showColor(CHSV(hueCon, satCon, briCon));

hueCon, satCon, briCon are my converted and mapped values coming from an external source but using the Rainbow values

Thanks…

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Have a look at this example. You can change it to use spectrum instead of rainbow.

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@marmil Thanks, i will try to work it out from that.
What i am actually trying to do use Amazon Alexa to control the LED strip, which it does but the hue’s are slightly off.

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I’m guessing you’re saying something like “Alexa, make lamp green”? Curious what sort of data and format does Alexa send?

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Alexa sends… 3 values back, Hue, Saturation and Value (Brightness).
Hue is in the range of 0 to 359
Saturation is 0.0000 to 1.0000
Brightness is 0.0000 to 1.0000

Alexa. Make light Green returns…
“hue”: 120, “saturation”: 1.0000, “brightness”: 1.0000

Make light Sky Blue returns…
“hue”: 197, “saturation”: 0.4231, “brightness”: 0.9176

I then map all the values from Alexa to the range of 0 to 255.

Here is my code for doing the conversion and mapping.

      // Convert string "saturation" to a floating point then map it in the range of 0 to 255
      float satCon = saturation.toFloat();
      satCon = satCon * 10000; // Move the decimal 4 places to the Right
      satCon = map(satCon, 0, 10000, 0, 255);
      // Convert string "brightness" to a floating point then map it in the range of 0 to 255
      float briCon = brightness.toFloat();
      briCon = briCon * 10000; // Move the decimal 4 places to the Right
      briCon = map(briCon, 0, 10000, 0, 255);
      // convert string "hue" to an integer between 0 and 255
      int hueCon = hue.toInt();
      hueCon = map(hueCon, 0, 359, 0, 255);

      delay(20);
      FastLED.showColor(CHSV(hueCon, satCon, briCon));
      delay(20);

There is probably a better way to do this, but i am quite new to coding. The code works, but the Hue’s are slightly out. Hence i need to change fastLED to use the Spectrum colour map. This i have not managed to do yet.

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@marmil Thank you, using your example i have managed to get the result i was looking for with this bit of code…

      // Assign values to the LEDs and then illuminate them
      CHSV hsv(hueCon, satCon, briCon);
      CRGB rgb;
      hsv2rgb_spectrum(hsv, rgb);
      for (int led = 0; led < (NUM_LEDS / 2); led++) {
        leds[led] = rgb;
        leds[(NUM_LEDS-1) - led] = rgb;
       FastLED.show();
       FastLED.delay(1); // create a wipe effect           
      }
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Great, glad to hear it @Jezz_Doobie !
Do you have any info or code shared about your project anywhere? My brother just got a Dot so now you’ve spurred my interest to do a project for him.

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@marmil Sure, I have uploaded the code to dropbox for you. Its not very tidy yet as its my 1st attempt at proper project.

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